SPECIFICATION FOR ROAD WORKS - Cloud Object Storages3.amazonaws.com/zanran_storage/ · the...

NATIONAL ROADS AUTHORITY An tUdaras um Boithre Naisiunta

MANUAL OF CONTRACT DOCUMENTS FOR ROAD WORKS

VOLUME 2

NOTES FOR GUIDANCE

on the

SPECIFICATION

FOR

ROAD WORKS

MARCH 2000

Volume 2 Notes for Guidance on the Specification for Road Works Contents

January 2009

MANUAL OF CONTRACT DOCUMENTS FOR ROAD WORKS

NOTES FOR GUIDANCE ON THE

SPECIFICATION FOR ROAD

WORKS

Contents

Series Title

NG 000 Introduction

NG 100 Preliminaries

NG 200 Site Clearance

NG 300 Fencing and Environmental Noise Barriers

NG 400 Safety Barriers and Pedestrian Guard Rails

NG 500 Drainage and Service Ducts

NG 600 Earthworks

NG 700 Road Pavements – General

NG 800 Road Pavements – Unbound Materials

NG 900 Road Pavements – Bituminous Bound Materials

NG 1000 Road Pavement – Concrete and Cement Bound Materials

NG 1100 Kerbs, Footways and Paved Areas

NG 1200 Traffic Signs

NG 1300 Road Lighting Columns and Brackets

NG 1400 Electrical Works for Road Lighting and Traffic Signs

NG 1500 Motorway Lighting

NG 1600 Piling and Diaphragm Walls

NG 1700 Structural Concrete

NG 1800 Structural Steelwork

NG 1900 Protection of Steelwork Against Corrosion

NG 2000 Waterproofing for Concrete Structures

NG 2100 Bridge Bearings

NG 2200 Parapets

NG 2300 Bridge Expansion Joints and Sealing of Gaps

NG 2400 Brickwork, Blockwork and Stonework

NG 2500 Special Structures

NG 2600 Miscellaneous

NG 2800 Trenchless Installation of Road Drainage & Service Ducts

NG 2900 CCTV Survey of Road Drainage Systems

Volume 2 Series 000 NRA Notes for Guidance on the Specification for Road Works

January 2009 i

INTRODUCTION

Contents

Clause Title Page NG 000 Introduction ..................................................................................................................... 1

NG 002 Terms and Abbreviations ................................................................................................ 2 NG 003 Appendices ....................................................................................................................... 2

NG 004 Standards and Other Reference Documents ................................................................. 4

NG 005 Thickness of Material and Tolerances ........................................................................... 4

Preamble to the Specification ......................................................................................... 5 NG Sample Appendices 0/1 to 0/4 .................................................................................. 6


January 2009 1

Introduction NG 000 Introduction

General

1 The Notes for Guidance on the Specification for Road Works are divided into Series corresponding to those in the Specification. The NG Clauses directly relate to Clauses in the Specification; however there are not corresponding NG Clauses to every Specification Clause.

2 The original Notes for Guidance as published in March 2000 were drafted on the assumption that the Specification for Road Works was to be used in conjunction with the IEI Condition of Contract. A set of standard amendments to the Specification for Road Works has been produced for use with the Public Works Contracts, but no similar set of amendments to the Notes for Guidance exists. Users of the Notes for Guidance must therefore take care to interpret terminology in a manner that is consistent with the form of contract being considered and to use appropriate terminology when compiling project specific Appendices to the Specification for Road Works. In this regard users should be guided by consideration of the standard amendments to the Specification for Road Works for use with the Public Works Contracts. For those series where the Notes for Guidance have been updated at January 2009 and thereafter the terminology has been amended for consistency with the Public Works Contracts.

3 Throughout the original Notes for Guidance as published in March 2000 the terms “Engineer” and “compiler” have been used both in relation to scheme preparation (including design) and supervision once the Contract is awarded. For those series where the Notes for Guidance have been updated since March 2000 the terms “Employer’s Representative”, “specialists responsible for the design” and “compiler” are used. These titles should be interpreted as follows:-

(i) The term Engineer when used in relation to

scheme preparation relates to the “designer/compiler” and not the Engineer under the Contract.

(ii) Where the context implies reference to the the supervisory function of the Engineer under the Contract this should be read as applying equally to the Employer’s

Representative and visa-versa as suits the form of contract being used.

(iii) For Works designed by the Employer the

term “specialist responsible for the design” means the Employer’s designer, be that a member of the Employer’s own staff or a consultant engaged by the Employer to undertake the design. For Works designed by the Contractor the term “specialist responsible for the design” means the Contractor’s designer, be that a member of his own staff or a consultant engaged by the Contractor to undertake the design, and in particular any “Specialist” named in the Contract.

(iv) The compiler is a generic term referring to the party responsible for preparing an element of the Specification, which may be any of the above.

Incorporation of the Specification into the Contract

4 The Specification for Road Works as published in March 2000 was drafted for use in conjunction with the IEI Conditions of Contract. To facilitate its use in conjunction with the Public Works Contracts (published by the Department of Finance) a set of standard amendments has been prepared and published by the NRA. This should be incorporated into the project specific Works Requirements. Individual series of the the Specification for Road Works that have been updated in January 2009 and thereafter been drafted to facilitate their use with the Public Works Contracts and these series have been omitted from the aforementioned standard amendments. Those series that were updated between March 2000 and January 2009 have generally been drafted to facilitate their use with the FIDIC suite of Contracts and as such continue to require a degree of amendment for use with the Public Works Contracts, as included for within the aforementioned standard amendments.

5 The Contract is to contain a Preamble to the

Specification and standard Preamble to the Specification is included in these Notes for Guidance. This includes an explanation of how alternative text is incorporated depending on whether the Contract is for Work designed by the Employer or Works designed by the Contractor.


January 2009 2

Proprietary Work, Goods or Materials

6 Proprietary work, goods or materials must not be specified unless their function cannot be described in any other way using specifications which are sufficiently precise and easily understood. Where the specification of proprietary work, goods or materials cannot be avoided, European law requires that the brand name or type be followed by the words “or equivalent”. Guidance on the assessment of equivalence is given in Advice Note SA 2 of the UK Highways Agency MCDHW Volume 6.

Use of the Specification for Road Works

7 The Specification for Road Works has been widely drawn to cover all road contracts from the provision of new to the improvement or reconstruction of existing roads and bridges. It also covers such schemes as the installation of road lighting, traffic signals or other traffic signing schemes on existing roads.

8 There is no need to reproduce the Specification for Road Works in the Contract documents as it is incorporated by reference in the Preamble to the Specification.

9 Contract-specific requirements should be incorporated in the Numbered Appendices to the Specification (without the need to alter Clauses, etc.) in one of two ways:

(i) Specific requirements referred to in the national requirements:

These are generally indicated by the words “as described/stated in Appendix -/-.”

(ii) Alternatives to national requirements:

These are generally indicated by the words “unless otherwise described in Appendix -/-”.

10 The Specification for Road Works should be used

as it stands wherever possible but when alterations to Clauses, Tables or Figures are considered necessary, these are to be agreed with the Employer/NRA.

11 The information contained in the Numbered

Appendices 0/1 to 0/4 and 1/1 onwards should be bound either in one volume or more as

appropriate. Each volume should be clearly titled as to the content.

12 The compiler's attention is drawn to the requirements of the Safety, Health and Welfare at Work (Construction) Regulations and in particular the need for a health and safety plan to be prepared and provided at the same time as the tender documents. In particular the compiler should ensure consistency between information referred to in the above plan and the detailed information included in Appendices to the Specification. Appendices likely to be referred to, include but are not confined to:-

Appendix 1/7 Site extents and limits of use Appendix 1/9 Control of noise and vibration

Appendix 1/13 Programme of works

Appendix 1/16 Privately and publicly owned services and supplies

Appendix 1/17 Traffic safety and management

Appendix 1/18 Temporary diversions of traffic

Appendix 1/19 Routeing of vehicles Appendix 1/23 Risks to health and safety

from materials or substances NG 002 Terms and Abbreviations 1 Terms and abbreviations used in Additional, and

Substitute Clauses and in minor alterations made by ‘delete and insert’ methods must be consistent with those described in Clause 002.

NG 003 Appendices Numbered Appendices – General

1 The Numbered Appendices to the Specification are to be drawn up for the specific project by the compiler and included in the Contract documents. Where it is considered appropriate to include project-specific Works Requirements on drawings, cross-reference should be made in the Numbered Appendix to the relevant drawing numbers.


January 2009 3

2 The Numbered Appendices are to be compiled using advice given in the Notes for Guidance Clauses and in the NG Sample Appendices given at the end of each Notes for Guidance Series. Depending on whether the Contract is for Works designed by the Employer or Works designed by the Contractor various of the Numbered Appendices are to be completed by the Tenderer, the Contractor or the Specialist responsible for the design.

3 The Numbered Appendices 1/1 onwards should only be used to extend the information in Specification Clauses, Tables or Figures and NOT to change them. Where the Contract requires new methods or special requirements these should only be introduced by Additional or Substitute Clauses in Appendix 0/1 or by minor alterations in Appendix 0/2.

4 Appendices 1/24, 1/25 and 1/26 should comprise

lists of accepted quality management schemes, product certification schemes and information relating to Irish Agrément Board Roads and Bridges Certificates.

5 New Numbered Appendices can be used to extend

Contract-specific alterations, but see Sample Appendix 0/3 regarding numbering of additional Numbered Appendices.

Numbered Appendices – 0/1 to 0/4

6 The “Zero” Series Numbered Appendices (0/1 to 0/4) should be compiled in accordance with the Samples following and as explained below.

7 The Contract-specific alterations to the

Specification for Road Works (having prior approval, see NG 000.9) should be described in Appendices 0/1 and 0/2 taking account of the following:

(i) Requirements relating to Clauses equally apply to Tables and Figures.

(ii) Care should be taken to ensure compatibility between Clauses and any associated Tables and Figures which are altered.

(iii) Text which conflicts with or duplicates the provisions of the Contract Conditions is to be avoided.

8 Appendix 0/1 is for incorporation of Contract-specific alterations to the Specification for Road Works as follows:

(i) Additional Clause – written in Appendix 0/1 with suffix “AR” added to the Clause number.

(ii) Substitute Clause – rewritten in Appendix 0/1 in full with existing Clause number and with suffix “SR”.

(iii) Cancelled Clause – Clause number with suffix “CR” followed by its title written in Appendix 0/1, with the word “Cancelled” alongside it.

If there are no Additional, Substitute or Cancelled Clauses to be included in the Contract write NONE in Appendix 0/1.

9 Appendix 0/2 is for incorporation of Contract-specific minor alterations to existing Clauses, Tables and Figures. These can be described by the “delete and insert” or “add new sub-clause” procedure, provided they are neither extensive nor confusing. The Clause is not then a Substitute Clause and there is no need to add a suffix. The instructions for these minor alterations are to be written in Appendix 0/2. If there are none write “NONE”.

10 Appendix 0/3 is to comprise a complete list of

Numbered Appendices included in the Contract. List A contains those referred to in the national Specification and List B contains any additional Numbered Appendices devised by the compiler. Where a Numbered Appendix in List A is not used, this should be marked “Not Used” alongside its number. Those to be completed by the Tenderer/Contractor/Specialist responsible for the design must be identified and blanks of “pro-formas”, copied from the Notes for Guidance, are to be included as appropriate).

11 Appendix 0/4 is to list the drawings in the Works

Requirements (including those from the NRA Road Construction Details).


January 2009 4

NG 004 Standards and Other Reference Documents

1 In general the date of the invitation to tender

establishes, for each standard or other referenced document incorporated in the Contract, the respective edition which is to be used. However, where the year of publication of a Standard or other referenced document is specified the specified edition applies. The year is specified throughout SRW where at least one reference to the Standard includes a specific clause, section, table or appendix. Similarly, if a Standard is amended in one reference, the year is specified throughout SRW.

2 The compiler should ascertain whether any

amendments or new editions of the reference documents have been issued since the last published national alteration of the relevant series of the SRW and where appropriate include Contract-specific alterations in Appendix 0/1 or 0/2. Where a Harmonised European Standard or a European Standard has been issued in the period between the date of the invitation to tender and the date of the last published edition of the SRW series, Contract-specific alterations should be made to ensure the European Standard is properly incorporated in the Contract. Use of European Standards issued prior to the date of the intivation to tender is mandatory and sub-Clause 004.4 provides for their incorporation in the Contract by default.

3 The compiler should ensure that there are no

inconsistencies between the reference documents specified in the Contract and those used in the design. Where necessary, Contract – specific alterations should be included in Appendix 0/1 or 0/2 to achieve consistency. Amendments to Harmonised European Standards are not permitted. Amendments to European Standards may be considered only in exceptional circumstances where there is clear and proper justification. In such circumstances, and in cases where the basis of design may be compromised unless amendments are made, the Employer/NRA should be consulted.

4 The Employer should consider whether reference

document amendments published after the Contract has been awarded should be incorporated in the Contract. Amendments making editorial changes will often have negligible cost implications and should usually be adopted. When the Employer considers an amendment should be

incorporated in the Contract but there are significant cost or delay implications, the NRA should be consulted.

NG 005 Thickness of Material and

Tolerances 1 It is not considered necessary or desirable to

specify tolerances for all dimensions. Where dictated by functional or aesthetic need, tolerances are included in the Specification for Road Works. Other tolerances are incorporated by reference to Standards and other publications. If the compiler requires further tolerances to apply these should be given on the drawings. Unnecessarily fine tolerances have the effect of increasing prices and should be avoided.


January 2009 5

Preamble to the Specification 1. The Specification referred to in the Contract

shall be the 'Specification for Road Works', published by the National Roads Authority as Volume 1 of the Manual of Contract Documents for Road Works in March 2000 and including all amendments to the Standards including the amendments up to the date of the invitation to tender and as extended by the following:-

(i) Appendix 0/1: Contract-specific Additional,

Substitute and Cancelled Clauses, Tables and Figures;

(ii) Appendix 0/2: Contract-specific minor alterations to existing Clauses, Tables and Figures;

(iii) The Numbered Appendices listed in Appendix 0/3;

(iv) Appendix 0/4 containing a list of the drawings referred to in the Specification.

2. An Additional Clause as indicated by a suffix

'AR' in Appendix 0/1 is a Contract-specific alteration.

3. A Substitute Clause as indicated by a suffix 'SR'

in Appendix 0/1 is a Contract-specific alteration. 4. A Cancelled Clause indicated by a suffix 'CR' in

Appendix 0/1 is a Contract-specific alteration. 5. Insofar as any of the Numbered Appendices may

conflict or be inconsistent with any provision of the Specification for Road Works the Numbered Appendices shall always prevail.

6. Any reference in the Contract to a Clause

number or Appendix shall be deemed to refer to the corresponding Substitute Clause number or Appendix listed in Appendix 0/1 or 0/2.

7. Where a Clause is altered, any original

Table/Figure referred to in the Clause shall apply unless the Table/Figure is also altered. Where a Table/Figure is altered, any reference in a Clause to the original Table/Figure shall apply to the altered Table/Figure.

8. Where a Clause in the Specification relates to work goods or materials that are not required for the Works it shall be deemed not to apply.

9. Any Appendix referred to in the Specification

that is not used shall be deemed not to apply.

10. References in the Specification to “NRA Road

Construction Details” shall be taken to refer to “Road Construction Details” as published by the National Roads Authority in March 2000 and including all amendments up to the date of the invitation to tender.

11. Text shown in grey highlight applies only to

Contracts where the applicable Conditions of Contract is the Public Works Contract for Civil Engineering Works Designed by the Employer, the Public Works Contract for Minor Building and Civil Engineering Works Designed by the Employer.

12. Text shown in square brackets immediately

following text shown in grey highlight, if any, is deemed to replace the text in grey highlight for Contracts where the applicable Conditions of Contract is the Public Works Contract for Civil Engineering Work Designed by the Contractor.

13. Throughout the Specification and Appendices to

the Specification, the following interpretations shall apply:

“Base Course” shall mean “Binder Course” “Roadbase” shall mean “Base” “Wearing Course” shall mean “Surface Course” “UK Department of Transport” shall mean “UK Highways Agency”

[Note to compiler:When using the Public Works Contracts for Civil Engineering Works Designed by the Employer, the Public Works Contract for Minor Building and Civil Engineering Works Designed by the Employer or the Public Works Contract for Civil Engineering Work Designed by the Contractor, the Preamble to the Specification must be reproduced unaltered and bound in the Works Requirements with the Numbered Appendices. If any other form of contract is utilized then both the above Preamble and the Specification as a whole must be reviewed and amended as necessary to ensure consistency between the Conditions of Contract and the Specification.]


January 2009 6

NG SAMPLE APPENDIX 0/1: CONTRACT-SPECIFIC ADDITIONAL, SUBSTITUTE AND

CANCELLED CLAUSES, TABLES AND FIGURES INCLUDED IN THE CONTRACT

[Note to compiler: See NG 000 regarding approval of contents of Appendix 0/1] List of Additional Clauses, Tables and Figures

Clause No.

(etc.)

Title Written on Page No. following

[Note to compiler: List here Contract-specific Additional Clauses, and Tables and Figures suffixed by the letters AR and preferably commencing with the 70th Clause, etc. of the respective Series]

List of Substitute Clauses, Tables and Figures

Clause No.

(etc.)

Title Rewritten on Page No. following

[Note to compiler: List here Contract-specific Substitute Clauses, Tables and Figures suffixed by the letters SR]

List of Cancelled Clauses, Tables and Figures

Clause No.

(etc.)

Title

[Note to compiler: List here Contract-specific Cancelled Clauses, Tables and Figures suffixed by the letters CR]

Additional Clauses, Tables and Figures

Clause No.

(etc.)

Title and written text

[Note to compiler: Write here the Additional Clause etc. listed above]

Substitute Clauses, Tables and Figures

Clause No.

(etc.)

Title and written text

[Note to compiler: Rewrite here the Substitute Clause etc. listed above]


January 2009 7

NG SAMPLE APPENDIX ) 0/2: CONTRACT – SPECIFIC MINOR ALTERATIONS TO EXISTING CLAUSES, TABLES AND FIGURES INCLUDED IN THE CONTRACT

Clause No.

(etc.)

Alterations to be made

[Note to compiler: Write here the minor alteration using ‘delete and insert’ or ‘add at end of Clause’ techniques]

NG SAMPLE APPENDIX 0/3: LIST OF NUMBERED APPENDICES REFERRED TO IN THE SPECIFICATION AND INCLUDED IN THE CONTRACT

[Note to compiler: Include the following explanatory statements relating to List A and List B] This Appendix 0/3 is comprised of a list of the Numbered Appendices referred to in the Specification and included in this Contract.

Responsibility for the compilation/completion of the appendices is indicated by the following symbols:

E Employer compiles C Contractor to compile and submit to the Employer’s Representative E/C Employer partially compiles and Contractor completes and submits to the Employer’s Representative T/C Tenderer compiles and returns with his Tender. Post award of Contract the Contractor reviews and submits to

the Employer’s Representative. (P) The symbol ‘P’ indicates the appendix is a national pro-forma and the format must not be altered.

Where a Contractor or Tenderer is required to compile or complete an Appendix, they shall do so in accordance with the Notes for Guidance on the Specification for Road Works, and providing information similar to that stated in the sample appendices as a minimum.

Appendix 0/3 is comprised of two lists, A and B, of Numbered Appendices as follows.

List ‘A’ is a complete list of the Numbered Appendices referred to in the Specification for Road Works with those not adopted marked “Not Used”. Those identified by the letters ‘T’ or ‘C’ shall be compiled by the Tenderer or the Contractor respectively. List ‘B’ gives a list of Contract – specific Numbered Appendices devised for this Contract.

[Note to compiler: Reproduce here the following sample List A deleting the word ‘Sample’ and adding Volume No. where each is located within the documents and stating those Numbered Appendices not used. Ensure the ‘Instructions for Tendering’ correspond with the requirements for submission of completed Appendices by the Tenderers.] [Note to compiler: Insert a List B of any project specific Appendices in a similar format to List A. Preferably commence the numbering of these Project-specific Numbered Appendices at the 70th Appendix of the respective Series (e.g. 1/70) to avoid conflict with future national Additional Numbered Appendices.]


January 2009 8

Sample List Of Numbered Appendices – List A

Contract for Works Designed by the Contractor

Contract for Works Designed by the Employer

Volume No.

Compiled/ Completed By


Appendix No.

Title

INTRODUCTION

E E 0/1 Contract-specific Additional, Substitute and Cancelled Clauses and Tables included in the Contract

E E 0/2 Contract-specific Minor Alterations to Existing Clauses and Tables included in the Contract

E E 0/3 List of Numbered Appendices Referred to in the Specification and included in the Contract

E E 0/4 List of drawings included in the Works Requirements

PRELIMINARIES

E E 1/1 Accommodation and Equipment for The Employer’s Representative

E E 1/2 Vehicles for the Employer’s Personnel

E E 1/3 Communication System for the Employer’s Representative

C E 1/4 Working and Fabrication Drawings

E / C E 1/5 Testing to be Carried out by the Contractor

E E 1/6 Supply and Delivery of Samples to the Employer’s Representative

E E 1/7 Site Extent and Limitations on Use

E E 1/8 Operatives for the Employer’s Representative

E E 1/9 Control of Noise and Vibration

C E 1/10 Principal Structures to be Designed by the Contractor

C E 1/11 Structural Elements and Other Features to be Designed by the Contractor


January 2009 9



Volume No.



Appendix No.

Title

E E 1/12 Setting Out and Existing Ground Levels

E E 1/13 Programme of Design and Execution and Completion of the Works

E E 1/14 Monthly Statements

E E 1/15 Accommodations Works

T / C E 1/16 Privately & Publicly Owned Services & Supplies

E E 1/17 Traffic Safety & Management

E / C E 1/18 Temporary Diversions for Traffic

E E 1/19 Routeing of Vehicles

E E 1/20 Recovery Vehicles for Breakdowns

E E 1/21 Information Boards

E E 1/22 Progress Photographs

C E 1/23 Substances Hazardous to Health

E E 1/24 Quality Management System

E E 1/25 Product Certification Schemes

E E 1/26 Irish Agrément Board Roads and Bridges Certificates

SITE CLEARANCE

E / C E 2/1 List of Buildings, etc, to be Demolished

C E 2/2 Filling of Trenches and Pipes

C E 2/3 Retention of Material Arising from Site Clearance

E / C E 2/4 Explosives and Blasting

E / C E 2/5 Hazardous Materials


January 2009 10



Volume No.



Appendix No.

Title

FENCING AND ENVIRONMENTAL NOISE BARRIERS

E / C E 3/1 Fencing, Gates and Stiles

C E 3/2 Fencing: NRA Road Construction Details

SAFETY BARRIERS & PEDESTRIAN GUARDRAILS

C E 4/1 Safety Barriers

C E 4/2 Pedestrian Guardrails

C E 4/3 Safety Barrier Terminals

E E 4/4 Safety Barrier Maintenance

C E 4/5 Anti-Glare Screens

C E 4/6 Safety Barriers: NRA Road Construction Details

DRAINAGE AND SERVICE DUCTS

C E 5/1 Drainage Requirements

C E 5/2 Service Duct Requirements

C E 5/3 Surface Water Channels and Drainage Channel Blocks

C E 5/4 Fin Drains and Narrow Filter Drains and Geotextiles for Filter Drains

C E 5/5 Combined Drainage and Kerb Systems

C E 5/6 Linear Drainage Channel Systems

C E 5/7 Drainage and Service Ducts: NRA Road Construction Details

C E 5/8 Thermoplastics Structural Wall Pipes and Fittings

E/C E 5/9 Attenuation


January 2009 11



Volume No.



Appendix No.

Title

EARTHWORKS

C E 6/1 Requirements for Acceptability & Testing of Earthworks Materials

C E 6/2 Requirements for Dealing with Class U2 Unacceptable Material

C E 6/3 Requirements for Excavation, Deposition, Compaction (other than Dynamic Compaction)

Not Used Not Used 6/4 Not Used

C E 6/5 Geotextiles Used to Separate Earthworks Materials

C E 6/6 Fill to Structures & Fill Above Structural Foundations

C E 6/7 Sub-formation & Capping & Preparation & Surface Treatment of Formation

C E 6/8 Topsoiling, Grass Seeding and Turfing

C E 6/9 Earthwork Environmental Bunds, Landscape Areas, Screening Mounds, Strengthened Embankments

C E 6/10 Ground Anchorages, Crib Walling and Gabions

C E 6/11 Swallow Holes & Other Naturally Occurring Cavities & Disused Mine Workings

C E 6/12 Instrumentation & Monitoring

C E 6/13 Ground Improvement


January 2009 12



Volume No.



Appendix No.

Title

ROAD PAVEMENTS – GENERAL

T/C E 7/1 Permitted Pavement Options

C E 7/2 Excavation & Reinstatement of Existing Surfaces

C E 7/3 Surface Dressing

C E 7/4 Bituminous Sprays

Not Used Not Used 7/5 Not Used

C E 7/6 Breaking Up or Perforation of Existing Pavement

KERBS, FOOTWAYS AND PAVED AREAS

C E 11/1 Kerbs, Footways and Paved Areas

TRAFFIC SIGNS

C E 12/1 Traffic Signs: General

C E 12/2 Traffic Signs: Reflective Marker

C E 12/3 Traffic Signs: Road Markings & Studs

C E 12/4 Traffic Signs: Cones, Cylinders, FTD's & Other Traffic Delineators

C E 12/5 Traffic Signs: Traffic Signals

C E 12/6 Traffic Signs: Special Sign Requirements on Gantries

C E 12/7 Traffic Signs: Preparation and Finish of Metal and Other Surfaces

ROAD LIGHTING COLUMNS & BRACKETS

C E 13/1 Information to be Provided by the Designer for the Road Lighting Works when Specifying Lighting Columns and Brackets


January 2009 13



Volume No.



Appendix No.

Title

C (P) C (P) 13/2 Column & Bracket Data Sheets 1 & 2

(P) (P) 13/3 Instructions for Completion of Column and Bracket Data Sheet

C (P) E/C (P) 13/4 Certification for Lighting Columns

C E 13/5 Road Lighting Column and Brackets: NRA Road Construction Details

ELECTRICAL WORK FOR ROAD LIGHTING AND TRAFFIC SIGNS

E E 14/1 Site Records

C E 14/2 Location of Lighting Units and Feeder Pillars

C E 14/3 Temporary Lighting

C E/C 14/4 Electrical Equipment for Road Lighting

C E 14/5 Electrical Equipment for Traffic Signs

C E 14/6 Preparation and Finish of Metal and Other Surfaces

MOTORWAY COMMUNICATIONS

C C 15/1 Motorway Communications

PILING AND DIAPHRAGM WALLING

C E 16/1-18 [Note to compiler: The standard amendments to the Specification for Road Works for use with the Public Works Contracts replace the 1600 Series of the Specification for Roadworks with the 1600 Series of the UK Specification for Highway Works. Therefore the compiler should prepare the appendices for this series in accordance with the See UK Notes for Guidance to the Specification for Highway Works.]


January 2009 14



Volume No.



Appendix No.

Title

STRUCTURAL CONCRETE

C E 17/1 Concrete – Classification of Mixes

C E 17/2 Concrete – Impregnation and Coating Schedule

C E 17/3 Concrete – Surface Finishes

C E 17/4 Concrete – General

STRUCTURAL STEELWORK

C E 18/1 Requirements for Structural Steelwork

PROTECTION OF STEELWORK AGAINST CORROSION

C E 19/1 Requirements for Bridges, Parapets and other Highway Structures except Bearings and Lighting Columns

C E 19/2 Requirements for Bearings

C E 19/3 Requirements for Lighting Columns and Bracket Arms

C E 19/3* (Alternative) Requirements for Lighting Columns & Bracket Arms

C E 19/3* (Alternative) G2 System for Flange Mounted Columns with a Plinth built over the Flange

C E 19/4 Requirements for Other Work

T/C (P) E/T/C (P) 19/5 Form BE/P2 (New Works) Paint System Sheet

C (P) E (P) 19/6 Form BE/P3 Paint Sample Despatch List (No ref. in SHW – see NG 1910)

C (P) (P) 19/7 Form BS/P4 Paint Sample Analysis Report (No ref. in SHW – see NG 1910)

C (P) C (P) 19/8 Form BS/P5 Paint Data Sheet

C E 19/9 General Requirements


January 2009 15



Volume No.



Appendix No.

Title

WATERPROOFING FOR CONCRETE STRUCTURES

C (P) C (P) 20/1 Form PWS Proprietary Waterproofing System Data Sheet (1991 & Annex 'A')

E / C E 20/2 Waterproofing for Concrete Structures

BRIDGE BEARINGS

C E 21/1 Bridge Bearing Schedule

PARAPETS

C E 22/1 Parapet Schedule

BRIDGE EXPANSION JOINTS AND SEALING OF GAPS

C E 23/1 Bridge Deck Expansion Joint Schedule

C E 23/2 Sealing of Gaps Schedule (other than in Bridge Deck Expansion Joints)

BRICKWORK, BLOCKWORK AND STONEWORK

C E 24/1 Brickwork, Blockwork and Stonework

SPECIAL STRUCTURES

C E 25/1 Requirements for Corrugated Steel Buried Structures

C E 25/3 Requirements for Reinforced Earth and Anchored Earth Structures


January 2009 16



Volume No.



Appendix No.

Title

C E 25/3 Requirements for Pocket Type Reinforced Brickwork Retaining Wall Structures

MISCELLANEOUS

C E 26/1 Ancillary Concrete

C E 26/2 Bedding Mortar

C E 26/3 Cored Thermoplastic Node Markers

E/C E 28/1 Trenchless and Minimum Dig Techniques

E/C E 29/1 CCTV Survey of Road Drainage Systems

[Note to compiler: * These Appendices relate to alternatives in the Sample Appendices where the choice is to be made by the

Contractor and all appropriate alternatives should be listed in List A.]. NG SAMPLE APPENDIX 0/4: LIST OF DRAWINGS INCLUDED IN THE CONTRACT

1 Contract-specific Drawings Supplied to Each Tenderer Drawing No. Title Volume No.

[Note to compiler: List here all drawings especially drafted for the Contract. Also include re-numbered NRA RoadConstruction Details which have Contract-specific amendments. See Noted to compiler on RCD’s below.]

2 Standard Drawings

2(i) Supplied to Each Tenderer

Drawing No. Title Volume No.

[Note to compiler: List here any Standard Drawings being supplied to each tenderer unless they have been renumbered and included in 1 above or aer included in 2(ii) below for inspection by tenderers.]


January 2009 17

2(ii) Inspected by tenderers The following drawings are made available for inspection by Tenderers at:

........................................................................................................................................................................................

........................................................................................................................................................................................

between the following dates .........................................................................................................................................

and at the following times ............................................................................................................................................

One copy will be supplied to the Contractor

Drawing No. Title Aspect required if not whole Drawing

[Note to compiler: List here all the drawings for Communications Cabling, its associated apparatus including any fog warning systems, etc. applicable to the work required in the Contract unless listed in 2(i) above.]

2(iii) Brought Into the Contract by Reference

The NRA Road Construction Details contain the following drawings brought into the Contract by reference. Unless otherwise stated below the whole drawing is brought into the Contract.

Drawing No. Title Date Aspect/Alternative(s) Required if Not Whole Drawing

[Notes to compiler regarding RCD’s: 1 The drawings in the RCD’s are intended to be used directly in the Contract without reproducing them in the

documents and without supplying them to the Contractor. The individual drawings to be included in the Contract are to be listed in 2(iii) by stating the drawing number (with amendment reference i.e. A, B etc.), date, and aspect or permitted alternative(s) where the whole drawing is not required.

2 Many drawings in the RCD’s contain more than one detail covering the same subject. Where alternatives are

shown it is essential that the particular requirements or permitted alternatives are identified. These are to be stated in 2(iii).

3 The intention is that the drawings in the RCD’s should be used without amendment but if this becomes essential,

approval from the National Roads Authority will be necessary. A copy of the amended RCD’s is then to be incorporated in the documents and listed in Appendix 0/4 with a unique drawing number and new date inserted in the date panel.]

Volume 2 Series NG 100

Notes for Guidance on the Specification for Road Works Preliminaries

PRELIMINARIES

Contents

Clause Title Page

NG 101 A c c o m m o d a t i o n and Equipment for the Engineer 14

NG 102 Vehicles for the Engineer 14

NG 103 Communica t ion System for the Engineer 14

NG 104 Standards , Quali ty Assurance Schemes, A g r e m e n t Certif icates

and Other Approvals 15

NG 105 Goods , Mater ia ls , Sampling and Testing 16

NG 106 Design of Permanent Works by the Contractor 17

NG 107 Site Extent and Limitations on Use 17

NG 108 Operat ives for the Engineer 18

NG 109 Control of Noise and Vibration 18

NG 110 Information Boards 18

NG 112 Set t ing Out 18

NG 113 P rog ramme of Works 19

NG 114 Month ly Sta tements 19

NG 115 A c c o m m o d a t i o n Works 19

NG 116 Privately and Publicly O w n e d Services or Supplies 19

NG 117 Traffic Safety and Managemen t 19

NG 118 Temporary Diversions for Traffic 20

N G 1 1 9 Route ing o f Vehicles 21

NG 120 Recovery Vehicles for Breakdowns 21

NG 122 Progress Photographs 21

NG 123 Ionising Radiat ions 22

NG 124 Substances Hazardous to Health 22

NG Sample Append ices 23

Table NG 1/1 42

March 2000 1 3

Volume 2 Notes for Guidance on the Specification for Road Works

Series NG 100 Preliminaries

Preliminaries

NG 101 Accommodation and Equipment for the Engineer

1 This Clause will generally need to be supplemented by drawings cross-referenced in Appendix 1/1. This Appendix is set out in two parts as follows:

(a) Temporary accommodation and equipment for the Engineer.

(b) Accommodation and equipment which shall become the property of the Employer on issue of the Maintenance Certificate.

In addition. Appendix 1/1 should indicate:

(i) accommodation and length of time it is required, if different from sub-Clauses 101.1 and 101.2;

(ii) the size and nature of accommodation needed;

(iii) all the required furniture and fittings, equipment (including surveying) supplies, definitive quantity of consumables, drainage facilities and other services. The Appendix should also include the standards of artificial lighting intensity and the minimum room temperature to be maintained during stated hours, including weekends where required.

2 The temporary accommodation, furnishings and fittings and equipment provided should be in good condition, but unless there is any particular reason need not be new. Accommodation, furnishings and fittings for the Employer's ultimate use, must, however, be new.

3 The provision of special temporary accommodation may be unnecessary in some instances where suitable existing property can be used. In such instances details of the property should be described in Appendix 1/1 together with the terms under which the property can be made available.

4 Appendix 1/1 should indicate, when applicable, the accommodation requirements (which may be either portable or in existing premises) needed by the Engineer to supervise major components of the Works likely to be manufactured and tested off Site.

5 Testing equipment to be listed in Appendix 1/1 should only include that to be used by the Engineer for tests which are necessary to ensure compliance with the Specification. In particular, the list should include equipment for

carrying out tests on samples described in Appendix 1/6, having regard to Irish Laboratory Accreditation Board (ILAB) requirements where appropriate.

Where nuclear gauges are likely to be required for the Engineer's use special provision should be made for their storage and requirements should be included in Appendix 1/1 (see NG 123).

The Engineer should note that ILAB accreditation for tests becomes invalid where test equipment is defective, therefore the Engineer should ensure that the Contractor takes prompt action to repair, replace and/or recalibrate any test equipment requiring such attention.

When the Contractor erects temporary accommodation for the Engineer on land which is part of the Site or adjoining the Site (i.e. has a common boundary with it) planning permission for the erection of the temporary accommodation is deemed to have been granted for the duration of construction operations.

NG 102 Vehicles for the Engineer

1 This Clause will need supplementing by Appendix 1/2 which should describe the number and type of vehicles and indicate the period for which each vehicle is required.

2 Vehicles should not be described by proprietary names; if they cannot otherwise be described, the words 'or equivalent' should be added. New vehicles should only be required where the Engineer has agreed with the Employer that the nature of the Works and Contract period make it essential.

NG 103 Communication System for the Engineer

1 When a communication system is required this should be stated in Appendix 1/3, together with requirements specific to the Contract which should include:

(i) Longitudinal involved.

section of roadworks

(ii) Type of equipment required and likely to be licensed by the Department of Communications.

March 2000 14


(iii) Location of base station and/or repeater stations if necessary.

(iv) Number and description of sets, (including spare batteries and charging apparatus) required for:

(a) Installation in vehicles; (b) Portable use.

(v) If a radio communication system is to be used the radio licence and frequency should be obtained by the Contractor for the Engineer. The Contractor will keep in force this business radio license.

2 The scale of provision should bear some relation to the length of the scheme and should not normally exceed one set per kilometre of a road scheme in addition to the base set, although variations may be necessary where particular problems of control arise.

3 When there are particular reasons for requiring the communication facilities earlier than the normal 4 weeks from the Date for Commencement of the Works (e.g. on major maintenance contracts where traffic management measures need to be commenced early after the Contract has been awarded) this should be stated in Appendix 1/3.

NG 104 Standards, Quality Assurance Schemes, Agrement Certificates and Other Approvals

Standards

1 Where there is no declaration of equivalence in respect of a proposed alternative standard, the Engineer should ascertain whether or not the proposed standard lays down levels of safety, suitability and fitness for purpose equivalent to those required by the specified standard. The Engineer may also need to seek advice from the designer and the Employer. The factors underlying the purpose of the specified standard and their criticality should be evaluated for each application. If the proposed standard only differs from the specified standard in a way not essential to the underlying purpose it should be considered equivalent. Similarly, if the proposed standard contains such factors but in a different technical form which achieves the same purpose as the specified standard, it should be considered equivalent.


Quality Assurance Schemes

2 Quality management schemes and product certification schemes in Appendices 1/24 and 1/25 should comply with the IS/EN 9000 Series and be third party certificated by a certification body satisfying the requirements of the IS/EN 45000 Series and accredited for the scheme.

3 The Engineer should consider the critical factors which form the basis of the acceptability of the listed scheme when ascertaining whether or not a proposed alternative quality management scheme or product certification scheme is equivalent. The Engineer should check that certification of the proposed quality assurance scheme has been undertaken by an independent body.

4 The Engineer should check and retain the certificates of conformity provided in compliance with sub-Clause 104.3 as evidence of the operation of quality management schemes and product certification schemes.

5 The need for inspecting of manufacturer's premises and the testing of goods and materials subject to a quality management scheme or product certification scheme should be reviewed by the Engineer. If the Engineer has a reasonable confidence in the operation of a quality management scheme or product certification scheme, he can substantially reduce the level of inspection and testing or in some cases eliminate it. The Engineer should note that a quality management scheme differs from a product certification scheme by being based solely on written management procedures. Such schemes do not guarantee the quality of the actual product or workmanship. In the case of product certification schemes, the goods and materials have already undergone independent testing. Nevertheless if the Engineer is not satisfied with a product appropriate testing should be undertaken. If in the opinion of the Engineer the performance of a quality assurance scheme is not satisfactory the certification body and the Employer should be informed.

Irish Agrement Board Roads and Bridges Certificates

6 The Engineer may accept equivalent certificates issued by Members of the European Union of Agrement (UEAtc).

Provision of Information

7 The Engineer should check that all information and certificates are valid. Where certificates relate to a particular batch, it is important to

March 2000 15


ensure that the goods or materials incorporated in the Works form part of that batch.

8 Frequently there is a need for the Contractor to submit working and fabrication drawings for the Engineer's approval. The Engineer should include in Appendix 1/4 relevant details of all works (e.g. steelwork, parapets, diaphragm wall details, waterproofing details, traffic signs, lighting, bearings, piles, precast concrete, joints, corrugated steel buried structures, combined drainage and kerb systems) for which he requires working or fabrication drawings to be prepared by the Contractor.

NG 105 Goods, Materials, Sampling and Testing

Goods and Materials

1 Samples of goods and materials should be retained by the Engineer until the completion of the Works.

Sampling and Testing

2 Details of testing to be carried out by the Contractor and test certificates to be supplied should be abstracted selectively from Table NG 1/1 and scheduled in Appendix 1/5 to enable tenderers to allow for these in their rates and prices as no separate items (except for proof loading of piles) are contained in the Bill of Quantities. The Contractor may propose that testing be carried out on his behalf by a testing laboratory, manufacturer or supplier.

3 The testing detailed in Table NG 1/1 is not necessarily exhaustive and other tests may be required. Where Contract-specific Clauses contain testing requirements, details should be scheduled in Appendix 1/5 or 1/6 as appropriate.

4 It is not intended that all the testing (appropriate to the Contract) specified in the Specification for Road Works should necessarily be undertaken by the Contractor. The Engineer should consider carefully and decide which of the specified tests would be better undertaken by him. The Specification requires those tests marked't ' in Table NG 1/1 to be undertaken by the Contractor and this requirement should not normally be changed. Advice as to who should undertake particular tests can be obtained from ILAB and the Employer.

5 The frequencies of testing marked '*' in Table NG 1/1 are given for general guidance and are only indicative of the frequencies that may be


appropriate. The Engineer should determine the frequencies to be used for the Contract, taking into account all relevant factors and circumstances such as size, location, time for completion, QA schemes. Where an Irish or British Standard or Specification Clause number is listed, the frequency of testing is specified therein and should not normally be changed.

6 Details of provision and delivery of samples by the Contractor for testing by the Engineer should be scheduled in Appendix 1/6, to enable tenderers to allow for these in their rates and prices as no separate items for supplying samples are contained in the Bill of Quantities. The Engineer should avoid duplication of testing wherever possible.

7 Where a part of the Permanent Works is to be designed by the Contractor and the associated materials and workmanship are to be tested by the Contractor, the Engineer should ensure that the tests scheduled in Appendix 1/5 cover all the options permitted by the design specification. Similarly, where a part of the Permanent Works designed by the Contractor is to be tested by the Engineer, the samples scheduled in Appendix 1/6 should cover all the permitted options. The same considerations apply where the Contractor selects materials from a range of permitted options (e.g. type of pavement, safety fencing, pipes for drainage and ducts).

8 It is the NRAs policy to require the use of testing laboratories accredited for certain tests by the Irish Laboratory Accreditation Board (ILAB) for on Site and off Site testing. Tbst results which are required to be ILAB accredited are indicated in Table NG 1/1.

Test Certificates

9 Appendix 1/5 should indicate, where appropriate, the requirement for a test certificate for each test or series of tests carried out by the Contractor, supplier or manufacturer.

10 British Standards which specify tests are usually written in a form in which test requirements are a matter between the supplier or manufacturer and the purchaser. The Contractor is the purchaser in this context and sub-Clause 105.2 requires him to obtain test certificates provided for in a British Standard (or other standard or specification) where stated in Appendix 1/5.

March 2000 16


NG 106 Design of Permanent Works by the Contractor

General

1 Appendices 1/10 and 1/11 should include for each structure, structural element or feature listed a design specification (or design specifications where a choice is offered) incorporating any relevant Appendices, Standards or other requirements appropriate to the design.

A Designated Outline should be shown on the Drawings for each structure to be designed by the Contractor and each structure for which a choice of designs is offered. Advice on the Designated Outline is given in UK Department of TVansport Standard SD 4.

Structures

2 The Engineer should ensure that the Contract has been compiled in accordance with UK Department of Transport Standard SD 4 in respect of:

(i) Each structure for which a design (based on a proprietary manufactured structure) is to be submitted by the Contractor. (These structures should be listed in Appendix 1/10 (A).)

(ii) Each structure for which the Engineer has prepared a (non-proprietary) design but for which a proprietary manufactured structure is a suitable option. (These structures should be listed in Appendix 1/10 (B).)

Examples of structures for which the suitability of proprietary systems should be considered are:

- drains (exceeding 0.9 m diameter); - crib walling; - precast concrete box culverts (up to 8 m

span); - corrugated steel buried structures (0.9 to

8 m span); - reinforced earth structures; - anchored earth structures; - footbridges; - small span underbridges (up to 8 m span).

3 The Engineer should ensure that each design specification includes an outline Approval in Principle form as referred to in UK Department of Transport Standard BD 2 : Part I and Advice Note BA 32 : Part I.

4 The design certificate, completed by the Contractor, should be forwarded to the Employer for acceptance, together with the check certificate, completed by the Engineer.


Lighting Columns and Brackets

5 Clause 1301 requires the Contractor to propose lighting columns and brackets which have been designed by the manufacturer (and checked by a checking consultant) in accordance with UK Department of Transport Standard BD 2 : Part IV and the 1300 Series. The Engineer should ensure that the design and check certificates provided comply with these requirements and where a sign is to be fitted to a lighting column, with the requirements of sub-Clause 1207.20.

Structural Elements and Other Features

6 The Engineer should ensure that structural elements and other features based on proprietary products have not been specified in the Contract. Such elements and features should be designed by the Contractor, or where appropriate, by the manufacturer and proposed by the Contractor. Such elements and features, examples of which are given below, should be listed in Appendix 1/11:

- combined drainage and kerb systems; - ground anchorages for anchored structures; - piles; - bridge bearings; - bridge expansion joints;

- parapets.

7 Non-proprietary structural elements and other features to be designed by the Contractor should also be listed in Appendix 1/11. An example of such elements is the foundations to lighting columns.

NG 107 Site Extent and Limitations on Use

1 The extent of the Site should normally be shown on the Drawings but for schemes where traffic management involves temporary traffic signs outside the area of the Works it may be more appropriate to describe the extent of the Site in Appendix 1/7. Care should be taken not to introduce text which conflicts with the definition of Site (in the Conditions of Contract). Where the Site is shown on the Drawings, the drawing numbers should be stated in Appendix 1/7.

2 Where the Contractor is responsible for temporary traffic signs giving advance warning of the Works, those areas of road necessary for the installation, maintenance and removal of advance signs, cones and road markings should be included in the Site, with the agreement of the Road Authority.

March 2000 17


3 Any limitations on the use of the Site, for example restrictions on the use of verges and paved areas that have been coned off adjacent to traffic, should be described in Appendix 1/7.

NG 108 Operatives for the Engineer

1 The number and function of operatives required by the Engineer should be included in Appendix 1/8.

NG109 Control of Noise and Vibration

Noise

1 Where it is envisaged that construction or reconstruction might involve noise disturbance, the Engineer should have informal discussions with the Local Authority during the scheme preparation and, where possible, an informal agreement to a noise control system should be concluded.

2 The noise control requirements informally agreed with the Local Authority should be described in Appendix 1/9 together with any specific requirements of the Engineer which are not covered by BS 5228 : Parts 1, 2 and 4 or by the Local Authority.

3 Appendix 1/9 should state that the Local Authority requirements are given as a guide to the Contractor, and it is for the Contractor to decide whether to seek the Local Authority's consent to his proposed method of work and to the steps he proposes to take to minimise noise.

4 Local Authorities have powers to impose requirements as to the way in which work is to be carried out and, in particular:

(i) the plant or machinery which is, or is not, to be used;

(ii) the hours during which work may be carried out;

(hi) the level of noise which may be emitted.

Vibration

5 Any requirements for the control of vibration should be included in Appendix 1/9. Clause 607 gives the requirements for explosives and blasting for excavation.


NG 110 Information Boards

1 The Engineer should provide in Appendix 1/21 details of any specific requirements, and cross-refer to drawings of the information boards required for the Works. Whenever possible information boards should be erected within the road boundary, consistent with the safety of road users. The Engineer should check that safety fencing has been detailed at the site of information boards where appropriate.

NG112 Setting Out

1 Generally on large schemes a pre-construction survey is undertaken by the Engineer to confirm the co-ordinates and levels of permanent ground markers (PGM's) and permanent bench marks (PBM's). The Engineer should ensure that missing ones are replaced and new ones provided where required to ensure that there are a sufficient number immediately adjacent to the Works.

2 The Engineer should include in Appendix 1/12 particulars of the setting out details which are available. This will usually include:

(i) Co-ordinates and levels of PGM's, PBM's.

(ii) Offset information,

(hi) Cross-section details,

(iv) Computerised data.

3 Normally it is not necessary to supply each tenderer with all this information prior to tender, but it should be made available for inspection. Once the Contract is awarded, the details should be given to the Contractor, who is responsible for setting out under Clause 17 of the Conditions of Contract.

4 No specific tolerances are given for setting out. The construction tolerances given in the Specification relate to the agreed lines and levels of the Works.

5 The Engineer and Contractor should agree the co-ordinates and levels of PGM's and PBM's before setting out and the Engineer should check the setting out as the work proceeds.

6 Any specific requirements for setting out should be given in Appendix 1/12.

March 2000 18


NG 113 Programme of Works

1 Appendix 1/13 should describe the Engineers requirements for the programme to be submitted to the Engineer in accordance with Clause 14 of the Conditions of Contract and all supplementary information related to the programme that the Engineer may require.

2 The Contract requires the Engineer to approve this programme and therefore it is essential that he requests all necessary information to enable him to do so realistically. In this respect it is often appropriate that a schedule of output and resources to support all activities shown in the programme is requested.

3 Contractors will vary in the detail into which they break down the activities of the programme and it will be for the Engineer to decide whether the supplied detail is sufficient. It should be remembered that there is little to be gained from requiring the Contractor to provide a programme in more detail than is his usual practice for construction projects of similar complexity. This is likely to lead to the submission of a programme which although feasible soon becomes out of date as the work progresses.

4 Regardless of how carefully the Engineer vets the programme, it is likely to require amendment as the work progresses. The aim should be for the programme to always represent the Contractor's current working programme throughout the Contract. This may require updating of the programme throughout the duration of the Contract. It is recommended that the Contractor should be requested to update the programme if necessary to match progress meetings.

NG 114 Monthly Statements

1 Appendix 1/14 should describe the Engineers requirements for the monthly statements submitted in accordance with Clause 60(1) of the Conditions of Contract. Standard requirements are described in NG Sample Appendix 1/14.

NG 115 Accommodation Works

1 Accommodation works should be described in Appendix 1/15, indicating where appropriate the periods for completion together with the requirements on individual plots for the benefit of each owner, lessee or occupier. Where accommodation works are not known at the


time of tender, Appendix 1/15 should state where CPO plans and schedules can be inspected. Details of accommodation works and where appropriate periods of completion that have been agreed after compilation of Appendix 1/15 should be available for reference where described therein.

NG 116 Privately and Publicly Owned Services or Supplies

1 Generally the Engineer will make preliminary arrangements with the Statutory Undertakers for the alteration of services and supplies affected by the Works. He should also, where possible, make similar arrangements for the alteration of other publicly and privately owned services and supplies.

2 The above particulars should be contained in Appendix 1/16 and include details of any advance contracts, agreements and pre-ordered material.

3 The position of all known services and supplies should be shown on the Drawings, cross-referenced in Appendix 1/16.

NG117 Traffic Safety and Management

1 When major reconstruction or maintenance work is carried out on roads carrying a heavy flow of vehicles, for which the Employer is the Road Authority, particularly where contraflow traffic management is intended or envisaged, the Contractor may be required to undertake maintenance functions on such roads within the Site. If so, this should be stated, together with a list of these functions, in Appendix 1/17. The limits of the road to be maintained should be stated together with the timescale during which the Contractor is responsible for maintenance.

2 Where contraflow traffic operation is specified by the Engineer for which crossovers are to be designed by the Contractor full design requirements should be given in Appendix 1/17. Where crossovers are specified in Appendix 1/17 the Engineer should ensure that the Road Authority has been consulted, and list in Appendix 1/17 any maintenance functions to be carried out by the Contractor. When crossovers are proposed by the Contractor, the Engineer may only consent if the Road Authority agree and the Garda Siochana should also be

March 2000 19


consulted before consent is given. The Contractor will agree details of construction and maintenance with the Road Authority and Clause 117 requires him to inform the Engineer of these details. The Engineer should state in Appendix 1/17 the timescale for submission and making of any statutory orders needed before work can commence.

3 If, in addition to routine maintenance functions, the Contractor is to be required when requested by a Road Authority to repair accidental or wilful damage to any road within the Site for which that authority is responsible (including any central reserve crossover specified by the Engineer), full details should be stated in Appendix 1/17. The Engineer should ensure that the Road Authority has been consulted.

4 Legally, it is the Road Authority's responsibility to maintain the road and it is not a valid defence that the Contractor was employed to carry out or supervise the maintenance of the road. However, compensation for breach of contract may be obtainable from the Contractor if damages are paid by the Road Authority because of a failure in maintenance due to fault by the Contractor.

5 It is essential that all traffic safety measures are in accordance, where applicable with the requirements and advice given in Chapter 8 of the Traffic Signs Manual, any amendments thereto and any other relevant instructions.

Any measures referred to in Chapter 8 of the Traffic Signs Manual and other relevant documents, which the Engineer requires the Contractor to carry out should be listed in Appendix 1/17. The Contractor's programme for traffic management and site access/egress should have the consent of the Engineer taking into account the views of the Garda Siochana and the appropriate Road Authority.

6 It may be necessary to erect, alter, cover, uncover and take down advance direction signs and other similar signs to be compatible with the state of the Works. The responsibility for this should be stated in Appendix 1/17. Where the Contractor is to be responsible, the areas of road affected by advance signs, cones and road markings should be included in Appendix 1/7 as forming part of the Site (see NG 107.2).

7 Authorisation of non-prescribed signs or temporary traffic signals should be obtained through the Employer giving at least 28 days notice. (This time period can vary.) Any other requirements which are likely to be needed should be included in Appendix 1/17.


8 The Engineer should state in Appendix 1/17 the timescale for the Contractor to submit his traffic management proposals. When the Contractor has submitted these for the Engineer's consent, the Engineer should ensure that they comply with the Employers criteria and any other specific requirements given in Appendix 1/17.

The Engineer should also ensure that necessary steps have been or are being taken to obtain any statutory orders required from the appropriate authority. Details of these orders should be stated in Appendix 1/17.

9 Appendix 1/17 should state the length of notice required for the Engineer to arrange for the making of orders necessitated by the Contractor's proposals, or if he wishes to vary the agreed measures.

10 Before the Contractor commences work on a road, or re-opens a closed road, the Engineer should ensure that the Garda Siochana and Road Authority agree with the proposals and are satisfied with the state of the road to be reopened.

11 Any requirements for temporary lighting should be included by cross-reference to Appendix 14/3.

12 The X heights of the lettering on vehicle sign boards of 37.5, 50, 62.5, 75, 100 and 150 mm relate to the lower case and the capital sizes are 52.4. 70, 87.5, 105, 140 and 210 mm in height.

13 The Engineer should detail in Appendix 1/17 the roads and private rights of way which are to be kept open, and those for which orders have been obtained for their closure.

NG 118 Temporary Diversions for Traffic

1 The definition of the term 'temporary diversion for traffic' is included in the Method of Measurement for Road Works, Chapter IV, Series 100, Paragraph 1 (c).

Temporary Diversions for Traffic Specified by the Engineer

2 The Engineer should ensure that:

(i) all temporary diversions for traffic required for reasons of safety or practicality, including any structures, have been specified in Appendix 1/18;

March 2000 20



(ii) details of their construction and maintenance, together with any constraints, have been agreed with the Road Authority, and described in Appendix 1/18;

(iii) where applicable, licences or other rights to operate on land not owned by the Employer have been obtained and such land has been included in Appendix 1/7 as forming part of the Site;

(iv) the necessary orders have been or will be made by the appropriate authority.

8 If, in addition to routine maintenance functions, the Contractor is to be required to repair accidental or wilful damage to any temporary diversion for traffic specified by the Engineer at the request of the Road Authority responsible for that diversion, full details should be stated in Appendix 1/18.

4 Where the Contractor is required to design a temporary diversion for traffic, or any temporary structures, design requirements should be stated in Appendix 1/18.

5 If the ground over which the diversion route is to be provided is not to be reinstated to its original condition on completion of the Works this should be stated in Appendix 1/18 together with details of any treatment required.

Temporary Diversions for Traffic Proposed by the Contractor

6 If the Contractor proposes temporary diversions for traffic, the Engineer may only consent if the appropriate authority agree and should consult the Garda Siochana before giving such consent.

7 The Engineer should state in Appendix 1/18 the timescale for submission of any statutory orders which would need to be made where required by the Contractor's proposals.

8 The Contractor will agree details of construction and maintenance with the appropriate authority and Clause 118 requires him to inform the Engineer of the details.

NG 119 Routeing of Vehicles

1 Appendix 1/19 should contain where applicable the Engineer's specific requirements. These should include details of:

(i) Routeing of vehicles to and from the Site;

(ii) The use of the Permanent Works by construction traffic;

(iii) Traffic control required for machinery and plant crossing public roads and notice required before this can be implemented;

(iv) Procedures to be adopted in complying with Clause 14(3) and Clause 30 of the Conditions of Contract to enable the Contractor to satisfy the Engineer of the adequacy of his proposals.

NG 120 Recovery Vehicles for Breakdowns

1 If recovery vehicles for breakdowns are required in the Contract because of the Works interfering with roads carrying a heavy flow of vehicles this should be stated in Appendix 1/20 together with requirements specific to the Contract which should include:

(i) Number, category of vehicle and period required. Vehicle categories are:

(a) Heavy recovery vehicles;

(b) Light recovery vehicles;

A list of equipment to be provided for each vehicle should be given in Appendix 1/20. In addition, it is recommended that towing trolleys should be required to be readily available on roads carrying a heavy flow of vehicles.

(ii) Location)s) where the recovery vehicle!s) must be sited.

(iii) Location(s) to which broken down or accident damaged vehicles must be removed.

(iv) Details of equipment for communication.

NG 122 Progress Photographs

1 When required, Clause 122 will need supplementing by Appendix 1/22, describing the number of, and interval between visits and the number, size, type and finish of photographs required.

2 It is preferable that the Engineer accompanies the photographer to ensure that only relevant photographs are taken.

3 The Engineer should arrange for photographs to be taken as a record of any procedures or features which are, or could be, the subject of a third party claim or complaint e.g. works which by their nature could generate considerable quantities of dust or existing damage to private property.

March 2000 21



NG 123 Ionising Radiations

1 When the Contractor proposes to use, or is required in Appendix 1/5 to use, nuclear gauges, the Engineer should ensure that the requirements of Clause 123 have been complied with.

2 When the Engineers staff will be using nuclear gauges on their own behalf, it will be necessary for the Engineer to draw up "Radiation Safety Procedures' covering their usage. The Engineer will also need to appoint a 'Radiological Protection Officer' and notify particulars to the Radiological Protection Institute of Ireland in accordance with the requirements of S.I. 166 of the Nuclear Energy General Control of Fissile Fuels, Radioactive Substances and Irradiating Apparatus) Order, 1977. The Engineer should advise the Contractor of his designated 'Radiological Protection Officer' and provide the Contractor with a copy of the Engineers 'Radiation Safety Procedures' (see also NG 1041).

NG 124 Substances Hazardous to Health

1 Clause 124 can be supplemented by Appendix 1/23 which should describe any limitations on the Contractor's method of working or monitoring requirements when using substances hazardous to health such as silane, bridge deck waterproofing systems, paints, where these are used in locations which could result in a risk to members of the public.

2 Where the Engineer identifies the need for protective clothing or other safety apparatus in relation to the specified use of substances hazardous to health, these should be listed in Appendix 1/1.

March 2000 22



N G S A M P L E A P P E N D I X 1/1 : A C C O M M O D A T I O N A N D E Q U I P M E N T F O R T H E E N G I N E E R

A. Temporary Accommodation and Equipment for the Engineer

Accommodation Required

1 Temporary initial accommodation ) [Location (if appropriate) and ) floor area to be inserted or

2 Principal office > referenced to drawing numbers]

3 Laboratory ) [sufficient space to be allowed to ) retain samples of materials] )

4 Subsidiary static office )

5 Subsidiary portable office )

6 Off Site accommodation at fabricator's ) or precaster's works )

Duration of Time Accommodation Required

[lb be included if the time when off ices I laboratories are required and equipment is to be installed rested and made operational is different from that stated in sub-Clauses 101.1 and 101.2]

Fittings and Furnishings of Accommodation

[The details should include a list of consumable stores, surveying and testing equipment, first aid equipment and details of room temperature needed]

B. Accommodation and Equipment for the Engineer (which shall become the property of the Employer at the end of the Maintenance Period)

Accommodation Required

1 Principal office

2 Laboratory [sufficient space to be allowed to retain samples of materials]

) [Location (if appropriate) and ) floor area to be inserted or ) referenced to drawing numbers]

)

)

Time Accommodation Required

[To be included if the time when offices /laboratories are required and equipment is to be installed tested and made operational is different from that stated in sub-Clauses 101.1 and 101.2]

Fittings and Furnishings of Accommodation (to be supplied new and unused)

[The details should include a list of consumable stores, surveying and testing equipment, first aid equipment and details of room temperature needed]

March 2000 23


N G S A M P L E A P P E N D I X 1/2: V E H I C L E S F O R T H E E N G I N E E R

Type Number Period (as defined below) Required Required

A B C D

Type "A" 8 Seat Station Wagon

The vehicle is to be non-commercial type, be suitable for off-road use, have 4 wheel drive, have seating for 8 persons and be supplied in such colour as the Engineer may approve. The vehicle shall be free from markings identifying any company associated with the Contract. The equipment shall include:

Fire extinguisher, heater and demister, hazard flashing unit, heavy duty suspension, spare wheel, petrol filler cap lock, bonnet lock and spare wheel lock, internal and external mirrors, mud flaps, link mats front and rear, mudshield for front and rear brakes, rubber pads for clutch and brake pedals, interior sun visors, gearbox covers, tow rope, towing hooks front and rear, laminated windscreen, wire mesh guards for side, tail, stop and flasher lamps and covers for universal joints.

Type "B" Long Wheelbase Vehicle

The vehicle is to be suitable for off-road use. have 4 wheel drive, have seating for 2 persons and be supplied with fully enclosed cab and hard top, in such colour as the Engineer may approve. The vehicle shall be free from markings identifying any company associated with the Contract. The equipment shall be as for the Station Wagon with the following variations:

Link mats and heater shall be supplied for the front only. The vehicle shall be adapted for CBR testing to the approval of the Engineer.

Type "C" Short Wheelbase Vehicle

The vehicle is to be as type B but not adapted for CBR testing.

Type "D" Light Van or Estate Car

The vehicle shall have a carrying capacity of at least 0.25 tonne, a minimum ground clearance (unladen) of 150 mm and independent suspension.

The vehicle shall be finished in such colour as the Engineer may approve. The vehicle shall be free from markings identifying any company associated with the Contract. The equipment shall include:

Reversing lamp, fire extinguisher, luggage rack complete with straps suitable for carrying survey equipment.


March 2000 24



N G S A M P L E A P P E N D I X 1/3: C O M M U N I C A T I O N S Y S T E M F O R T H E E N G I N E E R

Type of equipment -Location of base station (for radio communication system)

- Resident Engineers office Location of other sets -Each portable set shall have a spare set of batteries

No. Office /Laboratory Vehicle Personnel Period Required

Frequency for radio communication system

Base MHz. Mobile MHz.

N G S A M P L E A P P E N D I X 1/4: W O R K I N G A N D F A B R I C A T I O N D R A W I N G S

Series Description of Work

March 2000 25



N G S A M P L E A P P E N D I X 1/5: T E S T I N G T O B E C A R R I E D O U T B Y T H E C O N T R A C T O R

[Notes to compiler:

i) The scope of the testing covered in Table NG 1/1 should not be regarded as exhaustive. Routine tests carried out by manufacturers and suppliers in compliance with an Irish or British Standard or other standard or specification are not included but where a standard or specification makes provision for a test certificate this is indicated in the table.

ii) Where tests in Table NG 1/1 (March 2000) are based on British Standards these have been compiled only for those Standards published on or before 1 March 1993. Where tests are taken from Irish Standards, or British Standards which are undated in the Specification they should be checked to ensure that test requirements have not been altered.

iii) The schedule of tests for the Contract should be completed by selecting the tests and data from Table NG 1/1. Different frequencies and additional tests should be included as appropriate. Where the frequency of testing in Table NG 1/1 is given by reference to a Clause in the SRW, the frequency requirements of the Clause should be repeated in full in Appendix 1/5.

iv) Where ILAB accreditation is required this should be indicated by the symbol (IL) in the Test column. Tests where this should apply are indicated in Table NG 1/1. |

Clause Work, Goods or Material

Test Frequency of Testing

Test Certificate

Comments

Notes:

1 Tests comparable to those specified in this Appendix will be necessary for any equivalent work, goods or materials proposed by the Contractor (See sub-Clause 105.4).

2 (IL) indicates that a ILAB test report or certificate is required.

i Unless otherwise shown in this Appendix tests for work, goods or materials as scheduled under any one Clause are required for all such work, goods or materials in the Works.

4 Cube strength tests are not required for concrete complying with Clause 2602.

5 Unless otherwise shown in this Appendix test certificates for work, goods or materials as scheduled under any one Clause are required for all such work, goods or materials in the Works.

March 2000 26



N G S A M P L E A P P E N D I X 1/6 : S U P P L Y A N D D E L I V E R Y O F S A M P L E S T O T H E E N G I N E E R

[Note to compiler: Give details of the samples to be provided or made available by the Contractor for testing by the Engineer and the locations to which they are to be delivered.]

Clause Sample Description

Frequency of Sampling

Delivery Location

Comments

Notes:

1 Samples comparable to those specified in this Appendix will be necessary for any equivalent work, goods or materials proposed by the Contractor (See sub-Clause 105.4).

2 Unless otherwise shown in this Appendix samples of work, goods or materials as scheduled under any one Clause are required for all such work, goods or materials in the Works.

3 Unless otherwise scheduled under Clause 2602 samples of concrete complying with that Clause are

not required.

N G S A M P L E A P P E N D I X 1/7: S I T E E X T E N T A N D L I M I T A T I O N S O N U S E

[Note to compiler: Include details as appropriate, under the following headings:]

1 Extent of the Site.

[Cross-reference should be made to the Drawings where appropriate.

Include areas of roads for advance signing and coning by the Contractor where relevant./

2 Limitations on the Use of the Site.

[Cross-reference should be made to Appendix 1/23 where appropriate.]

N G S A M P L E A P P E N D I X 1/8: O P E R A T I V E S F O R T H E E N G I N E E R

Operatives Required

No. Period Required

Chainman/Driver Driver/Laboratory

Handyman

March 2000 27



N G S A M P L E A P P E N D I X 1/9 : C O N T R O L O F N O I S E A N D V I B R A T I O N

Noise

1 The Local Authority has informally agreed that the following measures would be appropriate and these are given as a guide; however it is for the Contractor to decide whether to seek the Local Authority's formal consent to his proposed methods of work and to the steps he proposes in order to minimise noise.

2 The normal working hours within the Site shall be Monday to Friday between .. and .. hours and Saturday between .. and .. hours, with no working on public holidays. Exceptionally, the Engineer's consent for work outside these hours may be given after any necessary consultation. .. days notice is required from the Contractor when seeking such consent.

3 The noise levels (see Note (i) below) scheduled below for periods outside the normal working hours will only be permitted when consent has been given to exceptional working.

4 The ambient noise level, Leq (see Note (ii) below) from all sources when measured 2.0 m above the ground at noise control stations numbers 1 to .. on Drawing Numbers shall either not exceed the appropriate level given in the Schedule or not exceed by more than 3dB(A) the existing ambient noise level, Leq (see Note (iii) below), at the control station measured over the same period, whichever level is the greater. The maximum sound level at any noise control station shall not exceed the level given in the Schedule. Exceptionally the Contractor may be given permission to carry out works which exceed the noise levels in the Schedule, provided that .. days notice of the date and timing of these works is given to the Engineer and the Contractor demonstrates that he intends to take all reasonable measures to mitigate the noise nuisance. After consultations with the Local Authority and any other interested bodies a decision will be given within .. days of receipt of the notice.

Schedule Tbtal Noise Levels at Control Stations

Period Hours Ambient Noise Level,

Leq measured at Control Station: dB(A)

Period of Hours over which Leq is applicable

Maximum Sound Level (see Note (iv) below) measured

at Control Station: dB<A)

Mondays to Fridays Saturdays Sundays All unattended plant outside normal working hrs

Notes:

(i) Noise levels relate to free field conditions. Where noise control stations are located 1 m from facades of buildings, the permitted noise levels can be increased by 3 dB(A).

(ii) The ambient noise level, Leq, at a noise control station is the total Leq from all the noise sources in the vicinity over the specified period.

(hi) The existing ambient noise level, Leq, at a control station is the total Leq from all the noise sources in the vicinity over the specified period prior to the commencement of the Works.

(iv) Maximum sound level is the highest value indicated on a sound level meter which meets the requirements of BS 5969 Type 1 or 2 set to SLOW response and frequency weighting A.

March 2000



Vibration

[Note to compiler: Include here:]

(i) Locations where vibration limits are to be complied with.

(ii) Limits of vibrational amplitude and resultant peak particle velocity.

(iii) Requirements for instrumentation and monitoring.

(iv) Engineer's arrangements for Contractor to monitor vibration in property off Site.

N G S A M P L E A P P E N D I X 1/10 : S T R U C T U R E S T O B E D E S I G N E D B Y T H E C O N T R A C T O R

[Note to compiler: List under (A) the structures to he designed by the Contractor and under (B) the structures for which a choice of designs is offered, i.e structures for which the Contractor may propose a design if he elects not to construct the design prepared by the Engineer. The design specifications and any special requirements should either follow immediately after the table or be cross-referenced to other Appendices.]

Structure Location Design Specification

(A)

(B)

March 2000 29



N G S A M P L E A P P E N D I X 1/11 : S T R U C T U R A L E L E M E N T S A N D O T H E R F E A T U R E S T O B E

D E S I G N E D B Y T H E C O N T R A C T O R

[Note to compiler: List here the structural elements and other features to be designed by the Contractor. The design specifications and any special requirements should either follow immediately after the table or be cross-referenced to other Appendices.]

N G S A M P L E A P P E N D I X 1/12: S E T T I N G O U T A N D E X I S T I N G G R O U N D L E V E L S

1 The information given below will be available for inspection during the tender period at:

Local Authority/Consultants Office Address Tel No

and will be supplied to the Contractor at the commencement of the Works.

[Note to compiler: Include here details of the setting out information that is available.]

2 Specific requirements for setting out.

3 References to drawings or schedules quoting existing ground levels [111.1].

Structural Element Location Design Specification

March 2000 30



N G S A M P L E A P P E N D I X 1/13: P R O G R A M M E O F W O R K S

1 The Contractor shall provide the programme in the form of a network diagram/bar chart [delete as appropriate! produced as a result of a "critical path analysis" and must abide by the constraints stated or implied in the Contract. It shall show the level of detail appropriate to each stage of the Works and all activities and restraints, each of which shall be given a short title. All events shall be numbered and annotated with earliest and latest event dates.

2 At the time of presentation of the programme the Contractor shall also provide a mass-haul diagram showing his intended earthworks movements and locations and capacities of anticipated plant and other resource input.

3 Schedule of Stated Constraints

[The constraints known at tender stage should be inserted here. Typical constraints, including those that

could have been commitments by the Employer, are as follows:]

(i) Work to privately and publicly owned services and supplies (although this is usually agreed informally giving the Contractor latitude in determining his programme!.

(ii) Possession (rail, property, wayleave, etc).

(iii) Traffic safety and management including notice requirements and restrictions arising from the use of substances hazardous to health.

(iv) Provision of environmental protection prior to the main construction operations

(v) Trials and demonstrations in advance of main construction.

(vi) Approval by the Engineer of domestic subcontractor nominations.

(vii) Completion of the communications installation 8 weeks before the date for completion of the Works.

(viii) Compliance with technical approval procedures in relation to structures designed by the Contractor, including awaiting approvals, resubmissions and modifications.

4 The level of detail should be not less than the following:

Level 1

Within 21 days after the acceptance of lender - Conditions of Contract Clause 14(1) and any subsequent revision (Clause 14(2)):

(i) Each bridge.

(ii) Earthworks - each cutting and embankment.

(iii) Roadworks - in lengths not exceeding 1.0 km for main route and for each side road, link road and

slip road:

(a) Fencing (b) Site clearance (c) Tbpsoil strip (d) Drainage (pre-earthworks and second stage) (e) Sub-base (f) Subgrade improvement layer (g) Roadbase or concrete paving (h) Surfacing.

(iv) Major privately and publicly owned services and supplies.

(v) Traffic management measures including operation of site accesses, plant crossings and temporary diversions for traffic.

(vi) Farm or householder Accommodation Works.

(vii) Landscaping Works.

March 2000 31



N G S A M P L E A P P E N D I X 1/13: P R O G R A M M E O F W O R K S (Continued)

Level 2

At least four weeks before the commencement of any item of work:

(i) For each bridge:

Piling

Substructure Superstructure Finishes

(ii) Roadworks:

As for Level 1 but intervals not exceeding 200m and including lighting, signing, soiling and seeding, road marking, cabling and communications equipment.

(iii) All public alterations or additions to privately and publicly owned services and supplies.

The monthly statements submitted to the Engineer in accordance with Clause 60( 1) of the Conditions of Contract by the Contractor shall, whenever dealing with matters covered by the Bills of Quantities, be set out under Part and Section headings similar to those in the Bills of Quantities and shall separately identify each item and specify quantity, unit, rate and value. Items not described in Bills of Quantities but appropriate for inclusion as measured work shall be shown at the end of the relevant section or under section headings as appropriate indicating quantity, unit rate and value. In respect of all other matters referred to in Clause 60(1) the Contractor shall separately show in the statement quantities, units and rates of goods and/or materials and also details of any other matters to which he considers himself entitled. The Contractor shall allow the Engineer to inspect invoices for goods or materials included in the statement pursuant to Clause 60(l)(b) and (c) as may be required.

Level 3

Further breakdown of items and other details as may be required.

N G S A M P L E A P P E N D L X 1/14: M O N T H L Y S T A T E M E N T S

March 2000 32



N G S A M P L E A P P E N D I X 1/15: A C C O M M O D A T I O N W O R K S

1 Schedule of Accommodation Works already determined and included in the Tender Documents.

2 Copies of Schedule of Accommodation Works and details which may be agreed during the Tender period

will be made available at:

Local Authority/Consultant's Office

Address

Tel No

3 Reference (where appropriate) to Accommodation Works and details which may be included in the Works

but are unlikely to be determined prior to receipt of tenders.

March 2000 33



N G S A M P L E A P P E N D I X 1/16: PRIVATELY A N D P U B L I C L Y O W N E D S E R V I C E S A N D

S U P P L I E S

1 Details of preliminary arrangements that have been made with Statutory Undertakers and others for the alteration of services affected by the Works are listed in this Appendix.

2 The Contractor shall make arrangements with the Statutory Undertakers and others concerned, for the co-ordination of his work with all work which needs to be done by them or their contractors concurrently with the Works. Compliance with the periods of notice given in this Appendix does not relieve the Contractor of his obligations.

3 Private services to individual properties have not generally been listed or shown on the Drawings. The Contractor shall make arrangements with the Statutory Undertakers and others concerned for the phasing of all necessary disconnections and diversion of private services affected by the Works.

4 Disconnected apparatus shall be removed by the Contractor only with the prior consent of the Authority concerned.

5 The names, addresses and telephone numbers of the authorities serving in the locality are listed below.

Names Address and Tel No. Contact

Statutory Undertakers

Other Authorities

6 Services and Supplies Affected by the Works

Location Description Group* Drawing No. Notice Required to Commence

Time for Completion

Statutory Undertakers

Other

Authorities/Bodies/

Individuals

* A Work expected to be completed before the commencement of the Works. B Work required in the Contract which does not require prior work by the Contractor. C Work required in the Contract which does require prior work by the Contractor. D Work expected to be under construction at the commencement of the Works. E Work required to be carried out jointly by the Contractor (all Civil Works) and the Statutory

Undertaker (Cabling only) in close liaison and co-operation with each other. F Work to be wholly undertaken by the Contractor (in liaison with the statutory undertaker)

7 [Note to compiler: Insert here details of any other preliminary arrangements that have been made]

March 2000 34



N G S A M P L E A P P E N D I X 1/17: T R A F F I C S A F E T Y A N D M A N A G E M E N T

[Note to compiler: The following should be inserted in the Appendix as appropriate and extended w/ien required:]

Traffic Safety and Management Requirements

[When the Contractor is not required to submit traffic management proposals or to supply sign faces, posts or fixings, this should be stated]

(i) Phasing of Works | include details of traffic orders that have been or are being made].

(ii) Drawings showing traffic management layout, including: (a) Geometric Design. (b) Position of traffic signals. (c) Width of lanes. (d) Working areas. (e) Safety zones. (f) Crossovers |include construction details, and geometrical design required where this has not

been shown on the Drawings]. (g) Running lane for emergency vehicles. (h) Location for emergency vehicles. (i) Access and exit locations for construction.

(iii) Timing of operations.

(iv) Road lighting requirements (Appendix 14/3).

(v) Whether hazard warning lights are an acceptable alternative to a roof-mounted amber flashing lamp and if so, in what circumstances (117.14].

(vi) Whether a traffic safety and control officer is required /117.18].

(vii) Restrictions arising from the use of substances hazardous to health [cross-reference should be made to Appendix 1/23].

Maintenance Requirements

(i) Crossovers

(ii) Roads

(iii) Timescale for responsibility if different from sub-Clause 117.7

Notice Requirements

Notice required by the Engineer for him to arrange for:

(i) amending or making traffic orders

(ii) authorising of non-prescribed signs

(iii) authorising temporary traffic signals

(iv) moving signs to be compatible with the state of the Works as described in sub-Clause 117.11

Details of Events That Could Have a Bearing on the Works

[These could include such events as:]

Race meetings, Football fixtures, and Road reconstruction work being carried out in the vicinity.

March 2000 35



N G S A M P L E A P P E N D I X 1/17: T R A F F I C S A F E T Y A N D M A N A G E M E N T (cont inued)

Roads, Private Roads, and Other Ways Affected by the Works

Description Predicted 24 Hour Annual Average

Daily Traffic AADT

Eighty Five Percentile Speed of

Cars (mph)

Speed Limit (mph) if Proposed

[State whether

Mandatory or Advisory |

Type(s) of Traffic Control

Special Facilities

[Pedestrian, Equestrian

etc.]

Whether to be Kept Open or Closed

Note: Particulars of temporary diversions for traffic are contained in Appendix 1/18.

Roads including footpaths, cycle tracks and other traffic routes, described above or listed in Appendix 1/19 are

the responsibility of:

Authority

Address

Tel No

March 2000 36



N G S A M P L E A P P E N D I X 1/18: T E M P O R A R Y DHTERSIONS F O R T R A F F I C

[Note to compiler: The following should be inserted in the Appendix as appropriate and extended when required:]

Temporary Diversions for Traffic Specified by the Engineer

(i) Roads Open to Vehicles

Description Drawing No. or Ref

Construction 1 Design

Requirements'"


(including timescale for

responsibility)

Remarks (including

constraints and reinstatement

details)

Major

Minor

(ii) Other Roads and Private Rights of Way

Description Drawing No. or Ref

Existing Usage

Construction / Design

Requirements*


(including

timescale for responsibility)

Remarks (including

constraints and reinstatement

details)

Footpaths

Cycle Tracks

Bridleways

+Private Means of Access

Note: Particulars of traffic are contained in Appendix 1/17.

f* This could include a schedule of different forms of construction and geometrical design required where this has not been shown on the Drawings.

+ Not always a. need to define individual accesses, particularly in urban situations. Reference can be made to road names or other appropriate means of identification.!

(iii) Temporary Structures Specified by the Engineer

[Give full particulars, including outline Approval in Principle forms where appropriate, if temporary structures are to be designed by the Contractor.J

Temporary Diversions Proposed by the Contractor

(i) Notice Requirements [118.5]

(ii) Details of any Constraints

March 2000 37



N G S A M P L E A P P E N D I X 1/19: R O U T E I N G O F V E H I C L E S

[Note to compiler: Insert details as appropriate under the following headings:]

(i) Permitted Access Routes lb and From the Site

[A list of drawings showing the permitted access routes and details of temporary traffic signs./

(ii) The Use of the Permanent Works by Construction Traffic

[The requirements with which the Contractor must comply in submitting details under Clause 14(3) and Clause 30 of the Conditions of Contract.]

(iii) Movement of Machinery and Plant Across Public Roads

[The requirements for the provision of haul route traffic signals, the equipment for which requires the approval of the Local Authority and An Garda SiochanaJ

(iv) Temporary Structures for Construction Traffic Spanning Areas Used by the Public

[Detail to which temporary structures must be designed including, in the case of structures spanning a public road, the requirement for the Contractor to follow the technical approval procedures contained in UK Department of Transport Standard BD 2 : Part 1. In the case of structures spanning a railway, river or canal, the requirements of the appropriate authority should be given.]

March 2000 38


N G S A M P L E A P P E N D I X 1/20: R E C O V E R Y V E H I C L E S F O R B R E A K D O W N S

Requirements for Recovery Vehicles

1 Recovery Vehicles to be Provided

1.1 [Include here details of circumstances when recovery vehicles are to he provided.]

1.2 Heavy recovery vehicles:

(a) ... No. heavy recovery vehicle!s) shall be provided. (b) A heavy recovery vehicle shall comply with the following: [Include here vehicle details and equipment and fittings required.]

1.3 Light Recovery Vehicle

(a) ... No. light recovery vehicle(s) shall be provided. (b) A light recovery vehicle shall comply with the following:

[Include here vehicle details and equipment and fittings required.]

2 Inspection Requirements

The Contractor shall arrange for all recovery vehicles to be inspected for roadworthiness and a copy of each report shall be provided for the Engineer. Each person manning the vehicle shall have a valid licence to operate the vehicle.

3 Locations for Recovery Vehicles

[Details of locations for recovery vehicles together with any specific requirements such as need for hardstandings.J

4 Communication System

/Details of communication system required.]

5 Location! s) for Vehicle Removal

[Details of location!s) to which broken down or accident damaged vehicles should be removed.]

N G S A M P L E A P P E N D I X 1/21: I N F O R M A T I O N B O A R D S

/Note to compiler: Include here the locations and details of information boards including supports, wind bracing, etc., or cross-references to the drawings giving the information.]


March 2000 39



N G S A M P L E A P P E N D I X 1/22: P R O G R E S S P H O T O G R A P H S

Location Type No. Aerial / Ground Frequency required

Remarks

N G S A M P L E A P P E N D I X 1/23: S U B S T A N C E S H A Z A R D O U S T O H E A L T H

INote to compiler: Details should be inserted in the Appendix as appropriate under the following headings:]

(i) Restrictions in relation to traffic management measures. [These should include need for additional safety zones or lane closures.]

(ii) Restrictions in relation to working practices. [These should include conditions in relation to wind speed and direction, night working and restrictions in relation to traffic conditions i.e. working to stop when adjacent traffic speed falls below a specified level.]

(iii) Measures to be taken to protect members of the public. (These should include measures such as screening and signing.]

(iv) Monitoring to be undertaken by Contractor. [Depending on substances or processes, air quality monitoring may be required where traffic, pedestrians or properties are adjacent to or close to the Works. Details of requirements should, be given.]

(Note to compiler: Further information on the need for specific requirements may be obtained from the Road Authority INRA.J

March 2000 40


Notes for Guidance on the Specification for Road Works Preliminaries

May 2005 41

NG SAMPLE APPENDIX 1/24: QUALITY MANAGEMENT SCHEMES

[Note to compiler: List here, in the format shown in the example below, the full list of quality

management schemes applying to, and certification bodies accepted in, the Contract.]

The following is the list of accepted quality management schemes referred to in sub-Clauses 104.3 and

104.4.

Scheme:

1 Description: Manufacture of Fencing Components

Certification Bodies: Name(s)

Address(es)

Specification: Fencing components shall be in accordance with the 300 and 400 Series of the

Specification and the Drawings referred to in the Contract.

2 Description:

Certification Bodies:

Specification:

NG SAMPLE APPENDIX 1/25: PRODUCT CERTIFICATION SCHEMES

[Note to compiler: Include here the full list of both marked and unmarked product certification

schemes accepted in the contract and referred to in sub-Clauses 104.4 and 104.6.]

NG SAMPLE APPENDIX 1/26: IRISH AGREMENT BOARD ROADS AND BRIDGES

CERTIFICATES

[Note to compiler: Include here the full list of types of work, goods or material for which proprietary

products are required to have an Irish Agrement Board Roads and Bridges Certificate.]

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

05

4

2

Table NG 1/1: Typical Testing Details

indicates a requirement in SRW for the test to be carried out by the Contractor; such tests should therefore be scheduled in Appendix 1/5.

indicates a statement in SRW that the test may/will be carried out under the direction of the Overseeing Organisation; samples for such tests should

therefore be required in Appendix 1/6.

indicates that the frequency of testing is given for general guidance and is only indicative of the frequency that may be appropriate (i.e. no frequency is

given in the SRW or reference documents). Where materials are known to be marginal or if initial test results show them to be such, the frequency of

testing should be increased. Conversely where material properties are consistently in excess of specified minimum requirements or well below specified

maximum limits, then the frequency of testing should be reduced.

indicates that an Irish National Accreditation Board test report or certificate is required.

[Notes to compiler:

The above symbols apart from (IL) are for guidance when preparing Appendices 1/5 and 1/6 and should not be reproduced in those Appendices.

Other guidance is printed in italics and should likewise not be reproduced in Appendices 1/5 and 1/6. Appropriate Contract-specific requirements

should be scheduled.]

Key

†

††

*

(IL)

1

2

I a


Clause Work, Goods or

Material Test

Frequency of Testing

Test Certificate

Comments

Series 300

306 Permanent fencing Quality management scheme applies

Concrete components Cover to reinforcement 1 per consignment (maximum 1 per 100 components)

{Tests /samples should not normally be required!

308 Gates and stiles Quality management scheme applies

Reinforced concrete posts Cover to reinforcement 1 per consignment (maximum 1 per 100 components) (BS3470)

1 Tests 1samples should not normally be required]

311 Preservation of timber Moisture content As required in sub-Clause

311.2

Required for each batch

Quality management scheme applies /Tests 1samples should not normally be required]

Series 400

402 Welding Welding procedures (Manufacturer's tests)

(Every seven years) Quality management scheme applies

Welder qualification (Manufacturer's tests)

(Every two years)

Production testing (Manufacturer's tests)

(Sub-Clause 402.5 (iv))

Welded joints Destructive testing [See sub-Clause 402.5(v)] K[SeeNG402<IL,l

Wire rope terminals Tensile tests (Manufacturer's tests)

I Annually and when production technique changed)

Required Tb provide evidence of tests by a testing laboratory

4^


bo Clause Work, Goods or

Material Test Frequency of

Testing Test

Certificate Comments

403 Anchorages and attachment systems for use in drilled holes

Ultimate tensile load (Manufacturer's tests)

Required lb provide well attested and documented evidence [See NG 403.51

404 Anchorages in drilled holes Loading test on site As required in Appendix 4/1 -

Post foundations [See NG 404.3]

Series 500

501 Pipes for drainage and service ducts

Vitrified clay

Product certification scheme applies [Note 1. Additional manufacturer's tests are provided [or in the relevant standard but should not normally be required.]

[Note 2. Certificates are provided for in the relevant standard but should not normally be required except for pipes which are not kite marked.]

Concrete -PC/SRC

not exceeding

[See Note 1] [See Note 2] Product certification scheme applies [Note 1. Additional manufacturer's tests are provided [or in the relevant standard but should not normally be required.]


Concrete -Pre-stressed

900 mm dia



Iron - cast



Iron - ductile [See Note 21



UPVC



Material lest


Test Certificate

Comments

Series 500 (continu ed)

to

8 "31

ft,

r

501 (continued) Pipes for drainage and service ducts

Plastics

Corrugated steel

Corrugated steel bitumen protection

Concrete PC/SRC exceeding 900 mm dia

(Manufacturer's tests >

Other materials

Proof load Maximum load Chloride ion Cube strength (Manufacturer's tests)

Sub-Clause 509.8

Required (AASHTO)

Required (AASHTO I

IAB certification applies

503 Pipe bedding Grading 1 per 500 tonnes (min of 3!

Soluble sulphate content (ID

1 per source"

W/< fines value i IL)

/Appropriate tents/samples for soundness and frost heave should be scheduled where required}

505 Filter medium backfill Plastic index (IL) 1 per source"

W/r fines value (IL)

Soluble sulphate content(IL)

Grading 1 per 500 tonnes"

I Appropriate tests! samples for soundness and frost heave should be scheduled where required/

Washing and sieving method to be

used

to r 3 2. " 5

I be




Testing Test


Series 500 (continued)

506 Sealing exis ting drains

Concrete

1 Appropriate tests 1 samples should he scheduled where not included under other Clauses]

507 Chambers 507

Precast concrete [See Note 1] Product certification scheme applies

507

Corrugated galvanized steel (Manufacturer's tests) Required

Product certification scheme applies

507

Manhole steps [See Note 2} Product certification scheme applies

507

Steel fitments

507

Covers, grates and frames [See Note 1] [See Note 21 Product certification scheme applies

507

Cover bolts [See Note 1) [See Note 2] Quality management scheme applies

508 Gullies and pipe junctions


508

Precast concrete [See Note 1J Product certification scheme applies

508

Cast iron and steel [See Note 1] [See Note 21


509 Watertightness of joints Air test All pipelines with watertight joints IAs required in Appendix 5/1 for partly watertight joints]




Testing Test



512 Backfill to pipe bays Grading 1 per 500 tonnes 1 min of 3)* /Appropriate tests Isamples for soundness and frost heave should be scheduled where required]

512 Backfill to pipe bays

Soluble sulphate content(IL) 1 per source*

/Appropriate tests Isamples for soundness and frost heave should be scheduled where required]

513 Permeable backing to earth retaining structures

Grading 1 per 200 tonnes i min of 3)*

/Appropriate tests/samples for soundness and frost heave should be scheduled where required]

513

Precast hollow concrete blocks (Manufacturers tests) Required

Series 600

601 631 to 633 635 to 637 640

Acceptable material 601 631 to 633 635 to 637 640

Class General Description

601 631 to 633 635 to 637 640

1 General granular fill Grading/uniformity coefficient

Twice a week*

1C only 10% fines value (IL) Weekly*

2 General cohesive fill Grading Twice a week*

mc/MCV/PL Undrained shear strength (IL)

2 per 1000 m1 up to max of 5 per day*

/Cross-reference should be made to any requirements in Appendix 6/1/

4 Landscape fill Grading/mc/MCV(IL) Daily*

•4

I Table NG 1/1: Typical Testing Details



Testing Test



601 631 to 633 635 to 637 640

(continued)

5 Topsoil Grading Daily* 601 631 to 633 635 to 637 640

(continued)

6 Selected granular fill Grading/ uniform i ty coefficient

1 per 400 tonnes:::

601 631 to 633 635 to 637 640

(continued) PI (IL) Daily*

10% fines value (IL) Weekly*

OMC/mc/MCV(IL) 1 per 400 tonnes*

Organic matter/water soluble sulphate content <IL)

Weekly*

pH/chloride ion content (IL)

Weekly*

Resistivity (IL) [As required]

Undrained shear parameters (IL)

[As required] /Cross-reference should be made to any requirements in Appendix 6/1/

7 Selected cohesive fill Grading/mc/MCV(IL) 1 per 400 tonnes*

PL (ID Daily*

Water soluble sulphate content (IL)

Weekly*

pH/chloride ion content (IL)

Weekly*

Undrained shear parameters (IL)

[As required] /Cross-reference should be made to any requirements in Appendix 6/1]

CBR (ID [As required/ 4 -CC

-r:

TO TO'

5s' CO

5- <

re' A

i Table NG 1/1: Typical Testing Details



Testing Test

Certificate

Series 600 (continuedI

Comments

601 631 to 633 635 to 637 640

(continued)

Miscellaneous fill

Fill adjacent to cementitious material or metallic items

mc/MCViIL)

Soluble sulphate content (IL)

Daily*

1 per 400 tonnes or per location if less than 400 tonnes*

602 Earthworks material beneath surface of a road or paved central reserve

Frost heave (IL) 1 per 5000 m**

609 621

Geotextiles Tensile load 1 per 400 square metres*

Permeability

Pore size

/Requirements should be given in Appendix 6/5 or 6/9 as appropriate/

612 Compaction of fills

Method compaction Field dry density (IL) [As required]

End product compaction Optimum mc (2.5 kg rammer/vibrating hammer method) (IL)

Each class or sub class of material*

Field dry density (IL) 1 per 400 tonnes*

I t

5

61.8 Topsoiling and grass seeding Rate of spread of fertiliser 1 per 1000 square metres*

Rate of spread of seeding

Chemical analysis of fertiliser

Grass seed germination and purity (Manufacturers test i

1 per source* ft

1 per source and mix variety*

Required prior to sowing

to a a a



Material Test


Test Certificate Comments


622 639

Earthworks for reinforced earth and anchored earth structures

Drainage layers

Reinforcing elements Anchor elements

Redox potential

Grading

Chemical analysis

Coeff. of friction

Adhesion

5 locations within the affected area*

1 per 400 tonnes"

Each type of element with each type of fill*

624 Ground anchorages Proof loading As required in Appendix 6/10

626 Gabions

Fill Grading 1 per 400 tonnes*

10% fines value (IL)

Geomesh [As appropriate to properties stated in Appendix 6/10]

PVC coated wire

1 per 400 square metres*

Required (ASTMG23)

642 Earthworks materials adjacent to structures Constrained soil modulus (M*)

3 on each side of each structure*

Series 700

705 Sub-base and roadbase material beneath Frost heave (IL) 1 per 500 ma*

OS

surface of a road or paved central reserve

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

04

5

1


Comments

Series 800

Composition testing only required if

using recycled aggregates

[Where required - See NG 803]


Test

Certificate


1 per 400 tonnes or per

location if less than 400

tonnes*

1 per 1000 tonnes or

minimum of 2 per day*

1 per week*

2 per year*

1 per 2 years*

[As required]



1 per week*

2 per year*

1 per 2 years*

[As required]

Test

Acid Soluble sulphate

content (IL)

Grading/Composition

Moisture Content

Methylene Blue (IL)

Flakiness Index (IL)

Plasticity index (IL)

CBR (IL)

OMC (IL)

Density (IL)

Los Angeles Coefficient (IL)

Magnesium Sulphate

Soundness (IL)

Water absorption (IL)

Grading

Moisture Content

Methylene Blue (IL)

Liquid Limit (IL)


OMC (IL)


Magnesium Sulphate

Soundness (IL)


Work, Goods or Material

Unbound sub-base and roadbase material

(other than slag) adjacent to cement bound

materials, concrete pavements, structures

or products

Granular material Type A

Granular material Type B

Clause

801

803

804

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

04

5

2


Comments



Test

Certificate




1 per week*

2 per year*

1 per 2 years*

[As required]



1 per week*

2 per year*

1 per 2 years*

[As required]

Test

Grading

Moisture Content

Methylene Blue (IL)

Liquid Limit


CBR (IL)

OMC (IL)

Density (IL)


Magnesium Sulphate

Soundness (IL)


Grading

Moisture Content

Methylene Blue (IL)

Liquid Limit


OMC (IL)


Magnesium Sulphate

Soundness (IL)



Granular material Type C

Wet-mix macadam

Clause

805

806

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

05

5

3


Comments

Series 900

[Where required – See NG

901.2]

Washing and sieving method

to be used

[More frequent tests/samples

should be scheduled for

modified binders]

Test Certificate

Frequency of

Testing

Monthly*

Monthly*

1 per 2 Years*

2 per Year

Monthly*

Monthly*

2 per year per

source*

2 per year per

source*

1 per 750 tonnes*

1 per 750 tonnes*

[As required]

1 per 75 tonnes*

(min 2 per day)

Test

Determination of resistance to fragmentation - Los Angeles

coefficient (IL)

Determination of percentage of crushed and broken surfaces

in coarse aggregate particles (IL)

Magnesium Sulphate test (IL)

Determination of particle density and water absorption (IL)

Determination of particle size distribution (mass passing

0.063mm sieve) (IL)

Determination of particle shape of aggregates - Flakiness

index (IL)

Determination of the polished stone value (PSV) (IL)

Determination of resistance to surface abrasion - Aggregate

Abrasion Value (AAV) (IL)

Penetration (IL)

Softening point (IL)

[Other IS EN/BS tests]

Determination of particle size distribution (IL)

Binder content (IL)

Work, Goods or material

Aggregates for bituminous

mixtures

Binders for bituminous

materials

Bituminous mixtures

Clause

901

925

938

942

903 to 914,

916, 925,

930, 932 to

934

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

05

5

4


Comments


†

As required in IAT guidelines

[More frequent tests/samples should

be scheduled for modified binders]

As required in IAT guidelines

Test Certificate


1 per contract*

Monthly*

1 per 75 tonnes*

1 per 75 tonnes *

Monthly*

2 per year per source*

2 per year per source *

[As required]

As required in Clause

918

[As required]

1 per 750 tonnes*

1 per 750 tonnes*

[As required]

Daily*

Test

Stability value

Flow value

Density

Determination of resistance to fragmentation -

Los Angeles coefficient (IL)


Binder content (IL)

Determination of particle shape of aggregates -

Flakiness index (IL)

Determination of the polished stone value (PSV)

(IL)

Determination of resistance to surface abrasion -

Aggregate Abrasion Value (AAV) (IL)

Hot sand test (IL)

Tests specified in Clause 918


Penetration (IL)

Softening point (IL)


Tests specified in IAT Publication “Guidelines

for Surface Dressing in Ireland”


Rolled asphalt surface

course (design mix)

Coated chippings

Slurry sealing

Site control

tests

Aggregates

Binder

Rate of spread

of binder

Surface

dressing

Clause

911

915

925

918

919

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

05

5

5


Comments


As per IAT guidelines

††

Test Certificate


As required for surface

dressing binder

1 per contract*

Daily*

1 per 1000m or complete

carriageway where less

[As required]

1 per source*

1 per source*

[As required]

2 per 1000 m2/shift

As required in BS 4987:

Part 2, Clause 901-20 and

Clause 929

Test

Tests as specified for surface dressing binder


Rate of application

Texture depth (Volumetric Patch Technique)

(IL)

Texture depth (TRL mini texture meter) (IL)

Determination of the polished stone value (PSV)

(IL) (Manufacturer’s test)


Rate of spread

Tensile strength

Elongation

Percentage refusal density test (IL)

Work, Goods or

material

Bituminous sprays

Binder

Blinding material

Surface texture of bituminous surface

course

Resin-based high skid resistant surface

treatment

Aggregate

Binder

Cured binder

Compacted bituminous material

Clause

920

921

924

901

929

Vo

lum

e 2

Series N

G 1

00

No

tes for G

uid

an

ce on

the S

pecifica

tion

for R

oa

d W

orks

P

relimin

aries

Ma

y 20

05

5

6


Comments

Series 1000

Quality management and product

certification scheme apply

Tests and test certificates are

required as scheduled under Clause

1702 to 1704

Tests and test certificates are

required as scheduled under Clause

1702 to 1704

Product certification schemes apply

Results of routine control tests by

the manufacturer/supplier to be

provided


Washing and sieving method to be

used for CBM aggregate

Test Certificate


1 per source*

[As required]

1 per source*

1 per source*

Monthly*

Daily*

Daily (1 per source for

CBM aggregate)

Test

Soundness value (IL)


Flakiness index (IL)

Shell content (IL)

10% fines value (IL)

Grading

Chloride content (IL)


Cement

Portland cement

Portland PFA cement

Pulverised-fuel ash

Admixtures

Aggregates

Clause



Material Test


Test Certificate

Comments


1001 1030 1035

(continued)

Fine aggregate Acid-soluble material (IL) Monthly* Not required for CBM aggregate 1001 1030 1035

(continued) Pulverised-fuel ash Required

(BS 3892: Part 2)

1003 1004

Concrete Density of in situ concrete cores (IL)

3 per 1200 m

Cube strength (IL) A.s required in Thble 10/7

1005 Workability Compacting factor (IL)

Vebe(IL)

As required in Table 10/7

1011 1012

Dowel bars Tie bars

Required (BS 4449)


Dowel bars and supporting cradles

Load test 1 per arrangement*

Sheathed dowel bars Bond stress 4 bars

Cranked tie bars (coated)

Bend test 4 bars*

Salt fog cabinet 4 bars*

01 •a

I to



Material Test


Test Certificate

Comments


1015 Joint filler board Weathering test 3 per source Normally undertaken by manufacturer

1015 Joint filler board

Compression and recovery 4 per source

Normally undertaken by manufacturer

1015

Extrusion 1 per source


1015

Cork filler board Immersion in water 2 per source


1015

Cork filler board

Immersion in acid 2 per source


1016 1017

Applied sealants Required (ASTM) (BS 2499) (BS 5212 : Part 1) (BS 4254)

1016 1017

Applied sealants

Penetration 1 per 1000 m or 1 per day

1026 Surface texture Sand patch (IL) 1 per day (set of 10)*

1027 Aluminised curing compound Efficiency index 1 per source*

1038 to 1040 Cement bound material Laboratory wet density 1 per cube 1038 to 1040 Cement bound material

In situ wet density (IL) As required in Clause 1040

1038 to 1040 Cement bound material

Cube strength (IL) As required in Clause 1040

i NO




Testing Test


Series 1100

1101 Precast concrete kerbs, channels, edgings and quadrants

Transverse strength

Water absorption

Minimum of 3 per 1000 units of each product (BS 7263 : Part 1)

1102 In situ asphalt kerbs Grading 1 test per 500 metres laid*

Binder content

1104 Precast concrete flags Transverse strength Minimum of 3 per 1000 units of each product (BS 7263 : Part 1)

Water absorption

Bedding granular material /Appropriate tests/samples should be scheduled where not included under other Clauses/

mortar

1107 Concrete block paving Compressive strength 16 per 5000 blocks (BS6717 : Part 1)

to


a-


Material Test



Series 1200

1202 Permanent traffic signs Required \where considered appropriate]

Certification that the traffic sign is capable of passing the tests in "Certification Scheme, Specification, and Guidance for the Construction of Traffic Signs -TS4" and the specified parts of BS 873 is required

1209 Holding down bolts and anchorages to bases of permanent bollards

Required I where considered appropriate]

Certification that the holding down bolts and anchorages are capable of complying with the performance requirements of BS 873 : Part 3 is required.

1211 Thermoplastic road marking materials Tests specified in the Standard/Specification given in Appendix 12/2

Quality management and product certification schemes apply Sampling procedures should be as given in the specified Standard/Specification

Road marking paints

Required (Standard/ Specification given in Appendix 12/3)

Quality management and product certification schemes apply

1213 Permanent traffic cones and traffic cylinders Required

Certification that permanent traffic cones and cylinders have been tested and comply with BS 873 : Part 8 is required

Tests specified in BS 873 : Part 8

2 of each size and category/type*

11 Where required]

Flat traffic delineators Required

Certification that FTD's have been tested

and comply with Clause 1213 is required

Tests specified in Clause 1213

[As required] t [Where required]


Work, Goods or Material Test


Test Certificate

Comments


1213

(continued)

Other traffic delineators

Required

Certification that the delineators have

been tested and comply with Clause 1213

is required

Tests specified in

Appendix 12/4 [As required] t [Where required \

Temporary cones, cylinders, FTD's and other

delineators

Required

Certification that at least 1 in 500 of any

batch of cones, cylinders, FTD's and other

delineators to be used in the Temporary

Works have passed the tests in Clause

1213 as appropriate is required

1216 Traffic signals Quality management scheme applies.

Statutory approval of equipment applies.

Cables

[Special sample tests to BS 6346 should be scheduled where appropriate I Product certification scheme applies

Controllers {Other

equipment] Tests specified in

Appendix 12/5

Each controller

before delivery to

Site and again after

installation

Cabling

Tests a, b, c, e. f, g, h, j

as defined in sub-Clause

1424.2

Each traffic signals

installation Required

Certification that the installation complies

with the National Rules lor Electrical

Installations is required.



Material Test


Test Certificate

Comments


1217 Detector loops

Cable Required Certification that completed cables comply with the specification stated in Appendix 12/5 is required

Epoxy resin Required | wliere considered appropriate]

Certification that the epoxy resin complies with Clause 1217 is required

Feeder cable Required Certification that completed cables comply with the specification stated in Appendix 12/5 is required

Joints Pull test (4 kgf) Each crimp

Installation Series resistance Each loop Required Certification in accordance with Clause 1217 is required

Insulation resistance

Certification in accordance with Clause 1217 is required

Inductance

Series 1300

1305 Anchorages for use in drilled holes

Tensile load (Manufacturer's tests) Required To provide well attested and documented evidence

1306 Anchorages in drilled holes to columns with flange plates

Loading test on site (As required] t 1310 Welding Welding procedures (Manufacturer's tests) (Every seven years) Quality management scheme applies

Welding qualification (Manufacturer's tests) (Every two years)

Production testing (Manufacturer's tests) (Clause 1310(7.1.4))

Welded joints Destructive testing [See sub-Clause 1310 (7.1.5)] tt

[(IL) See NG 1310] to

to S


Clause

1313


GFRP laminates

Test

Loss on ignition

Colour fastness

Electric strength

Water absorption

Impact strength


1 per 200 production columns

1 per batch


1314 Brackets for laminated GFRP lighting columns

Polyurethane foam Bulk density 1 per batch

Surface hardness

Apparent bulk density 2 per batch

Impact strength

Flexural stress

Series 1400

1421 Cable [Special sample tests to BS 6346 should be scheduled where appropriate] Product certification scheme applies

1424 Lighting Units Tests specified in Clause 1424

Each unit Required t Product certification scheme applies Certification that the installation complies with the National Rules for Electrical Installations is required

Networks Tests specified in Clause 1424

Each network Required + Certification that the installation complies with the National Rules for Electrical Installations is required

n




Testing Test


Series 1500

1506 Multipair communications cable Required Certification that each completed cable § complies with the specification given in Appendix 15/1 ^

1506

Fibre optic communications cable Required Certification that each completed cable >§j complies with the specification given in | Appendix 15/1 5'

1506

Power supply cable for communications systems

Required Certification that each completed cable complies with the specification given in Appendix 15/1 a.

1518 Motorway communications and power cable Tests specified in the specification given in Appendix 15/1

Each cable (Stage 11. As required in Appendix 15/1 (Stage 2)

f Results to be reported in accordance with the specification

1518

Motorway optical fibre communications cable Tests specified in the specification given in Appendix 15/1

Each cable (Stage 1). As required in Appendix 15/1 (Stage 2)

t Results to be reported in accordance with the specification

1518

CCTV co-axial cable [As required] [See NG 1518]

i Table NG 1/1: Typical Testing Details


Material Test


Test Certificate

Comments

Series 1600

1603 Cast-in-place piles

Soil samples

In situ soil tests

Bentonite

Drilling fluid (other than bentonite)

Apparent viscosity range

Gel strength range

(Manufacturer's tests)

Density

Fluid loss

Viscosity

Sand content

Shear strength

Daily

To be proposed by the Contractor and agreed by the Engineer

Required for

each

consignment

t /Where required] /Appropriate soil tests should be sclieduledj

Certification that the bentonite complies with Clause 1603 is required

*AR Steel piles

Steel permanent casing /*AR The no. of the Additional Clause giving full details should be inserted!

Welds Radiographic 10% of welded connections

1605 Piles Maintained load /As required} /Trials in advance of main construction

should not be scheduled in Appendix 115]

*AR/SR Piles Integrity testing /As required]

eg

PARISH The no. of the Additional I Substitute Clause giving full details should be inserted/

TIT

O O 5

I I C



Material Test




1607 1608

Diaphragm wall construction 1607 1608

Drilling fluid (bentonite)

Density 3 per panel

Apparent viscosity range Gel strength range (Manufacturer's tests)

Required for each consignment

Certification that the bentonite complies with Clause 1603 is required

Drilling fluid (other than bentonite)

Density Daily

Fluid loss lb be proposed by the Contractor and agreed by the Engineer

Viscosity

Sand content

Shear strength

pH

Series 1700

1702 1703 1704

Cement Certificate to be provided monthly* for each type of cement Quality management and product certification schemes apply

1702 1703 1704 Normal and Rapid

Hardening Portland

Required (IS 1)

Certificate to be provided monthly* for each type of cement Quality management and product certification schemes apply

White or Coloured Portland Required (BS 12)

Portland-blastfurnace Required (BS 146)

Sulphate-resisting Portland Required (BS 4027)



Material Test


lest Certificate

Comments


1702 1703 1704 (continued)

Portland pulverised-fuel ash Required (BS 6588)

1702 1703 1704 (continued) Low heat Portland Required

(BS 1370)

High Slag blastfurnace Required (BS 4246)

Pulverised-fuel ash

Colour index Monthly*

Required (BS3892: Part 1)

Certificate to be provided monthly* Product certification scheme applies

Ground granulated blastfurnace slag Required (BS 6699)

Certificate to be provided monthly* Product certification scheme applies

Cements (all type) Chloride content Monthly* Tests to be carried out by the manufacturer and results included on the test certificates required above Pulverised-fuel ash Sulphate content Monthly*

Tests to be carried out by the manufacturer and results included on the test certificates required above

Ground granulated blastfurnace slag Acid-soluble alkali content

Daily (PC) Weekly (PFAggbs)

Aggregates Grading 1 per delivery (min 1 weekly per source)

Results of routine control tests by the manufacturer/supplier to be provided Product certification scheme applies

Shell content (ILI Monthly*

Flakiness index (IL) Monthly*

W/r fines value (IL) Monthly*

Drying shrinkage (IL) Monthly*

- 1

—

I to

c



Material Test




1702 1703 1709 (continued)

Blastfurnace slag

Water

Admixtures

Chloride content (IL)

Sulphate content (IL)

Bulk density (ID

Stability (ID

Sulphur content (ID

Tests specified in BS 3148

Chloride content

Sulphate content

Acid-soluble alkali content

Chloride content

Sulphate content

Acid-soluble alkali content

Daily

Monthly*

1 per 500 tonnes*

1 per 500 tonnes*

1 per 500 tonnes"

[As required}

Monthly*

Monthly*

Weekly*

1 per consignment

1 per consignment

1 per consignment

Required (BS 5075)


1707 Concrete Cube strength (IL) Concrete greater than C40 - sample from 10 ni or 10 batches whichever represents the lesser volume

Contractor to cast and test sufficient additional cubes to demonstrate cube strength before transfer t

C30 or C40 concrete - sample from 20 ni or 20 batches whichever represents the lesser volume

Concrete less than C30 - sample from 50 m:' or 50 batches whichever represents the lesser volume

I to © ©




Testing Test



1707 (continued)

Fresh concrete

Cube strength - special testing as described in Appendix 17/4 (IL)

Density

Modulus of elasticity

Workability (IL)

Additional cubes for special purposes

A cube from each of 2 samples of each batch

[As required]

Each batch

Air content

Cement content

Water/cement ratio

Each batch

[As required]

[Tests I samples should be scheduled as required - See NG 1707.6]

[Requirements should be given in Appendix 17/4 as appropriate/

I Requirements should be given in Appendix 17/1 as appropriate/

1709 Silane Required for each delivery

Certification that the silane complies with Clause 1709 is required

1710 Concrete packing Mortar packing Epoxy resin bonding agent

[Appropriate tests /samples should be scheduled]

Precast concrete manufactured off Site

Cube strength (Manufacturers tests)

Contractor to make available records of tests by the manufacturer

1711 Grout Fluidity 1 per mix::

Bleeding 1 per mix-

Volume change 1 per mix*

Free expansion 1 per mix1' Only applicable if an expanding agent is used

Cube strength 3 cubes from each batch

Admixtures Required (BS 5075)



Material Test




1712 Reinforcement Product certification scheme applies 1712

Steel bars Required (BS4449)

Product certification scheme applies 1712

Steel wire Required (BS 4482)

Product certification scheme applies 1712

Steel fabric Required (BS 4483)


1713 Fabricated reinforcement Required Certification that fabricated reinforcement complies with the routine inspection/testing requirements of BS 4466 is required if the fabrication is not covered by a product certification scheme listed in Appendix 1/25.

1716 Reinforcement jointing systems Permanent elongation Characteristic strength (Manufacturers tests)

Required for each type of connection

1717 Reinforcement metal arc welding Welding procedure approval (BS 7123)

As required in BS 7123 {Where tests in addition to those specified in BS 7123 (tensile test and macroetch test) are required full details should be scheduled]

1717 Reinforcement metal arc welding

Welder approval

(BS7123)

As required in BS 7123 {Where tests in addition to those specified in BS 7123 (tensile test and macroetch test) are required full details should be scheduled]

- 1 9




Testing Test



1718 Prestressing tendons Product certification scheme applies

Steel wire Required (BS 5896)

Steel bar Required (BS 4486)

Seven-wire strand Required (BS 5896)

Prestressing steel (all types) Proof load Breaking load Elongation Ductility Relaxation Modulus of elasticity

[As required]

Super strand to BS 5896 or other than lowest strength 3-7 mm dia wires to BS 5896

0.1% proof load Breaking load

Each reel

1724 Post-tensioning anchorages Tests in accordance with BS 4447 (Manufacturer's tests)

Contractor to make available records of tests by the manufacturer

1726 Stainless steel bar Required (BS 6744)

1727 Inspection and testing of structures and components

[Tests should be scheduled as appropriate and requirements given in Appendix 1714]




Testing Test


Series 1800

1801 1803

Structural steels to BS EN 10025, BS EN 10113, BS EN 10137, BS EN 10155, BS EN 10210

Required [Give type of document required] [Options as appropriate should be listed in Appendix 1811]

Structural steels to BS 7668 Required (BS 7668) [Options B26 - B36 as appropriate should be listed in Appendix 18/11

Stainless steels to BS 970 Required (BS 970) [Intercrystalline. corrosion test should be scheduled where required/

Stainless steel to BS 1449 : Part 2 Required (BS 1449: Part 2)

[State condition of material if not softened condition. Give information required for test certificate as Clause 1.11 ofBS 1449 : Part 2 (1983)]

Steel plate Ultrasonic testing [As required] [See guidance Clause 3.1.4 of'BS 5400 : Part 6:1999]

Bolts, nuts and washers Quality management scheme applies

All types except HSFG Tests specified in BS 4395 : Part 2

As required in BS 4395 : Part 2

HSFG Tests specified in BS 4395 : Part 1 or Part 2

As required in BS 4395 : Part 1 or Part 2

[Tests 1 samples for the optional tests provided for in BS 4395 : Parts 1 and 2 should be scheduled where required]


a-


Material Test




1801 1803 (continued)

Welding electrodes 1801 1803 (continued) Covered steel Required

(BS EN 499)

Wire Required (BS4165)

Welding

Welding procedures Tests specified in BS EN 288 : Part 3

As required in BS EN 288 : Part 3 and Appendix 18/1

Results to be reported in accordance with Annex A of BS EN 288 : Part 3

Welder qualifications Tests specified in BS EN 287 : Part 1

As required in BS EN 287 : Part 1 for each welder

Required (BS EN 287 : Part 1)

Certificate to be in accordance with Annex B of BS EN 287 : Part 1

Butt weld 'run-off plates Destructive tests specified in BS 5400 : Part 6 : 1999

As required in BS 5400 : Part 6 :1999

Butt welds and adjacent areas of steelwork

Non-destructive tests using methods to be agreed

As required in BS 5400 : Part 6 :1999 and the following:

[As required]

[Full details should be scheduled. See Clause 5.5.2 ofBS 5400: Part 6:1999 and its guidance clauses]

Fillet welds Non-destructive tests [As required] IFull details should be scheduled]

Flame cutting and shearing Tests to demonstrate procedures comply with BS 5400 : Part 6 : 1999 and Appendix 18/1

As required in Appendix 18/1

Stud shear connectors Fixing (BS 5400: Part 6) Each stud

Bending (BS 5400 : Part 6) /AN required] 3



Material lest Frequency of

Testing Test


Series 1900

1903 Abrasives Grading [As required] ft [See NG 1903]

Hardness

1910 Paints

Samples A' and 'B' Specific gravity [See Clause 1910} tt [See NG 1910] Samples will be selected in accordance with Clause 1910 Colour match

tt [See NG 1910] Samples will be selected in accordance with Clause 1910

Composition

Application characteristics

1911 Galvanized coatings Tests specified in EN ISO 1461 [As required] Method of sampling to be in accordance with Clause 1912

Aluminium and zinc spray coatings Tests specified in ISO 2063 [As required] Areas to be tested to be in accordance with Clause 1912

Aluminium coating material Required (BS 1475)

Zinc coating material Required (BS 3436)

Sherardized coatings Tests specified in BS 4921 [As required] [Sampling procedure and any special adhesion requirements including test method should be scheduled]

Zinc electroplated coatings Tests specified in BS 3382 : Part 2 [As required]

Plating to HSFG bolts [Special tests to detect hydrogen embrittlement should be scheduled where required}

1912 Metal spray coatings Tensile test specified in ISO 2063 [As required] t Grid test specified in ISO 2063 [As required] t

8



Material Test Frequenc> of

Testing Test


Series 2000

2003 Mastic asphalt Test specified in BS 6925 1 per source* Required (BS 6925) Sampling to comply with BS 6925 2003

Proprietary waterproofing systems [As required - See NG 2003] IAB certification applies

2003

Additional bituminous protection Tests specified in BS 594 : Part 1 1 per 15 tonnes* Sampling to comply with BS 594 : Parti

2003

Stability value Tests specified in BS 598 : Part 107 1 per 15 tonnes*

2004 Tar Tests specified in BS 76 1 per source* Sampling to comply with BS 76 2004

Cut back bitumen Tests specified in BS 3690 : Part 1 1 per source* Sampling to comply with BS 3690 : Part 1 [The viscosity test is normally sufficient]

Series 2100

2101 Bridge bearings 2101

Elastomeric bearings Hardness [As required] Required (BS 5400: Section 9.2)

[Tests 1samples should be scheduled only where tests are required on samples cut from a finished bearing]

2101

Elastomeric bearings

Tensile strength

[As required] Required (BS 5400: Section 9.2)


2101


Elongation



2101


Ageing



2101


Compression set



2101


Ozone resistance



2101

Complete bearings Tests specified in Appendix 21/1 As required in Appendix 21/1

—I



Material Test


Test Certificate

Comments

Series 2200

2202 Metal parapets Required (BS 6779: Parti)

Quality management scheme applies

2204 Welding Welding procedures (Manufacturers tests)

(Every seven years)

Welder qualification (Manufacturers tests)

(Every two years)

Production testing (Manufacturer's tests)

(Sub-Clause 2204(19.2.4))

Welded joints Destructive testing [See sub-Clause 2204 (19.2.5)}

tt [(IL) See NG 2204J

2207 Parapet posts Production testing as specified in BS 6779 : Part 1 :1992 (Manufacturers tests)

Required Certification in accordance with Clause 2207 is required

2208 Anchorages in drilled holes Loading test on site [As required]

2

3

tv3



Material Test


lest Certificate

Comments


2407 Blocks

Concrete Required (IS 20)

2408 Reconstituted stone [Tests 1 samples (in accordance with BS 6457) should he scheduled as required]

2410 2411

Stainless steel

Wire/fabric Required (BS 970: Part 1)

Bars Required (BS 6744)

Series 2500

2501

00

Materials for corrugated steel buried structures

Steel plate

Nuts and bolts

Metal coating

Protective coating

Paved invert system

Required as appropriate to the standard or specification listed in BD 12 and Appendix 25/1

Approval by the Engineer Applies


NO

s

Table NG 1/1: Typical Testing Detai ls

3


Material lest


Test Certificate

Comments


2502 Materials for reinforcing elements, prefabricated facing and capping units, and washers


Aluminium alloy strip Required (BS 1470)

Mechanical properties to be stated on the certificate

Copper strip Required (BS 2870)


Carbon steel strip Required (BS 1449: Parti)

Silicon content and mechanical properties to be stated on the certificate

Stainless steel strip Required (BS 1449: Part 2)


Reinforcing bar for anchor elements Required (BS 4449)

Tests scheduled under Clauses 1716 and 1911 are required for welding and galvanizing of anchor elements

Materials for fasteners

Aluminium alloy bar Required (BS 1473) (BS 1474)

Copper alloy Required (BS 2874)

Steel alloy Required (BS3692) (BS 4449) (Euronorm 21)

Tests scheduled under Clause 1911 are

required for galvanizing

Stainless steel Required (BS 970: Part 1)

Black hexagon bolts, screws and nuts

Required (BS4190)

Tests scheduled under Clause 1911 are required for galvanizing

3 -



Material Test


Test Certificate

Comments


2503 Materials for pocket type reinforced brickwork retaining wall structures

Clay bricks (Soluble salt content Efflorescence Compressive strength Water absorption Initial rate of suction) (IS 91)

1 set of tests per type of brick*

Random sampling to IS 91 to be employed

Series 2600

2601 Bedding mortar materials

Bedding Mortar Flow cone test

Flow between glass plates

Compressive strength

Expansion test

Water absorption

Elastic stability

Flow cone test Compressive strength

Each batch

1 per source

Each load

Required for each batch

Certification in accordance with Clause 2601 is required

t (IL)

Laboratory tests

Site control tests

2604 Plastic coating to fencing posts, gates and ancillaries

Impact test Adhesion

Retention of adhesion Salt spray Accelerated weathering (Manufacturers testsi

Records of all tests to be available for inspection


3 "

§

5


Material lest Frequency of

Testing Test


Series 2400

2401 Masonry cement Required (BS 5224) Quality management scheme applies

Chloride content Monthly* Test to be carried out by the manufacturer and results included on the test certificate

2402 Sand Required per consignment (IS5)

Chloride content Monthly* Test to be carried out by the manufacturer and results included on the test certificate

2404 Mortar admixtures Required (BS 4887) (BS 5075)


2405 Lime Required (BS 890)

2406 Bricks

Clay (Soluble salt content Efflorescence Compressive strength Water absorption Initial rate of suction) (IS 91)

/Tests/samples Un accordance with IS 91) should be scheduled as required]

Calcium silicate Required (BS 187)

Concrete Required (IS 189)

- 1 - I

Tl

Volume 2

Notes for Guidance on the Specification for Road Works Series NG 200 Site Clearance

SITE CLEARANCE

Contents Clause Title

Page

N G 2 0 1 Clear ing . . 6 82

N G 2 0 3 Explosives and Blast ing

82 NG 204 Hazardous Materials

82 N G Sample Append ice s Q O

8o

March 2000 SI


Series NG 200 Site Clearance

Site Clearance

NG201 Clearing

1 A schedule of buildings and structures to be demolished should be included in Appendix 2/1. The locations should be indicated in the Appendix and clearly marked on the Drawings (with reference numbers for cross identification with the Bill of Quantities). Parts of buildings as foundations below ground which are to be removed (as an earthworks operation) should be indicated as such on the Drawings.

NG 203 Explosives and Blasting

1 Where blasting for demolition of structures or removal of tree stumps is to be permitted, details should be given in Appendix 2/4. This should include, or refer as necessary to, guidance on the Local Authority's requirements for control of noise and vibration given in Appendix 1/9. Further guidance is given in NG 607.

2 Generally, disused soil and surface water pipes over 1 m depth below formation should be left undisturbed, and need only be sealed as specified. There will, however, be occasions, particularly with the larger pipes (say 375 mm diameter and over) and when there is evidence of possible collapse, when the Engineer may consider that steps should be taken to avoid any subsidence. In this case the alternatives include:

(i) Excavation to remove pipe and refill trench with suitable material;

(ii) Sealing with concrete in accordance with Clause 506.

Requirements should be stated in Appendix 2/2, when necessary.

3 The Drawings should include a plan indicating by shading or hatching the area(s) included in the Bill of Quantities as general site clearance. Where sections of site clearance are markedly different in character, e.g. woodland, these should be separately identified on the Drawings.

4 The Drawings should clearly indicate any area of grassland or woodland, individual tree or shrub, required to be preserved, e.g. for landscaping purposes or because of Tree Preservation Orders.

NG 204 Hazardous Materials

1 Where site clearance could involve the handling and disposal of hazardous materials (e.g. asbestos) the Engineer should have discussions with the Local Authority and/or the Health and Safety Authority and include in Appendix 2/5 (as a guide) measures which would be acceptable to them.

5 Whilst the recovery of existing material is generally uneconomical, there are occasions (generally with reconstruction or small improvement schemes) when it may be required, particularly when it is not the property of the Employer. In such cases, the materials should be scheduled in Appendix 2/3.

Appendix 2/3 should include a list of materials which are to be retained and stored by the Contractor for re-use on the Site, or delivered to a store nominated in the Appendix for future use elsewhere.

March 2000 82



N G S A M P L E A P P E N D I X 2/1: LIST O F B U I L D I N G S , E T C . , T O B E D E M O L I S H E D

I Note to compiler: List the buildings and structures to be demolished together with any further requirements.]

Address Description Drawing No. RefNo. Requirements

[The column headed 'Requirements' is available for including such instructions as:]

(i) Restrictions on when buildings, etc. can be demolished.

(ii) Any particular precautions to be taken during demolition.

(iii) Extent of demolition.

(iv) Method of filling voids.

(v) Material to be retained.

(vi) Treatment of adjoining properties, waterproofing, etc.

N G S A M P L E A P P E N D I X 2/2: F I L L I N G O F T R E N C H E S A N D PIPES

[Note to compiler: If the Engineer wishes to vary the requirements of sub-Clause 201.4, state the particulars in this Appendix.

Examples are:]

(i) Removal of pipes, services, etc. over 1 m below formation.

(ii) Filling of pipes over 1 m below formation.

(iii) Backfilling of trenches.

(iv) Retention of pipes, services, etc. within 1 m of formation.

March 2000 83



N G S A M P L E A P P E N D I X 2/3: R E T E N T I O N O F M A T E R I A L A R I S I N G F R O M S I T E

C L E A R A N C E

[Note to compiler: The following is a list of more common materials arising from site clearance and should

be amended and developed as appropriate.]

Description Location Delivered to: Requirements

Kerbs, quadrants

Paving

Setts

Chamber covers

Gully gratings and frames

Gates and Fencing

Safety fence components

Traffic signs

Bollards

Road studs

Traffic signals

Road lighting columns

Lanterns

Electrical equipment

Communications equipment

Cables

Timber arising from trees

[The column headed 'Requirements' is available for including such instructions as:]

(i) Disconnection of electrical supplies.

(ii) Transportation of equipment.

(iii) Stacking/storage of material.

(iv) Reinstatement of voids left by removal of equipment.

March 2000 84

Volume 2

Notes for Guidance on the Specification for Road Works-Series NG 200 Site Clearance

N G S A M P L E A P P E N D I X 2/4: E X P L O S I V E S A N D B L A S T I N G

[Note to compiler: Insert the following text as appropriate, amended and extended as required:]

1 The Contractors attention is drawn to the measures for the control of noise and vibration which are included in Appendix 1/9.

2 Explosives shall not be used, except in the following locations; subject to the stated conditions and with the approval of the Engineer.

March 2000 85



N G S A M P L E A P P E N D I X 2/5: H A Z A R D O U S M A T E R I A L S

[Note to compiler: Insert the following text extended as required:J

The Local Authority has informally agreed that the following measures would be acceptable for the handling and disposal of hazardous material found in site clearance, and these are given here as a guide.

March 2000 86

Volume 2 Series NG 300 Notes for Guidance on the Specification for Road Works Fencing & Environmental Noise Barrier

January 2009

FENCING AND ENVIRONMENTAL NOISE BARRIERS Contents Clause

Title

Page

NG 301 Not Used.............................................................................................................. 1

NG 302 Requirements for Temporary and Permanent Fences ..................................... 1 NG 303 Temporary Fencing ............................................................................................ 1

NG 304 Timber Quality ................................................................................................... 1

NG 306 Permanent Fencing ............................................................................................ 1

NG 307 Permanent Fencing for Accommodation Works ............................................... 2 NG 308 Gates and Stiles .................................................................................................. 2

NG 309 Removing and Re-erecting Existing Fences and Gates ................................... 2

NG 310 Environmental Noise Barriers .......................................................................... 2

NG 311 Preservation of Timber ...................................................................................... 5 NG 312 Painting of Timber Fences, Gates, Stiles and Posts ........................................ 5

NG 313 Concrete Fencing ................................................................................................ 5

NG Sample Appendices ............................................................................................ 6


January 2009 1

Fencing and Envirnonmental Noise Barriers

NG 301 Not Used NG 302 Requirements for Temporary and Permanent Fences 1 Clause 302 sets out the action to be taken by

the Contractor, drawing particular attention to the requirements for temporary fencing in all situations where he does not provide permanent fencing immediately.

2 There may be specific temporary fencing

requirements for a particular location during the construction period, e.g. to isolate a semi-permanent diversion of a public right of way or a Statutory Undertaker’s works or apparatus. Such fencing should be shown on the drawings. The Contractor is obliged to provide at his own cost all temporary fences required for safety and security as a result of his particular method of working, and maintain such temporary fencing during the period of the Works.

NG 303 Temporary Fencing 1 A range of fencing has been included which

will cover the majority of situations arising where permanent fencing is not required or immediately erected.

2 The majority of fencing types have been

selected from the range in IS. 435 and BS 1722 and are of a quality which will provide a fence strong enough to protect property and be economical in repetitive use when the need arises. The high standard should encourage the immediate provision of permanent fencing, although this is not always practical because of the possibility of damage to the permanent fencing during the progress of the Works.

3 The height of the fence in the range selected

may have to be increased or, it may be considered excessive for the use it has to perform. Any further requirements or relaxation should be described on the drawings.

NG 304 Timber Quality 1 The requirements for timber for use in the

permanent Works are given in IS 435 ; this document should be consulted if further information is required.

NG 306 Permanent Fencing 1 The type of fence used should be sufficient to

meet all environmental, road safety and amenity factors and the chosen design, which should be decided after consultation with the Employer, should fit visually into each distinctive stretch of country, each situation having its appropriate type of fence. Wherever a change of fence type is made, the transition point should be carefully selected to coincide with a convenient feature which will give a logical reason for the change in fence design.

2 Where additional stockproofing is required

the provision of an additional rail or mesh or additional plain or barbed wire should be considered. The views of the landowner should be considered before deciding on the use and position of barbed wire. If, for instance horses are being contained it may not be satisfactory to fix barbed wire at a low level.

3 When the ground is uneven under the line of

the fence it is suggested that the ground be trimmed, particularly if the fence is desired to be stockproof, and that this requirement be included in Appendix 3/1.

4 The drawings should show where fencing is

required, and the position, length and height for each type of fence. Appendix 3/1 should include any further details required.

5 Fencing for all roads, unless otherwise

described in Appendix 3/1, shall be constructed with the rail on the field side of the post.

6 The compiler should state in Appendix 3/1 if

concrete surround is required to the base of fence posts of timber post and rail fences. The NRA Road Construction Details refer.


January 2009 2

NG 307 Permanent Fencing for Accommodation Works 1 Landowners should be encouraged to agree

to a type of fencing for boundaries from those contained in the NRA Road Construction Details, which, if it has to contain stock must be adequate for the purpose. Agreed requirements should be described in Appendix 1/15, or shown on the drawings.

NG 308 Gates and Stiles 1 The location and details of construction of

gates and stiles should be shown on the drawings. Reference should be made to the NRA Road Construction Details wherever possible.

NG 309 Removing and Re-erecting Existing Fences and Gates 1 The requirements for the disposal of existing

timber fences are given in the Waste Management Acts, 1996-2005 and should be consulted if further information is required. Copper Chrome Arsenic and Creosote treated fences are classified as hazardous according to the EU regulations and should be disposed of using a Waste Collector that has the appropriate Waste Collection Permit allowing the transportation of hazardous materials.

2 The Environmental Protection Agency

should be contacted for further clarification on the disposal of waste timber.

NG 310 Environmental Noise Barriers General

1 Environmental barriers shall be designed to meet the requirements of I.S. EN 1793 and I.S. EN 1794 and in general shall follow best practice principles outlined in the UK Highways Agency Advice Note HA 65. The drawings should show methods of fixing barriers to structures, which ensure that gaps below the bottom edge of the barrier are avoided. Where it is proposed to attach an environmental barrier to a road bridge parapet, only those combinations which have

been satisfactorily tested under vehicle impact should be used.

2 The drawings should show the position and

height of the barrier and where applicable the position of gates, the fittings required and the proposals for treatment at gaps to maintain the acoustic attenuation. The length and position of barriers behind any gap should ensure that there is adequate deviation of the noise path from the carriageway to any property being protected by the barrier. It should be noted that additional width may be required on embankments to install panels behind the general fence line where gaps are required.

3 Gates or gaps should be provided at about

200m intervals to provide access for the maintenance of both the barrier and any planting behind the barrier. Where possible these

access points should be located to provide

access to any traffic control and communications equipment and be designed in accordance to Annex D of I.S. EN 1794-2: 2003.

4 The criteria for the provision of safety barrier,

clearzone and clearance required behind it for the various categories of safety barrier are contained in NRA TD 19 of the NRA DMRB and in IS EN 1317.

5 Where the design of environmental barriers is

to be provided to the Contractor, the details of the complete installation, including foundations, should be shown on the drawings.

6 Where the Contractor is required to design

environmental barriers, inter alia, the following information should be included in Appendix 3/1.

(i) Criteria for Design. These should be

based on the Environmental Impact Statement, Schedule of Commitments, and any modifications and conditions imposed by An Bord Pleanála shall be designed and approved by the Designer as advised by an acoustic specialist taking account of site specific characteristics.

(ii) Materials and finishes that will be

acceptable in the barrier:


January 2009 3

(a) In addition to aesthetic considerations, materials should be suitable for the location eg. Factors such as risk of recurring vandalism or fire hazards should be considered.

(b) It is recommended that a

galvanized coating and paint system is used for steel members. Improved atmospheric corrosion resistant steel should be excluded where the barrier is adjacent to the carriageway and likely to be affected by salt spray. NRA Design Manual for Roads and Bridges Vol 2 BD 7 should be referred to for specific requirements regarding its use.

(iii) Design Features. Specific design

features required, eg:

(a) Where steps between panels are permitted, what limitations in size or regularity are needed to ensure that the visual impact of the aesthetic design is not disrupted.

(b) Is a sawn finish for timber

satisfactory or should it be planed.

(c) What are the aesthetic requirements (eg. colour scheme, texture of finish).

7 If sample panels are required for approval

the Contractor should supply them 6 weeks prior to mass production.

8 The following are some of the points which

should be considered when the Designer’s design is checked:

(i) The calculations for wind load and

acoustic performance.

(ii) The quality of the materials proposed to be incorporated in the barrier, particularly those, if any, that are not included in the Specification.

(iii) That the structural grades of materials

used are in accordance with those quoted in the calculations.

(iv) Workmanship, particularly the method

of fixing. For timber, the nails should be of sufficient length to penetrate the

rails by not less than 30 mm and in such a manner that nails do not pass through more than one board.

(v) That the acoustic properties are

maintained by the avoidance of gaps, including gaps due to shrinkage or thermal movement.

(vi) Easy replacement of parts following

accidental or wilful damage. (vii) Security of components and nature of

materials used to discourage wilful damage.

(viii) Acoustic screens up to 3 m high are to be

treated as Category 0 structures; higher screens (barriers) are to be treated as Category 1 in accordance with NRA BD 2.

Aesthetic Approval

9 Wherever possible Appendix 3/1 should include aesthetic factors which the Contractor will need to take into account when formulating his design. This design should be submitted to the Employer's Representative for aesthetic review and comments provided in accordance with the Contract.

Post Foundation Test

10 Testing should be carried out at any barrier location where there is doubt about the resistance of the embedment material. The number and position of tests and the required performance criteria should be stated in Appendix 3/1. Care should be taken to ensure that design assumptions and the required frequency of tests are fully described to enable the Contractor to make adequate provision for testing. Testing should not be carried out when the ground is frozen.

11 Details of foundations should be shown on the

drawings. Acoustic Performance

12 All environmental noise barriers shall have a minmum insulation performance of B3 as classified in I.S. EN 1793 Part 2.

13 All absorptive barriers shall have a minimum

absorptive index of A3 as classified in I.S. EN 1793 Part 1.


January 2009 4

14 The weightings for the range of frequencies covered by the standard are representative of urban conditions; this slightly accentuates performance at lower frequencies where there is most variation between the absorptive materials used in proprietary systems.

Mechanical Performance 15 Mechanical performance and stability of

complete barrier systems shall be specified in accordance with IS EN 1794-1. This provides harmonised methods of indicating resistance to the following factors: wind loads, other applied (static) loads, self weight, impact of stones, impact of vehicles, snow expelled by snow ploughs.

16 General safety and environmental protection

features of complete barrier systems may be specified in accordance with IS EN 1794-2. This provides harmonised methods of describing the following aspects of performance: resistance to brush fire, danger of falling debris, environmental advantages and disadvantages of components, dimensions and other requirements for emergency exits, light reflection and transparency.

Employer’s Representative’s Check list 17 The Employer’s Representative should

satisfy himself of the following matters with regard to the design and construction of Environmental Barriers:-

Acoustic Design –

i. Has there been a robust noise study and study of noise mitigation by a competent and qualified acoustician or noise consultant?

ii. Has the study taken into account any variations from the Preliminary Road design in the EIS?

iii. Has a detailed design been undertaken that encompasses noise mitigation as an integral part of the design? E.g. Has the noise barrier been designed in tandem with the drainage and geometric design? Does the noise barrier affect sightlines? Is there sufficient ground behind the barrier to achieve adequate bearing capacity? (Minimum of 1m)

iv. Has a noise model been completed allowing the designers to simulate

traffic noise and assess reflections etc. v. Has a performance specification and

IS EN 14388 specification been completed by the designer as specified in series 300.

Manufacturer Approval i. Is the Manufacturer ISO 9001

accredited for the manufacture of the specific noise barrier panels or components

ii. Is the barrier manufactured under ISO controls in audited premises? No on site fabrication to be allowed.

iii. If timber noise barriers are used, are they from a sustainable source?

Structural Design: i. Has a full structural design of the noise

barrier structure and foundations been done and assessed by the contractor before approval.

ii. Has a sample panel been erected and aesthetic approval been received by the Employer?

iii. Has a competent structural engineer designed the noise barrier structure and foundations

iv. Has a BD 2 report, in accordance with Clause 310.4 of the NRA Specification for Road Works, been submitted to the NRA Structural Section prior to detailed design of the barriers and their foundations?

v. Has the design been based on the provision of adequate site information, setting out information, ground conditions and service information.

vi. Has a verge section showing services, containment barriers and the noise barrier position with provisional foundation been submitted with the structural design?

Treatment and Durability i. Have the durability requirements of

Clause 310.11 been fulfilled. ii. Has any timber been sawn on site?

iii. Is the barrier suitable for its requirements? E.g. Is it likely to be vandalised or subject to graffiti or fire damage?


January 2009 5

Drainage i. Have Environmental Noise Barriers

been installed on the top of a fill slope? What drainage option other than over the edge drainage has been selected?

NG 311 Preservation of Timber 1 The requirements for preservation of timber

for use in the Permanent Works are given in IS 435 : Part 1 Appendix A and B and should be consulted if further information is required. Accommodation works fencing should be to the same standard of preservation as Permanent Fencing and fencing that is to be painted should be treated similarly, although not with creosote. Extra supervision is usually essential to obtain the necessary standard required to keep maintenance costs low in the long term.

2 Inspection of the timber before preservative

treatment is of the utmost importance and arrangements should be made for this to be carried out for each scheme. The extent of permitted defects generally is defined in IS 435 : Part 1 as indicated in Clause 304.

3 The treatment specified in IS 435 : Part 1

will generally provide the full required level of penetration in properly seasoned wood. It is necessary to accept the assurance of the treater, embodied in a certificate of treatment which should be provided with each batch. In any other case a quality control agent from the NSAI should be contacted to ensure that all timber destined for the Scheme is inspected.

NG 312 Painting of Timber Fences, Gates, Stiles and Posts 1 Appendix 1/15 should contain the details of

accommodation works required in the Contract and should include the type and colour of paint required for fencing and gates. If preservation treatment is not required this should also be stated.

2 Requirements for the use of water borne

acrylic paints or alkyd-acrylic paint instead of oil based paints should be given in Appendix 3/1.

3 Paint containing non-toxic constituents shall be specified for use where the painted surfaces are accessible to animals.

NG 313 Concrete Fencing 1 Concrete fencing should generally not be used

for road side fencing adjacent to carriageways due to safety implications.

2 Any additional requirements for concrete

fencing or requirements if different from the requirements of Clause 313 should be included in Appendix 3/1.


January 2009 6

NG SAMPLE APPENDIX 3/1 : FENCING, GATES AND STILES [Note to compiler: Include here:] 1. Wooden Fencing, Gates and Stiles

(i) Preservation, Treatment / Painting [Only included when the compiler wishes to specify the preservative or painting specifically].

(ii) Trimming ground to regular level on fence line. [Location. Only included when necessary.] (iii) Details of additional stockproofing required [Location and details] (iv) Concrete surround to base of posts [Location. Included when the compiler wishes to specify

concrete footings for post and rail fencing]. (v) Requirements for timber if different from the requirements of Clause 304 (vi) Requirements for permanent fences if different from the requirements of sub-Clause 306.2

2. Temporary Fencing

(i) Requirements for temporary fencing if different from requirements of sub-Clause 302.1 and 303.1 (ii) Timing of removal of temporary fencing if different from sub-Clause 302.2 (iii) Requirements for any preservation treatment to temporary fencing [303.3]

3. General

(i) Requirements for bolts, screws and nuts if different from the requirements of sub-Clause 305.1 (ii) Requirements for joining permanent fencing to existing hedges, fences and to other structures if

different from the requirements of sub-Clause 306.1 (iii) Painting or Stock proofing requirements [306.3, 308.1, 312.4 and 312.5]

4. Concrete Fencing

(i) Any additional requirements for concrete fencing or requirements if different from the requirements of Clause 313.

5. Environmental Noise Barriers

(i) Schedule of locations, extents, heights and noise performace requirements of barriers to be provided, with cross reference to the drawings [310.1 and 310.8] and/or

(ii) Details of all noise design commitments to be achieved by the Contractor including where appropriate by reference to the Environmental Impact Statement, Schedule of Commitments, and any modifications and conditions imposed by An Bord Pleanála. [310.1 and 310.2]

(iii) Any requirements for barriers to be other than vertical [310.10 (iii)] (iv) Aesthetics or graffiti resistant requirments [310.12] (v) Any requirements for timber surfaces to be other than sawn [310.15] (vi) Any particular requirement for fittings [310.16] (vii) Requirement for post spacing, integration with safety barriers and/or the construction of a

sample panel [310.22] (viii) Details of any stepping of panels where permitted [3.22 (vi)] (ix) Requirements for gates [3.22 (x)] (x) Load Testing Requirements [3.10.29 (i)]


January 2009 7

5. Environmental Noise Barriers

Barrier Specification to I.S. EN 14388

Characteristic

Standard / Method Required Level Tested

Sound Absorption Airborne Sound Insulation Wind and Static Loading Self Weight Impact of Stones Safety in Collision Dynamic Load (Snow) Resistance to Brush fire Risk of Falling Debris Environmental Protection Means of Escape Light Reflectivity Transparency Combined with Safety Barrier

I.S.EN 1793-1:1998I.S.EN 1793-2:1998 I.S.EN 1794-1 I.S.EN 1794-1 I.S.EN 1794-1 I.S.EN 1794-1 I.S.EN 1794-1 I.S.EN 1794-2 I.S.EN 1794-2 I.S.EN 1794-2 I.S.EN 1794-2 I.S.EN 1794-2 I.S.EN 1794-2 I.S EN 1317-2

[>A3 where required] [B3 minimum]

[Pass] [Pass] [Pass]

[Not required] [Not Required]

[Class Required] [Required on elevated structures]

[Check Preservative] [Check frequency]

[Required for transparent] [Required for transparent]

[Performance as per IS EN 1317]

NG SAMPLE APPENDIX 3/2 : FENCING : NRA ROAD CONSTRUCTION DETAILS Clause No. Road Construction Detail Drg. No. 302.1 & 303.1 [ListRCD’s for acceptable types of temporary fence] 306.1 [ List RCD’s for acceptable types of permanent fence, and include RCD/300/8 for

tie-in to parapets] 306.2 RCD/300/1, 2, 2B 306.3 RCD/300/19 308.1 [List RCD’s for gate types required from RCD300/9 to 14] 308.2 [List RCD’s for required stile types 1 or 2 from RCD300/15 and 16] 313.1 [List RCD’s for acceptable types of concrete fence, RCD300/3, 6, 7 and/or 18]

Volume 2 Series NG 400 Notes for Guidance on the Specification for Road Works Safety Barriers and Pedestrian Guardrails

January 2009

SAFETY BARRIERS AND

PEDESTRIAN GUARDRAILS

Contents

Clause

Title

Page

NG 401 General ............................................................................................................................................ 1

NG 403 Durability ........................................................................................................................................ 1

NG 406 Installation ...................................................................................................................................... 1

NG 407 Site Testing ..................................................................................................................................... 2

NG 408 Anchorages and Attachment Systems for Surface Mounted Posts ............................................. 2

NG 410 Temporary Safety Barriers ............................................................................................................ 3

NG 411 Terminals and Transitions ............................................................................................................ 3

NG 412 Provision of Information, Training, Materials and Equipment .................................................. 3

NG 413 Pedestrian Guardrails .................................................................................................................... 3

NG Sample Appendices ......................................................................................................................... 4


January 2009 1

Safety Barriers and Pedestrian Guardrails

NG 401 General

1 The specialist responsible for the design

of the road furniture should identify the

performance characteristics required to

protect each hazard within the scheme.

A schedule of these factors should be

placed on the Drawings or within

Appendix 4/1.

2 Following the implementation of IS EN

1317-5 manufacturers have until

January 2011 to seek authorisation to

incorporate CE marking onto their

products, defining the performance

characteristics for which the product has

been certified. Due to the time that it

will take for all products to be certified, it

will continue to be permissible to sell

products which do not bear CE markings

up until January 2011. In the

intervening period products are required

either to bear the appropriate CE

marking or for copies of the same

certification application details that are

required under IS EN 1317-5 to be

submitted to the Employer’s

Representative to demonstrate

compliance. Reference should be made to

IS EN 1317-5 to establish the full

requirements of the submission, which

include details of the system, its

components, constituent materials,

performance testing, production controls,

product traceability, durability

assessment, applicable site conditions,

installation and site testing

requirements.

3 Certification is granted to a particular

manufacturer for a specific product. If a

supplier sources the same product from

more than one manufacturer, then

separate certification is required for each

source.

4 The positioning of a safety barrier can be

affected by the location of drains, cables

etc within the verge or central reserve.

5 In many cases there will not be an

optimum position for the safety barrier

and a wide range of Set-backs could be

used. The specialist responsible for the

design of the road furniture, however,

should always identify one location for

the safety barrier and state this in

Appendix 4/1. Care should be taken to

ensure that the Set-back identified does

not unduly restrict the selection of safety

barrier. If the Contractor proposes a

safety barrier which requires a different

Set-back, the Contractor’s specialists

must undertake any redesign required in

order that this barrier can be installed

satisfactorily.

NG 403 Durability

1 One of the requirements for certification

under IS EN1317-5 is that the

manufacturer submits a formal

assessment of the anticipated durability

of the product. A copy of this assessment

should be provided with the product and

should be reviewed by the Employer’s

Representative relative to the stated

durability requirements.

NG 406 Installation

Installation Description

1 It is a requirement of IS EN 1317-5 that

detailed descriptions of the installation

requirements are provided by the

manufacturer, and it is very important

that these are readily available to all

relevant parties on site. These must be

carefully adhered to, to ensure that the

barrier is installed on site in the same

manner as when it was certified.

Handling and Storage

2 Handling and storage arrangements

should be appropriate to the materials

concerned. Requirements for the most

common materials, coated steel and

precast concrete are referenced

specifically, but the general requirement

applies equally to other materials.

Layout

3 The intended location of the safety

barriers and pedestrian guardrails

should be defined by the specialists

responsible for the design of the road

furniture in accordance with the

requirements and guidance contained in

the NRA DMRB and general good design.

The specification then permits a

maximum deviation from the designed

location in order to achieve satisfactory

performance and appearance.

Concrete Foundations and Anchor Blocks

4 Concrete foundations and anchor blocks

perform a vital component of the barrier


January 2009 2

system and must be constructed

appropriately in accordance with the

system manufacturer’s requirements and

general good practice. In particular of

concrete foundations are placed within

filter material it is essential for the

correct function of both the drain and the

foundation that concrete grout loss is

prevented.

Cutting of components

5 The layout of barriers needs to be

considered in the full knowledge of both

the hazards to be protected and other

obstacles to the correct installation of the

barrier. It is not acceptable simply to

select a system and then make site

adjustments to fit it the particular

circumstances encountered on site. Such

an approach will almost certainly

compromise the performance of the

barrier system. Where special, non-

standard components are required these

should be identified prior to ordering of

the barrier system, appropriate details

agreed with the manufacturer and

special components prepared in the

factory.

NG 407 Site Testing

Anchorages in Drilled Holes

1 The anchorage test results should be

included with the as-built records.

System

2 The manufacturer should provide a

schedule of testing for the safety barrier

system to demonstrate its correct

installation. This should be sufficiently

detailed to provide a high degree of

assurance that the barrier will perform

in a satisfactory manner.

Ground Conditions

3 All safety barriers ultimately transfer

the impact force into the ground and as

such rely on ground conditions being

compatible with the system design in

order to perform to their designed

criteria. It is vital that the performance

of a safety barrier is not compromised in

service through the provision of

inadequate ground conditions. IS EN

1317-5 requires that the manufacturer

provides a description of the ground

conditions required for the system to

perform as certified. Consequently,

testing shall be undertaken to

demonstrate that the ground conditions

are compatible with the selected barrier

system. The nature of the testing will

obviously depend on the type and form of

the barrier and it is therefore important

that the safety barrier manufacturer

specifies the testing.

4 Some barrier systems include knock

down posts which are held in post

sockets, with the intention that the posts

be replaced within the same socket

following impact. Experience has shown

that the most common ground conditions

related failure is for these sockets to

become dislodged or mis-aligned during

impact, such that they are no longer

suitable to receive the replacement post.

To overcome this, a requirement has

been included to demonstrate that the

sockets remain serviceable following

collapse of the post.

5 The interaction of a particular barrier

system with the particular ground

conditions at an individual location

requires specific assessment. This is

addressed by the requirement for an

independent Chartered Engineer to

certify the appropriateness of the

proposed site testing regime for the

particular barrier system in the

particular ground conditions. In order

for this independent certification

procedure to be of value it is essential

that the Independent Engineer is listed

as a specialist in the contract schedule

and required to provide at least €2M

Professional Indemnity Insurance cover.

NG 408 Anchorages and

Attachment Systems for Surface

Mounted Posts

1 Many barrier systems rely on anchorage

details, be it of tensioned beams,

tensioned ropes or attachment systems

for surface mounted posts. Where the

barrier system relies on a tensioned

beam or rope, which will inevitable lose

tension following an impact, it is

essential that the length of barrier which

is temporarily unserviceable is kept to a

reasonable minimum. The specified

intermediate anchorage requirements

are intended to set a minimum criteria in

this regard.

2 In most cases the anchorage details will

form part of the certified barrier system,

while in others, particularly in the case

of surface mounted posts, alternative

anchorage details may be permissible

provided they meet certain performance


January 2009 3

criteria. Anchorages for securing surface

mounted posts which utilise drilled holes

have been known to fail due to either a

lack of cleanliness of the hole or the

excess tolerance in the size of the hole.

The manufacturer of the anchorages

should provide details of the maximum

tolerances permitted and the evidence

should be submitted to the Employer’s

Representative. Such evidence should

show that the anchorages perform

satisfactorily when installed in holes

having these tolerances. With the

introduction bonded anchorage details it

is especially important that the

manufacture provides full details of the

system and its correct installation and

testing.

NG 410 Temporary Safety

Barriers

1 Temporary safety barriers can be

provided by:

(i) The Contractor as part of

Temporary Works and remaining

his property.

(ii) The Contractor but becoming the

property of the Road Authority on

completion of the Works.

(iii) The Road Authority for the

Contractor’s use during the Works.

Appendix 4/1 should state which of the

above applies, and where appropriate,

details of locations from which the

barriers can be collected and/or returned.

NG 411 Terminals and

Transitions

1 ENV 1317-4, which relates to Terminals

and Transitions, has not been formally

implemented, but a sufficient number of

terminal details have now been

developed and tested in accordance with

this voluntary standard that is now

considered appropriate for terminals to

be specified in these terms. In particular

full height terminals have been

developed and tested in accordance with

this standard that offer significant safety

benefits over ramped terminal on the

upstream ends of barriers. The specialist

responsible for the design of the road

furniture should identify the

performance characteristics required for

each specific barrier terminal location.

A schedule of these factors should be

placed on the Drawings or within

Appendix 4/3

NG 412 Provision of Information,

Training, Materials and Equipment

1 The Employer or other body which will

be responsible for the maintenance of the

barrier may require the provision of user

installation/maintenance manuals and a

stock of materials and equipment to be

retained in store for maintenance

purposes. Training of maintenance staff

may also be required for safety barriers

which have not previously been installed

on the road network. Where this is the

case, the compiler should provide a

schedule in Appendix 4/4 indicating

which materials are required as well the

barrier types for which manuals and

training are not required.

NG 413 Pedestrian Guardrails

1 The type and the location of pedestrian

guardrails should be described in

Appendix 4/2.


January 2009 4

NG SAMPLE APPENDIX 4/1: SAFETY BARRIERS

Sheet 1

1. The locations of safety barriers are shown on Drawings Nos ……………………… [generally the 1:500 or 1:1000 Site Plans].

2. The performance criteria for the safety barriers are shown on the above drawings/scheduled in the

following table. [Delete as appropriate.]

3. Schedule of Safety Barriers

Barrier Ref

No

Start

Chainage of

LoN

End

Chainage of

LoN

Hazard Information Barrier

Type

Single/

Double

Sided

Safety Barrier Performance Criteria

Hazard

Descriptio

n

Hazard

Chainag

e

Location Drawing

Reference

Containme

nt Level

Impact

Severit

y Level

Workin

g Width

Set-

back

[Safety barriers with different performance criteria within a continuous length should be split into sections such that the performance criteria for each section are unique. Alternatively, the safety barriers on a scheme may be assigned categories each of which define the performance criteria for that type of fence. The table should identify the performance criteria for each section of safety barrier at each barrier location or of each barrier type.

Where a Length of Need comprises many short lengths of barrier with different performance criteria (for example at lighting columns in a central reserve), standard details should be provided on the Drawings and each combination of barriers given a reference. This barrier reference should then be entered in the table once only for each length of combined barrier. There is no need to indicate each length of each type of safety barrier but performance criteria should be stated for all barriers in the combination (e.g. W6/W4/W3, H2/N2 etc.).

Barrier types will normally be indicated where:

1. the In-situ Concrete Barrier is to be used; or

2. there are exceptional and overriding reasons for specifying a particular barrier type.

In the latter case, the agreement of the National Roads Authority is required before particular barrier types are included in the Schedule of Safety Barriers.

The Compiler should indicate the Working Width required as an absolute value (e.g. W6) and not as a range of acceptable values.

The Start and Finish Chainages shall be derived from the Approach and Departure Lengths which have been determined in accordance with NRA TD 19 and the Designer’s risk assessment of the level of protection required.]

4. Temporary Safety Barriers

[Note to compiler: State here:]

(i) Who is to provide temporary safety barriers.

(ii) Location for removal of temporary safety barriers on completion of the Works.

(iii) Location(s) from which temporary safety barriers are to be collected and returned by the

Contractor if provided by the Employer.

(iv) Who is to own the temporary safety barriers on completion of the Works.


January 2009 5

5. Other Details [to be included as required]

(a) Any special details which are shown on the Drawings and have been designed by the

specialist with responsibility for the design of the road furniture.

(b) Any special requirements for setting out details.

(c) Details of testing requirements and frequency of testing not covered already within the

Specification.

(d) Any special testing requirements for anchorages in drilled holes.

NG SAMPLE APPENDIX 4/2: PEDESTRIAN GUARDRAILS

[Note to compiler: Details should be given here of locations and type of pedestrian guardrails required. Cross-reference may be made to the drawings where appropriate.]

NG SAMPLE APPENDIX 4/3: Safety Barrier Terminals

[Note to compiler: . Include here:]

1. The locations of safety barrier terminals are shown on Drawings Nos ………………………

[generally the 1:500 or 1:1000 Site Plans].

2. The performance criteria for the safety barrier terminals are shown on the above

drawings/scheduled in the following table. [Delete as appropriate.]

3. Schedule of Safety Barrier Terminals

Barrier

Ref

No

Upstream Terminal Downstream Terminal

Perform-

ance Class

P(1,4)

Impact

Severity

Level

Permanent

Lateral

Displacement

Class

Exit Box

Class

Z(1,2,3,4)

Perform-

ance Class

Impact

Severity

Level

Permanent

Lateral

Displacement

Class

Exit Box

Class

Z(1,2,3,4)

Ramp

down

Y/N

Flared

Y/N

X(1,2,3) Y(1,2,3,4)

Each length of permanent safety barrier listed in Appendix 4/1 should be cross referenced here providing details of both the upstream and downstream terminal performance requirements requirements.


January 2009 6

NG SAMPLE APPENDIX 4/4: Safety Barrier Maintenance

[Note to compiler: Where required by the Employer, the compiler should include a schedule of:

(i) Installation and/or maintenance manuals for each barrier and terminal type;

(ii) Any materials which are to be provided for maintenance purposes;

(iii) Special items of equipment etc required for the installation, testing, maintenance and demolition of the safety barriers and terminals.

The schedule should take account of the barrier and terminal types specified (if any) and the overall length of each barrier type. The schedule should generally include sufficient length of safety barrier (and components) to allow for the replacement of at least 50m of each safety barrier type or 5% of the overall length of each barrier type installed on that contract. At least one terminal and transition of each type should also be provided. However, reference should be made to the National Roads Authority and the body responsible for maintaining the barriers for replacement materials requirements. Manuals and training should normally be provided for all safety barriers.

Where a scheme is anticipated to be maintained by more than one maintenance body, the schedule should identify which barriers and terminals are provided to the individual maintenance depots. The schedule should also state where the barriers, terminals and components should be delivered to. An entry in the schedule for the safety barrier to be provided to a particular maintenance depot may be as follows.]

Barrier Materials for Maintenance

Barrier Information Barrier Quantity to be Supplied for

Maintenance

Provision of Information,

Training etc.

Address for

Delivery

Barrier

Type

Containment

Rating

Impact

Severity

Working

Width

Barrier

Length

Transitions Other Items Manuals Training

N/A N2 A W6 55m 1 No. (N2-

H2)

1 No. set of

tools for

installation

2 No. 1 No. course for

5 operatives

XXX Depot XXX

Terminal Materials for Maintenance

Terminal Information Terminals Quantity to be

Supplied for Maintenance

Provision of Information,

Training etc

Address for

Delivery

Terminal

Type

Performance

Class

P(1,4)

Impact

Severity

Level

Permanent Lateral

Displacement Class

Exit Box

Class

Z(1,2,3,4)

Number Other Items Manuals Training

X(1,2,3) Y(1,2,3,4)

N/A P4 A X2 Y2 Z1 5 1 No. set of

tools for

installation

2 No. 1 No. course

for 5

operatives

XXX Depot XXX


January 2009 7

NG SAMPLE APPENDIX 4/5: Anti-Glare Screens


The locations of anti-glare screens are shown on Drawings Nos ……………………… [generally the 1:500 or 1:1000 Site Plans].

[Include location details, preferably by chainage reference together with any specific performance requirements here.]

NG SAMPLE APPENDIX 4/6 : SAFETY BARRIERS : NRA ROAD CONSTRUCTION

DETAILS

[Note to Compiler: List the relevant 400 Series RCD’s, ensuring to include those listed below where the scope of works includes concrete barriers]

Clause No. Road Construction Detail Drg. No.

409.1 RCD/400/2, 3-5, and 7.

411.3 RCD/400/3.

Volume 1 Series NG 500 NRA Notes for Guidance on the Specification for Road Works Drainage & Service Ducts

October 2009 1

National Roads Authority

Manual of Contract Documents

for Road Works

(NRA MCDRW)

ERRATUM No. 1 (October 2009) to

NRA Notes for Guidance on the Specification for

Road Works Series 500 – Drainage & Service

Ducts Dated January 2009

The NRA Notes for Guidance on the Specification for Road Works (NRA MCDRW), Series NG 500 –

Drainage & Service Ducts, dated January 2009 is amended as follows:-

1. Page 3, Clause NG 507.2

Delete “600mm” and replace with “600mm x 750mm.”


Insert “a minimum of” before “D400”.


After the last line insert “For further guidance see HA 104.”

4. Page 4, Clause NG 513

Delete “it should be specified in Appendix 5/1” and replace with “any proposal to amend the

Specification shall be agreed with NRA structures department.”


Delete “(Table 5/8)” and replace with “(Table 5/9)”.


Delete “Table 5/8” and replace with “Table 5/9”.

7. Page 9, Sample Appendix 5/1: Drainage Requirements, Item (xxi)

After “and frames” insert “including grades, depths of frames, hinge and locking

requirements, etc”

8. Page 9, Sample Appendix 5/1: Drainage Requirements, Item (xxi)

After the last line insert “Refer to HA 104 for further details.”

9. Page 10, Sample Appendix 5/1: Drainage Requirements, Item (xxxv)

Delete Item (xxxv) and re-number remainder of list.


October 2009 2

10. This Erratum shall be implemented forthwith.

11. All technical enquiries or comments on this Erratum or the NRA Series 500 should be sent in

writing to:

Specifications Section

National Roads Authority

St. Martins House

Waterloo Road

Dublin 4

Instructions For Use The following version of the Manual of Contract Documents for Road Works (NRA MCDRW)

incorporates the above changes.


January 2009

DDDDRAINAGE AND RAINAGE AND RAINAGE AND RAINAGE AND SSSSERVICE ERVICE ERVICE ERVICE DDDDUCTUCTUCTUCTSSSS

Contents

ClauseClauseClauseClause

TitleTitleTitleTitle

PagePagePagePage

NG 501 Pipes for Drainage and for Service Ducts ................................................................1

NG 502 Excavation for Pipes and Chambers .............................................................................................2

NG 503 Bedding, Laying and Surrounding of Pipes ................................................................2

NG 504 Jointing of Pipes .............................................................................................................................2

NG 505 Backfilling of Trenches and Filter Drains ................................................................2

NG 507 Chambers ................................................................................................................................3

NG 508 Gullies and Pipe Junctions ................................................................................................3

NG 509 Testing and Cleaning ................................................................................................3

NG 510 Surface Water Channels and Drainage Channel Blocks .............................................................4

NG 511 Land Drains 4

NG 512 Backfilling to Pipe Bays and Verges on Bridges ................................................................4

NG 513 Permeable Backing to Earth Retaining Structures ................................................................4

NG 514 Fin Drains 4

NG 515 Narrow Filter Drains................................................................................................ 6

NG 516 Combined Drainage and Kerb Systems ................................................................ 7

NG 517 Linear Drainage Channel Systems ...............................................................................................7

NG 518 Not Used ................................................................................................................................

NG 519 Geotextiles for Filter Drains ................................................................................................8

NG 520 Attenuation 8

NG Sample Appendices ................................................................................................ 9


January 2009 1

Drainage and Service DuctsDrainage and Service DuctsDrainage and Service DuctsDrainage and Service Ducts NG 501NG 501NG 501NG 501 Pipes for Drainage and for Pipes for Drainage and for Pipes for Drainage and for Pipes for Drainage and for

Service DuctsService DuctsService DuctsService Ducts 1111 Pipes can be made of materials that deflect

relatively little under load before cracking (rigid pipes) or of materials that will tolerate large deflections under load before inward buckling occurs (flexible pipes). Flexible joints enable either type of pipe to take up differential settlement within the ground.

2222 The Specification includes a wide range of

pipe materials. The Contractor should normally be offered in Appendix 5/1 the full selection of alternative pipe and bedding combinations as detailed in the NRA Road Construction Details for pipes up to 900 mm diameter. Advice on the determination of alternative pipe and bedding combinations can be obtained in the U.K. Highways DMRB Note HA 40. The required pipe stiffness and impact resistance for plastics pipes should be specified in Appendix 5/1. The requirements will normally be:

(i) ultimate pipe stiffness (STES) in excess of 1400 N/m2 when tested in accordance with BS 4962; and

(ii) resistance to impact complying with BS 4962 except that the striker used in the test shall have a mass of 1 kg and a 25 mm hemispherical radius.

Drains exceeding 900mm diameter should be designed as structures. A box culvert should not be specified where either a (concrete) box culvert or a (corrugated steel) piped culvert would be technically acceptable. Wherever possible, the Contractor should be offered a choice and the NRA consulted during the scheme preparation. Box culverts, piped culverts (and other drains) of clear span or internal diameter exceeding 2000mm are structures subject to NRA technical approval. Care should be taken to ensure that there are no inconsistencies between any specific requirements for a particular drain and the general requirements of the 500 Series. Where necessary,

Contract-specific amendments should be included in Appendix 0/1 or 0/2 to achieve consistency.

Most of the pipes included in the Specification will normally be satisfactory from the hydraulic flow capacity factor. However some products, especially corrugated pipes, can vary from the norm (e.g. clay/concrete) and between manufacturers. The effect of a rougher pipe should be considered on the system as a whole and not just on the length in question. A pipe which is not acceptable on a straight exchange basis may be acceptable if diameters on adjacent lengths are adjusted. Appendix 5/1 should provide the basis on which the Contractor is to submit his proposals for pipe types and makes.

3333 Any tendency to attack by acidic ground

water or sulphates present in the backfill or the ground should be taken into account when the use of concrete, steel or iron pipes is being considered for inclusion in the schedule of acceptable alternatives in Appendix 5/1. When acid soils (pH less than 6.5) are encountered expert advice should be sought. There is some evidence that pipes made of sulphate-resisting cement will tolerate a pH as low as 6.0. The limiting value may be reduced to pH 5.5 when a bitumen coating is applied to the pipe. Sulphate attack on concrete is dealt with in Building Research Establishment Special Digest 1:2005. Protection to the lower third of the inside of corrugated steel piped culverts by means of an asphalt or in situ concrete coating will be required where stones and rocks are likely to be carried by the flow. Iron pipes are treated with a pitch or bitumen coating and have high durability in most soils, but when acid conditions are known to be present the additional protection of a polyethylene sleeve is desirable. Clay, pitch fibre and UPVC pipes are resistant to a wide range of groundwater chemicals.

4444 For corrugated steel pipes of lock seam

fabrication with a diameter not exceeding 900mm, specification of metal thickness should be given in Appendix 5/1. The tables


January 2009 2

issued by manufacturers recommend thicknesses corresponding to the diameter and depth of fill above the pipe.

5555 Plastics pipes may deteriorate after a long

period in sunlight. Where pipes have been manufactured and stored before being delivered to the Site, it may be necessary for the Contractor to cover them until they are installed.

6666 Any individual cable duct under a road may

have to accept a power or a communication cable although these are normally placed in separate ducts. Certain pipe materials have been excluded from the Specification for use as ducts because cables cannot be readily drawn through them. Clause NG 1421 gives further information on the use of ducts for electrical work. Ducts should be scheduled in a similar way to pipes in Appendix 5/2. Any special requirements of Statutory Undertakers etc. should be stated clearly.

NG 502NG 502NG 502NG 502 Excavation for Pipes and Excavation for Pipes and Excavation for Pipes and Excavation for Pipes and ChambersChambersChambersChambers

1111 In the preparation of Appendix 6/3, it may be

considered appropriate to permit battering of slopes where this would not affect adversely the permanent Works or the basis of structural design of the pipe/trench.

2222 In the event of excavation to a greater depth

than necessary the Contractor is obliged to reinstate. The use of concrete to remedy excess excavation should be restricted to areas where compaction is impracticable. Where the floor of the trench passes through a localised area of disturbed and uncompacted soil or softened clay further excavation and replacement with appropriate material may be required to allow pipe laying to proceed.

3333 Where pipes are to be installed beneath

heavily trafficked existing roads, etc, where it is undesirable that the existing ground surface should be disturbed, consideration should always be given to the possibility of inserting the pipe by suitable thrustboring or jacking processes.

NG 503NG 503NG 503NG 503 Bedding, Laying and Bedding, Laying and Bedding, Laying and Bedding, Laying and Surrounding of PipesSurrounding of PipesSurrounding of PipesSurrounding of Pipes

1111 Pipe bedding material should be readily

obtainable since a wide grading envelope is permitted including most gradings complying with IS EN 12620. It needs to flow readily and compact uniformly, thus a low coefficient of uniformity is necessary. In order to make savings in coarser granular materials a sand bed may be adopted. Surround to pipes should be in bedding material as appropriate to the alternatives shown in the NRA Road Construction Details. In some situations a lower provision of acceptable material (class 8) may be satisfactory.

2222 A distinction is to be made between the

requirements of bedding, haunching and surrounding and those of backfilling. The former comprise all operations of trench fill up to a level 300 mm above the top of the barrel of the pipe. Backfilling constitutes the remaining operations up to ground level in verges and open ground and up to formation or sub-formation level under carriageways. Work above formation level constitutes construction or reinstatement of the pavement (see NG 706).

3333 Concrete surround should be used

exceptionally, e.g. for protection of pipes against mechanical damage from subsequent operations after construction of the pipeline and where remedial measures due to over excavation are required. Protection of existing pipes where necessary may take the form of a concrete arch or slab above the pipe.

NG 504NG 504NG 504NG 504 Jointing of PipesJointing of PipesJointing of PipesJointing of Pipes 1111 Pipe joints for surface water drains, unlike

foul drains, do not always have to be completely watertight. Small amounts of seepage as allowed in sub-Clause 509.7 can be tolerated particularly where pipes are laid in cuttings or below the water table. However, joints in pipes in soils that are predominantly fine sands or coarse silts should have watertight joints to prevent soil particles passing through the joint into the pipe leaving voids on the outside of the pipe. Where fine sands or coarse silts might be a problem but the more expensive rubber ring flexible joint is unwarranted, consideration can be given to certain proprietary wrap type


January 2009 3 (including Erratum No. 1 October 2009)

joints that are available. These may also be specified where root penetration needs to be prevented. Requirements should be given in Appendix 5/1.

2222 Most watertight joints will be flexible joints

although rigid joints are occasionally used on clay pipes. In and under embankments, or if differential settlement is expected in compressible soils subject to non-uniform loading, then flexible joints and (except for pipes below the water table laid in non-erodible soils) watertight joints should be specified. The maximum length of pipe between flexible joints may have to be limited where considerable movement is expected. The limits of the exclusions should be shown in Appendix 5/1.

NG 505NG 505NG 505NG 505 Backfilling of Trenches and Backfilling of Trenches and Backfilling of Trenches and Backfilling of Trenches and

Filter DrainsFilter DrainsFilter DrainsFilter Drains 1111 When soils to be drained require a particular

grading of filter aggregate it should be specified in Appendix 5/1. Guidance on the design of filter materials is given in Transport Research Laboratory Report LR 346. The filter material in Table 5/5 is intended for use where the drain is designed to intercept surface water flowing to the pipe. Grit from the carriageway may slowly block this type of filter and it may require cleaning or replacement periodically. Where filter drains are located close to carriageways and are likely to be overrun by traffic, methods of preventing "stone scatter" should be considered.

NG 507NG 507NG 507NG 507 ChambersChambersChambersChambers 1111 Concrete chambers, precast or cast in situ

against forms, do not require strengthening with additional concrete surround. Access shafts in precast concrete should be strengthened, however, as a protection against loads from backfilling operations. Brick chambers, including shafts do not need a concrete surround for strengthening. It may however be necessary to backfill with concrete where space is insufficient to permit compaction of one of the earthworks acceptable materials. Inspection chambers are those that can be maintained from the surface and do not need to be entered. The types of brick to be used for brick chambers, and beneath chamber frames, in normal circumstances are specified in Clause 2406.

Where a different type of brick is required this should be described in Appendix 24/1. Any brickwork upon which chamber frames are seated shall be properly constructed.

2222 Safety precautions require that chamber covers have a minimum opening of 600 mm x 750mm diameter where personnel may be required to enter completely. In carriageways, hard shoulders and verges, chamber covers, frames and gratings should be a minimum of Class D400. For further guidance see HA 104.

NG 508NG 508NG 508NG 508 Gullies and Pipe JunctionsGullies and Pipe JunctionsGullies and Pipe JunctionsGullies and Pipe Junctions 1111 Trapped gullies are essential only on

connections to combined or foul drains in urban areas or on roads where traps are regularly and frequently emptied. In terms of pollution there is little difference in water quality between the flow through trapped or untrapped gullies although a trapped gully would normally retain the contents of a vehicle's sump in the event of an accident.

2222 Where concrete trapped gullies are cast in

situ using a permanent plastic mould, the part forming the trap should be equal in all respects to that of precast concrete or clay gullies.

3333 Any brickwork upon which gully frames are

seated should be properly constructed. 4444 Dished gullies should not be used in areas

trafficked by cyclists or pedestrians. NG 509NG 509NG 509NG 509 Testing and CleaningTesting and CleaningTesting and CleaningTesting and Cleaning 1111 Requirements for drain testing should be

specified in Appendix 1/5. The air test does not indicate the location of any large leaks that may be present. A water test may follow the failure of an air test.

2222 Fall of the test water level may be due to one

or more of the following causes:

(i) Absorption by pipes or joints.

(ii) Excessive sweating of pipes or joints.

(iii) Leakage from defective pipes or joints or plugs.

(iv) Trapped air.



Some pipes absorb more water or trap more air at the joints than others. Allowance should be made for this by adding water to maintain the test head for appropriate periods. While the aim should be to commence the test period proper 2 hours after filling, the appropriate period may best be determined by conferring with the pipe manufacturers.

3333 Closed circuit television (CCTV) inspection

is a suitable alternative to the mandrel test and should always be used on foul sewers and connections to sewers. To avoid subsequent disputes it is essential to liaise with the drainage authority when checking connections to existing sewers to ensure acceptability of the work and to determine the extent of the survey required on existing sewers.

4444 The test for partly watertight joints must be carried out before the pipe is laid because the water escaping from the joint has to be measured. The purpose of the test is to prove that the joint does not leak so excessively as to cause piping in any granular surround.

NG 510NG 510NG 510NG 510 Surface Water Channels Surface Water Channels Surface Water Channels Surface Water Channels and and and and Drainage Channel Drainage Channel Drainage Channel Drainage Channel BlocksBlocksBlocksBlocks

1111 Requirements for these should be included

in Appendix 5/3 and be compatible with the NRA Road Construction Details.

NG 511NG 511NG 511NG 511 Land DrainsLand DrainsLand DrainsLand Drains 1111 The Works are likely to disturb and render

ineffective existing drainage systems in adjoining land; it will therefore be necessary for the Contractor to carry out without delay any such temporary or permanent remedial works as may be described in Appendix 5/1. The designer should consider whether the most suitable arrangement for land drainage remedial works is to provide a system of drainage of land adjoining the road separate from the road drainage so that the reinstatement of the system is on the owner’s land and the matter falls to be dealt with as a matter of accommodation works. When such arrangements are not practicable or the cost is excessive, the existing land drainage system should be linked with the drainage system of the road.

NG 512NG 512NG 512NG 512 Backfilling to Pipe Bays Backfilling to Pipe Bays Backfilling to Pipe Bays Backfilling to Pipe Bays and Verges on Bridgesand Verges on Bridgesand Verges on Bridgesand Verges on Bridges

1111 Any special filling material, e.g. lightweight

material, should be described by providing additional information on the Drawings, cross-referenced in Appendix 5/1.

NG 513NG 513NG 513NG 513 Permeable Backing to Permeable Backing to Permeable Backing to Permeable Backing to

Earth Retaining StructuresEarth Retaining StructuresEarth Retaining StructuresEarth Retaining Structures 1111 For granular backing, where the designer

wants a filter compatible with a particular type of filling he wwwwishes to be employed adjacent to the structure, any proposal to amend the Specification shall be agreed with NRA structures department.

2222 Fin drains are not allowed as permeable

backing to structures because it is not yet possible to demonstrate that any of them will have the required design life of 120 years.

NG 514NG 514NG 514NG 514 Fin Drains Fin Drains Fin Drains Fin Drains 1111 These consist of a core which will allow the

free drainage of water entering through geotextile filters on the outside of the core. The core may consist of nets, webs, grids or preformed plastic sheets or strips. Some restrict entry through one side or confine water entering to part of the cross-sectional area of the core. Any such restrictions should be taken into account in assessing the flow characteristics of the drain. Fin drains are intended to be used for subsurface drainage, as shown in the RCD’s, to remove and keep out water from the road structure. They are provided to remove surface infiltration from the pavement layers, to prevent infiltration from shoulders, medians and verges into the pavement, and sometimes to cut off shallow groundwater seepage. They thus act as low-capacity filter drains. In normal circumstances, the Contractor should be permitted the choice of any of the types shown in the RCD’s. If however, for engineering reasons, exclusion of a particular type is required, this should be stated in Appendix 5/4. The minimum values for mechanical and hydraulic properties given in Clause 514 are intended for this particular usage and may not be relevant to fin drains used elsewhere. Additionally, the Clause requires specification of the pore size distribution of the geotextile and the inflow


January 2009 5

and discharge capacity of the fin drain determined for the site conditions.

2222 The pore size for the geotextile should be

selected using filtration criteria to be compatible with the adjacent soil or construction layer in order to prevent the occurrence of piping. The following soil retention criteria may be used in determining O90. Other criteria are available.

Woven and Meltbonded Woven and Meltbonded Woven and Meltbonded Woven and Meltbonded GeotextilesGeotextilesGeotextilesGeotextiles

Needle Needle Needle Needle punched punched punched punched GeotextilesGeotextilesGeotextilesGeotextiles

1 to 5 O90/d50 = 1 to O90/d50 = 3

O90/d50 = 4 to O90/d50 = 6

> 5 O90/d90 < 1 to O90/d50 <3

O90/d90 < 1.8 to O90/d50 < 6

dn = n% size in base soil (n% is finer) O90 = 90% opening (pore) size of geotextile

(90% of openings are smaller)

In general, it will be sufficient to specify only the maximum value of O90 that will satisfactorily retain the adjacent soil particles as the minimum O90 size will be governed by the permeability requirements in sub-Clause 514.4. Geotextiles will usually be in contact with variable surface soil deposits, as well as the more uniform materials composing the pavement, and great accuracy in specification may not therefore be feasible. The finest O90 relevant to the various soil deposits likely to be encountered may be specified. An O90 value of 1 mm should be considered as the upper limit even with large grained soils. With cohesive fine grained soils such as clays the use of the above criteria will result in such small pore sizes that sufficient water flow cannot be obtained. In such cases the cohesion of the soil particles themselves is relied upon to prevent piping and a maximum O90 value of 250 microns may be chosen. Dispersive silts can present particular problems and in these cases the O90 value may be less than 250 microns: however, the value to be specified should be carefully considered in order both to avoid piping and to ensure sufficient long-term flow. The British Standard test to determine pore sizes (sub- Clause 514.4) is inappropriate for some geotextiles, such as needle-punched materials, if more than 20% of the glass beads are retained in the fabric.

Pore sizes must then be obtained by other means such as wet sieving.

3 3 3 3 Sub-Clause 4(v) of Clause 514 requires the

designer to specify the flow rate normal to the geotextile wrapping to the filter drain. The specified flow rate should incorporate a margin of safety to allow for the impeded flow due to the adjacent core of the fin drain (or the filter material in a narrow filter drain) as described in sub-Clause 13 of Clause 514. It should also incorporate a substantial margin to allow for the reduction of flow with time due to clogging. The long- term flow through a geotextile in contact with the coarse gravel may not differ significantly from the short-term flow measured in the standard test. In contrast, the long term flow through a geotextile in contact with a dispersive silt may be one thousand times smaller than the short-term flow. There is some evidence that chemical or biological leachates may also cause severe clogging. Different rates of flow into the two sides of the fin drain may be specified, for example, if the water flows from the verges are expected to be very different to those from the pavement structure. A value of 10 litres/m2/sec is suggested for use against the unbound mixture for subbase and capping specified in Series 600 and 800. Very much smaller values are adequate for soils and backfills other than coarse gravels, and possibly dispersive silts or contaminated sites. It should be appreciated that, because of such long-term effects, these flow rates should not be used to determine the in-plane design requirements of the fin drain.

4 4 4 4 Sub-Clause 5 of Clause 514 requires specification of the in-plane flow capacity of the fin drain. This design capacity should allow for infiltration through the pavement and verges and any other source of ground water ingress. Until more accurate means of establishing infiltration rates through the pavement are available a value not less than the mean intensity of a one year 2 hour rainfall should be assumed. The fin drain Type 5 of RCD/500/32 acts both as a filter drain and a carrier pipe. Thus in-plane flow must be specified for flow both along the drain parallel to the road edge and near-vertically down the drain. For all other drain types, only near-vertical downward flow need be specified. Fin drain Type 10 in RCD/500/35 should either have an impermeable side or be covered by an impermeable membrane unless no



significant blocking of the core will occur during the slip-forming of the channel. Fin drains are normally laid at constant depth below the carriageway and their gradient will therefore follow that of the road. Drainage capacities should be designed for these gradients and outfall lengths determined accordingly. For drain Type 5 the flow rates that are stated in Appendix 5/4 should be the capacity required linearly extrapolated to the standard gradients in Table 5/8. Where fin drains utilise a pipe, capacities may be obtained from hydraulic tables and the required diameter specified.

5 5 5 5 Sub-Clause 9 of Clause 514 specifies the use of as-dug material for trench backfill. If this material when compacted is sufficiently less permeable to affect the efficiency of the drain, or contains stones larger than about 100 mm which could damage the drain, an alternative material compatible with the geotextile should be used.

6666 Proper functioning of the fin drain and its

ancillary components depends critically on adequate installation and joining procedures. Fin drains can be problematical during construction phase for the following reasons.

(i). They do not provide immediate

drainage for the unpaved subbase. (ii). They are not designed for surface

water flows. (iii). Fine particles transported by

surface water or vehicles may clog the filter or silt the drain.

(iv). They may be damaged by the passage of construction traffic.

Appropriate protection measures must be taken, eg polythene sheeting, temporary drainage channels, or warning fence. Alternatively, the drains may be installed towards the end of the construction phase.

7777 All fin drains and their constituents must be

the subject of an Irish Agrément Board Certificate which certifies the values achieved for the specified properties when tested in accordance with Clause 514. Fin drains are available in a variety of configurations with different types of core structure. In addition, several tests described in Clause 514 are modified British Standard tests or have been developed especially for the Specification and as yet there is little experience of their use. These

two factors mean that some variation or interpretation of the test method may sometimes be necessary. The Irish Agrément Board will agree details of any appropriate variations in the specified test methods following consultation with the manufacturer. It is intended that whenever the Contractor proposes the use of any fin drain or constituent material he must supply copies of the appropriate Irish Agrément Board Certificate to confirm that the material complies with the Contract requirements. (Further guidance may be sought from the National Roads Authority)

NG 515NG 515NG 515NG 515 Narrow Filter Drains Narrow Filter Drains Narrow Filter Drains Narrow Filter Drains 1111 Narrow filter drains are intended for use as

edge of pavement sub-surface drains and are suitable alternatives to fin drains for this purpose. Both types have the same requirements of performance and the guidance given in NG 514 is equally applicable to determining the soil retention and permeability criteria of the geotextile used in narrow filter drains and to the discharge capacity of the drain. In normal circumstances, the Contractor should be permitted the choice of any of the types shown in the RCD’s. If however, for engineering reasons, exclusion of a particular type is required, this should be stated in Appendix 5/4.

2222 In drain Type 8 the filtration function is achieved by a granular filter material and geotextile sock and in Type 9 by means of a geotextile wrapping to the drain. Both filters should be designed to be compatible with the adjacent soil or construction layer. For the Type 8 drain granular material the value of D15 to be specified (Table 5/9) should be based on the criteria D15F less than or equal to 5 x D85S (TRRL Report LR346) where D85S is the sieve size passing 85% by weight of the adjacent soil. The geotextile sock round the pipe is a second stage filter where it is required to retain the particles of the first stage granular material. However, the pipe when laid in the narrow trench may have insufficient ranular surround for fully effective first stage filtration to be achieved. Pore sizes for the sock material should therefore be designed to also retain the finer soil particles outside the trench.

3333 The specification for granular material in

Table 5/9 is intended to permit the widest


January 2009 7

range of available material to be used. These limits have been set to reduce the risk of damage to the geotextile, to avoid gap grading of the filter material and to ensure an adequate degree of permeability. For the material as specified a minimum value of permeability of about 1 x 10-4 m/second which is similar to that obtained by a clean coarse sand may be assumed. A higher permeability will rarely be necessary but if required it may be specified in Appendix 5/4.

4 4 4 4 Narrow filter drains require protection

during the construction phase similar to that provided for fin drains (see NG 514.6).

5 5 5 5 The geotextiles used in narrow filter drains

require Irish Agrément Board Certification (see NG 514.7).

NG 516NG 516NG 516NG 516 Combined Drainage and Combined Drainage and Combined Drainage and Combined Drainage and

Kerb SystemsKerb SystemsKerb SystemsKerb Systems 1111 The Drawings should show the location and

gradient(s) of the combined drainage and kerb system, the position of access, silt trap, outfall and end units together with the position and invert level of the surface water outfall connection. The position of any movement joints required in the system, e.g.. at joints in bridge decks or concrete carriageways, should be shown. Details of any ducts, cabling, etc, required to pass under the kerb should be shown. The extent of the work to be designed by the Contractor should be clearly defined.

2222 Combined drainage and kerb systems should be scheduled in Appendix 1/11 and cross-reference made to the design requirements given in Appendix 5/5.

NG 517NG 517NG 517NG 517 Linear Drainage ChanneLinear Drainage ChanneLinear Drainage ChanneLinear Drainage Channel l l l SystemsSystemsSystemsSystems

1111 The linear drainage channels specified in

Clause 517 may be used on national roads including motorways. Class D channels are designed to withstand loadings of all types of road vehicles that are permitted on national roads including motorways. Class C channels shall only be installed in locations which are protected from direct traffic loading, e.g. in areas behind safety fencing. The range of slot dimensions permissible

within Clause 517 is not compatible with safe usage by cyclists and pedestrians, and units with slot dimensions described in Clause 517 should not be used in areas subject to such traffic.

2222 The drawings should show the location of

the linear drainage systems and the positions of the surface water outfall chambers into which the systems are to outfall. The position of any movement joints required in the system, e.g. at joints in bridge decks or concrete carriageways, should be shown. Details of any ducts, cabling, etc. required to pass under the systems should be shown. The extent of the work to be designed by the Contractor should be clearly defined.

3333 Linear drainage channel systems should be

scheduled in Appendix 1/11 and cross reference made to the design requirements given in Appendix 5/6.

a) with the standards of the chambers

shown on the Drawings and any longitudinal drains connecting such chambers should also be connected into the intermediate chambers.

b) Not more than one intermediate chamber should be permitted between the upstream and downstream chambers of any drain shown on the Drawings.

c) Not more than one additional chamber should be permitted upstream of each upstream chamber shown on the Drawings.

4444 Variations to stated dimensions may be

considered providing that the product will meet the requirements of this specification.

5555 A system comprising units which may be

otherwise too small to accommodate design flows without surcharge may be acceptable in conjunction with the provision of additional intermediate or upstream chambers subject to the following requirements:

a) Intermediate chambers should be compatible with the standards of the chambers shown on the drawings and any longitudinal drains connecting such chambers should also be connected into the intermediate chambers.

b) Not more than one intermediate chamber should be permitted between the upstream and


January 2009 8

downstream chambers of any drain shown on the drawings.

c) Not more than one additional chamber should be permitted upstream of each upstream chamber shown on the drawings

NG519NG519NG519NG519 Geotextiles for Filter Geotextiles for Filter Geotextiles for Filter Geotextiles for Filter DrainsDrainsDrainsDrains

1111 The pore size for the geotextile should be

selected using filtration criteria to be compatible with the adjacent soil or construction layer in order to prevent the occurrence of piping. The following soil retention criteria may be used in determining 090. Other criteria are available. In general it will be sufficient to specify only the maximum value of 090 that will satisfactorily retain the adjacent soil particles as the minimum 090 size will be governed by the permeability requirements in sub-Clause 519.2(iv). However, with very fine grained soils such as clays, the use of the above criteria will result in such small pore sizes that sufficient permeability may not be obtainable. In such cases the cohesion of the soil particles themselves is relied upon to prevent migration and a maximum 090 value of 100 microns may be chosen. However, dispersive silts can present problems and in these cases the balance between the pore size and permeability requirements should be carefully considered. An 090 value of 1 mm should be considered as the upper limit even with large grained material. The British Standard test to determine pore sizes (sub-Clause 519.2(iii)) is inappropriate for some geotextiles, such as needle-punched materials, if more than 20% of the glass beads are retained in the fabric. Pore sizes must then be obtained by other means such as wet sieving.

2222 Sub-Clause 519.2(iv) requires the designer to specify the permeability of the geotextile. The permeability may be expressed independently of the geotextile thickness as a volume rate in litres/m2/ sec. It should incorporate a margin of safety to allow for reduction in permeability with time due to clogging. This margin should also include an allowance for the fact that the geotextile’s quoted permeability is obtained from an unimpeded water flow test, whereas the filter material in a filter drain will block some of the geotextile. A value of 30

litres/m2/ sec is suggested for use against granular sub-base and capping. A smaller value would be adequate for soils and backfills.

NG520NG520NG520NG520 AttenuationAttenuationAttenuationAttenuation

1111 Attenuation requirements and site specific details should be developed by the designer and detailed on the drawings and in Appendix 5/9 to fully define the contract requirements.


January 2009 9

NG SAMPLE APPENDIX 5/1: DRAINAGE REQNG SAMPLE APPENDIX 5/1: DRAINAGE REQNG SAMPLE APPENDIX 5/1: DRAINAGE REQNG SAMPLE APPENDIX 5/1: DRAINAGE REQUIREMENTSUIREMENTSUIREMENTSUIREMENTS [Note to compiler: This should include:]

(i). requirements for box culverts [501.1];

(ii). any additional requirements for drains excluding those constructed using corrugated steel pipes [501.2];

(iii). locations where more than one pipe type is permitted within individual drain or service ducts

between consecutive chambers [501.2];

(iv). the basis of the hydraulic design of the system on which the Contractor shall submit his proposals for pipe types and makes [501.3];

(v). plate thicknesses for bolted segmental plate pipes [501.4(i)] and minimum plate thickness for

corrugated steel pipes of lock seam fabrication if different from sub-Clause 501.4;

(vi). whether corrugated steel pipes are to have additional protection of hot-applied bitumen [501.5];

(vii). laying method for corrugated coilable perforated pipes [503.2];

(viii). a schedule of permitted alternative pipe and bedding combinations including those in the NRA Road Construction Details; [which should be determined in accordance with UK DMRB Advice Note HA 40] [503.3] and list of pipelines to be constructed other than in a trench [608.8];

(ix). where sulphate-resisting Portland cement is required for concrete pipes [Table 5/1];

(x). details of materials in bedding, haunching and surrounding of filter drains if differing from the

requirements of sub-Clause 503.3(v);

(xi). whether joints in surface water drains shall be watertight or partly watertight [504.2];

(xii). where rigid joints may be used [504.3];

(xiii). backfilling requirements differing from sub-Clause 505.2; level of backfill for trenches in carriageways or other paved areas if differing from the requirements of sub-Clause 505.2;

(xiv). grading limits for filter backfill materials in filter drains if differing from the requirements of

Table 5/5 [505.3];

(xv). references to drawings showing requirements for connecting existing drains to new drains and details of special connecting pipes [506.1];

(xvi). requirements for sealing, removal or grouting of existing drains [506.3];

(xvii). references to drawings which show chamber types [507.1];

(xviii). requirements for concrete to cast in situ chambers if differing from the requirements of sub-

Clause 507.4;

(xix). particular requirements for corrugated galvanized steel chambers [507.6];

(xx). requirements for testing chambers for foul drains for watertightness [507.9] and foul drain surveys by video camera [509.5];



(xxi). details of chamber covers, gratings and frames including grades, depths of frames, hinge and locking requirements, etc [507.10] and details for special duty covers for use in carriageways [507.13], refer to HA 104 for further details;

(xxii). requirements for minimum waterway area to gratings for catchpits [507.15];

(xxiii). requirements for setting existing covers and gratings to level if different from the requirements

of sub-Clauses 507.19 and 508.8;

(xxiv). whether gullies are to be trapped or untrapped [508.1];

(xxv). details of in situ concrete gullies [508.3];

(xxvi). the classes and sizes of cast iron and steel gully gratings [508.4];

(xxvii). requirements for gully gratings if different from the requirements of sub-Clause 508.5, including whether gully gratings are to be flat or dished;

(xxviii). whether saddles are permitted [508.7];

(xxix). requirements for the cleaning of chambers, gullies and drains [509.5];

(xxx). requirements for permeability testing of backfill material where required [509.9];

(xxxi). details of connecting existing land drains [511.1];

(xxxii). whether severed mole drains are to be intercepted by construction of a land drain [511.4];

(xxxiii). requirements for backfilling mole channels if different from the requirements of sub-Clause

511.4;

(xxxiv). references to drawings showing requirements for filling to pipe bays and verges if different from the requirements of sub-Clause 512.1;

(xxxv). requirements for thermoplastic structured-wall pipes and fittings if different from the

requirements of sub-clause 518.1;

(xxxvi). values of pipe stiffness class, creep ratio and impact resistance for thermoplastics pipes [518.5]. NG SAMPLE APPENDIX 5/2: SERVICE DUCT REQUIREMENTSNG SAMPLE APPENDIX 5/2: SERVICE DUCT REQUIREMENTSNG SAMPLE APPENDIX 5/2: SERVICE DUCT REQUIREMENTSNG SAMPLE APPENDIX 5/2: SERVICE DUCT REQUIREMENTS [Note to compiler: This should include:]

(i). references to drawings which show chamber types [501.2];

(ii). a schedule of service duct requirements [501.7] [similar to those in Appendix 5/1 for pipes];

(iii). details of duct construction [503.5] [cross-reference should be made to the NRA Road Construction Details where appropriate];

(iv). whether joints in ducts shall be watertight [504.2];

(v). details of permanent marker blocks and location posts required for service ducts [505.5]

[cross-reference should be made to the NRA Road Construction Details where appropriate].


January 2009 11

(vi). requirements for permanent marker blocks and location posts [505.10];

(vii). colour coding of ducts [518.4].

NG SAMPLE APPENDIX 5/3: SURFACE WATER CHANNELS AND DRAINAGE CHANNEL NG SAMPLE APPENDIX 5/3: SURFACE WATER CHANNELS AND DRAINAGE CHANNEL NG SAMPLE APPENDIX 5/3: SURFACE WATER CHANNELS AND DRAINAGE CHANNEL NG SAMPLE APPENDIX 5/3: SURFACE WATER CHANNELS AND DRAINAGE CHANNEL BLOCKSBLOCKSBLOCKSBLOCKS [Note to compiler: State here specific requirements cross-referring to drawing numbers where

appropriate, including NRA Road Construction Details listed in Appendix 0/4]

(i). requirements for the construction of surface water channels and drainage channel blocks [510.1].

NG SAMPLE APPENDIX 5/4 : NG SAMPLE APPENDIX 5/4 : NG SAMPLE APPENDIX 5/4 : NG SAMPLE APPENDIX 5/4 : FIN DRAINS AND NARROW FILTER DRAINSFIN DRAINS AND NARROW FILTER DRAINSFIN DRAINS AND NARROW FILTER DRAINSFIN DRAINS AND NARROW FILTER DRAINS AND AND AND AND GEOTEXTILES FOR FILTER DRAINS GEOTEXTILES FOR FILTER DRAINS GEOTEXTILES FOR FILTER DRAINS GEOTEXTILES FOR FILTER DRAINS [Note to compiler: This should include:]

(i). special requirements for fin drains and narrow filter drains [514.1 & 515.1];

(ii). permitted alternative types of fin drain and narrow filter drain [Normally the choice of type of fin or narrow filter drain should be left to the Contractor.];

(iii). drawing and/or schedule references showing locations and required levels;

(iv). the maximum permissible O90 determined from the pore size distribution curve of the

geotextile [514.4(iv) & 515.3];

(v). the permeability of the geotextile [514.4(v) & 515.3];

(vi). the long term in-plane flow for fin drains [514.5];

(vii). trench backfill material for fin drain if not as-dug material [514.9];

(viii). pipe diameters [514.10 & 515.6];

(ix). D15 particle size for granular material in narrow filter drain Type 8 [515.5];

(x). permeability of granular material in narrow filter drain where required [515.5];

(xi). maximum drain slope angle if different from 15% [514.10 and 515.6];

(xii). dimensions of fin drains and narrow filter drains if different from the requirements of sub-Clauses 514.10 and 515.6.

NG SAMPLE APPENDIX 5/5: COMBINED DRAINAGE ANNG SAMPLE APPENDIX 5/5: COMBINED DRAINAGE ANNG SAMPLE APPENDIX 5/5: COMBINED DRAINAGE ANNG SAMPLE APPENDIX 5/5: COMBINED DRAINAGE AND KERB SYSTEMSD KERB SYSTEMSD KERB SYSTEMSD KERB SYSTEMS [Note to compiler: Include here:]

(i). hydraulic design parameters including design flows [516.5]; [roughness coefficients should not be specified]


January 2009 12

(ii). limiting dimensions [516.6]:

a. Maximum width and depth of units [if applicable]

b. Kerb upstand

c. Kerb profile [if applicable];

(iii). requirements of inlets where used with porous asphalt [516.7];

(iv). strength requirements [516.8] and class of concrete or mortar bedding/surround; [units should normally be capable of bearing a wheel load of 11.5 tonnes];

(v). requirements for junctions, connecting pipes and any other fittings comprising the combined

drainage and kerb system [516.11]; NG SAMPLE APPENDIX 5/6: LINEAR DRAINAGE CHANNEL SYSTEMSNG SAMPLE APPENDIX 5/6: LINEAR DRAINAGE CHANNEL SYSTEMSNG SAMPLE APPENDIX 5/6: LINEAR DRAINAGE CHANNEL SYSTEMSNG SAMPLE APPENDIX 5/6: LINEAR DRAINAGE CHANNEL SYSTEMS [Note to compiler: Include here:]

(i). drawing reference showing locations, etc.

(ii). hydraulic design parameters including design flows [517.3]; [roughness coefficients should not be specified]

(iii). limiting dimensions [517.4]:

a. Maximum width and depth of units [517.4 and 517.18]

b. Dimensions of side-entry inlets of units to be used in or adjacent to porous asphalt [517.7];

(iv). requirements for grade of weathering resistance [517.7];

(v). strength requirements [517.8]

[units must be specified as class D or class C. Class D units must be used where there is a possibility of impact from all types of road vehicle that are permitted on trunk roads including motorways. Class C units must only be installed in locations which are protected from direct traffic loading, eg. in areas behind safety barriers. Further advice on other permitted classes can be found in clause 5 of IS EN 1433.]

(vi). any special fittings required [517.9]


January 2009 13

NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/7777 : DRAINAGE AND SERVICE DUCTS:: DRAINAGE AND SERVICE DUCTS:: DRAINAGE AND SERVICE DUCTS:: DRAINAGE AND SERVICE DUCTS: NRA ROAD CONSTRUCTION DETAILS.NRA ROAD CONSTRUCTION DETAILS.NRA ROAD CONSTRUCTION DETAILS.NRA ROAD CONSTRUCTION DETAILS. Clause No.Clause No.Clause No.Clause No. Road Construction DetailRoad Construction DetailRoad Construction DetailRoad Construction Detail 501.8 RCD/500/50

503.3 (i) RCD/500/1 & 2 503.3 (iii) RCD/500/1 & 2

505.7 RCD/500/1 507.1 RCD/500/3 to RCD/500/9 507.7 RCD/500/11

508.1 RCD/500/14 & 15

508.4 RCD/500/16 509.11 RCD/500/52

514.10 RCD/500/32 519.4 RCD/500/1 NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/8888: : : : THERMOPLASTICSTHERMOPLASTICSTHERMOPLASTICSTHERMOPLASTICS STRUCTURAL WALL PIPES AND STRUCTURAL WALL PIPES AND STRUCTURAL WALL PIPES AND STRUCTURAL WALL PIPES AND FITTFITTFITTFITTINGSINGSINGSINGS Information to be provided by the ContractorInformation to be provided by the ContractorInformation to be provided by the ContractorInformation to be provided by the Contractor The Contractor shall provide the following information, in accordance with sub-Clause 518.2, for the range of pipes and fittings (to be verified by the Certification body - see sub-Clause 518.15): (i). Technical drawings showing dimensions and tolerances including sealing rings and weight per

metre, together with properties, as specified in sub-Clauses 518.3 and 518.5. (ii). Material specification, as required in sub-clause 518.2:

Table 1: Table 1: Table 1: Table 1: Unplasticised polyvinUnplasticised polyvinUnplasticised polyvinUnplasticised polyvinylylylyl----chloride (PVCchloride (PVCchloride (PVCchloride (PVC----U)U)U)U) Property Test method reference Specification Tensile Properties IS EN ISO 6259,

IS EN ISO 527-1

Vicat IS EN ISO 2505 Longitudinal reversion IS EN 743 K-value IS EN 922 PVC content IS EN 1905 Density IS EN ISO 1183-3, ISO 4451 Heat Reversion ISO 12091 Effects of heating (injection moulded fittings only)

IS EN ISO 580


January 2009 14

Table 2: Polyethylene (PE)Table 2: Polyethylene (PE)Table 2: Polyethylene (PE)Table 2: Polyethylene (PE) Property Test method reference Specification Tensile Properties IS EN ISO 6259 IS EN ISO 527-1 Oxygen induction time IS EN 728 Melt Flow Rate IS EN ISO 1133 Density IS EN ISO 1183-3, ISO 4451 Melt Flow Rate ISO 4440 Heat Reversion ISO 12091 Effects of heating (injection moulded fittings only)

IS EN ISO 580

Table 3: Polypropylene (PP)Table 3: Polypropylene (PP)Table 3: Polypropylene (PP)Table 3: Polypropylene (PP) Property Test method reference Specification Tensile Properties BS EN ISO 6259,

BS EN ISO 527-1

Oxygen induction time BS EN 728 Melt Flow Rate BS EN ISO 1133 Density BS EN ISO 1183-3, ISO 4451 Melt Flow Rate ISO 4440 Heat Reversion ISO 12091 Effects of heating (injection moulded fittings only)

BS EN ISO 580

NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/NG SAMPLE APPENDIX 5/9999: : : : ATTENUATION ATTENUATION ATTENUATION ATTENUATION [Note to the compiler: This should include] (i). Attenuation design requirements e.g. storm return period and storm duration (if specified) to be

attenuated; (ii). Location of attenuation pond with reference to drawings and drainage schedules; (iii). Atteunation requirements – Volume to be attenuated, maximum discharge rate; (iv). Pond Geometry – Existing ground level, pond invert level, top length and width, side slopes; (v). Requirements for pond lining e.g. Clay Liner, Impermeable Geomembrane; (vi). Requirement for bunding around pond – Bund level, Side slopes; (vii). Requirement for fencing around pond; (viii). Additional water quality treatment requirements – volume to be treated, depressed invert,

vegetation.

Volume 2 Series NG 600 Notes for Guidance on the Specification for Road Works Earthworks

EARTHWORKS

Contents

Clause Title Page

N G 6 0 0 Introduct ion 109

NG 601 Classif icat ion, Definition and Uses of Ear thworks Materials and Table 6/1:

Acceptab le Ear thworks Materials: Classification and

Compac t ion Requirements 110

NG 602 General Requirements 110

N G 6 0 3 Forming of Cutt ings and Cutt ing Slopes 110

NG 604 Excavation for Foundations I l l

N G 6 0 6 Watercourses I l l

NG 607 Explosives and Blast ing for Excavation I l l

N G 6 0 8 Construct ion o f Fills I l l

NG 609 Geotext i les Used to Separate Earthworks Materials I l l

N G 6 1 0 Fill t o Structures I l l

N G 6 1 1 Fill Above Structural Concrete Foundations 112

N G 6 1 2 Compac t ion of Fills 112

N G 6 1 3 Sub-formation and Capping 112

NG 616 Preparation and Surface Treatment of Formation 112

NG 617 Use of Sub-formation or Formation by Const ruc t ion Plant 112

N G 6 1 8 Tbpsoiling, Grass Seeding and Turfing 112

NG 619 Ear thwork Environmental Bunds 112

NG 620 Landscape Areas and Screening Mounds 113

NG 621 Strengthened Embankment s 113

NG 622 Ear thworks for Reinforced Earth and Anchored Earth Structures 113

NG 623 Ear thworks for Corrugated Steel Buried Structures 113

N G 6 2 4 Ground Anchorages 113

N G 6 2 5 Cr ib Wall ing 114

N G 6 2 6 Gab ions 113

NG 627 Swal low Holes and Other Naturally Occur r ing Cavities 113

NG 628 Disused Mine Workings 113

March 2000 107


Series NG 600 Earthworks

Earthworks

Contents continued

NG 629 Instrumentat ion and Moni tor ing 113

NG 630 Ground Improvement 114

N G 6 3 1 Ear thworks Materials Tests 114

N G 6 3 2 Determination of Moisture Condit ion Value ( M C V ) of Earthworks Materials . . 114

NG 633 Determinat ion of Undrained Shear Strength of Remoulded

Cohesive Material 115

N G 636 Determinat ion o f Effective Angle o f Internal eviction ((J)') and

Effective Cohesion (c) of Ear thworks Mater ia ls 115

NG 637 Determinat ion of Resistivity ( r s ) to Assess Corrosivi ty of Soil , Rock or

Ear thworks Materials 115

NG 638 Determinat ion of Redox Potential ( E h ) to Assess Corrosivity o f Ear thworks

Materials for Reinforced Earth and Anchored Earth Structures 115

NG 639 Determinat ion of Coefficient of Friction and Adhes ion between Fill and

Reinforcing Elements or Ancho r Elements for Reinforced Earth and

Anchored Earth Structures 116

NG 640 Determinat ion of Permeabil i ty of Ear thworks Mater ia ls 116

NG 642 Determinat ion of the Constrained Soil Modulus (M*) of

Ear thworks Materials 116

NG Sample Appendices 117

March 2000 108



Earthworks

NG600 Introduction

1 The Notes for Guidance on this Series are intended to assist in the preparation of the Contract. The design of the earthworks and selection of limits for soil properties for their construction will follow the ground investigation. Certain materials may be utilised as 'acceptable' materials although processing, where appropriate, will be necessary to render unacceptable materials 'acceptable'. The Engineer should describe in Appendix 6/1 the requirement for processing of unacceptable material where this has been identified as appropriate. Unless there are specific reasons, the Engineer should leave the means of processing to the Contractor. The aim should be to minimise the import of materials both for economic and environmental reasons. The Engineer should therefore match, for use in fill areas, those materials likely to arise in the cuttings as far as the earthworks design permits. The Contract should not normally indicate from where on Site materials are to be obtained for the various zones of fill (but see also 6(h) below). Certain selected fills will normally have to be imported.

2 The term 'rock' is used in the Specification to describe a constituent of certain selected fills having durability and strength requirements and also to describe material in cutting faces and formations requiring special methods of trimming or regulation.

3 Particular requirements, not specifically stated in the Specification, for the Class of fill materials to be used or permitted, or for work to be undertaken, should be included in Appendices 6/1 to 6/13. Additional Appendices may be used if necessary (see NG 000).

4 It is necessary to show the full extent of formation and where there is capping, the sub-formation. Most road configurations will be catered for by the appropriate cross-section and edge detail drawings contained in the NRA Road Construction Details. These drawings should normally be used without modification and incorporated in the Contract by reference (in Appendix 0/4). In cases where they do not cover the work involved, Contract-specific drawings may be necessary which should be discussed with the NRA.

5 The Engineer when preparing Appendix 6/1 should list only the properties needed to meet his design requirements, omitting those which

are unnecessary, e.g. either mc or MCV, not both. Where the Engineer selects mc, it should be expressed in terms of one of the following:

(i) moisture content:

(ii) moisture content related to plastic limit; or

(iiii moisture content related to optimum moisture content.

Determination of moisture content should be made from that part of the material passing the 20 mm BS sieve.

6 Tenderers should be given the fullest available information about the materials to be excavated. The following should be included:

(i) any strata or deposits designated as Hard Material;

(ii) the in situ material properties, related as far as possible to the general material description and the properties used for acceptability in Table 6/1, taken from the borehole logs, which may be re-plotted on the drawings of the long-sections of cuttings and below embankments where excavation will be required;

(iii) the total net volume of each cut (neglecting bulking or shrinkage) including:

(a) estimated net volume of Class 5A material to be removed;

(b) estimated net volume of acceptable material;

(c) estimated net volume of unacceptable material above and below formation level including the volume to be processed to render it acceptable;

(d) the Class and estimated net volume of fill to replace any excavation required below formation level;

(iv) the total net volume of fill in each fill area (neglecting bulking or shrinkage) including:

(a) estimated net volume of topsoil to be removed, if any;

(b) estimated net volume of unacceptable material below existing ground level to be removed including the volume to be processed to render it acceptable;

March 2000 109


(c) the Class and estimated net volume of fill required above and below existing ground level;

(d) the Class, location and estimated net volume of capping material required or stabilisation of subgrade to form capping;

NG 601 Classification, Definition and Uses of Earthworks Materials and Table 6/1: Acceptable Earthworks Materials: Classification and Compaction Requirements

1 The key to the use of materials both arising on Site and imported lies in Table 6/1. These materials have been classified into 8 principal Classes and sub-divided for compaction purposes or because of particular properties or applications.

2 Classes 1 and 2, general fills, comprise the greater part of the materials normally encountered and which are satisfactory as fill in most embankment construction.

3 Classes 4 and 5 are for landscaping and top-soiling respectively.

4 Classes 6 to 8 selected fills all have a special role.

5 Class 6F3 or 71 materials should be considered for use only if 6F1 or 6F2 materials are not economically available, and only with the express permission of the NRA.

6 Many schemes will use only a few of the Classes in Table 6/1 and it will be unusual for every Class of material to be used on an individual scheme.

7 The Engineer may further sub-divide the Classes in Table 6/1 e.g. 2A into 2A1 and 2A2 in order to obtain the better use of materials by zoning.

8 Appendix 6/1 must include the relevant limits of acceptability for fill materials referred to in Table 6/1.

NG 602 General Requirements

1 Special requirements for determining acceptability, e.g. who classifies (Engineer or Contractor) and where, and whether, trial pits are required, should be stated in Appendix 6/1


(see also NG 631). The Engineer should retain the obligations for classification of earthworks materials unless, following consultation with the NRA, the Engineer decides that the Contractor should have the obligations for classifying earthworks materials; these obligations include sampling and testing in accordance with the contract.

2 All topsoil above cuttings and below embankments should normally be stripped for re-use with the average depths of excavation given in Appendix 6/8 verified when stripping. There is frequently less topsoil in wooded areas than expected and this should be recognised when estimating volumes of topsoil. In soft or marshy areas disturbance of the crust of topsoil and vegetation may be unwarranted and such topsoil should be shown on the Drawings to be left in place and details given in Appendix 6/8. The local authority should be consulted concerning requirements for surplus topsoil, which should be stored whenever practicable rather than disposed of by the Contractor. Storage areas should be shown on the Drawings and details given in Appendix 6/8.

3 The Drawings should indicate where battering of excavations for foundations and trenches is permitted and details should be given in Appendix 6/3. It should not be unnecessarily restricted; in some instances it might be preferable so as to avoid leaving a wedge of material loosened by excavation. Where battering is permitted, the requirements for benching prior to backfilling and compaction should be shown on the Drawings and details given in Appendix 6/3.

4 Where groundwater is to be lowered as a design requirement, or to make wet unacceptable material into acceptable material where a shortfall in earthworks volumes is likely, the location and extent of such operations should be shown on the Drawings. These should be cross-referenced in Appendix 6/1.

NG 603 Forming of Cuttings and Cutting Slopes

1 The Drawings should show all changes in cross-section for cuttings and any requirements for limiting the extent of undercutting of slopes and toes of cuttings, making use of Appendix 6/3 as necessary.

2 Requirements for pre-split blasting, a technique for minimising overbreak and instability, should be stated in Appendix 6/3 for any substantial rock cuttings, where blasting will

March 2000 110


be permitted. (See NG 607.) Requirements for exposed cutting faces should be described in Appendix 6/3. Advice on specification requirements for pre-split blasting can be obtained from TRL report LR 1094.

NG 604 Excavation for Foundations

1 The lines and levels of foundation excavations should be shown on the Drawings together with any blinding concrete, and its mix reference, to Clause 2602.

2 The Drawings should indicate where the requirement in Clause 602 for not battering excavations for foundations can be relaxed and details should be given in Appendix 6/3 (see NG 602).

NG606 Watercourses

1 Cross-sections for all work in connection with existing or new watercourses (which includes all ditch work) should show the extent of all treatment and other requirements. See NG Sample Appendix 6/3.

NG 607 Explosives and Blasting for Excavation

1 Blasting needs should be considered in relation to the likely disturbance to the environment and remaining material beyond the cutting face. Where blasting is likely to lead to savings in excavation costs, pre-construction consultation with all who may be affected is a prerequisite to permitting blasting in Appendix 6/3. Further guidance will be found, including benefits of pre-contract blasting trials during ground investigations, in TRL report RR 53.

NG 608 Construction of Fills

1 The Drawings should show locations and particular requirements for selected fills and general fills in specific zones including any additional sub-divisions of Classes in Table 6/1.

2 The Drawings should also show how, if permitted, embankments may be initially constructed other than to their full width and to steeper batter slopes. These should be cross-referenced in Appendix 6/3.


3 Staged construction and any surcharging of embankments and benching should also be shown, with requirements for any instrumentation in Appendix 6/12. Surcharge in this specification refers to material placed in the contract. Surcharge material placed in previous works should be treated as excavation material under the appropriate heading.

4 The Drawings should show each change in cross-section of fills.

NG 609 Geotextiles Used to Separate Materials

1 This Clause includes minimum properties for geotextiles used to separate materials except for durability where tests have yet to be developed to an acceptable standard. Evidence of longetivity is, however, required from the Contractor.

2 The minimum life stated in Appendix 6/5 should relate to the main function of the geotextile. For example, if used beneath an embankment it should exceed the time for primary consolidation of the underlying soil. Rate of sampling should be given in Appendix 6/5 together with any other requirements.

3 The tests in this Clause may be used for specifying geotextiles for other purposes, using appropriate values of properties, by means of a different Appendix, e.g. if used in strengthened embankments to Clause 621, Appendix 6/9 should be used. The requirements for a separating layer may however be quite different from those for other uses and the tests may need modification or extension.

NG610 Fill to Structures

1 The required or permitted alternative Classes of material to be used should be stated in Appendix 6/6 for each structure together with their locations and extent, and any requirements for benching, cross-referring to Drawings where necessary. The acceptable limits of material properties for these Classes should be stated in Appendix 6/1. Choice of acceptable limits, e.g. c and 0 or c' and <J)' should depend on design assumptions and where they are used, values for moisture content or MCV may be unnecessary.

March 2000 111


NG 611 Fill above Structural Concrete Foundations

1 Full details of extent and type of permitted materials for filling above structural concrete foundations should be shown in Appendix 6/6.

NG 612 Compaction of Fills

1 Method compaction will be used for the majority of earthworks. Tkble 6/4 compaction should produce a minimum state of compaction equal to 10% air voids at an mc at the dry limit for acceptability. The mc at which 10% air voids or less would be achieved is roughly equivalent to a maximum MCV of 12.5 for cohesive soils (Classes 2 and 7); air voids of 5% or less will be achieved at MCV 11.5 or less. With granular soils the equivalent MCV will be higher e.g. for a well graded sand an MCV of 14.5 will achieve 10% air voids or less.

2 End product compaction is restricted to some selected fills to structures including corrugated steel buried structures. Density testing of the materials to be used will be necessary in order to comply with an end-product specification.

NG 613 Sub-formation and Capping

1 The Contract, either on Contract-specific Drawings or in Appendix 6/7, should state if capping is required and in which locations. They should also show the required thicknesses of capping (including any details of sub-formation having a different slope to the formation above it e.g. at flat areas of transition). Also permitted options for Classes of capping related to the properties of the material likely to form the sub-formation should be described.

The lateral extent of capping/sub-formation

should be shown.

Appendix 6/7 should show the minimum thickness of capping or sub-base to be placed for weather protection, where the fill characteristics do not require the full thickness immediately.


NG 616 Preparation and Surface Treatment of Formation

1 Where it is known that formations of rock will arise which cannot achieve the tolerances of sub-Clause 1 of Clause 616 the requirement to meet sub-Clause 4 should be stated in Appendix 6/7 and located on the Drawings.

NG 617 Use of Sub-formation or Formation by Construction Plant

1 The Engineer may permit construction plant for the supply and deposition of sub-base to use formations of capping or of materials having similar characteristics.

NG 618 Tbpsoiling, Grass Seeding and Turfing

1 See Clause 602 and NG 602 relating to stripping, use and storing of topsoil.

2 Where the ground investigation indicates that existing topsoil which is to be stripped for topsoiling, has a high clay content, the requirements of sub-Clause 618.3 to limit excavation etc. from topsoil stockpiles which have been open to prolonged rainfall should be invoked in Appendix 6/8 to prevent degradation. The 100 mm rainfall figure in sub-Clause 618.3 may also need to be revised but it should not be over-restrictive.

3 The seed mixture in Table 6/5 should not be changed without prior consultation with the NRA.

4 Weed control treatment should be carried out during a period of active growth before plants commence seeding and should not take place at times when rain is forecast during the next 24 hours.

NG 619 Earthwork Environmental Bunds

1 Earthwork environmental bunds may, depending on land availability and height, be constructed in various ways, e.g. normal embankment, strengthened embankment, reinforced earth structure, anchored earth

March 2000 112


structure, or be treated as a landscape area utilising Class 4 fills to Clause 620. In the latter case no reference to an earthwork environmental bund should be made so as to avoid confusion.

2 Pull details of earthwork environmental bunds should be shown on the Drawings with any requirements for early construction shown in Appendix 6/9 and Sectionalised in the Appendix to the Form of Tender.

NG 620 Landscape Areas and Screening Mounds

1 Landscape areas and screening mounds are areas where the standards of construction of fills and their material quality can afford to be of a lower standard than for normal embankment construction.

2 General or selected fills should be allowed for Class 4 landscape fill with appropriate limits on material properties being stated in Appendix 6/1. These limits should draw on those materials, listed within Class Ul unacceptable material in Clause 601, which would be acceptable as landscape fill.

3 Landscape areas and screening mounds should be shown on the Drawings cross-referenced in Appendix 6/9.

4 Environmental bunds should not be constructed on landscape fill (Class 4) unless special foundations are provided or the fill is improved.

NG621 Strengthened Embankments

1 Strengthening by interlayering geotextiles or geomeshes into an embankment or an embankment shoulder will resist the tendency for the outer edges to soften and slip after considerable time. This technique will reduce future maintenance costs and enable steeper slopes to be built. Embankments including, for example, earthwork environmental bunds may thus be built to a greater height within the available base width.

2 The properties of geotextiles (see NG 609) and geomeshes should be described in Appendix 6/9 together with construction requirements, cross-referring to Drawings where necessary.


NG 622 Earthworks for Reinforced Earth and Anchored Earth Structures

1 Classes of fill required or permitted and acceptability limits for their material properties, as referred to in Table 6/1, should be stated in Appendix 6/1 and identified on the Drawings. The thickness and types of drainage layer required or permitted should also be shown.

2 Drawings should show the maximum height to which fill may be placed above the wall during construction.

NG 623 Earthworks for Corrugated Steel Buried Structures

1 Acceptability limits for MCV, if required, for Class 6K (lower bedding) and Class 6M (surround) fills, as referred to in Table 6/1, should be stated in Appendix 6/1.

2 Where ground investigations have shown that the existing material adjacent to the location of the corrugated steel buried structure has a constrained soil modulus less than the value assumed in the design, or a corrosivity classification determined in accordance with UK Department of Transport Standard BD 12 at which corrosion of metal components could occur, the extent of additional width etc. of excavation should be shown on the Drawings. The Drawings should also show the extent of selected fill materials to be used for the construction of embankments over the structure.

3 Further details on the requirements for earthworks associated with corrugated steel buried structures are given in UK Department of Transport Standard BD 12.

NG 624 Ground Anchorages

1 Unless there are special reasons, the Contractor should design ground anchorages for anchored structures. Full requirements should be shown on the Drawings and described in Appendix 6/10. The Engineer should specify proof loading and/or design calculations to enable him to check the Contractors design.

March 2000 113

2 BS 8081 can give further advice.


NG625 Crib Walling

1 Outlines shown on the Drawings should allow for the full range of alternative systems. Design requirements should be given in Appendix 6/10 and the Engineer should ensure that the NRA is consulted in formulating these.

2 Where the design retained height exceeds 1.5 m, an outline Approval in Principle form should be included in Appendix 6/10.

NG626 Gabions

1 If extensive use is to be made of gabions Clause 626 may need extending by means of Appendix 6/10.

2 The Drawings should allow for the full range of alternative systems, except that plastic materials should not be permitted where there is a risk of damage by fire unless further protection is provided.

NG 627 Swallow Holes and Other Naturally Occurring Cavities

NG 628 Disused Mine Workings

1 Full requirements, including location, probing to determine extent, filling methods and materials, any grouting and details of mass or reinforced concrete caps should be described in Appendix 6/11.

NG 629 Instrumentation and Monitoring

1 Full requirements including all details of equipment position, depths, protection to pipe or cable connections, installation techniques, and methods of calibration and reading should be described in Appendix 6/12.

NG 630 Ground Improvement

1 Only one system of dynamic compaction, end-product or method, should be used in the Contract and the appropriate requirements should be listed in Appendix 6/13.


2 Other methods of ground improvement such as vertical drains, vibro-flotation and stone or lime columns should be detailed on the Drawings and listed in Appendix 6/13, where they are required.

NG 631 Earthworks Materials Tests

1 Where the limiting values of acceptability are determined from tests which are relatively time consuming, other tests may be considered for rapid evaluation during construction. If the Engineer is satisfied that simpler tests will produce equivalent and consistent results he should describe the acceptable tests and apparatus in Appendix 6/1 and, from preliminary trials, obtain equivalent values of acceptability which should be monitored during construction by carrying out the definitive test periodically. For example moisture content determination may be obtained using quicker drying methods than are required by BS 1377 : Part 2 or nuclear moisture gauges may be permitted. See also NG 633.

2 Appendix 6/1 should state whether the Contractor or the Engineer will be responsible for testing and, where the Contractor, the testing details should be given in Appendix 1/5 and cross-referenced in Appendix 6/1.

3 Where the Engineer is carrying out testing he should list in Appendix 1/1 the apparatus and materials he requires, and in Appendix 1/6, details of samples. For some unusual tests such as 300 mm and 60 mm shear box tests, redox potential and resistivity it may be more appropriate for testing to be carried out by an approved testing laboratory. The 300 mm shear box should not normally be required on Site.

4 See also NG 602.1.

NG 632 Determination of Moisture Condition Value (MCV) of Earthworks Materials

1 The Engineer should state in Appendix 6/1 whether the MCV/mc relationship of all imported material requiring an MCV property should also be plotted.

March 2000 114


NG633 Determination of Undrained Shear Strength of Remoulded Cohesive Material

1 Where shear strength is used as the acceptability criterion, routine site testing may be more conveniently carried out by e.g. hand vane or hand penetrometer monitored by periodic triaxial test comparison to give adequate correlation. (See NG 631.)

NG 636 Determination of Effective Angle of Internal Friction ( ( j ) ' ) and Effective Cohesion (c') of Earthworks Materials

1 For granular Class 6N, 6P. 61 and 6J materials, consistency of supply may be checked by comparing samples with the grading, particle shape, plasticity and other characteristics of the material used for the shear box test.

2 Where the results of control tests using the 60 mm shear box for Class 7C and 7D materials differ from the initial values obtained during the initial determination of fill properties by more than 20f/r, the variability should be investigated, and if necessary, further tests using the 300 mm box should be carried out to check that the material remains within the limits of acceptability.

NG637 Determination of Resistivity (rs) to Assess Corrosivity of Soil, Rock or Earthworks Materials

1 When laboratory tests are required in Appendix 6/1 (1/5), the Engineer should state which of the three types of test described in BS 1377 : Part 3 should be employed.

2 In considering the Contractors proposals required by sub-Clause 637.3, the Engineer should take account of the following:

(i) In order to achieve meaningful results it is essential that proper contact between the electrodes and the fill should be obtained particularly where the electrode penetration is shallow.

(ii) Tests should be carried out at the anticipated maximum natural moisture


content in order to obtain the lowest resistivity.

(iii) The locations should be chosen so as to cover the entire area of the structure, cutting, borrow pit or stockpile. The distance between locations should exceed three times the maximum spacing of the electrodes but not be more than 50 m.

(iv) The field testing procedure is not suitable for massive rock material which is to be crushed before use in the Permanent Works. In this case laboratory tests should be carried out on samples of crushed material using a procedure which the Engineer should approve.

(v) Unexpected variations in resistivity with depth should be investigated. Typical values of the resistivity likely to be obtained for various types of strata are shown in CP 1013.

NG 638 Determination of Redox Potential (E^) to Assess Corrosivity of Earthworks Materials for Reinforced Earth and Anchored Earth Structures

1 In considering the Contractors proposals required by sub-Clause 638.3 the Engineer should take account of the following:

(i) Tests should be carried out on each soil type and at not less than five locations within the area of the cutting or of the proposed borrow pit or stockpile. It is normally sufficient to test material at a depth of 1 m below original ground level. However, it will be necessary to test at lower levels where the type of material is known to vary with depth.

(ii) When possible, tests should be carried out at the anticipated maximum natural moisture content in order to obtain the lowest redox potential.

(iii) It is advisable to determine the pH of the fill at the location before measuring redox potential. Where the pH lies outside the range 5.5 to 9.5, and it is known that it will remain so for the life of the structure, redox potential measurements need not be made since it is considered that microbiological corrosion is unlikely to occur under these conditions.

(iv) The field testing procedure is not suitable for massive rock material which is to be

March 2000 115



crushed before use in the Permanent Works. In this case laboratory tests should be carried out on samples of crushed material using a procedure which the Engineer should approve.

NG639 Determination of Coefficient of Friction and Adhesion between Fill and Reinforcing Elements or Anchor Elements for Reinforced Earth and Anchored Earth Structures

1 The test for reinforcing elements should be carried out for each type of element and each fill material proposed to be used.

2 Sub-Clause 639.5 for anchor elements is drafted so that such a test may be introduced in future when it is developed. Appendix 6/1 (1/5) should not require a test until that time.

NG 640 Determination of Permeability of Earthworks Materials

1 Details of tests for the permeability of soils and fills are given in BS 1377 : Part 5 and Part 6. Details of a test for the horizontal permeability of road drainage layers are given in UK Department of Transport Advice Note HA 41.

NG 642 Determination of the Constrained Soil Modulus (M*) of Earthworks Materials

1 BS 5930 gives further information on, and illustrations of, suitable plate loading test equipment.

March 2000 116



N G S A M P L E A P P E N D I X 6/1: R E Q U I R E M E N T S F O R A C C E P T A B I L I T Y A N D T E S T I N G E T C . O F W O R K S M A T E R I A L S

[Note to compiler: This should include]

1 Acceptable limits for the fills in Table 6/1 appropriate to the Contract [Table 6/1, 602.1 and 608.1] and including:

(i) permitted Classes where alternatives are listed in the Specification,

(ii) those materials, which may be used for landscape fill Class 4 |6*07.2(ii)|;

(iii) cross-references to Drawings showing location of'zoning' of general and selected fills;

(iv) additional sub-divisions of Classes in Table 6/1 required for the Contract;

(v) alternative and additional requirements for triaxial and shear box tests 1633 and 636].

2 Special requirements for determining acceptability, who classifies and where, and whether trial pitting is required [602.1\. [See NG 602.1. Where the Contractor is responsible for testing, the tests required should be scheduled in Appendix 1/5 and cross-referenced here. \

3 Any requirement for processing to render unacceptable material Class Ul acceptable, cross-referring to Drawings where necessary, for each type of material to be processed and class of material to be produced [Wherever possible the means of processing should be left to the Contractor [ [601.4].

4 Requirements for groundwater lowering or other treatment [602.17].

N G S A M P L E APPENDLX 6/2: R E Q U I R E M E N T S F O R D E A L I N G W I T H C L A S S U 2

U N A C C E P T A B L E M A T E R I A L


1 Drawing references for excavation and disposal of known Class U2 material.

2 Pre-agreed environmental requirements for disposal including specific sites (DOE. Local Authority, etc.).

3 List of known hazardous materials likely to be encountered.

4 Methods of excavation, precautions and requirements for handling.

5 Special requirements for dealing with leachate and contaminated water.

6 Requirements for special drainage and for sealing exposed surfaces of contaminated materials.

March 2000 117



N G S A M P L E A P P E N D I X 6/3: R E Q U I R E M E N T S F O R EXCAVATION, D E P O S I T I O N ,

C O M P A C T I O N ( O T H E R T H A N D Y N A M I C C O M P A C T I O N )

[Note to compiler: This should include I

1 The drawing numbers of all drawings which give related earthworks requirements including line and level.

2 Blasting for excavation:

(i) Locations where blasting is permitted [607.2].

(ii) Time limits when blasting can take place [607.4]. [Ensure compatibility with Clause 109 and Appendix 119 requirements for noise and vibration].

(iii) Pre-split blasting requirements [603.4].

(iv) Engineer's arrangements for Contractor to monitor noise and vibration in property off Site.

3 Cutting faces requirements for:

(i) Undercutting restrictions - extent and limitations for sequential excavation and backfilling, where Contractor is required to undercut slopes or toes of cuttings [603.21. [Note that where similar requirements exist for embankments e.g. where drainage excavations are close to the toe, these should also be covered in this Appendix].

iii) Clearing loose material, where no topsoiling is required, by airline hose or water hose including maximum pressure and nozzle arrangements |603.5(iv)J.

(iii) Making face stable, where no topsoiling is required, including depth of cut-back and thickness of cementitious material to be applied if different from Clause 603, location and type of reinforcement and details of weep holes. [Rock bolting should be described in Appendix 6110. [

(iv) Protecting face of soft or insecure material interlayered with rock, where no topsoiling is required, including depth of back and details of masonry infill.

(v) Making good prior to topsoiling [indicating which, if any, of the measures in 603.7 are required, and where.]

4 Watercourses including ditches etc.

(i) New or modifying old - details including protection, lining etc. [606.1].

(ii) Redundant where draining and clearing required, extent of excavation and Classes of fill for their infilling 1606.41.

5 Embankment Construction:

(i) Limits on oversteepening or in increase in width [608.5].

(ii) Stage construction of fills details and rates of controlled filling [606.61.

(hi) Surcharging details including time period, type of surcharge material, initial level of top of surcharge above designed formation or sub-formation 1608.71.

(iv) Description of location, class and thickness of starter layers 1608.21.

6 Compaction 1612]:

(i) General:

(a) Requirements if compaction not to comply with Clause 612 [612.1].

(ii) Method compaction:

(a) Locations where extra compaction in top 600 mm for Classes 1A, IB, 2A, 2B, 2C and 2D is not required for full width of embankment or between outer extremities of verges. [List Drawing Nos. of appropriate cross-sections (612.10(H))].

(b) Requirements for compaction of drainage materials other than Class 6H.

March 2000 118



(iii) End-product compaction:

(a) Whether a nuclear surface density gauge is to be used or is permitted for measuring field dry densities [612.15].

7 Limiting distance for deposition of materials referred to in sub-Clause 601.9 or 601.10.

8 Locations of excavations that are permitted to be battered and requirements for benching prior to backfilling and compaction [602.12]

9 Locations where excavation supports are to be left in position [602.12].

10 Requirements for benching or shaping to natural or earthworks slope faces to receive fill [608.10]. Location of and benching requirements for cutting slopes to receive Treatments I or II \618.5].

N G S A M P L E A P P E N D I X 6/4: N O T U S E D

N G S A M P L E A P P E N D L X 6/5: G E O T E X T I L E S U S E D T O S E P A R A T E E A R T H W O R K S

M A T E R I A L S

[Note to compiler: This should include:]

1 Drawing references for locations where geotextiles are to be used in separation layers. [609.1].

2 Whether the geotextiles are to be of synthetic or other fibres. [609.1].

3 Minimum life expectancy. [609.2].

4 Numbers of samples for subsequent testing. [609.4].

5 Testing criteria if different from those in sub-Clause 609.4.

6 Details of laying and lapping if other than as in sub-Clause 609.5.

7 Number of tests on samples. [609.8]

N G S A M P L E A P P E N D L X 6/6: F I L L T O S T R U C T U R E S A N D F I L L A B O V E S T R U C T U R A L

F O U N D A T I O N S


1 Drawing references for fill to structures and fill above structural foundations.

2 Whether Classes 6N or 6P require full scale determination of stable slope, and value of slope if not 1 to 1.5 [610.6].

March 2000 119



N G S A M P L E A P P E N D I X 6/7: S U B - F O R M A T I O N A N D C A P P I N G A N D P R E P A R A T I O N A N D

S U R F A C E T R E A T M E N T O F F O R M A T I O N


1 Capping and sub-formation:

(i) Drawing references which show locations where capping is required and its thickness 16*2.3.1 | for each

type of pavement.

(ii) Permitted Classes of capping singly and in combination [623.21.

(iii) Drawing references [including use of appropriate Drawings, by reference, in NRA Road Construction Details which give shaping requirements for sub formation. (613.4)].

(iv) Locations where treatment of formation in accordance with sub-Clause 616.4(1) or 616.4(h) is

required.

N G S A M P L E A P P E N D K 6/8: T O P S O I L I N G , G R A S S S E E D I N G A N D T U R F I N G


1 Height limits of topsoil stockpiles permitted, if other than 2 m [602.10].

2 Whether imported topsoil Class 5B is required. 1618.2].

3 Whether the requirements of sub-Clause 618.3 apply [only when majority of topsoil (Class 5A) to be stripped for re-use has high clay content, to avoid degradation following prolonged rainfall]. Cumulative rainfall if not 100 mm.

4 References to drawings which show the areas to receive Treatments I, II or III. 1618.4].

5 Thickness of topsoil to be deposited in Treatments I and II and when a tracked vehicle may not be used for spreading. [618.6(i)[.

6 When hydraulic mulch seeding is not permitted for Treatment I. [618.4(i)J.

7 List of areas of cutting slopes which do not need harrowing or harrowing depth if not 50 mm. [618.5(H)]

8 Rate of distribution of fertiliser to be raked in, if other than 75g/m\ [618.6(iv)(b)].

9 Rate of distribution of seed if different from sub-Clause 618.7(h).

10 Measures for retaining turf on slopes. [618.8(iv)J.

11 Requirements for glass fibre or other material to form a retaining agent in hydraulic mulch seeding.

[618.9(H)].

12 Drawing references which show areas of grass not to be mown or to be mown three times. [618.10].

13 Mowing plant requirements, if any. /618.101.

14 Seed mixture requirements which differ from those listed in Table 6/5 and drawing references showing

areas where required. [618.13].

15 Whether surplus topsoil is to be stored or disposed of by the Contractor. Details of topsoil storage areas such as location, height, contours and batter slopes [602.11].

16 Drawing references which show the locations where topsoil and vegetation is to be left in place 1602.9].

17 Drawing references which show average depths to which topsoil is to be stripped [602.9/.

March 2000 120



N G S A M P L E A P P E N D I X 6/9: E A R T H W O R K E N V I R O N M E N T A L B U N D S , L A N D S C A P E

A R E A S , S C R E E N I N G M O U N D S , S T R E N G T H E N E D E M B A N K M E N T S

[Note to compiler: This should include:!

1 Earthwork Environmental Bunds

(i) References to Drawings which show locations and which state type of construction [619.1, 2 and 3]:

(a) a normal embankment to Clause 608; if so whether method compaction to Clause 612 is required and which Method in Table 6/4 to adopt and Classes of fill permitted or required;

(b) a strengthened embankment to Clause 621; if so requirements as listed in 3 below;

(c) a reinforced or anchored earth structure to Clause 622; if so full details of construction.

(ii) Requirements for early construction.

I iii) Requirements for topsoiling and seeding/turfing.

2 Landscape Areas and Screening Mounds

(i) References to Drawings which show locations.

(ii) If compaction to be method to Clause 612 and if so which method in Table 6/4 to adopt.

(iii) Details of contouring required.

(iv) Locations where landscape areas may be constructed simultaneously with adjoining embankments.

(v) Requirements for topsoiling and seeding/turfing.

3 Strengthened Embankments

(i) Reference to Drawings which show locations, details of construction and Classes of fill.

(ii) Requirements for strengthening materials. /See NG 609.31.

March 2000 121



N G S A M P L E A P P E N D I X 6/10: G R O U N D A N C H O R A G E S , C R I B W A L L I N G A N D G A B I O N S

1 Ground Anchorages /624J


(i) Design requirements.

(ii) References to Drawings showing installation and construction requirements, including:

(a) specifications for drilling, tendons, grouting and tensioning;

(b) proof loading, monitoring and re-tensioning;

(c) trial installations;

(d) rock bolting.

2 Crib Walling [625]

[Note to compiler: Include here:!

(i) Design requirements. [Where the design retained height exceeds 1.5 m, include the requirement for the design to comply with UK Department of Transport Standard BD 2: Part I.]

(ii) References to Drawings showing locations and outlines.

3 Gabions [626]


(i) References to Drawings showing locations and details including:

(a) additional requirements and type of mesh [626.1 and 3];

(b) core dia. and its BS for mesh if different from 626.3(i);

(c) properties of plastic geomesh, if permitted [626.3(H)];

(d) size of mesh openings and gradings of fill [626.5].

N G S A M P L E A P P E N D L X 6/11: S W A L L O W H O L E S A N D O T H E R N A T U R A L L Y O C C U R R I N G

CAVITIES A N D D I S U S E D M I N E W O R K I N G S


1 Drawing references showing locations of voided ground or abandoned workings. [627 and 628].

2 Location methods for identifying and inspecting shallow workings or voids where required.

3 Requirements for bulk fill and methods of placement.

4 Grouting, types and procedures.

5 Details of excavation, clearance and flushing of soft infilling.

6 Details of other treatments or support requirements.

7 Requirements for concrete caps to voids or soft areas.

8 Requirements for inspecting, monitoring, clearing, flushing, filling, caps or other treatments of disused

mine workings. [628.1].

March 2000 122

Volume 2 Notes for- Guidance on the Specification for Road Works


N G S A M P L E A P P E N D I X 6/12: I N S T R U M E N T A T I O N A N D M O N I T O R I N G

[Note to compiler: This should included

1 Drawing references showing locations and extent of instrumentation including that required for staged construction 11629.1 and 2 and 608.6). Note: instrumentation and monitoring for blasting should be covered in Appendix 6/3 and for dynamic compaction in Appendix 6/13].

2 Schedules of instruments by type and description with alternatives where possible.

3 Details of housings required.

4 Installation techniques.

5 Calibration requirements.

6 Protection to instruments, connections and housing.

7 Requirements for electric power.

8 Frequency of reading and method of reporting readings where the Contractor is required to carry out these tasks.

N G S A M P L E A P P E N D I X 6/13: G R O U N D I M P R O V E M E N T

/Note to compiler: This should include:/

1 Drawing references showing locations where dynamic compaction is required.

2 For end-product: performance requirements in terms of tolerable further settlement after process has been completed.

3 For method: the following where applicable:

(i) Special drainage requirements /e.g. de-watering; 602.17/.

(ii) Class and thickness of granular layer.

(iii) Mass, shape and contact area of pounder.

(iv) Height(s) of drop and spacing ofimprints.

(v) Number of drops.

(vi) Arrangements and numbers of passes.

(vii) Requirements, including class of material, for filling of imprints.

(viii) Requirements for instrumentation, monitoring and testing.

4 For other methods of ground improvement:

(i) Drawing references showing location and type.

(ii i Details of spacing, depth, size etc. referring to drawings if necessary,

(iii) Specification details.

March 2000 123

Volume 2 Series NG 600 Notes for Guidance on the Specification for Road Works Earthworks

March 2000 124


Series NG 700 Road Pavements - General

ROAD PAVEMENTS - GENERAL

Contents

Clause Title Page

N G 7 0 1 Pavement Construct ion 126

NG 702 Horizontal Alignments , Surface Levels and Surface Regulari ty of

Pavement Courses 126

NG 703 Weather Condit ions for Laying of U n b o u n d Granular and

Cement i t ious Materials 127

N G 7 0 4 Use of Surfaces by Traffic and Construct ion Plant 127

NG 705 General Requirements for Sub-bases and Roadbases 127

NG 706 Excavation, Tr imming and Reins ta tement of Exis t ing Surfaces 128

NG 708 Weather Condit ions for Laying of Hot Rolled Aspha l t Wearing Course and Other Bi tuminous Pavement Layers 128


March 2000 125



Road Pavements - General

NG 701 Pavement Construction

1 The permitted options should be agreed with the NRA or Department of the Environment as appropriate.

2 A separate Appendix 7/1 Sheet 1 or Sheet 2 as appropriate is to be included in the contract for each permitted pavement option.

Sheets 1 and 2 of Appendix 7/1 should cover all permitted alternatives for each length of carriageway and paved area.

3 A summary may be included as sheet 3 of Appendix 7/1.

NG 702 Horizontal Alignments, Surface Levels and Surface Regularity of Pavement Courses

1 All levels of pavement courses are related to the specified level of the final road surface. Tblerances and limits in levels and irregularity are given in Tables 7/1 and 7/2 respectively. These should be strictly enforced to maintain a good ride and constant thickness of material. As they are based on the capabilities of most pavers to lay to a level they do not allow for any intentional reduction of the pavement thickness.

2 Surface levels of different pavement courses should be measured at points on a grid described in Appendix 7/1 in order to be able to determine the thickness of each course from the successive measurement of levels at the grid points. The spacing of the grid should normally be 10 m longitudinally and 2 m transversely. Where a greater degree of level control is required, e.g. at junctions of the carriageway with side roads, on slip roads and roundabouts, but not joints in the carriageway, the grid points should be at some lesser spacing. Measurement of surface levels at points on a grid does not mean that the surface can be outside the permitted tolerances at other points between the grid.

3 The tolerances on surface levels of wearing course and concrete slabs are set in order to provide as good a ride as possible and avoid undulations of an individual or cyclic nature, which are of a wavelength outside the range detectable by the rolling straight-edge or

equivalent apparatus. If, however, through a fault in the paving plant the whole surface as laid is consistently high over long lengths, it would be unnecessary to impose the limits of the true surface level tolerances, provided:

(i) Clearances under bridges are adequate, and allow for overlays.

(ii) The drainage of the carriageway is not impaired.

(iii) All tolerances except those on the final road surface design level comply with the Specification.

(iv) The area affected is of such length as to provide an acceptable ride.

4 The limits for surface regularity of sub-bases under concrete pavement surface slabs is necessarily less when the slabs are laid in a single layer and only compacted by surface compacting beams. With a standard surcharge and a fixed degree of compaction with such equipment, upward variations in the sub-base can be reflected in the surface when the concrete is fully compacted, whereas downward variations will result in lack of compaction locally. These tighter tolerances do not apply when internal vibration is used.

5 Two categories of road are given in Table 7/2 and for each different section of road the category must be stated in Appendix 7/1. The Engineer should decide the category on the quality and quantity of traffic, on the road layout and potential speeds of traffic. Category B generally will apply to minor roads.

6 The surface should be thoroughly swept to remove extraneous matter before measurements are taken. All such measurements should be taken early, and any deficiencies in the pavement should be reported as soon as possible to allow the Contractor sufficient time to complete all remedial work and to allow for concrete to cure before opening the road to traffic. The rolling straight-edge should be used at about 2 km/hour. Some coarse textures can lead to incorrect readings if the surface is traversed too quickly. Areas shown not to comply with the Specification should be rectified as soon as possible and checked by a 3 m straight-edge or, for longer lengths, by the rolling straight edge or equivalent apparatus.

7 Traces from profilometers are useful in picking out particular areas for remedial work from the whole stretch shown not to comply with the

March 2000 126



Specification by the rolling straight-edge or equivalent apparatus.

8 For rectifying concrete slabs use of a bump cutter with a long wheel base is essential to produce an even plane without local over-cutting. Grinding down either side of depressions may improve the riding quality, if they are small. Deeper depressions should normally be rectified by cutting out and refilling over the full area of unreinforced slabs, and a minimum length of 5 metres of reinforced slabs.

after placing the concrete, high strength mixes may be used. To estimate the time when the required strength may be achieved trial mixes should be tested at various early periods to establish a rate of strength development. These times can be confirmed by testing cubes which were placed alongside the pavement in moulds insulated around the sides. However, such results can only be used as an expedient for the purpose and not for compliance with the Specification.

NG 703 Weather Conditions for Laying of Unbound Granular and Cementitious Materials

1 Thermal insulation blankets laid on the finished concrete can enhance the rapidity of curing by the retention of heat. This is of benefit not only in cold weather, but also at other periods to accelerate the curing of the concrete slabs.

NG 704 Use of Surfaces by Traffic and Construction Plant

1 Under the Conditions of Contract the Contractor is responsible for care of the Works including the protection of the sub-base and subgrade. The Engineer will not know when drawing up the documents what materials, plant, methods and programme the Contractor will adopt.

2 As unbound sub-bases are moisture susceptible and are unsuitable for construction traffic in wet periods, the Contractor's programme and methods of laying the roadbase and subsequent layers should take cognisance of this. Traffic running on the sub-base may cause irreparable damage to the subgrade or capping. Protection of the sub-base against weather can best be achieved by laying the subsequent layers as soon as possible. Work should preferably be programmed so that the roadbase is applied before the sub-base is wetted.

Any thickening shall be across the full width of that part of the pavement which is in new construction. If temporary haul roads are laid and later removed they must be placed so that drainage of the formation and sub-base surface is not impeded.

3 Where there is a need to open a section of concrete pavement or roadbase to traffic early

NG 705 General Requirements for Sub-bases and Roadbases

1 Clause 705 applies to all sub-base and roadbase materials whether unbound (800 Series), bituminous bound (900 Series) or cement bound (1000 Series).

Frost Heave

2 The frost heave test described in BS 812 : Part 124 : 1989 is costly and time consuming and is not suitable for routine control checks on Site. The test has been developed from earlier test methods to overcome problems of repeatability and reproducibility. The test is primarily intended as a method to establish whether or not an aggregate from a particular source is likely to be frost-susceptible when used in an unbound condition within that part of the road pavement subject to frost penetration. Material for the frost heave test must be representative of the source and comply with all other requirements of the Specification otherwise the test is superfluous. Once a material has been established as non-frost-susceptible the test need only be repeated if the Engineer considers that the material varies from the original sample, or where the source is changed.

3 Clause 6 of BS 812 : Part 124 : 1989 sets down the procedure for adjusting the water level in the self-refrigerated unit (SRU). A possible problem has been identified that with the tolerances given to the dimensions for the cradle and specimen carriers it is possible for the porous discs in the specimen carriers to be located incorrectly in relation to the water level. In order to guard against this it is recommended that before testing commences the cradle and specimen carriers be put into the SRU without samples. A check is then made to ensure that discs are set at the level specified in the above-mentioned standard.

4 The requirement for material to be non-frost-susceptible within 450 mm of the surface of a

March 2000 127


road or paved central reserve may be reduced to 350 mm if the Mean Annual Frost Index (MAFI) of the site is less than 50. The Frost Index is a measure of the severity of a period of cold weather and provides a means of assessing likely penetration of frost into a road. Frost index is measured in 'degree days Celsius below zero' and is calculated by taking the mean air temperature for each twenty four hour period and adding those values together. Frost penetration into a modern road in the British Isles may be estimated using the formula x = 40 I where x is the approximate penetration in mm and I is the frost index for the freezing spell. The Annual Frost Index is the frost index accumulated over a year commencing September 1st. Mean Annual Frost Index (MAFI) is the average of all the frost index values computed for each year since September 1959. The MAFI for a site is determined using records from one or more meteorological stations close to the site, taking account of local geographical variation, such as high ground or frost hollows. The Engineer may consider different requirements for different parts of a contract length. Further information on the MAFI can be found in UK Department of Transport Standard HD 25. Advice on the frost index may be obtained from the Meteorological Service, Glasnevin Hill, Dublin 9.

NG 706 Excavation, Trimming and Reinstatement of Existing Surfaces

1 Clause 706 describes a method of excavation and reinstatement of existing paved and unpaved surfaces:

(i) Where the Contractor is required to break into paved areas for the installation of utilities.

(ii) Where the Contractor unavoidably has to break into work which he has carried out as part of the Works.

(iii) Where he is required to break into paved areas existing prior to the Works being constructed.

(iv) Where pavements are constructed to abut or join into existing pavements.

2 As much information as possible should be provided in Appendix 7/2 and on the Drawings for l(iii) and (iv) above, especially to show the areas and depth of pavement required to match levels between new and existing construction. The intention is to ensure that at least a new wearing course should be provided over the minimum area of existing pavement as will


avoid feathering below 40 mm thickness, after preparation of the existing surface by scarifying and planing. Where existing and new concrete pavements abut or join into each other it is normal practice to use a bituminous pavement between the two sections, details of which should be given in Appendix 7/2.

3 Approval to excavate paved areas already constructed as part of the Permanent Works should only be given when it is necessary to carry out the Permanent Works or where no other practical means of completing the Permanent Works can be devised.

4 Advice and methods of reinstating concrete pavements are given in the "Manual for Maintenance and Repair of Concrete Roads" produced jointly by the UK Department of Transport and the Cement and Concrete Association (now the British Cement Association).

NG 708 Weather Conditions for Laying of Hot Rolled Asphalt Wearing Course and Other Bituminous Pavement Layers

1 This clause sets requirements for laying hot rolled asphalt wearing course. It takes into account the cooling effect of wind, in addition to air temperature, on hot rolled asphalt wearing course.

2 The thickness of hot rolled asphalt wearing course incorporating 30 per cent coarse aggregate should be 45 mm, unless otherwise stated in Appendix 7/1.

3 When site conditions are such that the time available for compaction is excessively long, such as when air temperatures are high, wind speeds are low or solar radiation is high, the delivery temperature may be reduced subject to the agreement of the Engineer. However, the delivery temperature for hot rolled asphalt wearing course materials should not be less than 150°C for a layer thickness of 45 mm.

4 The term Tight precipitation' is considered as rainfall less than 0.5 mm per hour.

5 The requirements of Clause 708.3 are based on a minimum available compaction time of ten minutes from the time the material emerges from the paver. The requirements of Clause 901 still apply, unless specifically amended by this Clause.

March 2000 128

Volume 2

Notes for Guidance on the Specification for Road Works Series NG 700


N G S A M P L E A P P E N D I X 7 /1: P E R M I T T E D P A V E M E N T O P T I O N S

S H E E T 1 - F L E X I B L E OR F L E X I B L E C O M P O S I T E

[Note to compiler: Complete one sheet per option see NG 701.2].

Location \ e.g. Chainage, Road Name, Carriageway Reference]

Grid for checking surface levels of pavement courses, if different from the requirements of sub-Clause 702.4:

Surface regularity ]702.7/:

Longitudinal dimension: Transverse dimension:

Category of road: [A or B]

Requirements for determination of compaction level if different from the requirements of sub-Clause 901.19 and 927.1.

Coated chippings. if different from the requirements of sub-Clause 910.5 and 911.8 and Clause 915:

Nominal Size: Minimum PSV: Maximum AAV: Maximum Flakiness Index:

Requirements for hardness, durability and cleanness of aggregates if different from the requirements of sub-Clause 901.2.

Requirements for regulating course 1907].

Clause Material Grade of Binder

Thickness (mm)

Special Requirements

Surfacing

Wearing Course

[see Note 2] [see Note 3] BS 594 : Part 1 Table Nos: Column Nos: Marshall Stability range: Marshall Flow: [Clause 911] BS 4987 : Part 1 Clause Nos: Nominal Size: Minimum PSV: 19121(9161:

Base-Course

Roadbase

Upper Roadbase

Lower Roadbase

Sub-base

TOTAL PAVEMENT THICKNESS:

March 2000 129



N G S A M P L E A P P E N D I X 7/1: P E R M I T T E D P A V E M E N T O P T I O N S

S H E E T 1 - F L E X I B L E OR F L E X I B L E C O M P O S I T E (continued)

/Notes to compiler:

1 Select the Clauses appropriate to option permitted and only state those required.

2 Grade of binder is to be specified only when the wearing course is to comply with Clause 912, i.e. 100 pen or 200 pen only.

3 Refer to NG 708.2 concerning the thickness of hot rolled asphalt wearing course.]

S H E E T 2 - R I G I D C O N S T R U C T I O N

1 Location [e.g. Chainage, Road Name, Carriageway Reference]

2 Grid for checking surface levels of Longitudinal dimension: pavement courses, if different from Transverse dimension: the requirements of sub-Clause 702.4:

3 Surface regularity [702.7]: Category of road: [A or B]

Slab Type Slab Thickness

Max Transverse Joint Spacing (m)

Longitudinal Steel

Reinforcement

Particular Requirements

Slab Type Slab Thickness

Contraction. Expansion

Longitudinal Steel

Reinforcement

Particular Requirements

Un-reinforced concrete surface slabs (URC)

None 1. Maximum transverse joint spacing may be increased by 20% if limestone coarse aggregate is used throughout the depth of the slab.

Jointed reinforced concrete surface slabs (JRC)

mmVm width 1. The range of reinfmt. and max transverse joint spacings corres. to slab thicknesses given and intermediate values may be interpolated.

2. Max transverse joint spacings may be increased by 209c if limestone coarse aggregate is used throughout the depth of the slab.

3. Transverse reinforcement [if required for differential settlement!

Jointed reinforced concrete surface slabs (JRC)

Clause Material Thickness (mm)

1. The range of reinfmt. and max transverse joint spacings corres. to slab thicknesses given and intermediate values may be interpolated.



Sub-base

1. The range of reinfmt. and max transverse joint spacings corres. to slab thicknesses given and intermediate values may be interpolated.



March 2000 130

Volume 2



N G S A M P L E A P P E N D I X 7/1: P E R M I T T E D P A V E M E N T O P T I O N S

S H E E T 2 - RIGID C O N S T R U C T I O N (Continued)

Notes:

1 Concrete for surface slabs and roadbases shall be Grade C40 complying with Clause 1001.

2 Reinforcement shall comply with Clause 1008.

3 Capping is not required/is required as described in Appendix 6/7. [Compiler to delete as appropriate]

4 References to drawings showing reinforcement layout and bay layouts at slip roads and junctions, if required.

S H E E T 3 - S U M M A R Y OF A L T E R N A T I V E S

[Notes to compiler:

1 Sheet 3 of Appendix 7 /1 may be used to summarise all the permitted types of pavement and inherent options as stated in Sheets 1 and 2 of Appendix 7/1.

2 Where this summary is considered better placed on a Drawing, Sheet 3 of Appendix 7/1 should be omitted and sheets 1 and 2 should cross-refer to the Drawing Number.]

NG S A M P L E A P P E N D I X 7/2: EXCAVATION A N D R E I N S T A T E M E N T OF EXISTING SURFACES

/Note to compiler: Include here:]

1 Locations of any trenches, pits, etc, which require to be excavated in existing paved surfaces in order to carry out the Works. Reference to any drawings giving further details./706'.2/

2 Locations and estimated areas of existing paved areas which require to be trimmed, regulated and reinstated to match levels where new and existing pavements abut. Reference to any drawings giving further details. [706.7]

3 Cross-section diagram of typical trench reinstatement in bituminous and concrete pavements giving details of materials.

4 References to drawings which show construction at junctions between concrete pavements and between concrete and bituminous pavements /706.13].

/Note to compiler: Include here details of:]

Location:

Type of binder [919]: Grade of binder [919]: Target rate of spread of binder [919]: Chippings: Nominal size:

N G S A M P L E A P P E N D I X 7/3: SURFACE D R E S S I N G

Coated or uncoated: Minimum PSV Maximum AAV: Maximum ACV:

Other special requirements:

March 2000 131



N G S A M P L E A P P E N D I X 7/4: B I T U M I N O U S S P R A Y S

[Note to compiler: Include here details of:]

Location:

Type of binder [920.2]:

Rate of spread: Blinding material 1920.5):

N G S A M P L E APPENDLX 7/5: N O T U S E D

N G S A M P L E APPENDLX 7/6: B R E A K I N G U P O R P E R F O R A T I O N O F E X I S T I N G P A V E M E N T

[Note to compiler: Include here details of the treatment required, cross-referring to drawings as necessary.]

March 2000 132

Volume 2 Series NG 800 Notes for Guidance on the Specification for Road Works Road Pavements – Unbound Materials

ROAD PAVEMENTS – UNBOUND MATERIALS

Contents Clause Title Page

NG 800 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

NG 802 Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

NG 803, 804 and 805 Granular Material Types A, B and C . . . . . . . . . . . . . . . 2

NG 806 Wet-Mix Macadam . . . . . . . . . . . . . . . . . . . . . . . . 3

May 2004 1


Road Pavements - Unbound Materials NG 800 General 1 Advice on the design and construction of

sub-bases is published in the U.K. Highways Agency Design Manual for Roads and Bridges (DMRB) Vol. 7 as amended by the NRA DMRB.

2 IS EN 13285 specifies the requirements for unbound mixtures used for construction and maintenance of roads, airfields and other trafficked areas. Under the construction products directive this standard must be fully implemented. All 800 series unbound mixtures must comply with IS EN 13285. The requirements for aggregates used in mixtures complying with IS EN 13285 are defined with appropriate cross reference to IS EN 13242.

3 Because IS EN 13285 mixtures are not directly equivalent to the established types of granular subbase material specified in previous editions of the Specification for Road Works the gradings and material properties chosen reflect a material of similar quality and product conformity. The grading requirements for the materials specified in accordance with the standards IS EN 13285 and IS EN 13242 refer to gradings carried out with the ISO 565 series of sieves.

4 Presently insufficient data exists on the correlation details of the methylene blue and liquid limit tests and therefore it is not considered satisfactory for the purpose of determining harmful fines content in the fine aggregate.

5 Sonnenbrand of basalt is a type of rock decay that is tested in order to determine the susceptibility of certain types of young basalt aggregates, found in some European countries, to degradation through mineralogical instability. This phenomenon is not experienced and it is not anticipated that this test will be applied in Ireland. It is recommended that

category SBNR (No Requirement) is adopted, although further information should be obtained on the susceptibility of imported basalt aggregates.

NG 802 Compaction 1 Sub-Clause 802.5 (viii) permits

combinations of different types of compacting equipment provided each type contributes its correct proportion of the total compactive effort. Thus if a machine when operated singly is required in Table 8/1 to apply a minimum of X passes and that same machine actually applies K passes, then the sum of the values of K/X for each of the types of plant used in combination should equal or exceed unity.

NG 803, 804 and 805 Granular

Material Types A, B and C 1 Clause 803 material allows the use of

recycled crushed mixed concrete aggregates as defined in Annex A of IS EN 13285. In accordance with the requirements of IS EN 13285 the composition of mixtures containing recycled crushed mixed concrete aggregates shall comply with Table A.1 of Annex A. The compositions in this table reflect established practice in some countries. Recycled Crushed Mixed Concrete Aggregates in accordance with IS EN 13285 allows for the inclusion of masonry as a component of the mix. Crushed masonry may include crushed concrete brick or block, or cut natural stone or rubble.

2 Clause 804 excludes all gravels from

Granular Material Type B. In practice clean boulders and cobbles retained on a 100 mm sieve can be crushed to produce a satisfactory Granular Material Type B.

3 The magnesium sulphate soundness test

should initially be used for source approval of aggregates and thereafter only in cases where the Employer's Representative suspects their durability. Where local experience indicates that an aggregate with a higher soundness category than that specified may be acceptable, this value should be inserted

May 2004 2


in Appendix 7/1. The water absorption test can be used as a routine check test of such aggregates. Where required, details of the tests should be scheduled in Appendix 1/5.

4 In the past gravel meeting the

specification requirements for Granular Material Type C has performed successfully in Irish road pavements. In areas where suitable crushed rock is not available locally, consideration should be given to using gravel complying with Clause 805 on less heavily trafficked roads. Because of the variability in naturally occurring gravels, control of the quality of such materials is important.

5 IS EN 13285 details additional

requirements to control individual batches of unbound mixtures with overall grading Categories GA, GB and GO within a system of factory production control. The supplier must nominate a supplier declared value for the intermediate sieves in the grading envelope as part of the system of factory production control for the mixture. The nominated value must lie within the supplier declared value grading range applicable to the overall grading category in Table 6 of IS EN 13285. Individual batches are then assessed using the tolerances in Table 7 of IS EN 13285, applied to the supplier declared values. As explained in Annex B (informative) of IS EN 13285, the use of tolerances does not change the overall grading range.

6 IS EN 13285 Table 8 also includes

requirements for the calculated difference between the values of percentage by mass passing selected adjacent sieves. These requirements are to ensure a ‘well graded’ mixture by controlling the continuity of the grading curve.

7 Whilst there is no specified moisture

content for laying and compacting unbound mixtures to Clause 802, in order to satisfy the requirements of this clause it will be necessary to carry out these operations at the optimum moisture content or within the range identified in the applicable clauses.

8 It is important to maintain the material

within the optimum moisture content range stated in the applicable clause for each mixture. The method of maintaining the mixture within this range may depend

on environmental conditions and the time to overlay.

NG 806 Wet-Mix Macadam 1 Experience has shown that limestone

aggregate produces the most satisfactory wet-mix macadam where satisfactory production systems are in place. Satisfactory wet-mix macadam can be produced with aggregates other than limestone, but requires a greater control during production and a higher rate of quality control testing than is necessary with limestone.

2 Past experience indicates that most well graded wet-mix macadams have an optimum moisture content of about 3%-4%, and that high in situ strengths can be mobilised in wet-mix macadam if it is compacted at about 0.5%-1.0% below the optimum moisture content in accordance with the requirements of Table 8/1. However the optimum moisture content for some unbound materials with low fines content may be difficult to determine accurately and, where uncertainty about the optimum moisture content occurs, guidance on the most suitable moisture content range for laying and compaction can be obtained by carrying out CBR tests at a range of moisture content so that the appropriate moisture content range for mobilising maximum strength can be determined. The compaction technique to be used for this purpose should be the vibrating hammer method described in IS EN 13286 - 4. Further information on this topic is given in An Foras Forbartha report RC188 and Environmental Research Unit report RC 358.

May 2004 3


This page is intentionally blank.

May 2004 4


Notes for Guidance on the Specification for Road Works Road Pavements – Bituminous Bound Materials

May 2005 1

ROAD PAVEMENTS – BITUMINOUS

BOUND MATERIALS

Contents

Clause Title Page

NG 901 Bituminous Base and Surfacing Materials ………………………………. 3

NG 902 Reclaimed Bituminous Materials ………………………………………... 5

NG 904 Not Used ………………………………………………………………… 5

NG 905 Not Used ………………………………………………………………… 5

NG 908 Not Used ………………………………………………………………… 5

NG 910 Rolled Asphalt Surface Course (Recipe Mix) …………………………... 5

NG 911 Rolled Asphalt Surface Course (Design Mix) …………………………... 5

NG 912 Close Graded Macadam Surface Course ………………………………... 6

NG 913 Not Used ………………………………………………………………… 6

NG 914 Not Used ………………………………………………………………… 6

NG 915 Coated Chippings for Application to Rolled Asphalt Surface Course ….. 6

NG 916 Open Graded Macadam Surface Course ………………………………… 6

NG 917 Cold-milling (Planing) of Bituminous Bound Flexible Pavement ……… 6

NG 918 Slurry Sealing …………………………………………………………… 7

NG 919 Surface Dressing ………………………………………………………… 7

Contents – continued on next page



May 2005 2

ROAD PAVEMENTS – BITUMINOUS BOUND MATERIALS

Contents – continued

NG 920 Bond or Tack Coats and other Bituminous Sprays ……………………… 9

NG 921 Surface Texture of Bituminous Surface Courses ………………………... 10

NG 922 Not Used ………………………………………………………………… 10

NG 923 Not Used ………………………………………………………………… 10

NG 924 Resin Based High Skid Resistant Surface Treatment …………………… 10

NG 925 Testing of Bituminous Mixtures and Their Component Materials ……… 11

NG 926 Not Used ………………………………………………………………… 11

NG 927 Not Used ………………………………………………………………… 11

NG 928 Not Used ………………………………………………………………… 11

NG 929 Design, Compaction Assessment and Compliance of Base and Binder

Course Macadams ……………………………………………………….. 11

NG 930 Heavy Duty Macadam Base with Grade 50 Penetration Binder ………... 13

NG 932 Dense Macadam Base with Grade 50 Penetration Binder ………….…… 13

NG 933 Heavy Duty Macadam Binder Course with Grade 50 Penetration Binder. 13

NG 934 Dense Macadam Binder course with Grade 50 Penetration Binder…...… 13

NG 935 Not Used ………………………………………………………………… 13

NG 936 Not Used ………………………………………………………………… 13

NG 937 Not Used ………………………………………………………………… 13

NG 938 Porous Asphalt Surface Course ……….………………………………… 13

NG 942 Thin Surface Coarse Systems …………………………………………… 13



May 2005 3

Road Pavements – Bituminous Bound Materials

NG 900 General

1 Advice on the design, construction and

maintenance of bituminous roads is

published in The Design Manual for

Roads and Bridges (DMRB) Volume 7.

NG 901 Bituminous Base and

Surfacing Materials

General

1 Current pavement design methods may

give the Contractor a choice of

construction materials. The extent of this

choice should be stated in Appendix 7/1

and the alternative materials identified by

reference to the Specification Clause

numbers.

The designation of products such as

DBM50 refers to the penetration

reference for 40/60 grade as defined in

Table 1 of IS EN 12591. The penetration

reference is defined in the „Foreword‟ of

BS 4987-1 and for most bitumen grades

is a mid-point of the permitted

penetration range which is regarded as a

target for that grade.

Requirements included in Appendix 7/1

may include penetration reference of

binder and binder modifier and aggregate

properties such as polished stone value,

aggregate abrasion value, Los Angeles

coefficient value, magnesium sulfate

soundness value and water absorption as

specified in IS EN 13043.

DMRB, Volume 7, HD 36 gives guidance

on aggregate properties for new

bituminous surfacings. In general the

minimum Polished Stone value (PSV)

requirement for aggregates for surfacing

materials and pre-coated chippings for

application to HRA surface courses shall

be PSV60declared. In some heavily

trafficked, high stress locations more

onerous physical properties will apply.

Reference should be made to Table 3.1 of

DMRB, Volume 7, HD 36.

Aggregates for Bituminous Materials

2 With the implementation of IS EN 13043

“Aggregates for bituminous mixtures and

surface treatments for roads, airfields and

other trafficked areas”, it will be

necessary to incorporate the mechanical

test values and test methods specified in

this standard.

The use of natural and artificial

aggregates is permitted.

There is no current test procedure for

cleanness other than the requirement for

aggregates to meet the specified BS 594

and BS 4987 requirements for the fraction

passing the 0.063 mm sieve. Provided the

aggregates meet requirements for particle

size distribution, based on the washing

and sieving techniques of IS EN 933-1, it

is considered the cleanness aspect of the

aggregates will be acceptable.

However, the coarse aggregates should be

checked to ensure they are not coated

with clay or silt after having gone through

the drying plant and before being coated

with bitumen.

The soundness value test should initially

be used for source approval of

aggregates, and thereafter only in cases

where their durability is suspect. The

water absorption test can be used as a

routine check test of such aggregates.

When required, details of the tests should

be scheduled in Appendix 1/5.

A water absorption value of 2% or less

for coarse aggregates is considered to

indicate a satisfactory aggregate source.

(This value may be exceeded by fine

aggregates). When absorption values of

coarse aggregates exceed the

recommended WA242, magnesium sulfate

soundness tests should be carried out for

compliance purposes.

Volume 2 home page

Transporting, Laying and Compacting

3 The purpose of Clause 901 is to place

reliance on mechanisation of operations

to facilitate compliance with the thickness

and surface regularity requirements,

particularly of surface courses, and to

ensure operation of the paver is such that



May 2005 4

hand raking and making up of surface

course material is virtually eliminated,

except at edges and joints. Hand-laying is

also limited to places where operation of

a paver is impracticable.

4 Clause 901 does not relate to laying

waterproofing systems on bridge decks.

The laying of hot paving materials on

bridge deck waterproofing systems

should be adequately supervised to ensure

the waterproofing system is not damaged

by excessive heat. Stockpiling of hot

materials should take place off the

structure or on suitably protected areas.

5 There is no conclusive evidence to show

all vibratory rollers provide consistently

greater compaction than that achieved

with conventional deadweight rollers. It is

desirable that compaction should be

maximised so a requirement for site trials

of vibratory rollers, proposed as an

alternative to conventional deadweight

rollers, is included. The trial should not

only determine the required number of

passes of the vibratory roller, but also the

frequency and amplitude of the vibrating

rolls and roller speed. Additional advice

is included in TRRL Report LR 1102.

Where evidence is provided by the

Contractor to indicate a proposed

vibratory roller will achieve adequate

compaction, the evidence should be

representative of the conditions likely to

be encountered in the Works. Factors

which are relevant include types of

compacted material and source of

aggregate, the thickness and temperature

of layers and the condition of the

proposed roller compared with that

previously used.

6 The frequency and amplitude of vibrating

roll and travelling speed of the roller

which have been found to be satisfactory

in the trials should be used for

compaction.

7 The assessment of compaction of base

and binder courses shall normally be

carried out by means of PRD tests or by

determination of air voids content for

design mixes. PRD is the ratio of the bulk

density of core samples of laid material

compared with the refusal density of the

material when determined from the same

core samples. It is therefore a direct

measure of the degree of compaction of

the material.

8 When reliance is placed on a method

specification for the control of

compaction of bituminous materials,

close attention should be paid to the

temperature of the material. BS 594-2, BS

4987-2 and Clauses 930, 932 to 934 lay

down minimum temperatures at which

compaction should be substantially

complete. It will therefore be necessary to

commence rolling at temperatures

exceeding the minimum, making due

allowance for weather conditions, which

may affect the rate of cooling of the laid

material. For all practical purposes where

material is tested for adequacy of

compaction in accordance with Clauses

929, the requirements should have been

achieved above the minimum rolling

temperature. Any subsequent rolling at

temperatures below the minimum should

only be necessary to remove roller marks

and regulate the surface.

9 BS 4987: Part 2 provides for compliance

testing based on material laid in areas of

1,000 m2 or the material laid in any one

day where this is less than 1,000 m2. At

the discretion of the Employer's

Representative a reduction may be made

in the amount of testing by not carrying

out the full PRD test method on each area

of 1,000 m2 or days work when less. On

those areas which are not cored, nuclear

density gauges may be used on a relative

basis, having first established the gauge

density reading equivalent to a level of

compaction of 93% PRD for a particular

source of material. Two determinations of

density using a nuclear density gauge

should be substituted for each core.

Nuclear density gauges should only be

used for control purposes. Compliance

with the Specification should be judged

from values determined from the coring

procedure specified. Further savings in

the amount of testing can be made by not

carrying out the part of the test method

which determines refusal density of the

core material. This should only be

omitted, however, once a consistent level

of refusal density has been established for

a particular source of material. In both

cases full PRD tests should be carried out

on a regular basis alongside the modified

testing methods. Further information

regarding the use of nuclear density

gauges is given in the Transport and Road

Research Laboratory Supplementary

Report SR 754.



May 2005 5

10 The objective of the PRD specification is

to obtain uniform compaction of 95%

Refusal Density in the dense macadam.

The Specification limit of 93% has been

chosen following precision trials which

have indicated a standard deviation for

the test used on macadam base of about

1.5% on single core pairs (TRL Reports

SR 717 and CR1 refer). Using this data it

can be shown that for a mean density of

95% Refusal Density not more than one

in one hundred results of the average of

three core pairs should fall below 93%.

For compliance with the Specification

this can be taken as no result falling

below 93%.

NG 902 Reclaimed Bituminous

Materials

1 Reclaimed bituminous materials include

millings, planings, return loads from site

and offcuts from bituminous layer joint

preparation. Return loads can include

bituminous materials rejected from site

due to temperature problems or visual

defects. Waste bituminous materials

stockpiled at the plant may also be

suitable.

2 To ensure homogeneity and consistency

of the final product, all reclaimed

materials should be granulated or crushed

or similarly prepared before mixing with

fresh aggregate and bitumen.

3 A check on the penetration and

penetration index of the binder recovered

from mixtures containing reclaimed

bituminous materials must be performed

when the amount of reclaimed

bituminous materials to be added to the

mix exceeds 10%. Mix design procedures

are not specified, these being left to the

expertise of the Contractor. The

requirement for trials to ensure that the

materials comply with the requirements

of this Clause in addition to the

requirements of this Series should be

sufficient to ensure the materials are

suitable for use in the pavement.

4 Materials containing tar or tar-based

binders should not be recycled. The

environmental impact of recycling

materials containing polymer-modified

binder should be assessed, together with

the properties of the mixture, and

reported to the Employers Representative.

There is no requirement to check the

quality of the aggregate in the recycled

materials, it being presumed that as these

come from existing pavements, or from

material that was intended for new works,

and that the aggregate quality is adequate

for reuse.

NG 904 Not Used

NG 905 Not Used

NG 908 Not Used

NG 910 Rolled Asphalt Surface

Course (Recipe Mix)

1 The composition of the permitted mixture

shall be in accordance with BS 594-1 and

is listed in Table 9/2.

NG 911 Rolled Asphalt Surface

Course (Design Mix)

1 The special requirements included in

Appendix 7/1 may include the

appropriate table and column numbers of

permitted mixtures from BS 594-1.

Additionally the required Marshall

stability and flow and the required

properties for coated chippings, such as

PSV and AAV, should be included.

2 The method of determining the design

binder content for surface course

mixtures is described in BS 598: Part

107. Determination of the target binder

content, by adjustment of the design

binder content, is described in BS 594-1

for surface course design mixtures. The

target binder content is always at or

above the design binder content. The

design binder content is the quantity of

bitumen required for the mix in order to

achieve the required stability. There are

occasions when this design binder content

would be too low for long term

durability. Therefore, a minimum target

binder content is required by the British

Standard and this may be above the

design binder content.

3 The required Marshall stability and flow

values, when tested on laboratory

specimens made in accordance with BS

598: Part 107, should comply with the



May 2005 6

requirements of BS 594-1, Annex B.

Verification of the design should be

carried out in accordance with that

Annex. Samples prepared from plant-

produced material, and tested in

accordance with the procedures of BS

598: Part 107, are not directly comparable

with those obtained on laboratory

prepared specimens. The range of values

of Marshall stability given in BS 594-1,

Annex B permit a number of mixtures

using locally available materials; however

the specified stability should be the mid-

point of the range.

4 Checks on production material should

normally be by analysis, in accordance

with BS 598: Part 102 and comparison

with the composition of the design,

together with checks on the properties of

the constituent materials. Advice on the

possible use of Marshall tests on

specimens produced from production

material is given above.

NG 912 Close Graded

Macadam Surface Course

1 Table 2.2.I from NRA addendum to

DMRB Vol. 7 standard HD 36 does not

allow the use of Coated Macadams on

High Speed roads. Accordingly, it is for

use on low speed roads where the 85th

percentile traffic speed is 50 km/h or less.

2 The nominal size of aggregate for close

graded surface course will depend upon

the required layer thickness for the

compacted surface course and should be

selected from Table 9/2 and stated in

Appendix 7/1.

3 The traffic category in relation to the

tables of BS 4987-1 should be specified

in Appendix 7/1. BS 4987-1 Category A

traffic may be taken as being equivalent

to 2.5 million standard axles (msa), or

more, for a 20 year design life.

4 Special requirements included in

Appendix 7/1 may include grade of

binder and type of aggregate. Advice is

given in BS 4987.

NG 913 Not Used

NG 914 Not Used

NG 915 Coated Chippings for

Application to Pre-mixed

Surfacings

1 It has been suggested that the use of cold

pre-coated chippings from site stockpiles

can cause rapid cooling of the surface of

hot rolled asphalt surface courses,

potentially contributing to premature

chipping loss. During periods of low

ambient air temperature, it may be

prudent for Contractors to consider the

use of covered stockpiles.

2 Design mix rolled asphalt surface course

materials are often stiffer than recipe mix

compositions. They are less workable

and, to obtain effective compaction and

retention of chippings rolled into the

surfacing, constraints on laying

conditions may have to be considered.

3 Coking of chippings can occur during

prolonged storage at high temperature.

BS 594-1 covers action to be taken,

including cooling of the chippings and

limiting the height of stacking to reduce

the possibility of coking occurring.

4 The hot sand test described in BS 598:

Part 108 provides a means of identifying

and rejecting chippings which are

unlikely to be retained in the surfacing

under traffic due to coking or

contamination.

NG 916 Open Graded

Macadam Surface Course

1 The nominal size of aggregate for open

textured macadam surface course will be

0/10 mm as stated in Table 9/2.

2 Special requirements included in

Appendix 7/1 may include grade of

binder and type of aggregate. Advice is

given in BS 4987.

NG 917 Cold-Milling (Planing)

of Bituminous Bound

Flexible Pavement

1 Clause 917 relates to the milling of

pavements on existing road carriageways.

It is not relevant to the rectification of

bituminous layers in new construction.



May 2005 7

Rectification of new construction should

be carried out in accordance with sub-

Clause 702.10.

NG 918 Slurry Sealing

These notes include and extend in some

respects the main points of advice on slurry

sealing given in BS 434: Part 2.

1 For works of magnitude the full control

testing programme should be undertaken,

but for a small area of work it may be

preferred to judge the material on the

basis of the required field trials.

2 Gradings of blended aggregate for 1.5

mm and 3 mm thick finished surface are

given. In the event of a greater thickness

being required the grading should be

revised in consultation with the

manufacturer of the particular process.

3 The usual additives used to control

consistency, mix segregation, and setting

rate are Portland cement (CEM I) to IS

EN 197 : Part 1 or hydrated lime to BS

890. However, it is advisable to consult

the emulsion manufacturer for advice on

this point.

4 Techniques for mixing and laying vary

according to the type of emulsion used

and in some cases the use of a cationic

tackcoat Class K1-40 is recommended

before laying the slurry. The machines

should be equipped to give a light spray

of water onto the tackcoat film just before

the slurry is spread. After the slurry has

set sufficiently it may sometimes be

necessary to roll it with a multi-wheeled

smooth tread rubber-tyred roller. The

manufacturer of the emulsion should be

consulted on the desirability of rolling

and also tack coating.

5 Variation in colour of the slurry seal,

which can sometimes occur, should

normally be self-rectifying within 24

hours, but this period may be extended

depending on weather conditions and

traffic. With some processes using

hydrated lime as the additive a degree of

efflorescence can become apparent during

the first 24 hours and persist for a while

afterwards. This is not an indication of

uneven mixing or segregation and it

should disappear after 2-3 weeks.

6 Slurry seal made with emulsions specially

formulated for the slurry seal process is

sufficiently stable to form a free flowing

slurry and is capable of sustaining this

condition throughout the laying procedure

adopted. Setting time of the mix may be

within a few minutes or extended as

desired. For less rapid setting slurry the

emulsion should be Class A4 slow

setting. This can be used where the rate of

set is not important, i.e. when work is

being carried out on areas where the

slurry can be expected to dry out

naturally before being subjected to traffic

or rain.

NG 919 Surface Dressing:

Recipe Specification

1 This specification is of the conventional

Recipe/ Method type.

2 The surface dressing should be designed

in accordance with the requirements of

the Institute of Asphalt Technology (IAT)

guidelines for Surface Dressing in Ireland

2003.

3 The Contractor should state with his

tender submission the source of his

aggregates and provide accredited results

of the physical and geometrical properties

for each source.

4 The Contractor should state the source

and type of binder he proposes to use

together with the data required by

Appendix 7/21.

5 The Contractor‟s attention should be

drawn to the need for best practice as set

out in Section 5 of the IAT guidelines.

6 Product Identification Test: Penetration,

softening point, Fraass Brittle point,

toughness, tenacity, and other viscosity

measurements are not in themselves

sufficient as product identification tests,

although they can be useful as quick or

low cost Quality Assurance tests to check

consistency from load to load of the

binder. The Contractor should provide a

Binder Data Sheet giving at least the

information specified.

7 The binder sprayer should be checked for

accuracy of transverse distribution using

the test method stated. This assesses the

ability of the spraybar in real working



May 2005 8

conditions and may be carried out quickly

using the correct binder. The Depot Tray

test to BS 1707 averages the rate of spray

over 60 seconds in a static condition and

therefore does not simulate site

conditions such as the influence of

varying spraybar height above the road,

or any tendency to pump or pressure

surging. The performance of the binder

sprayer is classified in accordance with

the value of the coefficient of variation

(cv) for the regularity of transverse

distribution. The class required for the

sprayer, to be specified in Appendix 7/21,

should be selected from Table NG 9/9.

TABLE NG 9/9: Accuracy of Binder

Sprayer

Site

Coefficient

of Variation

(Cv)

Class

Motorways and

Dual

Carriageways

< 10% 3

Single

Carriageways < 12% 2

Lightly

Trafficked

Single

Carriageways

< 15% 1

8 The compiler should specify the

minimum PSV required for a particular

site together with the maximum AAV.

9 The chipping spreader should be checked

for accuracy of transverse distribution

using the stated method. With multi-

layered surface dressings it is very

important to obtain the correct rate of

spread of the larger chipping as under or

over chipping will reduce the quality of

the dressing and may result in it failing to

perform as a multi-layered system.

Particular attention should be paid to the

rate of spread in the vicinity of the

overlaps in the chipping spreader

mechanism as the performance,

particularly of worn spreaders, can be

significantly different in these areas from

the rest of the spreader.

10 Remedial work to the existing road, for

example, patching, should be carried out

prior to surface dressing. It should be

carried out in such a manner that the

hardness and macrotexture of the

remedial work is sufficiently similar to

the rest of the road to avoid problems of

variable appearance and behaviour in the

completed dressing for at least the

duration of the maintenance period; for

example, patching using close textured

bitumen macadam should be carried out

in the previous summer otherwise it will

absorb bitumen into the voids and chip

loss may ensue. If the existing surface is

hot rolled asphalt then the patches will

have to be laid with hot rolled asphalt and

preferably sufficiently far in advance of

the Works for the binder to wear off the

surface otherwise there will be excess

binder in that area. Patches should not

have a horizontal sealing strip applied as

this will show through the dressing very

rapidly and has been known to initiate

fatting failure. The use of binder rich

materials should not be used to pre-seal

areas especially longitudinally in the

wheel tracks as the dressing will fat up

and macrotexture will be lost.

11 Cleanliness of the existing road surface is

extremely important. The binder will

adhere only to the top layer of the

material on which it is sprayed and if

there is mud or dust then the surface

dressing will fail rapidly, through the lack

of bond with the underlying structure. It

may be necessary in some circumstances

to use high pressure washing to remove

strongly adherent material. The masking

of street furniture should be carried out

with care as the interface between the

furniture and the surrounding surface

should be sprayed in order to exclude

water from the road structure, but any

cover must not be rendered immovable.

12 The mode of operation of surface

dressing contracts can necessitate the

adoption of techniques requiring

equipment for traffic management and

safety over and above that normally

required by static works. For example,

where traffic lights are required as part of

the traffic management scheme, in order

to facilitate the relocation of the lights,

some sites may require the provision of

additional sets over and above the

minimum necessary, so that the work

progresses with a minimum of

interruption and disruption to road users.

13 In order to ensure that only the binder is

overlapped on transverse joints the

chipping application should stop short of

the end of the binder film wherever

possible. When spraying from a

completed section some hand canning



May 2005 9

and masking of the end is necessary in

order to abut the joint without forming a

ridge.

14 Longitudinal joints should have slightly

overlapped binder films obtained by

leaving a wet edge approximately 100

mm wide. Care should be taken to ensure

that double chipping does not take place

as this will form a ridge. As the binder

overlap is generally in a lightly trafficked

location the additional thickness of binder

film is unlikely to be a problem.

Quartering (spraying of a part bar) should

be avoided wherever possible, but may be

necessary at tapers and other similar

locations. An overlap (up to 300 mm)

should be provided to ensure full rate of

spread of binder at all points.

15 The frequency of testing for rates and

accuracy of spread of binder and

chippings should be stated in Appendix

1/5. The rate of testing should be reduced

once the Contractor has demonstrated his

ability to consistently meet the

requirements. The more consistent a

Contractor is in his work the lower the

rate of testing that can be employed, a

minimum rate of 1 test per day could be

reached if the Contract is large enough.

The Employers Representative may carry

out testing at audit frequency, typically at

about 10% of the specified frequency for

the Contractor. If the results from this

audit testing are significantly different

from those of the Contractor, for

example, by more than the reproducibility

of the test, then the Employers

Representative and the Contractor should

work together to determine the source of

difference. With this type of specification

it is important that all the required testing

is carried out, preferably under

supervision, as it is not possible to assess

the rate of spread of either binder or

aggregate subsequent to the spreading of

those materials.

16 Traffic control immediately after surface

dressing is most crucial in the production

of good quality surface dressing. On high

speed roads the best way of doing this is

to introduce convoy vehicles into the

traffic stream in order to keep speeds low.

The deployment of 20 kph signs, when

permitted, is an extremely useful method

of inducing caution in the road user. If

possible cones should be used to vary the

lane position so that as much of the

dressing as possible is subjected to slow

speed traffic. The lane should be suction

swept prior to removal of the convoying

vehicles from the traffic stream, care

being taken not to remove chippings,

which would otherwise become part of

the mosaic. With multi-layered surface

dressing it may not be necessary to

sweep, unless there are windrows which

should be removed. If the work has been

carried out correctly there will be no

loose large chippings. Provided there are

no loose large sized chippings it may be

useful to gradually increase the speed of

the convoying vehicles to disperse excess

small chippings to the side of the lane for

subsequent removal.

NG 920 Bond Coats, Tack

Coats and Other

Bituminous Sprays

Bond Coats and Tack Coats

1 This Clause specifies tack coats and bond

coats for coated macadam, hot rolled

asphalt, porous asphalt, and regulating

courses. Bond coats and tack coats are

applied prior to overlay to promote the

development of a homogenous pavement

structure. Bond is particularly important

in highly stressed areas. Useful advice is

provided in the Design Manual for Roads

and Bridges (DMRB), Volume 7, HD37.

2 Bond coats and tack coats promote

adhesion between layers of material. The

choice of tack coat or bond coat depends

on the condition of the substrate, the

stiffness and binder content of the layers

and the type of site. Tack or bond coat

should be used between all bituminous

layers. A bond coat may be more

appropriate where materials are to be laid

less than 30 mm thick, or where a

particular site has a binder lean substrate

and permeability is considered a problem.

Advice on the choice of tack coat or bond

coat, together with recommended target

application rates, is provided in BS 594-2

and BS 4987-2 for hot rolled asphalts and

coated macadams, respectively. Bond

coats generally have a higher binder

content containing modifiers and are

usually used at a higher rate of spread

thus promoting improved adhesion with

some waterproofing capability, important

to prevent water ingress below porous or

permeable materials. Additional



May 2005 10

information is provided in HD37 (DMRB

7.5.2).

3 Rates of spread of binder should follow

the recommendations of Series 900 and

the British Standards as appropriate.

Rates of spread may need to be altered for

varying macrotexture and porosity of the

existing road and an increased rate at the

kerb or road edge is beneficial to

minimise water ingress where compaction

by traffic is least.

Bituminous Sprays

4 Bituminous sprays may be used to seal

and protect earthworks, drainage media,

recycled material and cementitious

materials including cement-stabilised soil.

The primary purpose is not necessarily to

promote bond with an overlay, but to

limit the evaporation or ingress of water

and in cementitious materials, to facilitate

proper curing.

NG 921 Surface texture of

Bituminous Surface

Courses

1 The depth of surface macrotexture is

more important on high speed roads than

on low speed roads.

2 Embedment of chippings, resulting in

loss of surface macrotexture and reduced

resistance to skidding at high speeds,

accompanies deformation. This problem

occurs most frequently in the slow lane of

roads carrying a high volume of heavy

commercial traffic.

3 The level of surface macrotexture on high

speed roads required for 1000 metre

sections of carriageways with bituminous

surfacings is an average of 1.5 mm or

more. This is easily achieved with surface

dressings. Experience with rolled asphalt

surface course indicates that the required

macrotexture can be consistently

achieved if proper attention is paid to all

the relevant factors at time of laying and

applying the chippings.

4 To achieve high rates of spread,

chippings must be of good shape and free

flowing. The chipping machine must be

capable of spreading coated chippings at

a uniform and consistently high rate.

Regular checking of the rate of spread,

together with any necessary adjustments

to the machine, should be carried out

throughout the laying of the surface

course.

5 Whilst measurement of macrotexture

depth for compliance purposes is to be by

the volumetric patch technique specified

in IS EN 13036-1 only, the TRL Mini

Texture Meter, may be used as a

screening procedure, as recommended by

BS 598: Part 105.

6 Calibration trials should be undertaken at

the start of work to derive a relationship

between the volumetric patch technique

and the TRL Mini Texture Meter.

7 In the event of dispute, or discrepancy

between the two methods, only results

obtained using the volumetric patch

technique will be considered for


8 Calibrations carried out on site are only

applicable to that site and that surfacing.

9 Sensor Measured Texture Depth (SMTD)

is numerically different from

macrotexture depth measured by the

volumetric patch technique. Volumetric

patch macrotexture depth is a

measurement of the average depth of the

hollows in the surface below the general

level of the peaks. SMTD is the standard

deviation of the sample height

measurements.

NG 922 Not Used

NG 923 Not Used

NG 924 Resin Based High Skid

Resistant Surface

Treatment

1 High skid resistant durable surface

treatments are now available which

consist of a thin film of resin based

binder sprayed on to a sound surface and

covered with small size calcined bauxite

aggregate of high PSV. Surface

treatments comprising high PSV

aggregates mixed with resin before

spreading on the surface do not comply

with the requirements of Clause 924.



May 2005 11

2 Experience has shown these surfacings

are highly effective in reducing traffic

accidents on sites with high traffic density

and skidding risk. Typical sites are the

approaches to signal controlled junctions,

roundabouts and pedestrian crossings

subject to a heavy flow of vehicles.

3 These surfacings are very expensive,

particularly where productivity is affected

by the geometry of the site and the

number of areas to be treated. They

should only be used after consideration

has been given to the use of cheaper

alternative measures such as surface

dressing with a high PSV natural

aggregate, improved road signs and

markings, improved street lighting, etc.

4 The Specification is based on high skid

resistant surface treatments which have

been proven over a number of years and

are known to give very good skid

resistance and a high level of durability.

The treatment should only be used on

surfaces which are dry, clean, hard and

sound. Surfaces not suitable for treatment

include slurry seals, fatted and multilayer

surface dressings and surface dressings

over soft or unsound bases. Performance

on concrete may not be as good as on

bituminous surfacings.

5 Attention is required to ensure the surface

is properly prepared. The surface to

which resin is applied shall be dry and

free from dust, oil, excess bitumen and

other contaminant that may cause lack of

adhesion.

6 The level of relative humidity and

temperature affects production rates so

levels should be stated in Appendix 7/1.

The manufacturer‟s recommendations

should be sought for the particular system

in use.

7 The polished stone value test cannot be

carried out on material supplied to site.

The supplier has to provide a suitably

graded sample.

NG 925 Testing of Bituminous

Mixtures and Their

Component Materials

1 Methods of sampling and testing of

mixtures or materials not covered by a

British Standard or European Norm, eg

sampling plates behind the paver, should

be specified in Substitute or Additional

Clauses. Non-standard sampling

procedures are not recommended.

2 Where alternative sampling procedures

are given in the British Standard or

European Norm it is recommended that

site sampling should be adopted.

3 The frequency of acceptance testing for

mixed materials should be approximately

one test for every 100 tonnes of material

laid in straight runs, but not less than two

samples of mixed material manufactured

to any one specification should be taken

daily. On contracts where the output of

mixed materials is large, frequency of

testing may be reduced if the quality of

the material being supplied is consistently

satisfactory.

NG 926 Not Used

NG 927 Not Used

NG 928 Not Used

NG 929 Design, Compaction

Assessment and

Compliance of Base and

Binder Course Macadams

1 The Specification for Road Works (SRW)

requires that where a design mix is

approved for bitumen macadam, DBM50

or heavy duty macadam (HDM50), for

use as base or binder course, then

compaction trials shall be carried out,

unless otherwise stated in Appendix 7/1.

Volume 2 home page

2 Clause 929 permits Contractors to design

macadams to meet an „end product‟

specification and represents a major

departure from the traditional „recipe‟

approach previously used in Ireland and

the UK. BS 4987-1 sets out well

established recipes for macadams based

on past experience but regardless of

material source or type. Clause 929

requires that a Contractor‟s proposed

target aggregate grading and target binder

content lie within the fixed composition

envelopes and binder contents specified

in BS 4987-1. However, in order to allow

as much freedom as possible to the



May 2005 12

Contractor in designing a mix appropriate

to the materials to be used, the tolerances

that may be applied to the proposed target

aggregate grading and the target binder

content are set out in Table 9/5. The

Contractor‟s design trials may involve

mixtures compacted in the laboratory or

field laying trials, at the option of the

Contractor. This note should be read in

conjunction with NG 929.11.

3 BS 4987 provides no guidance on the

design of mixes to achieve stable

mixtures resistant to deformation nor any

guidance on trials to validate mix designs.

The objectives of the Job Mixture

Approval trial are to demonstrate that the

mix will be stable and resistant to

deformation and that it will be durable.

This should be achieved by ensuring that

there is always a minimum air void

content in the mixture even at the

ultimate state of compaction at the

Refusal Density, as determined by the

procedures set out in BS 598: Part 104,

and by ensuring that the in situ void

content is not excessive. It should be

noted that a design procedure is not being

proposed, rather a means by which a

Contractor‟s proposals for a macadam

mixture may be evaluated.

4 Nuclear density gauges in general use

typically penetrate to a depth of

approximately 80 mm. Where layer

thicknesses exceed 80 mm it is especially

important that cores are visually

inspected to ensure that they are

reasonably uniform. A slight increase in

voidage at the base may be expected but

it should not be excessive. If voidage is

excessive additional cores will establish

the area affected. Further information

regarding the use of nuclear density

gauges is given in the Transport and Road

Research Laboratory Supplementary

Report SR 754.

5 The average binder content by volume at

each location in the trial area is

determined to check that the minimum

binder content of the Contractor‟s mix

design exceeds the minimum volume

specified to ensure the durability of the

mixture.

6 The stiffness modulus and deformation

resistance determined from cores in the

trial area are required to enable both

Contractors and Employers

Representatives to gain experience of

values achievable with mixtures currently

in use.

7 When assessing trials, it is necessary to

ensure the materials can be laid to

achieve the regularity requirement

specified in the Series 700.

8 On completion of successful trials, the

target aggregate grading and target binder

content are established by the Contractor.

This becomes the mixture (referred to as

„the job standard mix‟ in some

specifications), about which the

tolerances in Table 9/5 are applied for the

purposes of assessing compliance.

9 The compaction of macadam layers

should be checked for compliance as each

constructed layer is completed. The

maximum depth of sample permitted in

the PRD test is 150 mm. This is also the

maximum layer thickness permitted in BS

4987.

10 If a layer exceeds 150 mm thickness it

should not do so by more than the

tolerance permitted in Clause 702, which

is 30 mm. The maximum layer thickness

(core length) is therefore 180 mm. Should

a core exceed 150 mm in this manner,

then the lower excess portion should be

removed by saw-cutting which will

increase the core density slightly. This is

not unexpected and reflects the boundary

conditions known to exist.

11 Some aggregate types do not readily

compact in laboratory trials and „full‟

refusal density will not be obtained. It has

been noted in TRL research (SR 717) that

a difference in compaction level can be

achieved with loose mixtures compacted

to refusal in the laboratory, compared to a

core of the same mixture compacted to

refusal after being laid in the field, with

the field mixtures giving lower air void

contents. For this reason, checking of air

void contents at refusal should be

performed on cores from the mat.

Nevertheless, Contractors may use a

laboratory compaction technique in order

to gain an indication of the possible levels

of air void content that might be achieved

on site.

12 Problems have sometimes been

experienced in achieving complete

coating of coarse aggregates in base and



May 2005 13

binder course macadams and this is often

related to the use of a particular aggregate

source. The use of a design approach

should assist Contractors to overcome

this by permitting designed adjustments

to the grading and binder content of the

mixture, subject to meeting the

requirements set out in Clause 929. This

note should be read in conjunction with

NG 930.

NG 930, NG 932, NG 933 and

NG 934 Heavy Duty Macadam

and Dense Bitumen Macadam

with Grade 40/60 Penetration

Binder, Base and Binder

Course

1 The stiffer binder in these materials

requires a higher mixing temperature to

achieve the required binder viscosity and

coat the aggregate properly. A longer

mixing time should be expected with the

increased proportion of filler in heavy

duty macadam in order to distribute the

binder and coat the aggregate properly. It

may be possible for manufacturers to

avoid increased mixing times by

increasing the binder content within the

permitted range. Inspectors should ensure

that the material is properly mixed and

coated, especially with the first deliveries

to the site. Laying temperatures will

normally be higher to achieve the

required workability with stiffer binder.

2 For binder course, the traffic category in

relation to the tables of BS 4987-1 should

be specified in Appendix 7/1. BS 4987-1

Category A traffic may be taken as being

equivalent to 2.5 million standard axles

(msa), or more, for a 20 year design life.

3 Attention is drawn to the notes to Clause

4.5.1 of BS 4987-1.

NG 935 Not Used

NG 936 Not Used

NG 937 Not Used

NG 938 Porous Asphalt

Surface Course

1 Guidance to the requirements specified in

Clause 938 is contained in HD 27

(DMRB 7.2.4).

2 Clause 938 contains requirements for

porous asphalt. The binder shall be

preblended polymer modified bitumen.

3 The type of binder permitted,

requirements for the physical and

geometrical properties of the coarse

aggregate and the traffic category should

be stated in Appendix 7/1. The

specification of specific proprietary

modifiers in Appendix 7/1 is not

permitted.

4 Before use of a modifier or modified

binder the Contractor should provide all

necessary information to enable

evaluation of the modifier to be carried

out and suitable specification clauses for

its use to be prepared.

5 Landscaping operations should preferably

be completed before laying porous

asphalt surface course, to avoid

contamination of the surface.

Volume 2 home page

NG 942 Thin Surface Course

Systems

1 Thin surface course systems are

proprietary bituminous products with

suitable properties to provide a surface

course that is laid at a nominal depth of

less than 40 mm. As such, this

classification can include hot-mixed

asphalts.

2 This Specification for thin surface course

systems is not intended to be an

exhaustive specification for the use of

proprietary-type mixtures, but rather to

form a set of minimum requirements for

Contractors to tender for work.

3 In accordance with HD36 and the NRA

Addendum to HD36 (NRA DMRB Vol. 7

Section 5, Part 1) thin surfacings are for

use with restriction. All thin surfacings

proposed for use shall have obtained prior

approval from the National Roads

Authority and in addition approval for the

specific site where the system is to be

installed.



May 2005 14

Quality Control for Manufacture

4 The initial assessment as to the suitability

of thin surface course systems relies on

the systems, at a minimum, complying

with the quality control requirements in

sub-Clauses 942.2, 942.3 and 942.4 of the

specification for road works. Due to the

introduction of European (CEN) Norms

in the near future, Clause 942 of the

specification attempts to introduce the

methodology employed in specifying thin

surfacings to these standards and the

concept of Factory Production Control.

However, because of the diversity of both

systems and roads on which they may be

applied, compliance with the minimum

requirements in Clause 942 does not

automatically mean that the particular

system is suitable for every situation

where a thin surface course system is

required. The appropriate properties need

to be checked against the properties of the

system as recorded in the quality control

for manufacture and Factory Production

Control documentation.

5 Although compliance with Clause 942 is

a mandatory requirement manufacturers

may also specify additional testing and

quality control procedures to ensure

satisfactory performance of the thin

surfacing.

6 The minimum polished stone value of the

coarse aggregate should be selected from

Table 3.1 and the maximum aggregate

abrasion value from Table 3.2 in HD 36

(DMRB 7.5.1).

Performance Levels

7 The deformation resistance of thin

surface course systems can be set in terms

of wheel tracking level. In deciding on

the level, and hence the limiting

wheeltracking rate, the limiting wheel-

tracking rut depth and the temperature of

the test are specified in table 9/18 of

series 900 of the specification. The wheel

tracking level of the thin surface course

system are as stated in table 9/18,

however other applications on the Non-

National network may reference lower

levels in accordance with their

requirements.

8 Specified road/tyre noise levels are only

necessary in noise-sensitive areas. The

Levels of noise, in terms of reduction

relative to hot rolled asphalt, where

applicable should be stated.

Surface Macrotexture

9 The minimum macrotexture depth

required from hot rolled asphalt surfacing

on high-speed National Roads is 1.5 mm.

There are no surface macrotexture

requirements for low speed roads (a road

where the 85 percentile traffic speed is

less than 50 km/h) surfaced with hot

rolled asphalt, reliance being placed on

the macrotexture produced by the

minimum rate of chippings required by

BS 594-2. However, the surface

macrotexture obtained with a thin

surfacing cannot necessarily be compared

to that of a conventional single surface

dressing or hot rolled asphalt. With thin

surfacings , the choice of target aggregate

grading is the Contractor‟s provided that

the limits specified in table 9/16 are

satisfied and the specified minimum

surface macrotexture is achieved. To

ensure that a macrotexture is provided

and maintained on all roads, an initial

macrotexture depth of 1.5 mm is

specified and a minimum requirement of

1.3 mm after three years has been

included as part of the Contractor‟s

guarantee.

10 The performance levels of macrotexture

depth, i.e. 1.5 mm initial and 1.3 mm

after 3 years of trafficking, should be

used as the basis for setting the

macrotexture depth requirements. For

thin surface course materials with

“negative” macrotexture, the noise tends

to decrease with higher macrotexture

because there are more paths for the

trapped air to escape from, which is

contrary to the experience with

conventional surfacings having “positive”

macrotexture. For urban roads with speed

restrictions of 50 km/h or less the initial

texture depth may be reduced to 1.2 mm

initially and 1.0 mm after three years of

trafficking.

11 Whilst measurement of macrotexture

depth for compliance purposes is to be by

the volumetric patch technique specified

in IS EN 13036-1 only, the TRL Mini

Texture Meter (Sensor Measured Texture

Depth (SMTD)), may be used as a

screening procedure, as recommended by

BS 598: Part 105.



May 2005 15

12 Calibration trials and checks should be

undertaken at the start and during the

course of work to derive and confirm a

relationship between the sand patch

method and the SMTD.

13 In the event of a dispute, or discrepancy

between the two methods, only results

obtained using the volumetric patch

technique will be considered for


14 Calibrations carried out on site are only

applicable to that site and that surfacing.

15 SMTD is numerically different from

macrotexture measured by the volumteric

patch technique. The volumetric

macrotexture depth is a measurement of

the average depth of hollows in the

surface below general level of peaks.

SMTD is the standard deviation of the

sample height measurements.

16 In a similar way to measuring

macrotexture prior to opening to traffic,

assessment of macrotexture in the wheel

tracks at the end of the guarantee period

can be carried out by SMTD methods or

mini texture meter, subject to them being

calibrated against the volumetric patch

technique prior to carrying out a survey.

Surface Preparation, Transportation,

Placement and Compaction

17 The design and manufacture of the

materials is the Contractor‟s

responsibility, within the constraints of

the Quality Control for Manufacture and

the Factory Production Control

documentation for the system. This

transfer of responsibility provides scope

for the Contractor to design and place the

materials to suit the Contractor‟s system.

Road Markings

18 Contraflow and maintenance operations

often require the application of temporary

retroreflecting road studs. There are many

proprietary types of stud available. Trials

have indicated that many types of stud

leave a sticky deposit of bituminous

adhesive which clogs the surface voids

and some studs also cause pluck-out of

surface aggregate. Therefore, trials may

need to be performed, at the outer edge of

the hard shoulder, to ensure that the studs

proposed for use can be removed from

the surface without plucking-out surface

aggregate or leaving an excessive deposit.

19 Problems have also been reported with

preformed marking tapes on negatively

macrotextured surfaces coming unstuck

in wet weather. Trials should be

performed to select the best material.

Guarantee Period

20 The guarantee period should be clearly

stated as relating only to the surface

course. An appropriate Special

Requirement should be included in the

Conditions of Contract or the Employers

Requirements, which draws particular

attention to sub-Clause 942.17.



May 2005 16

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Volume 2 Series NG 1000 Notes for Guidance on the Specification for Road Works Road Pavements - Concrete and Cement Bound Materials

Road Pavements - Concrete and Cement Bound Materials

NG 1001 Grades and Constituents of Concrete

1 Clauses 1001 and 1002 give the requirements for materials and limits for mix proportions for designed concrete mixes in the form required in BS 5328.

2 In addition to Portland cement (PC) the term 'cement' includes blends of PC and pulverised-fuel ash (PFA,), whether they are blended on site or manufactured by blending or intergrinding.

3 For durability it is necessary to have a water/ cement ratio below 6.45 for a pavement surface slab. The water/cement ratio is defined as the ratio of free water to total cement content of the mix.

4 PC/PFA concrete has a long term increase in strength greater than PC concretes for the same 28-day strength and provide greater durability and resistance to chemical attack. If PFA is included in the mix it permits lower water/cement ratios for a required workability, so providing denser concrete of lower permeability and greater durability.

Admixtures

5 Air entraining agents are essential in pavement surface slabs to reduce permeability and frost damage. They also have a plasticising effect. They are not necessary in roadbase concrete unless the concrete is to be exposed to frost before the surfacing is applied. A small loss in strength is to be expected with air entrained concrete compared with plain concrete with the same mix proportions.

6 Plasticisers can be used to reduce water in the mix, increase strength and maintain workability at the required level. They can be beneficial in mixes with blends of PC with PFA, as the water reduction partially compensates for the loss of early strength.

7 Where low water/cement ratios are used to obtain C40 strength, retarders can be used in high summer temperatures, to ensure that the finishing processes can be completed in time.

Aggregates

8 The maximum size of aggregate allowed is 40 mm, but the Contractor's choice of size will

depend on construction methods, and his ability to achieve surface regularity, properly constructed joints and correct alignment of dowels. Larger aggregate provides an advantage in producing a more stable concrete in the lower layer, while 20 mm aggregate is preferable in the top course for forming joints and achieving a good finish.

9 Popouts can occur in the surface of the concrete slab when frost-susceptible particles are included in the aggregate. If there is a sufficient proportion of such particles this can lead to 'D' cracking which is a form of cracking caused by expansion due to frost, close to transverse and longitudinal joints.

10 The use of aggregate with high water absorption values is not desirable. In addition to frost damage due to absorption of water there is a higher risk of alkali silica reaction in the presence of moisture in the porous aggregates. Details of the required tests should be scheduled in Appendix 1/5.

11 The soundness test should be used for source approval for aggregates, the durability of which the Engineer considers questionable. It is not intended as a mandatory test for known durable aggregates. The water absorption test can be used as a routine check test of such aggregates.

NG 1003 Density

1 Density is required to be measured at regular intervals during paving as well as the trial length. Until nuclear density meters are proven as acceptable for plastic concrete, cores will be required to be cut. lb prevent undue damage to the slabs, cores should not be taken at points of high stress such as corners of slabs. The most desirable position for taking cores for routine density and inspection checks is as follows:

(i) Between quarter points along the slab.

(ii) Within 0.5 m of any longitudinal joint in a hard shoulder, hard strip or the least trafficked lane of the section being inspected.

2 Where cores contain tie bars or other reinforcement, allowance for the amount of steel should be made in any calculation of the density of the concrete.

March 2000 142


3 As a rough rule for assessment of strength, 1% reduction in density equates to a 5% loss of strength of concrete.

4 Calculation of the theoretical maximum dry density (TMDD) of the concrete, for comparison with cores, should take into account the bound water due to the hydration of the cement. This will vary with the age of the concrete. In calculating the TMDD the mass of hydrated cement is found by multiplying the mass of cement in the fresh cement mix by a time factor (F) determined from the following Table NG 10/1.

Table NG 10/1: Time Factor (F) for Hydrated Cements and Cement Blends

Age (Days) PC PC/PFA

1-3 1.13 1.11 >3-7 1.15 1.14 > 7-91 1.19 1.17

> 91-365 1.22 1.22

The theoretical maximum dry density (TMDD) of the concrete shall be calculated from the formula:

TMDD = [ ( F x W ' i + W' + W'Jx 1000

~ w w 4 w — + — + — + w a

pi J J 4

Where:

F =

W' = W- =

W* = W 4 =

P' =

F =

P4 =

Note:

time factor for hydration of cement from Table NG 10/1 mass of cement (kg) mass of total water (in aggregate + added)(kg) mass of oven-dry fine aggregate (kg) mass of oven-dry coarse aggregate (kg) relative density of cement apparent relative density of fine aggregate

apparent relative density of coarse aggregate

(i) The apparent relative density and moisture content shall be determined in accordance with the method described in BS 812 : Part 2.

(ii) Where more than one size of coarse aggregate is used then:

W' = W' + W- + W' + W"

and

W 4 W" p .

W h

p., w< p

+ .... W"

P"

Where W" is the mass of oven-dry aggregate of a certain fraction and Pn is the apparent relative density of that certain fraction.

(iii) Where blends of PC and PFA are used then:

W 1 = W + W"

and

W 1

P'

W"

p

where suffix

values of

W"

p P

= PC " = PFA

P° = 3.12 Pp = 2.00 are recommended

Table NG 10/2 gives a worked example of the determination of the theoretical maximum dry density (TMDD).

NG 1004 Quality Control of Concrete Strength

1 BS 5328 : Part 4 is used as the basis for control testing of pavement concrete but the rate of sampling and testing has been modified.

2 The 7-day strengths are used to give early warning of the possibility of low results and any need for additional cement after 7 days can be verified by the test results at 28 days. The ratio between 7 and 28 days should be established on laboratory trial mixes, but once paving has started this ratio can be updated from the most recent test results of 7 and 28 days on the same batches.

3 When two radically different mixes are used in the slab in two-layer construction, the statistical check on strength results should be carried out on the mixes separately.

4 The average value of 4 results represents 300 nr of work at the minimum specified rate of testing. If the Contractor wishes to reduce the area of pavement at risk he may wish to arrange with the Engineer for a higher rate of testing.

5 Cores may be taken and tested in compression and assessed in accordance with BS 6089 in order to assess whether (and how much) concrete should be rejected in the event of compression strengths of representative batches not meeting the specified value. The number and position of cores should be agreed with the Contractor before cores are taken.

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Table NG 10/2: Density of Concrete

Constituent Batch J

Weight

kg

Moisture Content

%

Water in

Aggregate

kg

Oven Dry

Weight

kg

Relative Density glcm*

Absolute Volume

m'

Mass of Partially Hydrated Material

kg

Cement 336 336 3.12 0.108 386.4** Water 137 0.191|t

Fine Agg 689 4.7 30.9 658.1 2.63* 0.250 658.1 Coarse 40-20 657 1.2 7.8 649.2 2.60* 0.250 649.2

20-10 330 1.9 6.2 323.8 2.60* 0.125 323.8 10-5 221 4.1 8.7 212.3 2.62* 0.081 212.3

53.6 1.005 2229.8

Apparent Relative Density tf Volume of total water (water in aggregate + water added at mixer) ** Time Factor (F) of 1.15 used

Theoretical Maximum Dry Densitv (TMDD) = = 2219 kg/m' 1.005

Minimum dry density requirement of 97<# = 2219 x 0.97 = 2152 kg/m' (non-air entrained concrete)

Minimum dry density requirement of 93# # = 2219x0.93 = 2064 kg/m3

inon-air entrained concrete)

Notes: t In practice the batch weights for air entrained and non-air entrained concretes are unlikely to be the same

# 92^r for 20 mm maximum size

NG 1005 Workability

1 The compacting factor (CF) is a suitable workability test for most of the stiff mixes required for machine paving, because it can be carried out alongside the paver. The volumetric method for the CF test as in BS DD90 or the Vebe, or other vibrating tests should be used on trial mixes of cohesive mixes, e.g. when PFA is used, to measure the effect of vibration for a range of CF values.

2 The optimum compacting factor at the paver will need to be re-assessed at intervals depending on the climatic conditions.

3 Workability should be constant. A useful check on whether the workability is constant can be obtained by noting the power input to the mixer. If necessary, plasticising or retarding admixtures should be used to suit local or weather conditions.

4 The target values for CF will vary with the mixes and materials used and with the weather. Approximate values are:

(i) single layer construction 0.80 - 0.85

(ii) two layer construction top layer 0.80 - 0.83, bottom layer 0.75 - 0.78

Low workabilities are required in the concrete to ensure that inserted dowel bars are retained in position. Higher workabilities are necessary to allow the texturing and finishing to be completed satisfactorily within the time available. In practice a compromise is required depending on the method of construction.

5 As consistently correct workability is of prime importance for the slab to meet the requirements of the Specification, it is in the Contractor's interest to control it by frequent testing at the batcher so that adjustments can be made quickly before too much concrete is transported to the paver. Tests at the paver are also required to ensure that the concrete placed in the paver is within specified limits.

NG 1006 Trial Mixes

1 Unless suitable data is offered to and accepted by the Engineer, trial mixes are required for each source of material to be used. Cements from different sources used with the same mix will have varying effects on the strength and workability of the concrete.

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2 The trial mix in the laboratory should be assessed, not only for strength but also for workability and the effects of vibration. It should be used to assess the rate of gain of strength between 7 and 28 days. It is important to know what the ratio will be during the trial length as 28 day results may not be available before normal working is likely to commence.

3 Trial mixes should be used to obtain the rate of gain of strength of concrete to assess the time when the pavement layer may be used by traffic. The tests should be completed in advance of the start of urgent work such as reconstruction or widening existing roads.

NG 1007 Separation Membrane

1 A separation membrane is required to prevent loss of water from the fresh concrete. For jointed pavements a degree of slip is desirable, so polythene sheet is normally used.

NG 1008 Steel Reinforcement

1 Supports for reinforcement should be sufficiently numerous and rigid so that the reinforcement will withstand a man's weight with no greater vertical distortion at any point than half the allowable vertical tolerance for the position of the reinforcement.

2 When fixed height supports are used, e.g. rings of standard mesh reinforcement, it is necessary to ensure a good surface regularity to the sub-base or roadbase on which the reinforcement is laid.

3 When pre-fabricated sheets are laid in two layer construction it is permissible to lay alternate sheets along the pavement with transverse steel uppermost. This allows the transverse lap to be made by placing one transverse bar of one sheet within the first mesh of the next sheet. This requirement will not apply if flying ends are provided in the prefabricated sheets at the position of the laps.

NG 1009 Transverse Joints

1 Transverse joints are normally contraction or expansion joints. Warping joints are retained in Clause 1009 for special cases, e.g. for extra joints in long narrow or tapered unreinforced concrete slabs between normal joint positions.

Series NG 1000 Road Pavements - Concrete and Cement Bound Materials

to reduce the length/width ratio of the slabs to 2 or less, and in other similar situations. Alternatively, instead of extra joints, slabs with an aspect ratio greater than 2 may be reinforced. The spacing of transverse joints should be described in Appendix 7/1.

2 Expansion joints can be omitted in summer and this period can be extended at the discretion of the Engineer to enable paving to be completed, provided the mid-day air temperature does not fall below 10 CC. Expansion joints should be included in kerbs, channels or hard strips which are constructed in winter or a different paving season from the main pavement, and which are tied to the pavement.

3 Structures below the pavement can be isolated by at least 150 mm of granular fill and the pavement continued over them. Structures within the pavement depth should be isolated by expansion joints or fully flexible construction with at least 25 m of flexible construction on either side of the structure.

NG 1010 Longitudinal Joints

1 Longitudinal joints are required at such a spacing as will reduce the combination of thermal warping stresses and loading stresses to a minimum and reduce the risk of longitudinal random cracking. The maximum bay width is therefore set at 4.2 m, except when reinforced pavements are constructed in widths up to 6.0 m (or 5.0 m and 7.6 m respectively with limestone aggregate).

2 When it is intended to add in the future an additional lane or hard shoulder, provision should be made to tie the new and old slab together. This can be done by the inclusion of cranked tie bars in the edge of the old concrete slab at the time of its construction. This requires the addition to the specification in Clause 1010 of an additional sub-clause such as "The longitudinal (inner/outer) edge of concrete slab, excluding the edges to slip road tapers, shall have cranked tie bars as in Clause 1012", and a further addition in Clause 1012 such as "Tie bars to (inner/outer) edges of concrete slabs shall be cranked and embedded into the concrete slab with a cover of 15 mm. The cranked section of bar shall be covered by a protective coating against corrosion." A drawing showing a typical configuration should be included in the contract drawings.

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NG 1011,1012, 1019 Placing and Inspection of Dowel Bars and Tie Bars

1 When dowel and tie bars are to be inserted vertically into fresh concrete the concrete should be fully compacted over them. Tie bars may be inserted into the side of a slab provided the method ensures a good bond to the concrete.

2 The fixings for dowel bar assemblies should be tested for strength in the trial lengths. Once the type of assembly has been approved, sample testing should be carried out in the main construction in the Permanent Works to ensure that standards are maintained.

3 lb check the alignment of dowel bars it is necessary to remove the fresh concrete carefully to expose the top half of each end of each bar across the whole width of the slab under construction. The position of the ends of the bars can be measured relative to the side forms or wires by means of steel tapes stretched between the forms or wires, using a vertical spirit level placed alongside the bars.

The alignment for level can be measured from nylon lines pulled taut across the forms or measured using a gauge incorporating a spirit level with legs 300 mm apart with forks at the ends for placing over the bars. The legs can include rules to measure the position of the bar ends below the steel tapes.

4 As the measurement of all the bars in any one joint is time consuming it will not be possible to complete the measurement, recompact and finish the concrete within the normal time allowed in Table 10/5. It will be necessary to reinstate with a 1 m long reinforced slab as a full depth repair. Alternatively the penultimate joint in a day's work could be selected for the dowel ahgnment check. The remaining concrete in the last slab is then discarded before work starts again.

5 Dowel bars, tie bars and transverse reinforcement across a longitudinal joint need to be protected from corrosion. Thin flexible plastic sleeves have been found to be effective for dowel bars. Suitable bituminous protective paint is allowed for reinforcement. Tie bars should be protected by bonded polymeric coatings.

NG 1013 Joint Grooves

1 The timing of sawing the hardened concrete is critical. If sawn too soon the aggregate will be plucked out, if too late, the concrete will have

Series NG 1000 Road Pavements - Concrete and Cement Bound Materials

cracked already. If a crack forms before or during sawing, it should be left without sawing alongside it until the time comes to seal it. If the crack cannot be encompassed within a 40 mm wide joint, the slab should be repaired. In slabs constructed in more than one pass of the paver (one rip), cracks may occur earlier in the second pass under the influence of joint movement of the first pass unless sawing is carried out as soon as possible.

2 Narrow crack-inducing grooves should be sawn first and widened for sealing later. In order to meet the requirements for high paving speeds with an economical number of saws and still reduce the risk of random cracking, it is common practice for approximately every third joint to be sawn as early as possible; the intermediate joints being sawn within the next few hours.

3 With wet-formed joint grooves with bottom crack inducers it is important that the concrete is fully recompacted around the former or cork seal. As the joint groove former is placed just below the surface of the concrete, it is important to ensure that the surface of the concrete is a straight plane between the forms at wet-formed joints. Otherwise if the surface level is bowed by excess concrete the former will be tilted by the diagonal finisher when planing off the excess concrete. The depth of the top layers should be considerably greater than the depth of the joint former so that the positions of the formers are not influenced by the stiffness of the bottom layer.

4 The joint groove must form a complete discontinuity across the slab, so that the concrete will crack along the joint position.

5 In normal summer work in unreinforced concrete only about one joint in four will crack initially. These joints tend to have greater movement at first until the other joints crack later with seasonal temperature changes or under traffic. In pavements constructed in two or more slabs the movement of joints in one slab will influence the cracking of uncracked joints in the adjacent slab.

NG 1015 Joint Filler Board

1 Expansion joint filler board should have a pointed ridge and the top of the ridge should be below the surface of the concrete but just within the depth of the sealing groove. It acts as a crack inducer initially and the sealing groove is sawn out later.

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NG 1016, 1017 Preparation and Sealing of Joint Grooves

1 One of the main causes of compression failures and damage to joints is the ingress and build up of solids or water-borne silt in the joint over a long period preventing or limiting proper movement at the joint. The requirements of a pavement joint sealant are:

(a) It should prevent the ingress of any solid matter into the joint.

(b) It should form a waterproof seal and prevent most of the surface water from entering the joint crack.

(c) It should be robust, have high extensibility, be resilient, be resistant to tearing, have a good bond to concrete and be unaffected by ageing and weathering.

2 Preparation of the sealing groove is most important. In order to remove any laitance from the groove sides and to provide a good key for applied seals, the joint sides must be grit blasted. Grinding may be permitted to clean small lengths of groove where grit blasting is impracticable. Wire brushes may be used to remove filler board prior to grit blasting.

3 Cracks will appear at transverse joints sporadically in new unreinforced concrete construction. Those that crack the earliest tend to have greater movement than would be expected if all the joints cracked evenly. This means that the groove width in winter may be wider than originally constructed, and allowance for future compression of the sealant should be made when sealing in cooler periods and the joint grooves should not be overfilled.

4 With all sealants it is important to keep the top of the sealant below the surface at transverse joints to prevent damage by traffic when the joints are compressed in summer. When sealing in colder periods the level of the seal should be lower than in summer to allow for the compression of the seal upwards in warm periods. When longitudinal joints are sealed, the seal should be just below the surface.

NG 1020 Side Forms, Rails and Guide Wires

1 In order to avoid adverse effects on the riding quality it is most important to check that all the sensors on any wire-guided machine are functioning within the correct tolerances during all paving, especially if the machine has been standing overnight in wet conditions.

The sub-base and any bedding for forms should be of sufficient strength to carry the train or paver without vertical movement and where necessary to carry any construction traffic. Cement bound bedding should have sufficient time to reach the necessary strength before paving begins. The Engineer should ensure that precautions are taken to prevent any construction traffic from damaging the subgrade next to the rails or paver tracks and so altering the levels after they have been set. Bedding other than the sub-base itself should be broken out after any section of pavement has been constructed and before any adjacent concrete is laid alongside, so that drainage of the sub-base and pavement is not impaired.

NG 1021 Delivery, Storage and Batching of Concreting Materials

1 The requirement for 8 hours storage of materials containing sands is to ensure that moisture contents are stabilised so reducing batch variability in the mixed concrete.

2 Checks should be made on the method of delivery and forming stockpiles to prevent segregation and accumulation of moisture. Aggregates can be contaminated during stockpiling, by 'dozing' or digging into the soil at the base of the stockpile.

NG 1022, 1023 Mixing, Transport and Delivery of Concrete

1 A constant supply of concrete with consistent workability is essential to maintain steady progress in paving. Disruption to this steady progress inevitably results in loss of workability making finishing difficult and leading to bad riding quality. To maintain an adequate supply to the paver, pavement quality concrete should be mixed on site in a batch type mixer with an output greater than the capacity of the paver when proceeding at the average planned speed.

2 Supplies from off-site mixing can be very dependent on local traffic conditions outside the Contractor's control, but they may be permitted for small works or other areas at the Engineer's discretion.

The variability of concrete mixed in truck mixers may be greater than that mixed in batch mixers so they are unlikely to be suitable

March 2000 147


for large quantities of pavement quality concrete. Truck mixers may be permitted to mix pavement quality concrete for small individual slabs, otherwise they may be used only as agitators, the concrete having been mixed at the central batching and mixing plant. Tb maintain constant workability and consistent concrete its temperature should be kept as constant as possible during the day. In high ambient temperatures there is a considerable advantage in cooling the mixing water. Similarly in cold weather heated water is often necessary, but in both cases the temperature of the mixing water should not be excessive.

NG 1024 Construction by Machine

1 Descriptions of two main types of pavers (fixed form and slip-form) are given in the Guide to Concrete Road Construction (HMSO 1978). With either type of machine the slab may be laid in one or two layers. However, there are more restrictions on single course paving.

2 With fixed form paving, the control of surface levels is mainly governed by the spreader being able to spread the concrete evenly to the correct surcharge. It is bad practice to rely on subsequent regulating beams and the diagonal finisher to achieve the correct levels by a major planing operation. If the first regulating beam in the compactor/finisher has too big a roll of concrete anywhere along the beam the setting of the spreader should be changed. The roll in front of the regulating beam or diagonal finisher should be between 100 mm and 150 mm evenly distributed along the beam. If the roll is too great then adjustment should be made at the spreader. If segregation occurs in the roll, adjustments to the workability of the mix may be necessary.

3 With slip-form pavers there is a tendency for edge slump in the concrete immediately after leaving the paver. If this occurs, fixed side forms are required where concrete being placed has to be matched to another section of pavement, e.g. at slip road tapers or when construction is in two or more strips. In other work it is advisable for transverse finishing operations to be made against the crossfall to reduce the effect of flow towards the low side. Similarly on steep longitudinal gradients construction should preferably be up the gradient.

NG 1025 Construction by Small Paving Machines or Hand Guided Methods

1 If sufficient internal vibration is provided and truss type finishing screeds with multi-vibration points are used together with scraping straight edge and bull floats where necessary, a well compacted slab with a satisfactory level finish can be achieved. More even distribution of the concrete is obtained if auger spreaders are fitted to the screeds.

2 Slip road tapers adjacent to a concrete pavement should always be of a similar construction for the full length of the taper, which is adjoining the concrete slab, in order to keep the same depth of construction across the whole pavement width. If the remainder of the junction or roundabout is of flexible construction, a standard transverse transition slab should be included at the end of the taper after the slip road has diverged and is separate from the carriageway. The slip road taper slab should not be tied longitudinally to the main carriageway after the point where the traffic lanes of the slip road leave the main carriageway, as this is the point at which changes in level and direction of movement of the slabs can occur. Joints in that part of the slip road taper which is tied to the carriageway and constructed at the same time can be normal to the axis of the main carriageway and in the same line of the main carriageway joint.

NG 1026 Surface Texture

1 It is important that a uniform texture is achieved both along and across the slab. It is therefore necessary to take full account of the workability of the concrete at the time of brushing and the operator must have the ability to gauge the optimum time for brushing after compaction and finishing of the concrete. Care should be taken to minimise variations which may occur with differences in ambient conditions and the workability of the concrete.

2 From experience a suitable texture can be obtained by using a wire brush made of 32 gauge tape wires grouped together in tufts and initially 100 mm long. The brush should have two rows of tufts. The rows should be 20 mm apart and the tufts in one row should be opposite the centre of the gap between tufts in the other row. The brush should be replaced when the shortest tuft wears down to 90 mm long.

March 2000 148


3 If the texture depth is over 1.25 mm it will produce unacceptable tyre noise. Trial lengths should be closely monitored and if the texture depth is outside the limits, adjustments should be made to the workability of the concrete mix, or to the pressure on the brush, or to the time when brushing is carried out after compaction, or the type of brush changed. Thereafter spot checks should be made on the concrete surface as necessary.

4 Where the surface texture from the average of ten results has been found to be deficient or excessive the areas to be rectified can be assessed from the individual measurements. If necessary, additional measurements can be made in a particular lane to decide the limit of treatment. If four or more successive individual measurements are deficient or excessive, the area relating to those measurements should be treated across the full lane (or lanes) width.

5 Isolated areas less than 6 m in length need not be treated unless the texture has been omitted altogether or riding quality is impaired. If such areas are close or occur in a regular pattern or chain, they should not be left untreated.

6 Measurements should be carried out in sufficient time before opening to general traffic to allow the Contractor to complete remedial works, taking into account the effect of wear of heavy construction traffic.

7 The depth of grooved texture (hardened concrete) should be measured by means of a tyre tread gauge.

NG 1027 Curing

1 Curing is essential to provide adequate protection from evaporation and against heat loss or gain by radiation and so permit the concrete to achieve its designed strength. The retention of moisture is particularly important with cement or cement blends which have a slow rate of increase in strength. Without moisture the hydration process cannot be completed. Without adequate curing the concrete strength could be half the strength of the corresponding cubes cured in water in the laboratory.

2 The use of tentage will reduce the risk of rain damage but unless closed at sides and ends it could cause a wind-tunnel effect which would reduce the curing. Where tentage is used measures should be taken to prevent drips falling on to unhardened concrete. Tentage covers should overlap by a minimum of 500 mm.

3 Thermal insulation blankets provide accelerated curing and an increased rate of strength development.

NG 1028 Trial Lengths

1 The Engineer may only approve machinery and plant which is known or proved to be capable of constructing a pavement to meet the Specification. Trials to prove new or modified machinery should be carried out off Site or below pavement level. The Contractor is permitted to choose whether he lays the trial as part of the pavement or elsewhere, but if the former, he is not allowed to proceed with other trials or further paving at pavement surface level until any defective trial lengths have been removed, or can be rectified with the agreement and to the satisfaction of the Engineer.

2 The Engineer should notify the Contractor as soon as any deficiency is apparent and not necessarily await the full 10 days allowed for assessing concrete strength. The Engineer may allow normal working within 10 days of laying the last trial length if it is satisfactory in all respects, other than strength, and if he is satisfied from experience gained in earlier trial lengths that the strength can be easily achieved with the mix used.

NG 1029 Texturing of Hardened Concrete

1 Experience has shown that grooving, with the grooves at an irregular spacing and of average size 3 mm wide by 4 mm deep as required, produces less tyre noise than surface dressing. It is the only acceptable method of retexturing the surface of concrete pavements as it will provide a long life texture.

Grooving across joints should be avoided as this could lead to minor spalling and damage to the seal. In order to obtain the minimum depth of 3 mm the setting of the machine should take into account the transverse irregularity of the surface. Isolated areas of substandard texture less than 1 m in length along the carriageway would be unlikely to require treatment except in special circumstances.

149 March 2000


NG 1035 General Requirements for Cement Bound Materials

General

1 Lean concrete has been renamed Cement Bound Material Category 3 (CBM3). A new and stronger category, CBM4, has been included for higher traffic category roads.

Mix Design for Cement Bound Materials

2 Cement-bound materials are mixtures of raw material and cement that have a moisture content compatible with compaction by rolling. If the requirements for surface level, regularity and surface finish are to be achieved, compaction will need to be carried out at or close to optimum moisture content (omc). The compaction tests described in BS 1377 : Part 4 can be used to determine omc or alternatively Clause 2.1.5 of BS 1924 : Part 2 : 1990. Difficulty in determining the exact omc for clean gravel mixtures is sometimes experienced due to the lack of fines present which allows the cement/water paste < to be pumped out under vibration. However a sufficiently accurate estimate of omc can usually be made from the results obtained.

3 Using the value of omc, the cement content needed to achieve the required strength can be determined by establishing the compressive strength of the CBM over a range of cement contents.

4 With some aggregates the strength requirements of CBM3 and CBM4 can be met with very low quantities of cement. Ratios of aggregate to cement greater than 24:1 are unlikely to result in an acceptable homogeneous mix and if permitted should be closely monitored throughout the works.

5 PFA may be used in combination with PC as cementitious binder for CBM. The strength gain for such mixes after 7 days is likely to be higher than for mixes using PC alone. The Contractor may wish to take account of this when using PFA blends, and this may be achieved by testing at 28 days rather than 7 days, subject to the approval of the Engineer. It will be necessary for the Contractor to show from trial mixes that the 28-day strength of the blended cement mix compares with that of the PC mix which meets the Specification requirements at 7 days. The curing period before use by traffic and overlaying should be extended to ensure that the specified 7-day strength is reached. The pozzolanic reaction of PFA requires the products of hydration of PC before

it can take effect. Care will be necessary in mixes where the amount of PC is very low, due to the difficulty of dispersion of the PC during mixing. This can lead to local variations in strength with the risk of very weak patches. When using blended cements in winter there is an increased risk of frost damage if the early strength of the CBM is very low.

Delivery and Storage of Materials

6 It is important to prevent contamination and degradation of materials. The deposition of stockpiles of materials and subsequent extraction from them should be carried out in such a way that segregation is minimised.

Mix-in-plant Method of Construction

7 In this method the material, cement and water are mixed in a central plant with the resulting mixture being transported to the point of laying and spreading.

8 To ensure completed distribution of the relatively small quantities of cement, mixing should preferably be carried out in a forced action mixer of either the batch or continuous type, carefully selected such that the plant can process the material and produce a uniform CBM to the requirements of Table 10/8. If the Contractor proposes a mixer other than a forced action mixer the Engineer should ensure during the trials that a satisfactory mixing is achieved. The mixer should have an output to satisfactorily meet the demands of the spreading and compacting operations.

9 Vehicles transporting mixed CBM should be of sufficient number and capacity to meet both the output of the mixer and spreading and compacting operations.

Laying

10 The formation of satisfactory joints between adjacent areas of CBM or other material and of longitudinal joints is vital to the performance of the layer. When laying against compacted cement-bound or other material, cut back vertical joints prevent wedges of CBM which may crack or allow the riding up of one area on another.

Compaction

11 When CBM has begun to harden it is important that the matrix is not disturbed, hence the requirement that compaction must be completed

March 2000 150


within two hours of the addition of the cement. However, some cement-bound materials are more critical than others in this respect. Equally the weather conditions at the time of construction affect this particular aspect. In all circumstances the two hour requirement should be adhered to unless site trials indicate a tightening or relaxation of this limit. Great care must be exercised when compacting CBM at joints to ensure that compaction plant does not bear on previously compacted CBM after the two hour period until the specified 7-day cube strength has been reached.

Use by Traffic

12 CBM is susceptible to overstressing if traffic is permitted to run on it before it has obtained its specified strength. Use by traffic earlier than the specified times may be permitted once the specified strength has been achieved, which may be obtained by high cement contents or special mixes. Alternatively, if high density CBM's using PFA as a filler to reach densities above 97% of theoretical density are used, early use by traffic to lay subsequent layers may be permitted.

Preliminary Trial

13 The size of the preliminary trial relates to larger areas of CBM. Where small areas are to be laid the Engineer should consider allowing trial areas of less than 400 m s .

NG 1038,1039 Cement Bound Materials

1 The aim is to achieve a uniform layer meeting the strength and density requirements of the Specification. This is particularly important with CBM where the cement content is relatively low, and mixing and quality control need to be adequate so as to produce a homogeneous mix. The correct application of the trial and test regime clauses is most important to ensure that this is being achieved in the field and the Engineer should consider increasing the rate of testing in cases of non-uniformity.

strengths are consequently higher than would be expected from cubes compacted at field density. Field density requirements are met by comparing in situ measurements with those of the strength cubes.

2 Nuclear density gauges can be operated in either direct transmission or backscatter mode. As the backscatter mode only measures the density of the top 50 mm - 60 mm of the layer, the direct transmission mode is used for CBM.

NG 1041 Use of Nuclear Density Gauges With Cement Bound Materials

1 Nuclear density gauges utilise radioactive substances and unless used in accordance with the manufacturer's instructions may be hazardous to the health of users. Regulations cover the use, transportation and storage of gauges (see NG 123). Gauge suppliers and manufacturers will usually advise on these regulations. Supervisory staff need to be familiar with the appropriate regulations and the manufacturer's operating instructions. In exceptional circumstances, where nuclear gauges cannot be used for the measurement of in situ wet density, the sand replacement method given in BS 1924 may be used as an alternative with the approval of the Engineer. The tests should be made between 4 hours and 24 hours of completion of compaction of the layer.

2 A preliminary check is included because Transport and Road Research Laboratory Report No. LR 1109 indicates that certain materials can give biased results when tested with nuclear density gauges. This is due to the radiation absorption characteristics of the material and is allowed for by re-calibration of the gauge or adjustment of the displayed result. It may be necessary to repeat the preliminary check from time to time where the materials used for CBM are variable. The mass of each block may be determined by weighing the concrete in batches before it is placed into the mould, providing accuracy is maintained.

NG 1040 Testing of Cement Bound Materials

1 Cubes for strength testing for all cement-bound materials are effectively compacted to refusal when made in the specified manner. The cube

NG 1043 Foamed Concrete for Backfilling Excavations

1 Foamed concrete is a lightweight material produced by incorporating a preformed foam into a base mix of cement paste or mortar, using standard or proprietary mixing plant.

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2 Foamed concrete is normally prepared on site, either from basic constituents, or using ready-mixed base mortar delivered to site. However, subject to experience, gained by prior development, that the mix is suitable for transport by road, foamed concrete may be delivered to site entirely ready-mixed.

3 Foamed concrete should be prepared in accordance with a mix formulation proven, by prior development testing, to yield a compressive strength within the required range. The mix wet density corresponding to the specified strength should be determined in the development testing.

4 The wet density of the foamed concrete should be checked prior to and during placement or as agreed.

5 On sites presenting special drainage or groundwater problems the foamed concrete should be formulated to have a permeability not less than that of the surrounding ground. Alternatively a backfill layer of pea gravel, of 100 mm minimum thickness and surrounded by a geotextile filter fabric where appropriate, may be considered to offer an equivalent drainage potential.

6 Foamed concrete flows very easily and may infiltrate and block any damaged drainage or ducting existing within, or immediately adjacent to, the excavation. Unguarded reinstatements can represent a drowning hazard for children.

NG 1044 Construction of Concrete Pavement with Exposed Aggregate Surface

1 Sub-Clause 1044.11 specifies that the depth of the mortar layer cover to the selected aggregate shall be uniform. Variable mortar layer cover to the selected aggregate should be avoided as this will result in unacceptable surface depressions after exposure.

March 2000 152

Volume 2 Series NG WOO Notes for Guidance on the Specification for Road Works Road Pavements - Concrete and Cement Bound Materials

ROAD PAVEMENTS - CONCRETE AND CEMENT BOUND MATERIALS

Contents

Clause Title Page

NG 1001 Grades and Consti tuents of Concrete 142

NG 1003 Densi ty 142

NG 1004 Quali ty Control of Concrete Strength 143

NG 1005 Workabili ty 144

NG 1006 Trial Mixes 144

NG 1007 Separat ion Membrane 145

NG 1008 Steel Reinforcement 145

NG 1009 Transverse Joints 145

NG 1010 Longi tudinal Joints 145

NG 1011, Placing and Inspection of Dowel Bars and Tie Bars 146 N G 1012 and 1019

NG 1013 Joint Grooves 146

NG 1015 Joint Filler Board 146

NG 1016 Preparation and Sealing of Joint Grooves 147

and 1017

NG 1020 Side Forms, Rails and Guide Wires 147

NG 1021 Delivery, Storage and Batching of Concret ing Materials 147

NG 1022 Mixing, Transport and Delivery of Concre te 147

and 1023

NG 1024 Construct ion by Machine 148

NG 1025 Construct ion by Small Paving Machines or Hand Guided Methods 148

NG 1026 Surface Texture 148

NG 1027 Cur ing 149

NG 1028 Trial Lengths 149

NG 1029 Texturing of Hardened Concrete 149

NG 1035 General Requirements for Cement Bound Materials 150

NG 1038 C e m e n t Bound Materials 151

and 1039

NG 1040 Testing of Cement Bound Materials 151

NG 1041 Use of Nuclear Densi ty Gauges with C e m e n t Bound Materials 151

NG 1043 Foamed Concrete for Backfil l ing Excavations 151

NG 1044 Construct ion of Concrete Pavement with Exposed Aggregate Surface 152

March 2000 141


Series NG 1100 Kerbs, Footways and Paved Areas

KERBS, FOOTWAYS AND PAVED AREAS

Contents

Clause Title Page

NG 1101-1107 General 154

NG 1103 In Situ Concrete Kerbs, Channels and Edge Details 154

NG Sample Append ix 155

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Kerbs, Footways and Paved Areas

NG 1101-1107 General

1 Care should be taken in preparing detailed drawings to ensure good drainage from the carriageway construction either through or under the kerb foundation.

2 In concrete pavements, adjacent in situ concrete edge details such as combined marginal strips and drainage channels should be provided with expansion joints if laid in winter, and these should coincide with any joints formed in adjacent slabs.

3 The construction adopted for footways will depend very much upon the availability of local materials and local conditions. The cheapest alternative should normally be used unless there is good reason to do otherwise.

4 For footways which are known to be subjected to vehicle overrun the use of smaller and thicker paving flags laid on a thin layer of sand may be considered. Other alternatives would be concrete block paving, clay pavers, in situ concrete, or for flexible footways increased construction thickness and the use of denser surfacing materials.

5 Concrete block paving and clay pavers may be considered in certain low speed traffic situations, e.g. service areas, and lay-bys, because of their resistance to oil spillage and to deformation due to wheel loads. The block or paver layout and other details should be described in Appendix 11/1 wherever possible and incorporate whole units immediately adjacent to the edge of a carriageway or hard strip and avoid trimming of units to less than one third of their surface area.

6 The construction adopted for cycle tracks should be one of those given for footways and paved areas.

400 mm or less in height where past experience in the use of a particular aggregate, or the result of trials, demonstrate that a satisfactory profile can be achieved.

2 The precise level of concrete workability will depend on the type of construction plant used, for example:

Extrusion auger (small kerbs).

Ram compaction (small kerbs, kerbs, channels).

Slip-form (kerbs, channels).

NG 1103 In Situ Concrete Kerbs, Channels and Edge Details

1 Experience suggests that for the in situ construction of relatively high drainage channels by slip-forming or extrusion techniques, the use of crushed or partially crushed aggregate will ensure a more consistent and stable profile. The Engineer may relax this requirement for surface water channels of

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N G S A M P L E A P P E N D I X 11/1: K E R B S , F O O T W A Y S A N D PAVED A R E A S


1 Details of kerb joints at bridge expansion joints designed by the Engineer /1101.2].

2 Dimensions of in situ asphalt or concrete kerbing/1102.2, 1103.1/.

3 Concrete curing requirements if different from Clause 1027 [1103.3].

4 Details of required bond for flags [1104.2]

5 Details of flexible surfacing materials to be used [If different from Clause 1105]

6 Required thickness of surfacing and sub-base [If different from sub-Clauses 1105.2, 1105.3, 1106.2 or 1106.4, e.g. where vehicular access is to be provided].

7 Requirements for laying and curing in situ concrete [If different from sub-Clause 1106.1 ]

8 Required finish and grade of in situ concrete [If different from sub-Clause 1106.1]

9 Requirements for shapes, dimensions and colours of precast concrete paving blocks [1107.1].

10 Paving block layout details [1107.3J.

March 2000 155

Volume 2 Series NG 1100 Notes for Guidance on the Specification for Road Works Kerbs, Footways and Paved Areas

March 2000 156

Volume 2 Series NG 1200 Notes for Guidance on the Specification for Road Works Traffic Signs

TRAFFIC SIGNS

Contents

Clause Title Page

NG 1200 General 158

NG 1201 Definit ions, Sign Classification and Regulat ions 158

NG 1202 General Requi rements for Permanent Traffic Signs 158

NG 1203 Foundations for Permanent Traffic Signs and Signals 159

NG 1204 Posts for Permanent TVaffic Signs 159

N G 1 2 1 0 Reflective Markers 159

N G 1 2 1 1 Road Mark ings 159

NG 1212 Road Studs 160

NG 1213 Traffic Cones , TVaffic Cylinders, Flat TVaffic Delineators and

Other Traffic Delineators 160

NG 1215 Temporary Signs, Signals, Road Mark ings and Delineators 160

N G 1 2 1 6 TVaffic Signals 161

NG 1217 Detector Loops 161

N G 1 2 1 8 Pedestrian Cross ings 162

NG 1219 Traffic Signs on Gantr ies 162

NG 1220 Preparation and Finish of Metal and Other Surfaces 162


March 2000 157


Series NG 1200 Traffic Signs

Traffic Signs

NG 1200 General

1 The 1200 Series covers all traffic signs including permanent, Engineer's temporary and temporary. It draws on BS 873 and the Department of the Environment Traffic Signs Manual (1996) for the majority of its requirements. For illuminated signs and traffic signals it utilises the 'electrical work' aspects of the 1400 Series.

NG 1201 Definitions, Sign Classification and Regulations

1 The Engineer should examine the Contractor's proposals for temporary traffic signs (including haul route signals) and discuss these with the Contractor, the Garda Siochana and the appropriate road authority.

2 The Contractor's proposals for traffic signal and control equipment, variable message signs and reflecting road studs will include details of any approvals previously obtained for their use.

3 The information to be given in Appendix 12/1 for Engineer's temporary signs should be the same as that for permanent signs. Where a sign is to be erected for less than 6 months, the Engineer may require that the sign be a fixed short life sign. The Engineer should state in Appendix 12/1 those signs which are to be fixed short life signs.

4 The Engineer should check that the current legal requirements have been met before a traffic sign is installed. Advice on current legal requirements can be obtained from the National Roads Authority or the Department of the Environment as appropriate.

NG 1202 General Requirements for Permanent Traffic Signs

1 Appendix 12/1 should include a Schedule of Traffic Signs containing the details listed in sample Appendix 12/1 and should also contain all the other information required to supplement the Specification Clauses which state 'as described in Appendix 12/....'. This other information may be shown on fully detailed drawings cross-referenced from the relevant Appendix.

10

The Engineer should determine the legend layout and therefrom the sizes of sign faces, adding on extra area for light-spill screens, where required. From this information he will be able to determine the actual sizes of sign posts and foundations.

Unless the Engineer requires otherwise the Contractor should have freedom to adopt the type of sign plate and should determine the stiffening and framing, if any, for the plate he adopts, so as to meet the requirements of the "Certification Scheme, Specification, and Guidance for the Construction of Traffic Signs -TS4" .

Impact Category 1 of BS 873 : Part 5 should normally be specified unless the sign panels are so located that the likelihood of damage by vandals is remote.

Category 2 luminances to comply with BS 873 : Part 5 are suitable for locations with a high background luminance such as those described in BS 873 : Part 5.

It is not intended that the tests in BS 873 shall be carried out on each sign as BS 873 implies but that each sign shall be capable of passing the tests therein.

The Engineer should ensure when approving the Contractor's fabrication drawings that where dissimilar metals are used they are separated by electrical insulators.

Full details of the legend layout for faces of Contract-specific traffic signs (e.g. directional informatory and informatory) should be shown on fully detailed drawings listed in Appendix 12/1.

Legend layout of faces of non-prescribed traffic signs that have been authorised by the National Roads Authority or Department of the Environment as appropriate should also be fully detailed on drawings listed in Appendix 12/1.

Other traffic signs which have standard symbols and markings (with permitted variants) need not be drawn in detail. These signs are shown in the Department of Environment Traffic Signs Manual. The diagram number and where necessary the required permitted variant and the overall size of the sign or where no size is given, the x height of lettering required should be included in Appendix 12/1.

March 2000 158


11 The standard of reflectivity and whether the sign is to be internally or externally lit, retro-reflective or non-retroreflective should be specified in Appendix 12/1 for each permanent traffic sign.

12 Guidance on the use of variable message signs on all-purpose roads and motorways is given in U.K. Department of Transport Advice Note TA 60 and Standard TD 33.

13 When it is proposed to fit signs to new lighting columns, technical approval from the appropriate road authority should be received before erecting the proposed signs. If many signs are to be added to existing columns it is likely that several different combinations of column and luminaire will be involved. In all cases where the columns are over 5 years old the possibility of reduced strength due to corrosion should be considered. A site inspection of the condition of the columns, particularly at ground level, should be carried out and allowance made for any loss of material.When considering the possibility of drilling holes in lighting columns the effect of the holes both on the strength and fatigue resistance of the column should be considered.

NG 1203 Foundations for Permanent Traffic Signs and Signals

1 It has been assumed that all traffic signs and signals will have a concrete foundation. However, where the Engineer considers a sign can be founded purely in the soil this should be specified in Appendix 12/1.

2 The design of concrete foundations should be prepared by the Engineer adopting the advice given in NG 2602 utilising the wind loading described in BS 873 : Part 1.

3 The foundations for free-standing luminaires should be designed by the Engineer to the same standards as those for sign posts, the Engineer assessing the size of luminaires likely to be adopted.

NG 1204 Posts for Permanent Traffic Signs

1 The Engineer should decide the number, type, size and material of post required to satisfy the structural requirements of BS 873 : Part 7.


2 The National Roads Authority should be consulted with regard to the design of posts using steel circular and rectangular hollow sections and reinforced or prestressed concrete.

3 The Engineer should determine whether he requires 'large' or 'small integral' base housings or a separately attached 'root box', or a 'switch box' to accommodate electrical equipment and should describe these requirements in Appendix 12/1.

NG 1210 Reflective Markers

1 For reflective markers and posts the Engineer should decide the rate and type of testing of samples selected from the batch of reflective markers and posts supplied under the Contract. The requirements should be included in Appendix 12/2.

NG 1211 Road Markings

Permanent Road Markings

1 For road markings on motorways and all other roads, reference should be made to the Department of Environment Traffic Signs Manual.

2 It should be stated in Appendix 12/3 (cross-referring to the appropriate Drawing) where and whether thermoplastic or paint or other special materials are required and, if thermoplastic, whether it should be screed or spray applied. If a special material is required, full specification requirements should be included in Appendix 12/3.

3 Thermoplastic material, either screed or spray applied is recommended for use on all types of roads particularly those that carry a heavy flow of vehicles and at locations which are subject to turning movements.

4 Road marking paints are best used in situations where they are not subject to heavy traffic wear or are required as temporary markings. They are often suitable for edge lines on rural roads and yellow waiting restriction lines.

5 The following additional information should be stated in Appendix 12/3:

(i) Whether a tack coat is to be used. Generally a tack coat is only required on concrete or on some old, polished surfaces.

March 2000 159


(ii) Whether white or yellow colour is required.

(iii) Whether the material should be reflec-torised, i.e. contain and be surface dressed with spherical glass beads. All road markings on motorways are to be reflectorised. The need for reflectorisation of road markings on other roads and on side roads forming part of the Works should be determined in conjunction with the appropriate roads authority. The Engineer should state in Appendix 12/3 that all temporary road markings shall be reflectorised.

(iv) Whether raised rib edge lines are required. (Approval for the use of these must be obtained from the appropriate road authority who will provide the appropriate advice.)

(v) Where gaps are required in raised rib road markings.

6 A figure of 55 for the skid resistance of road markings should be specified at potentially hazardous locations, e.g. where braking or turning is likely to occur on large areas of road surface covered by the road marking materials.

Temporary Road Markings

7 Permanent road marking material should not normally be permitted for temporary road markings on carriageways which form part of the Permanent Works. Instead, one of the prefabricated materials now available should be adopted but the limitations referred to in 8 below, as to their use, should be considered.

8 The Engineer should include in Appendix 12/3 the limitations as to where only certain of the prefabricated materials will be acceptable. For example materials which are only available in 100 mm and 150 mm wide strips should not be used to form warning arrows, etc. Others should not be used on particularly rugous surfaces such as a surfaced dressed finish.

NG 1212 Road Studs

Reflecting Road Studs

1 The Department of Environment Traffic Signs Manual shows the positions of permanent reflecting road studs on motorways and other roads.

2 Appendix 12/3 should list those locations where reflecting road studs are to be used, together with any other requirements.


3 Reflecting road studs should not be installed by any method other than that recommended by the manufacturer and approved by the roads authority. Full compliance with these installation instructions is essential. Some general advice for the installation of road studs is also included in BS 873 : Part 4.

4 Temporary reflecting road studs are special studs designed to be effective for a minimum of 3 months. After this period their colour may deteriorate and compliance with the photometric and colorimetric values may be outside the set limits. If the period of installation is expected to be much in excess of 3 months the temporary studs should be examined and renewed as necessary or permanent reflecting road studs may be used with the Engineer's approval, depending on the total expected duration and Site conditions of the Works.

NG 1213 Traffic Cones, Traffic Cylinders, Flat Traffic Delineators and Other Traffic Delineators

1 For permanent cones, cylinders, FTDs and other delineators the Engineer should decide whether testing of samples selected from the batch to be supplied under the Contract is required.

2 Where testing of permanent cones, cylinders. FTDs and other delineators is to be carried out it is recommended that not less than 1 item in 500 should be selected at random for testing. However, the minimum number to be tested should be determined by the numbers required for a single test; for example, for a single test to BS 873 : Part 1, two samples of cones and four samples of cylinders are required. For FTDs it may only be necessary to have extra samples of the blades. The requirements should be listed in Appendix 12/4 and cross-referenced in Appendix 1/5.

NG 1215 Temporary Signs, Signals, Road Markings and Delineators

1 The term temporary in the context of the Contract includes signs known as portable in BS 873 : Part 2.

March 2000 160


NG 1216 Traffic Signals

General

1 Information on the installation and maintenance of permanent traffic signals together with technical advice, is available from the appropriate road authority.

2 The installation and commissioning of traffic signal controllers is a task calling for specialist skills and experience in this type of work. The Engineer should satisfy himself that, if the Contractor wishes to sub-contract the work under Clause 4 of the Conditions of Contract, any sub-contractor proposed has the necessary skills and experience.

Provision of Controllers

3 A minimum of four spare cores should be specified in cabling between each post and the controller. All cables should be marked or tagged at each end and at each intermediate joint or connection so as to identify the function of each cable clearly in the phasing sequence. The Engineer should specify the method of marking in Appendix 12/5.

4 All cables within the controller/signal installation should be specified to be of adequate size and rating to meet the electrical current requirements and electrical protection system and should be increased if necessary to ensure there is no voltage drop on longer cable lengths, e.g. extensions to mast arm or bracket assemblies.

5 The Engineer should design low voltage and extra low voltage cables to be kept separate and not used in the same multi-core cable.

6 The Engineer's minimum requirements for the location of all traffic signal equipment should be included in Appendix 12/5. The Engineer should include a Drawing to a scale of 1:500 which should include the position of the controller cabinet, all posts, signal heads and push button equipment, interconnecting ducts and cable requirements, loop detector locations and the mode of operation for the signal control cycle.

7 The Engineer should specify the cable core to function allocation for all cables.

Permanent

8 The Engineer should describe his requirements for permanent traffic signals, including installation of loop detector cables, in Appendix 12/5. This should be written for the particular


installation ensuring compatibility with the 1200 Series and the 1400 Series.

9 Any special requirements for servicing of the equipment once in use should be included in Appendix 12/5.

Temporary

10 The Engineer should determine whether temporary haul crossings and other Site accesses joining the public roadway are likely to be required and include his requirements for traffic signals for these or any other purposes (in addition to any requirements required under Clause 117.) in Appendix 12/5. The Engineer's requirements for standards of operation and for maintenance of all temporary traffic signals (including portable traffic signals used to control alternate one way working) should be included in Appendix 12/5.

NG 1217 Detector Loops

1 The Engineer should check the Contractors submitted loop installation record drawings and satisfy himself that they are complete before submitting them to the appropriate road authority. The requirements of sub-Clause 17 of Clause 1217 may be waived if the information is contained in other installation drawings or on the Drawings. The Engineer should provide the appropriate road authority with a copy of the loop circuit test results for their maintenance records.

2 If during slot cutting the saw breaks through into a hardcore bed or any other roadbase or into any reinforcing material, the Engineer should stop the work, inform the appropriate road authority that the loops cannot be installed to the Specification and seek alternative instructions.

3 For guidance on all matters relating to electrical work and safety, refer to the NG 1400 Series.

4 The following formula can be used to calculate the approximate inductance of a square or rectangular loop:

L = 0.82.P.N(N+1)

where L = Inductance of loop of microhenries P = Perimeter of loop in metres N = Number of turns in a loop

When connecting more than one loop to a detector channel in series the total loop inductance will be the sum of the inductances of the separate loops.

March 2000 161



Vehicles can also be reliably detected when up to 300 m of feeder cable is connected to a loop system, therefore a length longer than 200 m may be installed provided approval has been granted by the appropriate roads authority. The Engineer should check with the appropriate roads authority that the detectors to be used are effective for their specified use with feeders in excess of 200 m.

NG 1220 Preparation and Finish of Metal and Other Surfaces

1 Any additional requirements not contained in the "Certification Scheme, Specification, and Guidance for the Construction of Traffic Signs - TS4", or requirements different to those stated, should be contained in Appendix 12/7.

NG 1218 Pedestrian Crossings

1 The Engineer should describe his requirements for pedestrian crossings in Appendix 12/5. The appropriate roads authority will advise on particular equipment specifications.

2 The required type, e.g. thermoplastic (screed or spray applied) or paint, for road markings related to pedestrian crossings other than on the crossing area should be stated in Appendix 12/5.

3 For the crossing area, the required material, e.g. screed applied thermoplastic or prefabricated plastic tiles, should also be stated in Appendix 12/5. The choice of material should be decided by the Engineer based upon traffic-flows or other requirements specific to the Site.

4 Details of pedestrian guard railing associated with pedestrian crossings should be detailed in Appendix 4/2 to comply with Clause 412.

NG 1219 Traffic Signs on Gantries

1 The Engineer's requirements for traffic signs on gantries including variable message signs and matrix signals should be included, in the same way as other traffic signs in Appendix 12/1.

2 Any illumination and electrical work on or to the gantry should also be specified utilising the 1400 Series supplemented with any special requirements in Appendix 14/5, cross-referring to gantry detail drawings as appropriate. Requirements for fabricated steel gantries which include sign supports and electrical apparatus e.g. cable trays etc. should be given in Appendix 12/6.

March 2000 162



S A M P L E A P P E N D I C E S

[Note to compiler: Include in Appendices 12/1 to 12/8 the information listed below, referring to any drawing numbers where this information is otherwise located.]

NG S A M P L E A P P E N D I X 12/1 T R A F F I C S I G N S : G E N E R A L

1 Schedule of Traffic Signs:

(i) Location of traffic signs included in Clause 1201 other than those in Appendices 12/2 to 12/6 inclusive.

(ii) Drawing number or diagram number in Department of Environment Traffic Signs Manual and drawing numbers giving Contract-specific details.

(iii) Overall sizes of sign plates and details of any light-spill screens.

(iv) Requirements for type of material, preparation and finish, for sign plates, posts, etc. /For painting, cross-reference should be made to Appendix 12/7 where required.]

(v) Details of foundations including cable ducting, reinstatement and any requirements for anchorages and attachment systems including their loadings and torque settings.

(vi) The number, type and size of posts including details of any baseplates or flange plates.

(vii) Details of any electrical equipment compartments.

(viii) The type of sign face material including the Class of any retroreflective material.

(ix) The type of any direct illumination; whether internal or external, overhead mounted or upward pointing luminaires and whether free standing on separate foundations. Also the luminance and impact categories of the signs and luminaires.

(x) The method of switching the illumination /e.g. photo-electric control, time switch].

(xi) Whether any bollards are to be internally illuminated or reflective only.

2 In addition, the following information should be given:

(i) Any particular requirement for the covering of signs [1206.1J.

(ii) Where sign fabrication drawings are not required, and the details to be provided for warning and regulatory signs [1202.8]

(iii) The number of keys required for locks to traffic sign housings [1202.9].

(iv) Details of location identifying marks /1202.10/.

(v) Requirements for filling pockets in concrete foundations if different from the requirements of sub-Clause 1205.4.

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N G S A M P L E A P P E N D I X 12/2 T R A F F I C S I G N S : R E F L E C T I V E M A R K E R S

(i) The types and requirements of reflective markers and posts.

(ii) The requirements for reflectors and reflecting material.

(iii) Details and dimensions of foundations for marker posts.

(iv) The testing requirements and method of testing of reflective markers and posts.

N G S A M P L E A P P E N D I X 12/3 T R A F F I C S I G N S : R O A D M A R K I N G S A N D S T U D S

(i) Requirements for permanent road markings including colour, location and material type. [Any requirements for reflectorisation and for a tact coat should also be stated as should those for raised rib edge lines.]

(ii) Locations where gaps are required in raised rib road markings.

(iii) Locations where a skid resistance level of 55 is required for permanent road markings.

(iv) Requirements for temporary road markings.

(v) Limitations on the use of prefabricated temporary road marking materials.

(vi) Requirements and locations for reflecting road studs.

(vii) Requirements for the temporary covering of road studs and road markings.

N G S A M P L E A P P E N D I X 12/4 T R A F F I C S I G N S : C O N E S , C Y L I N D E R S , F T D s A N D O T H E R

T R A F F I C D E L I N E A T O R S

(i) Types of traffic delineators other than cones and cylinders and FTDs.

iii) The requirements and method of testing delineators other than cones and cylinders and FTDs /cross referenced in Appendix 1 /5].

NG S A M P L E A P P E N D L X 12/5 T R A F F I C S I G N S : T R A F F I C S I G N A L S

1 Permanent Traffic Signals

(i) Locations for:

(a) Signal heads.

(b) Controller.

(c) Ducting of carriageway and cable crossings.

<d) Electricity supply.

(e) Detection (including control units).

(f) Posts and gantries.

(g) Cables and routes.

(h) Telecommunications carrier interface.

(i) Inspection chambers,

(j) Road markings.

March 2000 164



NG S A M P L E A P P E N D I X 12/5 T R A F F I C S I G N S : T R A F F I C S I G N A L S (Cont inued)

(ii) Equipment:

(a) Vehicular signal heads.

(b) Pedestrian signal heads.

(c) Signal heads for cyclists.

(d) Light Rapid Transit (LRT) signal heads.

(e) Push buttons for pedestrians (including audible and tactile equipment).

(f) Additional signs.

(g) Green arrow aspects.

(h) Twin head or more with or without combinations of the above.

(iii) Operation:

(a) Phasing/staging.

(b) Timings.

(c) Special functions.

(d) Linking.

(iv) Detection:

(a) Type (Loop and above ground detection).

(b) Loop : location, configuration, size, shape, facilities.

(c) Power supply and cabling.

(v) Testing:

(a) Factory.

(b) Site.

(vi) Special road surfacing.

(vii) Locations of other services (gas, water, electricity, etc.).

(viii) Maintenance and servicing requirements.

March 2000 165



NG S A M P L E APPENDED 12/5 T R A F F I C SIGNS : T R A F F I C S I G N A L S (Cont inued)

2 Temporary TVaffic Signals Specified by the Engineer

Generally as for 1 above with the exclusion of:

(i) as this is liable to alteration during the progress of Works, it should state at what stages during the Works temporary traffic signals are required.

(iii), (b) to (d) inclusive.

(v), (a).

(vi).

(vii).

( v i i i ) .

Add with regard to:

(i) "a power supply may be a portable generator".

(ii) cable crossing protection.

TVaffic Signs

3 Signal Pedestrian Crossings

[Generally as for 1 above. 1

4 Zebra Crossings

(i) Location.

(a) Road markings.

(b) Beacons.

(c) Electricity supply.

(ii) Materials.

(a) Road surfacing.

(b) Road markings.

5 Specifications

(i) traffic signal equipment.

(ii) controllers.

(iii) cabling.

(iv) detector loops.

(v) testing specifications.

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N G S A M P L E A P P E N D I X 12/6 T R A F F I C S I G N S : S P E C I A L S I G N R E Q U I R E M E N T S O N

G A N T R I E S

'it Material and constructional requirements for gantries.

(ii) Mounting details for traffic signs and any sign lighting luminaries on gantries.

[Electrical equipment should be described in Appendix 14/5. Traffic signs including variable message signs and matrix signals should be described in Appendix 12/1 J.

N G S A M P L E A P P E N D I X 12/7 T R A F F I C S I G N S : P R E P A R A T I O N A N D F I N I S H O F M E T A L

A N D O T H E R S U R F A C E S

[Note to compiler: List here any additional requirements not contained in the "Certification Scheme, Specification, and Guidance for the Construction of Traffic Signs - TS4", or requirements different to those therein.]

March 2000 167

Volume 2 Series NG 1200 Notes for Guidance on the Specification for Road Works Traffic Signs

March 2000 168


Series NG 1300 Road Lighting Columns and Brackets

ROAD LIGHTING COLUMNS AND BRACKETS

Contents

Clause Title Page

N G 1 3 0 1 General 170

NG 1302 Design of Lighting Columns, Brackets, Foundations, Anchorages and

At tachment Systems 170

NG 1303 Data Sheets 171

NG 1304 Identification and Location Markings 171

NG 1305 Installation of Foundations, Anchorages and At tachment Sys tems 171

NG 1306 Site Tests on Anchorages in Dril led Holes 172

NG 1307 Mater ia ls and Surface Finishes 172

NG 1309 A m e n d m e n t s and Addit ions to BS 5649 : Part 2 : 1978 172



NG 1313 Laminated Glass Fibre Reinforced Plastic (GFRP) Columns 174

NG 1315 Specif icat ion for Design Loads : BS 5649 : Part 6 : 1982 174


March 2000 169



Road Lighting Columns and Brackets

NG 1301 General

1 UK Department of Transport Standard BD 26/'94 is complementary to the Specification and includes details of acceptable materials and dimensional limitations.

The Specification includes design requirements since the Contractor is required to propose columns and brackets, which have been designed by the manufacturer; where required to design foundations for planted columns to meet the Engineer's stated requirements, and to submit designs to the Engineer for acceptance and aesthetic approval where appropriate. This responsibility where required includes for the design of planted column foundations for each of the types of soil listed in Appendix 13/1 and where required, the design of foundations for columns with flange plates. Where the Engineer designs anchorages and attachment systems, the use of proprietary systems should be avoided.

2 Electrical engineering requirements are given in the 1400 Series.

3 Wall mounting bracket positions should be detailed on the Drawings by the Engineer. Details of the provision to be made for electrical services e.g. ducting, conduits, junction boxes, etc. should be shown on the Drawings.

4 Where wall mounted brackets and fixtures are required, wayleaves, i.e. permission to fix, may be necessary.

5 The Engineer should obtain confirmation from the Contractor that the appropriate electricity suppliers have confirmed their approval to the clearances provided to overhead lines. The Engineer should ensure that the Contractor has done this in advance of installation.

6 Road lighting columns as specified in this series should be set back from the carriageway edge or edge of hard shoulder in accordance with the definition and the general principles outlined in Clause 9 : BS 5489 : Road Lighting : Part 1: 1987.

When used for the lighting of roads outside urban areas the following practice has applied for lighting columns 12 metres or less in nominal height:

(i) Clearance from edge of carriageway or edge of hard shoulder is at least 2.5 metres;

(ii) Column material is either Aluminium or Formed sheet steel, octagonal in shape.

This practice should be continued unless guard rail is provided and should be specified in Appendix 13/1 where appropriate.

7 The information to be provided by the Engineer at the time of inviting tenders should be given in Appendix 13/1.

NG 1302 Design of Lighting Columns, Brackets, Foundations, Anchorages and Attachment Systems

1 The Contractor should submit to the Engineer a facsimile of the design and check certificates for the design of each lighting column, bracket and for columns with flange plates their associated anchorages and attachment systems as required by sub-clause 1302.2 and certification as described in Appendix 13/4.

The Contractor should submit certificates specified in sub-Clauses 1302.3 and 1302.4 to the requirements described in Appendix 13/1.

2 In the case of a bridge it is necessary to agree the details of the lighting column attachments to the bridge with the engineer responsible for the bridge.

The Contractor should normally be made responsible for providing the design of wall mounted brackets and fixings. The Engineer should ensure that the wall on which mounted brackets are to be fixed is capable of carrying the additional loads and other forces that may be transmitted by the bracket.

Aesthetic Approval

3 The Engineer may require to submit the Contractor's designs of columns and lanterns, including bracket arms, to the appropriate Road Authority for aesthetic approval, and notify the Contractor accordingly when this approval has been received.

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NG 1303 Data Sheets

1 The information required on the completed Data Sheets is that which is necessary to ensure that the equipment being offered satisfies the requirements of this Specification and is acceptable to the Engineer. A typical Standard Data Sheet is included in these Notes for Guidance. The information provided by the Engineer, including that in Appendix 13/1 should be all that is necessary to enable the Contractor to complete the Data Sheets in accordance with the "Instructions for Completion of Data Sheets" shown in Appendix 13/3.

In completing and submitting the Data Sheets the Contractor confirms compatibility of the columns and lanterns being offered.

The Engineer should specify in Appendix 13/1 the date by which completed Data Sheets are to be submitted. Where these are required at the time of tender this should be stated in Appendix 13/1 and the information provided by tenderers should be sufficient to evaluate the tenders and suitability of equipment being offered.

The Engineer should list in Appendix 1/4 the Contractors detail drawings which are to be submitted. Such drawings are normally submitted after the Contract is awarded unless there is good reason to specify otherwise. Drawings are usually required to give details unique to the scheme which can be of assistance to the road authority, e.g. sizes and centres of foundation holding down bolts, etc. Drawings which show only general construction details are not usually required.

NG 1304 Identification and Location Markings

1 The location marking required for each column will vary throughout the country and instructions in the Contract should generally be agreed with the road authorities concerned. The following should be specified:

(i) The direction in which the numbers should face.

(ii) The colour and background of the numbers.

(iii) The size of the numbers and distance above ground.

(iv) Method of marking e.g. in paint or plastic, etc.

(v) Number of marks on each column shaft (generally two for columns on central reserve).


(vi) The mark which will enable a particular column to be located.

(vii) Any distinctive system in order to highlight the location number at night.

NG 1305 Installation of Foundations, Anchorages and Attachment Systems

1 Examples of the evidence required by sub-Clause 1305.10(i) include:

(a) the results of testing to BS 5080 by a testing laboratory accredited by ILAB for such tests; or

(b) A certificate from any UEAtc (European Union of Agrement in construction) member together with the results of testing to the UEAtc Directive for the Assessment of Anchor Bolts MOAT (Method of Assessment & Test) No. 42: 1986 (adapted to include only anchorage types permitted by the specification).

An example of the evidence required by sub-Clause 1305.10(ii) is the result of testing to Clause 5.4.2.5 of MOAT No 42 (adapted to include only anchorage types permitted by the Specification).

If the four week time period required by sub-Clause 1305.10 is unrealistic then the appropriate time period should be stated in Appendix 13/1.

2 Failures of anchorages in drilled holes are known to occur due to either the lack of cleanliness of the hole or the excessive tolerances of the size of the hole. The manufacturer of the anchorage should give the maximum tolerance permitted and the evidence submitted in accordance with sub-Clause 1305.10 should show that the anchorages are satisfactory when installed in holes having these maximum tolerances.

3 Where lighting columns are to be installed on bridge decks, columns with flange plates should be used. Care should be taken to avoid damaging bridge deck waterproofing. Normally an anchorage and attachment system which avoids this problem should be used. In exceptional circumstances, where damage to the waterproofing is unavoidable, the Engineer should agree a compatible sealing system to prevent ingress of water and avoid corrosion.

4 Where attachment systems are used, the Engineer should ensure that the bolts or nuts

March 2000 171



are tightened adequately in accordance with the manufacturer's instructions, to ensure that the attachment system does not work loose when subject to wind loading. In addition, it is important to ensure an adequate length of thread engagement.

Sealing of voids in anchorages, attachment systems and flange plates with a non-setting passive filler is important to prevent ingress of water and to avoid corrosion.

NG 1306 Site Tests on Anchorages in Drilled Holes

1 The Contractor is responsible for having Site tests carried out and, where required, for providing designs for the anchorages. The Engineer should select which anchorages he requires to be tested within the frequency given in Appendix 1/5 and instruct the Contractor accordingly.

2 Where designs for anchorages in drilled holes are provided by the Contractor, the Engineer should satisfy himself that the Contractor's calculations for the nominal tensile load have been correctly carried out and have been checked, before selecting the anchorages for testing.

3 The Contractor's test record documents should be included in the as-built records.

NG 1307 Materials and Surface Finishes

1 The Engineer should select the system of protection for steel columns relevant to the intended location and environment utilizing the information given in NG 1900 and he should state his requirements in Appendix 19/3.

2 The Engineer should ensure that the quality of the surface protection for temporary lighting columns and brackets is adequate. The full requirements of the 1900 Series for such lighting may not be necessary.

3 Metal fixings to concrete columns should also comply with the requirements of the 1300 Series. No protection to the concrete is normally required.

NG 1309 Amendments and Additions to BS 5649 : Part 2 : 1978

1 The amendments to Page 5 Clause 4 introduce the width of cable entry slot dimension "X" which should be 75 mm for all columns of nominal height of 8 m or more and may be 50 mm for columns of lesser height. The value of "X" should be stated in Appendix 13/1.

2 The additional sub-clause 8.7.1.3 in Specification Clause 1309 specifies the material thickness tolerance. In the event of the thickness of the material supplied being outside the —5c/r tolerances but still being within the tolerances specified for steel in BS 4360 or appropriate Euronorms as listed in IS EN 10 025, the material may be used providing its actual certified yield strength is not less than the product of the ratio of nominal thickness to actual thickness and the specified nominal yield strength, i.e.:

<*ya ^

where

° y a = ° y n =

h = t„ =

actual certified yield strength nominal specified minimum yield strength in BS 4360 or BS EN 10 025 nominal specified thickness actual thickness

Note: A similar approach may be adopted in the case of aluminium

The door dimensions should be determined. For steel road lighting columns (8 m to 12 m nominal height) NRA RCD Detail 2 in Clause 1311 of the Specification applies unless otherwise specified. It is essential to verify that the dimensions of the door opening and of the base compartment (NG 1311) are large enough to accept the electrical equipment that is to be fitted within the base compartment.

The height to the bottom of the door may be specified. A height of 1.2 metres is current practice. See also NG 1311.

Planting depth: Practice indicates a minimum value for metal columns as follows:

Nominal Height 12 K)

8

Planting Depth 1.7 metres 1.5 metres 1.2 metres

Planting depths may be standardised by varying the dimensions of the mass concrete backfill for different soils in accordance with Appendix B : BS 5649 : Part 2 : 1978 as modified by sub-Clause 8.2 of UK Department of Transport Standard BD 26/94.

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Volume 2

Notes for Guidance on the Specification for Road Works

6 These requirements should be included in Appendix 13/1 as considered appropriate.


Welding

1 Prior to the anticipated start of manufacture of columns, the Engineer should request copies of the most recent certified destructive test reports covering those component types to be supplied under the Contract. It is important to note that when relying on destructive tests or Welding Inspection Consultants ' reports previously carried out as permitted by sub-Clause 7.1.5 it is necessary to confirm that the materials and welding consumables used in the manufacture at the time of the previous test or report are to the same specification as currently used.

2 The Engineer should arrange for sample column components and/or joints for destructive testing to be selected by an appropriately qualified Welding Inspector or equivalent. Selection should be made taking into account the manufacturer's inspection reports, previous destructive test reports and observations of current production practice on similar column types. Samples should be selected on the basis that they represent the lower end of quality in the production batch. Particular attention should be given to any features which could adversely affect the true throat size or the mechanical properties of the materials or introduce stress raisers transverse to the member axis.

3 For the purposes of defining lighting column types in 7.1.5, differences in either member cross-sectional shape, joint configuration or weld type, constitute a change in lighting column type. Variations in parent metal thickness or weld throat dimension from the specified sizes on the sample selected for destructive test may be included within the same lighting column type up to a limit of ± 40%.

4 Sample components and/or joints selected for destructive testing should be indelibly marked by the Engineer who should dispatch them to a testing laboratory appropriately accredited by ILAB for weld testing.

5 The Engineer should consider the following points when ascertaining the acceptability of components subject to destructive testing:


(a) Circumferential welds should be sectioned on at least 2 diameters. Seam welds should be sectioned at a minimum of 4 locations along their length. For welded reinforcement at door openings at least one section should be taken along each straight length of weld and at each change of weld direction. Where gusset plates are used the welding of at least one of the gusset plates shall be sectioned with a minimum of two sections one on each welded length. Other welds should be sectioned at intervals not exceeding 100 mm and at changes of direction. One side of each section should be ground, filed, linished or machined to a finish at least as smooth as that produced by a 120 grit paper to BS 871, so that the actual throat and leg dimensions can be measured and any discontinuities exposed. One nick break test in accordance with BS 709 on a length of weld of not less than 25 mm should be made for each joint type on each component. Additional sections and nick break tests may be required in cases of borderline acceptance. Non-confor-mances with IS EN 288 should be recorded. Non-conformances with the requirements of 7.1.4 should be cause for rejection, except that in 7.1.4.2 the throat and leg dimensions should be the true rather than the apparent dimensions.

(b) One representative section from each joint type for each type of column should be prepared for macro-examination. A hardness survey should be done where any of the parent material thickness exceeds 20 mm. An additional macro-examination should be made of each non-conforming weld.

6 The results of the destructive tests including macrographs should be reported and a certified copy sent to the manufacturer. In the event of non-conformances being found the Contractor and manufacturer should be notified as soon as possible. The test specimens, uniquely identified by hard stamped marks should be returned to the manufacturer's works.


1 The requirements for attaching electrical equipment, including the minimum dimensions in the base compartment, may be specified. The minimum dimensions required are determined by ease of access and the dimensions of the electrical equipment that is to be fitted into the base compartment.

March 2000 173



2 For steel columns 8 metres to 12 metres in nominal height, practice indicates:

(i) A baseboard of hardwood (varnished with 3 coats of intumescent varnish to provide protection against fire propagation) or other suitable non-hygroscopic material of dimensions 550 mm x 95 mm x 15 mm.

(ii) A distance of 100 mm between the face of the baseboard and the inside face of the door has usually proved satisfactory. It is essential however to verify that this dimension caters adequately for the electrical equipment that is to be fitted within the base compartment.

3 The requirements should be stated in Appendix 13/1 as appropriate.

NG 1313 Laminated Glass Fibre Reinforced Plastic (GFRP) Columns

Manufacture of GFRP Laminates

1 The internal surface of the column should not contain any dry patches but may show the presence of cracking in resin-rich layers or occasional bubbles. These do not affect the strength of the column and may be ignored.

2 The thickness of the column may vary stepwise along its length. Around the door area, additional reinforcement layers should generally be provided dependent on design requirements.

NG 1315 Specification for Design Loads BS 5649 : Part 6 : 1982

The k value referred to in Clause 1315 should be obtained in accordance with Clause 6 of CP3, Chapter V : Part 2 : 1972. The basic wind speed required for this calculation is indicated in the Department of Environment, Building Regulations 1991, "Technical Guidance Document A Structure". The required value should be stated in Appendix 13/1 in accordance with Clause 1315.

March 2000 174

Volume 2


Road Lighting Columns and Brackets

N G S A M P L E APPENDED 13/1 : I N F O R M A T I O N T O B E P R O V I D E D B Y T H E E N G I N E E R

W H E N S P E C I F Y I N G L I G H T I N G C O L U M N S A N D B R A C K E T S

[Notes to compiler:

1 Appendix 1311 should be specific and provide all the information which a tenderer will need in addition to information provided elsewhere in tfie documents, in order to submit a tender. Reference should be made in Appendix 13/1 to other relevant documents, e.g. drawings.

2 The requirements for each type of lighting column should include the following information as applicable:]

(i) number of columns;

(ii) nominal height of column;

(iii) bracket projection, single or double: or whether post-top fitting;

(iv) lantern weight and windage area and centres of application of the forces from the centroid of the column shaft;

(v) size, length and angle of lantern fixing;

(vi) location of column, i.e. location factor k, 2.5, 3 or exceptionally greater than 3;

(vii) height of installation above ground level, i.e. for lighting columns mounted on a structure or embankment the height of installation should include the nominal height of the column plus the height of the datum above the adjacent ground level;

(viii) type of column base, i.e. planted with or without base plate or column with flange plate;

(ix) list of columns, planted and with flange plates where the Contractor is to design the foundations, anchorages and attachment systems;

(x) information on soil types for design in accordance with BS 5649 : Part 2 : 1978 Appendix B for individual or groups of columns;

(xi) requirements for base material and for backfilling if not to be as described in sub-Clause 1305.1;

(xii) size (NG 1309) and number of door openings, number of doors to be fitted with hinges or metal chains and direction doors are to face; height of door above ground level; door fastening details: alternative door requirements for columns where standard doors are not appropriate;

(xiii) size (minimum) requirements for base compartments and baseboard requirements, NG 1309 and NG 1311;

(xiv) acceptable column materials; shape if appropriate [NG 1301];

(xv) any specific requirements for aesthetic approval of lighting column and bracket combinations;

(xvi) number of door keys;

(xvii) identification and location markings;

(xviii) requirements for wall mountings including fixings;

(xix) requirements for certification. Specify particular requirements [1302];

(xx) requirements for earthing [see NG 1420/;

(xxi) columns to be mounted on structures or in situations where there is a risk that a detached door could cause an accident if it fell onto the area below;

(xxii) any other special requirements, e.g. dimension *X' for cable entry slot width; requirements related to testing of anchorages [NG 1305.1];

(xxiii) requirements of electricity supplier including warning notices regarding proximity to overhead power lines.

3 Latest time by which completed Data Sheets shall be provided.

March 2000 175



N G S A M P L E A P P E N D I X 13/2 : T Y P I C A L C O L U M N A N D B R A C K E T DATA

T Y P I C A L C O L U M N A N D B R A C K E T DATA - S H E E T 1

Name of Manufacturer:

NAME OF CONTRACT:

PART A General

Column nominal height

Column material

Material design strength

No. of door openings

Door opening size - Height

-Width

Cross-section of base compartment

(m)

(N/mnr)

(mm i

Column Reference No.

Revision No.

Date

Height (mm!

Width (mm)

Depth (mm)

Acceptable positions of bracket arms relative to door position

Door Opening

Manufacturers drawing ref. no.

PART B Foundation Data

Planted base Planting depth

Diameter of concrete surround (if any)

Standard Soil Type Factor G

630 390 230

Flange base Bolt hole centres Hole diameter Design load/bolt

(mm) (mm) (N)

Relevant forces and moments at ground level

Line of action of max. moment relating to door opening

NOTE: For flange plates with slotted holes a diagram shall be included with this Data Sheet.

March 2000 176



N G S A M P L E A P P E N D I X 13/2 : T Y P I C A L C O L U M N A N D B R A C K E T DATA (Cont inued)

TYPICAL COLUMN AND BRACKET DATA - SHEET 2

LANTERN: MAXIMUM CHARACTERISTICS

PART C Acceptable Lanterns Standard k Factors

(see BS 5649)

PART C Acceptable Lanterns

2.5 3.0

Post Top Column Lantern MaxWt

(kg)

Maximum Windage Area (m-) for standard k factors

Lantern Connection

Diameter

immi

Length

(m)

Single Arm Bracket Column: Lantern Lever Arm l mm l

Due to wt. of lantern

Due to windage

Bracket Projection

(m)

Ref No.

Drawing No.

Material Lantern Fixing Angle

Lantern Connection

Lantern Maximum Maximum Windage

Wt (kg) Area (m2) for standard k

factors

Bracket Projection

(m)

Ref No.

Drawing No.

Grade Design Strength (N/mm;)

Lantern Fixing Angle

Diameter

Imm)

Length

(mm)

Lantern Maximum Maximum Windage

Wt (kg) Area (m2) for standard k

factors

Double Arm Bracket Column: Lantern Lever Arm (mm)

Due to wt. of

lantern

Due to windage on

lantern

Bracket Projection

im)

Ref No.

Drawing No.

Material Lantern Fixing Angle

Lantern Connection

Lantern Maximum Wt (kg)

Maximum Windage Area (m*) for standard k factors

Grade Design Strength (N/mm1')

Diameter (mm)

Length (mm)

PART D Certification

It is certified that the information given in this Data Sheet has been obtained in accordance with the requirements of the National Roads Authority Specification for Road Works Series 1300.

Signed on behalf of the Contractor Date

March 2000 177



N G S A M P L E A P P E N D I X 13/3 : I N S T R U C T I O N S F O R C O M P L E T I O N O F C O L U M N A N D B R A C K E T DATA S H E E T S

General

1 When information is not required a dash shall be inserted in the appropriate boxes.

2 Where a Data Sheet is amended it shall be given a new revision number with a date.

3 The revision numbers shall be consecutive letters of the alphabet, commencing with "A".

4 The date of the revision shall agree with the date of the Contractor's signature.

5 The column, or bracket material shall be material approved for use in the Contract.

6 The material design strength shall be the minimum specified in the design. Where more than one material is used values for all materials shall be given.

7 All relevant entries shall be made on the Data Sheet before the document is certified by the Contractor.

Co lumn Data

8 The column nominal height shall be selected from clause 2 or 3 of BS 5649 : Part 2 : 1978 as appropriate.

9 The number of door openings shall agree with the manufacturer's drawing.

10 The cross-section of the base compartment shall be indicated by a dimensioned diagram/sketch.

11 The acceptable positions of bracket arms relative to the door position shall be indicated on the diagram. Where all positions are acceptable the box noted "ANY" shall be ticked.

12 Where concrete is necessary around the planted base in accordance with sub-Clauses 1305.3 and 1305.4 the minimum diameter shall be entered.

13 For flange bases all forces and moments used (or for use) in the design of the foundations, anchorages and attachment systems shall be given.

14 The corrosion protection system used on the column when new shall be recorded. Where additional steel is provided for sacrificial purposes the amount shall be recorded.

Bracket Data

15 The lantern lever arms, weight and maximum windage area quoted shall be based on the most adverse loading on the bracket when it is attached to any of the columns quoted in the compatible column sections.

(Note: The lantern lever arms are the horizontal distances from the centre of gravity of the lantern and, if applicable, the centroid of the windage surface area, to tfie end of the bracket joint).

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N G S A M P L E A P P E N D I X 13/4 : C E R T I F I C A T I O N F O R L I G H T I N G C O L U M N S

CONSULTANT'S CHECK CERTIFICATE

We certify that the design of the lighting column system accurately shown on drawing!s) No(s) has

been checked by us and fully complies with :-

(i) National Roads Authority Specification for Road Works: 2000

(ii) Range of parameters for which column system has been checked as follows :-

We further certify that the design has been accurately transferred to the working drawings.

Signed

Team Leader

Signed

Partner / Director

Name of Consultant

Date

M A N U F A C T U R E R ' S D E S I G N C E R T I F I C A T E

We certify that the design of the lighting column accurately shown on drawing(s) No(s) has been

designed in accordance with and fully complies with :-

(i) National Road Authority Specification for Road Works: 2000

(ii) Range of parameters for which column system has been designed as follows :-

Signed

Designer

Signed

Director

Name of Manufacturer

Date

CERTIFICATE OF REGISTRATION ISO 9001 / 9002 (where applicable)

Manufacturer/Design House : Details of Quality Assurance System

March 2000 179

Volume 2 Series NG 1300 Notes for Guidance on the Specification for Road Works Road Lighting Columns and Brackets

N G S A M P L E A P P E N D I X 13/5: R O A D L I G H T I N G C O L U M N S A N D B R A C K E T S : N R A R O A D

C O N S T R U C T I O N D E T A I L S

Clause No. Road Construction Detail

1309 This Detail should normally be RCD/1300/2.

1311 (Detail 1) This Detail should normally be RCD/1300/1.

1311 (Detail 2) This Detail should normally be RCD/1300/2.

March 2000 180

Volume 2 Series NG 1400 Notes for Guidance on the Specification for Road Works Electrical Work for Road Lighting and Traffic Signs

ELECTRICAL WORK FOR ROAD LIGHTING AND TRAFFIC SIGNS

Contents

Clause Title Page

NG 1401 General 182

NG 1402 Site Records 182

NG 1403 Location of Light ing Units and Feeder Pillars 182

NG 1404 Change of Lighting Arrangements 182

NG 1405 Temporary Light ing 182

NG 1407 Luminaires 182

NG 1408 Lamps 183

NG 1409 Photoelect ronic Control (PECs) 183

NG 1410 Shor t ing Plugs 183

NG 1411 Time Switches 183

N G 1 4 1 2 Ballasts 183

NG 1413 Ignitors for Discharge Lamps 183

N G 1416 Cut-outs, Fuse Holders, Fuses and Miniature Circuit Breakers ( M C B s ) . . . . 183

NG 1418 Feeder Pillars 184

NG 1419 Wir ing 184

NG 1420 Ear th ing 184

NG 1421 Underground and Ducted Cables 185

NG 1422 Cable Joints 185

NG 1424 Inspect ion and Testing to be Carr ied Out by the Contractor 185

NG 1425 Preparat ion and Finish of Metal and Other Surfaces 185


March 2000 181

Volume 2 Series NG 1400 Notes for Guidance on the Specification for Road Works Electrical. Work for Road Lighting and Traffic Signs

Electrical Work for Road Lighting and TVaffic Signs

NG 1401 General

1 The Engineer should check that the electricity supplier has been consulted on requirements for terminating power supply cable in Lighting Units and feeder pillars in the design stage, to avoid delay in connecting an electricity supply.

2 The Engineer's attention is drawn to the 'Code of Practice for Electrical Safety in Public-Lighting Operations' available from the Institution of Lighting Engineers (ILE) and the references in sub-Clause 1401.1.

3 The term 'lantern' is defined as a 'luminaire designed for road lighting' in BS 4533 : Section 103.1 and used throughout BS 5489. Both terms are therefore used in the Specification.

4 The term 'network' is defined to ensure that testing to Clause 1424 is not applied to Lighting Units and feeder pillars where it could cause damage to equipment.

5 Where cable owned by the electricity supplier is utilized for the power supply to individual locations and the Contractor is not required to provide and install cables, the reference to 'network' is not applicable.

NG 1402 Site Records

1 'As-built' drawings, which should include inserts to a larger scale when layouts are complex, may be produced either by the Engineer from daily records or by the Contractor (these being checked by the Engineer against his records). The requirements should be described in Appendix 14/1 for road lighting and traffic signs. If it is considered practical, any motorway communication details should also be added.

2 During construction, the longitudinal locational measurements may have to be related initially to chainages and converted to refer to permanent highway features such as bridge abutments, or marker posts when these are defined.

3 The production of accurate daily site records, which should be on a form supplied, or approved, by the Engineer is of assistance in the preparation and checking of the 'as-built' drawings, and more particularly for the location of underground cables etc. and for

March 2000

fault-finding in the interval between the issue of a Certificate of Completion and the availability of 'as-built' drawings.

NG 1403 Location of Lighting Units and Feeder Pillars

1 The approximate position of all Lighting Units and feeder pillars should be indicated on the Drawings and differentiation made between each type of Lighting Unit and feeder pillar. Location of overhead power lines should also be indicated to ensure that minimum safety clearances are maintained. Appendix 14/2 can be used to describe the location and type of all Lighting Units and feeder pillars. For example, the Appendix can be used to show in table form the set-back of lighting columns from the kerb or the edge of carriageway.

NG 1404 Change of Lighting Arrangements

1 New Lighting Units should not normally be switched on and left in operation, apart from testing, before the road is opened to traffic. They are liable to mislead and confuse drivers particularly where temporary diversion routes have been introduced or a newly completed road has not been opened to traffic. Existing Lighting Units should not be switched off until the new permanent, or appropriate temporary. Lighting Units are available.

NG 1405 Temporary Lighting

1 Appendix 14/3 should include details of the Engineer's requirements for the provision of temporary Lighting Units required by the Engineer, and design and specification requirements for temporary lighting which the Contractor may require in the execution of the Contract.

NG 1407 Luminaires

1 Any particular requirements should be listed in Appendix 14/4 giving details of glare control

182


(whether low threshold increment (LIT), moderate threshold increment (MTI) or other), lamp type and wattage, whether fitted with integral gear and whether to have higher IP rating. In practice lanterns have a three prong twist lock socket to take a PEC fitted on top at the spigot end and suitably sealed with a weather proof gasket and fixed to the lantern body by non-corrosive fixing screws. Lanterns not to be fitted with photoelectronic control sockets should be included in the Appendix. If two part PECs are specified, PEC sockets will not be required in the lanterns but alternative fixings should be detailed.

2 The Engineer should state in Appendix 12/1 which signs are to be lit by internal illumination and which by overhead or free-standing luminaires.

3 The Engineer should give in Appendix 12/1 his particular requirements for Lit Sign Units.

4 If fuses are required in any integral gear compartment their rating should be specified in Appendix 14/4.

5 The Engineer should note the procedure given in Clause NG 1302 regarding aesthetic approval.

NG 1408 Lamps

1 Lamp type and wattage should usually be listed with the associated luminaire.

2 For road lighting design, the term 'lighting design lumens' linked to 2000 hours is being replaced by new definitions in BS 5489 : Part 1. The light output for normal design purposes is defined in sub-Clause 1408.2. The initial luminous flux of a lamp is the luminous flux in lumens after an initial ageing period under stated running conditions. The lamp flux maintenance factor is the proportion of the initial luminous flux of a lamp that is produced after a set time.

NG 1409 Photoelectronic Controls (PECs)

1 Photoelectronic controls may be one part or two part. Where ballasts are incorporated in luminaires, one part units are generally more appropriate.

2 A time delay of 20 to 30 seconds should be incorporated into PEC switch operation to

Series NG 1400 Electrical Work for Road Lighting and Traffic Signs

prevent the lamp being switched in response to transient changes in light conditions.

3 The switching level and differential of the PEC should be specified in Appendix 14/4.

NG 1410 Shorting Plugs

1 Shorting plugs (i.e. dummy PECs) when used: Consideration should be given to their location so as to facilitate planned maintenance access to PECs.

NG 1411 Time Switches

1 Photoelectronic controls are preferred but where it is not practical for them to be used, time switches may be specified in Appendix 14/4.

NG 1412 Ballasts

1 If ballasts are for other than 230 V operation this should be specified in Appendix 14/4.

2 If information related to control gear watt losses and power factor is to be provided this should be stated in Appendix 14/4.

NG 1413 Ignitors for Discharge Lamps

1 Ignitors integrated with lamps may be accepted as an alternative.

NG 1416 Cut-outs, Fuseholders, Fuses and Miniature Circuit Breakers (MCBs)

1 The rating of fuses and MCBs in luminaires, columns, feeder pillars etc. should be specified in Appendix 14/4.

2 Proper discrimination in their operation should be ensured to avoid unnecessary interruption of supplies.

3 Where service cut-outs are provided by the electricity supplier, the Engineer should ensure that sufficient space has been left by the Contractor in Lighting Units and feeder pillars to accommodate them.

March 2000 183


4 The type of cut-out, fuse holder and MCB required will be dependent upon the cabling system and cable size and should be specified in Appendix 14/4.

5 The class of MCB will depend on the maximum prospective fault current and should be specified in Appendix 14/4.

NG 1418 Feeder Pillars

1 As the electricity supplier may require an undertaking to pay for energy before agreeing to provide a supply, the Engineer should normally make arrangements with the supplier for the provision of services to Lighting Units and feeder pillars although it remains the Contractor's responsibility to ensure that supplies are available to meet his programme.

2 The material and construction of the feeder pillar case, and the finished treatment should be described in Appendix 14/4; see NG 1425. Intumescent varnish should be applied to the backboard in three coats to provide protection against fire propagation.

3 The Engineer should specify in Appendix 14/4 the equipment required in the feeder pillar as follows:

(i) Mounting facilities for the electricity supplier's cable cut-out.

(ii) Terminations, glands, trunking, method of fixing and sizes for cables and wiring.

(iii) A suitably rated 1 or 3-phase switch fuse to BS 5419 as appropriate for the supply cable.

(iv) Distribution boards fitted with MCBs or fuses for the outgoing cables. The maximum breaking capacity of the MCB should be not less than the prospective maximum short circuit current.

(v) An earth stud with washers and clamping nuts.

(vi) Circuit diagrams, and labelling as required by the Engineer showing details of interconnection of equipment and the connection of cables to and from the pillar; all indelibly drawn or engraved on a material not subject to damage by the environment or normal use.

(vii) When required, a thermostatically controlled 60 watt heater should be mounted at the bottom of the base board.


4 In cases where the Engineer requires the supply of keys to the pillar door he should specify his requirements in Appendix 14/4.

5 In cases where the Engineer requires group control of Road Lighting Units he should specify his requirements in Appendix 14/4.

6 A drawing, of each type of pillar should be provided showing:

(i) The desired layout of the equipment. (It should be noted that the variety of suitable equipment available may make it impracticable to define specific sizes).

(ii) Internal wiring details, including main earth connections as required by the National Rules for Electrical Installations for the type of system of which the installation is to form a part, to take account of the requirements of the electricity supplier.

(iii) The method of sealing the base of the pillar.

7 The Contractor should be required to detail any variation from the feeder pillar layout described.

NG 1419 Wiring

1 The Engineer should detail his requirements for component layout and wiring on typical schematic drawings; guidance is given in NG 1401.2. The Contractor may be required to prepare detailed drawings for approval by the Engineer.

2 If the wiring specified in Clause 1419 is to be altered, Contract-specific requirements should be described in Appendix 14/4.

NG 1420 Earthing

1 The Engineer should detail his requirements for earthing arrangements on typical schematic drawings.

2 The National Rules for Electrical Installations specify the electrical requirements for safety and reference should be made to those Rules when there is doubt on the extent of bonding and of earth electrode provision required.

March 2000 184


NG 1421 Underground and Ducted Cables

1 If the cable type required in Clauses 1420 and 1421 is to be varied (e.g. concentric or split concentric) Contract-specific requirements should be described in Appendix 14/4.

2 Cable type conductors, sizes and materials should be shown on the Drawings, cross-referenced in Appendix 14/4 related to cable runs. It should be made clear where cables are to be laid in troughs, or in ducts, where they are to be attached to structures, and where additional protection and support is required. Where ducts are required these should comply with Clause 501 unless there are any particular requirements, which should be listed in Appendix 5/2. The Engineer should ensure that the Drawings show that cables have a minimum clearance of 500 mm from safety fence foundations.

3 Cable supports should be provided as necessary where cables cross drawpit chambers etc. so as to maintain a maximum of 450 mm between supports. Where cables are laid in public footpaths and in other cases where additional protection is required, cable covers should be shown on the Drawings, cross-referenced in Appendix 14/4. Cover sizes should be 150 x 225 mm for one cable not exceeding 50 mm diameter and 225 x 300 mm for one cable exceeding 50 mm diameter or two not exceeding 37 mm diameter each.

4 The minimum requirements for depth of cover on cables are those specified by the National Rules for Electrical Installations.

5 Where existing buried cables are required to be removed, details should be included in Appendix 2/2 and the advice given in NG 201 followed.

NG 1422 Cable Joints

1 If several different types of joint are to be provided the various types, e.g. through, breeches and tee, should be shown on the Drawings, cross-referenced in Appendix 14/4 including cable sizes for both main and branch cables.

2 Provision of joints not shown on the Drawings is generally unacceptable. Shortage of cable through incorrect measurement, wilful or accidental cable damage, should not be considered as justification for additional joints.


3 The Engineer should ensure that jointing is carried out under adequate supervision and complies with BS 6910 : Part 2. The Engineer should, in considering evidence of the jointers competence, consider if the jointer has recently attended a recognised course and his length of experience. If there are any doubts on the competence of a jointer, a sample joint should be required from the jointer prior to commencement of the work.

NG 1424 Inspection and Testing to be Carried Out by the Contractor

1 The use of methods of testing other than those given in the National Rules for Electrical Installations is not precluded provided the Engineer is satisfied they give no less effective results.

2 An acceptable test of cable sheath insulation is provided by the application of 1000 V from an insulation tester.

3 The certificate from the Contractor verifying compliance with the National Rules for Electrical Installations and the test results provided by the Contractor in compliance with Clause 1424 should form part of the completed documentation and be forwarded by the Engineer to the relevant Road Authority along with other site records.

NG 1425 Preparation and Finish of Metal and Other Surfaces

1 The requirements for Preparation and Finish of metal and other surfaces should be in accordance with the following as appropriate:

(i) Steel Feeder Pillars (and other external enclosures) should be finished inside and out by galvanizing, zinc or aluminium spray or painting as follows:

(a) Galvanizing in accordance with the relevant sub-Clauses of Clause 1307;

(b) Sprayed metal coatings to comply with BS 2569 : Part 1 and with the following:

Aluminium coating to be material with composition in accordance with BS 1475 and zinc coating to be material Zn' with composition in accordance with BS 3436.

March 2000 185

Volume 2 Notes for Guidance on the Specification for Road Works Electrical Work for Road Lighting and Traffic Signs

Series NG 1400

The thickness of the coating should not be less than 100 microns.

The strength of adhesion of metal spray coatings should not be less than the following:

Aluminium 50 kgf/cm-Zinc 80 kgf/cm2

3 These requirements should be described in Appendix 14/6.

Metal spray coatings should be applied continuously over each 0.5 m2

per gun or the area of the component whichever is the lesser until the specified thickness has been achieved.

The procedures for applying metal spray in separate layers described in BS 2569 should not be used.

All surfaces to be metal sprayed, including that of the reference panel described in BS 2569, are to be blast cleaned with chilled cast iron grit and the standard to be clean steel.

(c) Painting should be in accordance with the relevant Clauses of the 1900 Series. Final coats of paint are to be applied on Site after final installations including the fitting of internal apparatus required as part of the Permanent Works. Internal surfaces should receive the same treatment as for external surfaces except that final paint coats should be applied before internal components are installed.

(ii) Aluminium Feeder Pillars (and other external enclosures) may be left untreated or painted. Surfaces to receive paint should be lightly abraided, cleaned and primed. Final painting as in (c) above.

2 In the case of fixings and other ancillaries appropriate Preparation and Finish may be required as follows:

(a) Sherardized Coatings:

Sherardized coatings to comply with Class 1, Table 1 of BS 4921 : 1988.

(b) Electroplated Coatings:

Electroplated coatings to comply with BS 3382 : Part 2. Additionally BS 3382 : Part 2 may be deemed to cover the electroplating of components up to and including 36 mm in diameter. Electroplated surfaces which are to be painted should not receive chromate passivation treatment.

March 2000 186

(c) Other Finishes as in 1 above.


NG S A M P L E A P P E N D I X 14/1 : SITE R E C O R D S

[Note to compiler: Include as appropriate]

1 As-built drawings will be produced by the Engineer/shall be produced by the Contractor, on number

copies of drawing no which will be provided by the Engineer and shall be in accordance with the

requirements of Clause 1402.

2 Motorway communications details shall/shall not be included on the drawings.

3 Indicate the details to be provided 11402).

N G S A M P L E APPENDED 14/2 : L O C A T I O N O F L I G H T I N G U N I T S A N D F E E D E R P I L L A R S

[Note to compiler: Include either:]

The position and description of Lighting Units and feeder pillars are shown on the following drawings

I or: |

The position and description of Lighting Units and feeder pillars are scheduled below:

Description of Equipment Location of Equipment

[Notes to compiler:

1 Information on the design of road lighting in accordance with the appropriate Part or Parts of BS 5489 implemented by the relevant Standard may be included.

2 The various types of Lighting Unit will call for different location dimensions and descriptions. Both position and description entries may be divided into normal and special categories for drawings or schedules.

3 Details of the electricity supply (i.e. single-phase 230V or three-phase 400V, 50 Hz) should be stated.]

March 2000 187


NG S A M P L E A P P E N D I X 14/3 : T E M P O R A R Y L I G H T I N G


(i) The requirements for any temporary lighting. [For example for traffic management during temporary diversions for traffic, and at central reserve crossovers.]

(ii) The requirements for any advance fixed Road Lighting Units [in final positions as far as practicable [ to fulfil the requirements of li).

N G S A M P L E APPENDLX 14/4 : E L E C T R I C A L E Q U I P M E N T F O R R O A D L I G H T I N G

The Contractor shall insert below details of the equipment which he proposes to use in the Works and shall submit the information as soon as the Contract has been awarded

(i) Lanterns and Lamps

The lanterns shall be compatible with the columns and brackets offered in Appendix 13/2 and the information shall include the lamp type and wattage, lantern circuit wattage and toe in angle if applicable.

[The compiler should state here any particular requirements described in NG 1407. For example: lantern design attitude, lantern (glare control) classification, LTI, MTI, flat glass or bowl or other, IP (Ingress Protection) enclosure rating, any exclusion of PEC sockets, mounting height (nominal), ratings of fuses in integral gear compartments., Specification for lamps used in the Contract, Location of PECs]

Manufacturer Cat. No.

Glare Control

Class (TI)

IP Rating PEC Socket

(Design Table

Ref No.) *

(Isoluminance Template

Ref No.) *

[^If required, to ensure the assembly of Road Lighting Units conforms to the performance requirements of BS 5489 :Part 2.1

(ii) Ancillary Equipment

[Note to compiler : Include here:]

1 The positioning of equipment described in Clauses 1411 to 1416 within the base compartment of columns [1417.1]

2 Requirements for wiring and installation of components within columns [1419.1].

3 Requirements for group switching [1409.4].

4 Data required related to gear losses and power factor.

March. 2000 188


NG S A M P L E APPENDIX 14/4 : ELECTRICAL E Q U I P M E N T F O R ROAD LIGHTING (Continued)

Clause Item Manufacturer Catalogue or Type No.

Requirements [Compiler to

complete]

1409 Photoelectronic controls

Differential and switching levels (if required)

1410

1411

1412

1413

1414

1415

1416

Shorting plug

Time Switches

Ballasts

Ignitors

Starters

Capacitors

Cut-outs

Fuse Holders

Fuse Links

MCBs

Current rating

Conductor size

Current rating

MCB class

1419 Wiring

Note: Compiler may add other items.

(iii) Feeder Pillars

Feeder pillars shall be suitable for the layouts shown on drawing nos and confirm with the

requirements shown on the Drawings and in the following list.

[The compiler should state here:]

1 Any particular requirements for locks, keys, circuit details, earth electrodes.

2 Requirements for the bonding conductor cross-sectional area and for earth electrode /1420]

3 Requirements for Labelling [1418.8].

4 Materials to be used, Construction Details.

Location of Feeder Pillar

Manufacturer Catalogue No.

March 2000 189



NG S A M P L E APPENDIX 14/4 : ELECTRICAL E Q U I P M E N T F O R ROAD LIGHTING (Continued)

(iv) Cables and Cable Joints

I The compiler should state here:}

1 References to drawings which show requirements for the installation of cable covers \ 1421.3].

2 Reference to drawings which show cable lines, cable joints and cable joint marker blocks [1421.4, 1422.3, 1422.6].

3 Requirement for cable trenches: Particular requirements for ducts should be listed in Appendix 5/2 [1421.4 NG 1421.2].

4 Particular requirements for cable laying, additional protection and support [1421.5].

5 Requirement for cables following the same route if different from the requirement of sub-Clause 1421.7.

6 Requirements for installation of power supply cables adjacent to communication cables if different from the requirements of sub-Clause 1421.8.

7 Reference to drawings which show identifying marks to be indented in permanent marker blocks [1421.11 J. I Cross-reference should be made to RCD drawing where appropriate].

8 Requirements for terminating armoured cables 11423.1[.

Location of (a) Cables

(h) Cable joints

Manufacturer Catalogue No. Reference No.

or Name of Cable

March 2000 190


N G S A M P L E APPENDLX 14/5 : E L E C T R I C A L E Q U I P M E N T F O R T R A F F I C S I G N S


1 The positioning of equipment described in Clauses 1411 to 1416 within the base compartment of posts

[1417.1].

2 Requirements for wiring and installation of components within posts and Lit Sign Units /1419.1]

3 Special requirements for illumination and electrical work on or to gantries /1220.3]

[Note to compiler: Electrical equipment for traffic signals should be described in Appendix 1215].

N G S A M P L E A P P E N D I X 1476: P R E P A R A T I O N A N D F I N I S H O F M E T A L A N D O T H E R

S U R F A C E S

[Notes to compiler: State here the Preparation and Finish required for enclosures, fixings and other ancillaries. The requirements indicated in NG 1425 may be used.]

March 2000 191


March 2000 192


Series NG 1500 Motorway Communications

MOTORWAY COMMUNICATIONS

Contents

Clause Title Page

NG 1501 Introduct ion 194

NG 1502 General Requirements 194

NG 1504 Site Records 194

NG 1506 Cables 194

NG 1507 Cable Laying 194

NG 1508 Installation of Cabinets and Signal Posts 195

NG 1510 Installation of Telephone Posts and Housings 195

NG 1511 Cable Joints 195

NG 1512 Installation of Ancil lary Items 196

NG 1516 Termination of Power Supply Cables for Communica t ions 196

NG 1517 Ear th ing and Bonding 196

N G 1 5 1 8 Cable Testing 196

NG 1519 Label l ing and Number ing 196

NG 1520 Load ing 196

NG 1521 Removal and Resit ing of Existing Equipment 196

NG 1523 L o o p Detec tors 197

NG 1524 Trial Pits 197


March 2000 193

Volume 2 Notes for Guidance on the Specification for Road Wor-ks


Motorway Communications

NG 1501 Introduction

1 A Motorway Communications System (MCS) includes telephones, matrix signals and the associated power supplies and control systems. The Road Authority should be consulted during the design and preparation of contract documents.

2 In the normal motorway construction contract the installation of cables, cabinets, signal posts, telephone posts and housing will be the responsibility of the Contractor. Drawings for motorway installation work should be included in the Contract as described in Clause NG 003.

3 Normally the Road Authority will be directly responsible for the installation of the matrix signals and the commissioning of the whole system and will arrange this work by means of a separate contract.

4 The Road Authority is responsible for arranging with the electricity supplier for provision of a power supply for the communications system. The Road Authority is responsible for negotiating the provision of connections to a telecommunications carrier's private wire network where required. In both cases negotiations must be initiated and the interface cabinets erected in sufficient time to ensure that completion of the system is not delayed and power supplies to Cabinets must be available at the time of installation.

NG 1504 Site Records

1 As-built drawings which should include inserts to a larger scale where layouts are complex, should be produced by the Engineer from daily records. The Contractor should maintain record drawings as described in this Clause. Should additional information be required on the record drawings this should be described in Appendix 15/1. If considered practical, one set of drawings can be used for recording both motorway communications and road lighting details (see NG 1402).

NG 1506 Cables

1 Cables will normally be supplied by the Contractor as specified in Appendix 15/1. The Engineer's site staff must check the manufacturer's test certificate for each drum of cable before it is installed.

2 Communications cable lengths in excess of 550 metres are not permitted and lengths less than 450 metres for longitudinal cables should be allowed only on agreement with the Road Authority who will provide the appropriate loading schedule.

3 The Road Authority must be consulted whenever it is proposed to use any cable not complying with the cable specification.

NG 1502 General Requirements

1 Motorways should not be opened to traffic unless the telephone system is operational.

2 It is essential that the communications installation is installed and successfully tested 4 weeks before opening to allow adequate time for commissioning.

3 If a Contract contains Sectional completions it may be necessary to make provision in Appendix 15/1 for the appropriate part or parts of the system to be completed 4 weeks before completion of each Section. Testing in sections may also be required.

NG 1507 Cable Laying

1 All communications equipment must be sited within the motorway boundary. Experience has shown that the best location for longitudinal cables is near the motorway boundary fence. Special attention should be paid to the relative positions of cables, drains, environmental/noise barriers and safety fences, tree planting areas, signs and lighting columns during the design to prevent subsequent construction or maintenance operations damaging the cables.

2 Where practicable, provision should be made for an additional length of the main longitudinal cable at the site of each terminal cabinet to allow for future re-terminations.

3 Ducts must be provided in accordance with the NRA Road Construction Details and with

March 2000 194


Clause 501. The position of ducts should be adjusted from the standard spacing so that they coincide with the siting of equipment and to keep the length of cabling in verges to a minimum. Additional ducts may be required to meet the specific design being catered for. The position of ducts in existing motorways to be used where new schemes overlap them should be ascertained and accurately located on the ground and on the Drawings before tenders are invited. Draw pits for cables may be necessary in long ducts, (e.g. in viaducts and other lengthy structures).

4 As an alternative to laying cables in trench the Contractor may, subject to the Engineer's approval use a purpose-built cable laying machine. It should be of a type approved by the Engineer and capable of forming a slit in the soil before guiding and laying the cable and marker tape without strain. A sand surround to the cable need not be provided if this method of laying is used.

5 If alternative methods of laying cables in trenches are offered and approved the Contractor may elect to use multi-passes of the purpose built cable laying machine in order to lay several parallel cables instead of laying all the cables in one operation. Care must be taken in such cases to ensure that cables already laid are not damaged by subsequent passes of the machine.

NG 1508 Installation of Cabinets and Signal Posts

1 Cabinets are generally expected to be sited near the boundary fences. However, some locations, e.g. cut/fill lines may put them in a position where they are particularly vulnerable to damage from vehicles leaving the carriageway. In such cases they should be protected by means of safety fencing or the extension of an existing safety fence. It is recommended that a safety fence should always be provided when equipment is located near the hardshoulder. Signal posts should be protected in accordance with the current requirements for the provision of safety fences.

2 Power supplies may be provided from a supply point which is either near to or remote from a group of communications cabinets. Where the supply point is greater than 100 metres away from a group or across a main carriageway then an additional power cabinet should be provided in the group.


3 Paved areas are required to form platforms adjoining cabinets and gantry bases for maintenance purposes. Easy access must be available to the cabinets as heavy testing equipment needs to be carried to them in all weather conditions. Slopes exceeding 1 in 3 should be provided with steps, and crossings should be provided over ditches, where appropriate. In some cases it may be necessary to site cabinets on a slope thus involving the construction of suitable platforms. All such details should be included in Appendix 15/1.

NG 1510 Installation of Telephone Posts and Housings

1 Telephone housings should be installed so that the rear of the housing faces on-coming traffic-except that when located next to safety fencing the housing should be turned through 90° to allow access to the instrument from the traffic side of the safety fence.

2 In the interests of safety it is imperative that telephones which have not been commissioned and are, therefore, not available for use are covered with "Not in Use" bags.

NG 1511 Cable Joints

1 Joints in any cables are most undesirable and are only permitted in power cable when prior written approval for the jointing of the cable has been given by the Road Authority.

2 In power supply cables for communications, approval will not be given for more than one joint in any one cable between terminations, or where the combined length of the 2 cables to be jointed is less than 70 metres.

3 Shortage of cable through incorrect measurement, wilful damage, cable faults, cable damage or such other causes will not be accepted as a justification for cable joints. Such circumstances must be overcome by the Contractor installing a completely new length of cable.

4 Where joints are permitted, joint markers must be provided and these must be accurately recorded on the record drawings.

5 Minor sheath repairs to communications cable may be permitted in accordance with the cable specification, where approved by the Engineer.

March 2000 195


NG 1512 Installation of Ancillary Items

1 Distributive and protective devices must be specified in Appendix 15/1 and may include fused cut-outs, distribution boxes, miniature circuit breakers and/or residual current devices (RCD's) of a suitable rating.

2 Where required, post mounted entry stop signals, which comprise a 1 metre square target board on a post must be positioned on site to ensure that they are clearly visible before entering on to the motorway and will not be obscured by signs or other street furniture.

NG 1516 Termination of Power Supply Cables for C ommunic at ions

1 The requirements for termination of power supply cables must be fully detailed on the Drawings, cross-referenced in Appendix 15/1.

NG 1517 Earthing and Bonding

1 The provisions of Clause 1516 are to cover the interna] earthing and bonding of the system. In some areas the requirements of the electricity supplier or the results of testing may require additional earth(s) to be provided and these requirements must be incorporated in the design. Specific requirements for earthing and bonding are to be detailed in Appendix 15/1.

NG 1518 Cable Testing

1 The Road Authority should be consulted about testing requirements.

2 Details of cable tests, frequency, reporting etc. are to be shown in Appendix 1/5.

3 The cable sections upon which Stage 2 tests are to be carried out must be stated in Appendix 15/1. They are best shown on the loading schedule or on a cable drawing. Sections to be tested may comprise the complete length of longitudinal cable in the Contract or such shorter lengths as circumstances may demand. In some cases tests may also be called for on lengths of cable which include lengths previously laid under another contract. If faults are revealed on the latter or any tests fail to

March 2000


produce results which meet performance requirements, the Engineer should seek advice immediately from the Road Authority.

NG 1519 Labelling and Numbering

1 The importance of labelling cannot be over-stressed and compliance with the Specification is essential to future maintenance operations. Where alternatives are proposed, the prior approval of the Road Authority should be obtained to such proposals.

NG 1520 Loading

1 In certain special situations, and wherever a cable length is less than 450 metres it becomes necessary to build out the circuits with appropriate capacitors inserted into the terminators and a loading drawing/ schedule agreed with the Road Authority shall be provided in Appendix 15/1 as part of the Contract. Where significant changes are made in the lengths of longitudinal cables the Road Authority must be advised without delay.

NG 1521 Removal and Resiting of Existing Equipment

1 It may be necessary to make provision for the removal and re-siting of existing communications equipment, particularly at a new motorway interchange with an existing motorway where re-routing of cables is required.

2 Boxes and cabinets and their contents are worth recovery for re-use, but plinths and cables are not. If any equipment is not immediately required it can be stored for future use by the Road Authority. The location of the store should be described in Appendix 2/3.

3 Existing cables which are no longer required should be removed where to do so will not result in consequential damage to the existing in-service cables in order to prevent interference with the operation of the communications system.

4 Clear instructions should be given in Appendix 15/1 as to the removal and disposal of equipment.

196



NG 1523 Loop Detectors

1 This Clause covers only the installation of the loops and cabinets.

2 Inductive loops should have a minimum clearance of 50 mm above road reinforcement and slots should be at least 1 m, in the lateral plane from any ferrous objects such as metal reinforcement bars, chamber covers etc. Also, in concrete roads, slots should not be cut less than 1.5 m from transverse joints between adjacent concrete sections. Where these requirements cannot be met, detailed discussions/tests will be required in order to establish the design of a viable system.

3 Clause 1217 covers the requirements of the installation of loop detectors and the UK Department of Transport HCD G Series Drawings may be used as Contract Drawings where appropriate. The designer should ensure that the location and type of loop configuration is shown on suitable drawings and that consideration has been given to the effect of any slab reinforcement in the concrete. He should also include sufficient ducts in the Contract to accommodate the number of feeders required at a particular location.

4 Loop installations should be sited as near as possible to an existing power supply which will usually be taken from a power supply point for the communications system. Failing this an independent supply will have to be provided by negotiation with the local electricity supplier.

5 The Road Authority will advise on the use of cold poured epoxy resin compounds. Where hot poured sealants are used, it should be noted that to avoid damage to the detector loop insulations, the Contractor may use only those for which the manufacturer's recommend pouring temperatures do not exceed 85°C.

1 The Engineer should describe the method of excavation of trial pits (by hand or other means) and the locations, in Appendix 15/1.

NG 1524 Trial Pits

March 2000 197



N G S A M P L E A P P E N D I X 15/1: M O T O R W A Y C O M M U N I C A T I O N S

[Notes to compiler:

1 Appendix 15/1 should be specific for each scheme and provide all the information which a Tenderer requires. Appendix 15/1 should include references to any other specifications and drawings as necessary.

2 Appendix 15/1 should include the following information as applicable:/

(i) any additional information to be provided on records drawings (1504.1]

(ii) types and specification for communication cable required [1506.1]

(iii) types and specification for power cable required [1506.2/

(iv) requirements for surface reinstatement to trench [1507.15]

(v) termination requirements for power supply cables /1516.1J

(vi) cable sections for stage 2 testing [1518.3]

(vii) description of labelling requirements for gantries, signal posts, cabinets and telephones [ 1519.1]

(viii) details of electrical loading requirements for communication cable /1520.1]

(ix) resiting details of equipment [1521.5] [provision for dismantling and storage should be made in Appendix 2/3]

(x) details of trial pit excavation; including number, size, method of excavation and locations [1524]

(xi) references to drawings which show approximate positions of cable trenches, cables and their terminating cabinets /1506.3, 1507.3]

(xii) requirements for installation of cable covers [1507.2/

(xiii) particular requirements for cable laying, additional protection and support /1507.5]

(xiv) requirements for cables following the same route if different from the requirements of sub-Clause

(xv) references to drawings which show construction of paved areas and foundations incorporating

plinths for cabinets and signal posts [1508.1]

(xvi) reference to drawings which show construction of paved areas and foundations for telephone posts

(xvii) requirements for orientation of telephone housing if different from the requirements of sub-Clause

(xviii) reference to drawings which show location of cable joints and cable joint marker blocks and details of indented mark [1511.2, 1511.6] [cross-reference should be made to the NRA Road Construction Details where appropriate]

(xix) references to drawings which show installation details for ancillary items [1512]

(xx) requirements for terminating cables if different from the requirements of sub-Clause 1513.3

(xxi) requirements for reinstatement if different from the requirements of sub-Clause 1521.7

(xxii) requirements for completion and testing in Sections /1502.2]

1507.7

[1510.1]

1510.2

March 2000 198


Series NG 1600 Piling and Diaphragm Walling

PILING AND DIAPHRAGM WALLING

Contents

Clause Title Page

N G 1 6 0 1 General 200

N G 1 6 0 2 Precast Concrete Piles 201

NG 1603 Cast-in-place Piles 202

N G 1 6 0 4 Steel Piles 203

NG 1605 Proof Loading of Piles 203

NG 1607 Diaphragm Wall Construct ion 205


March 2000 199



Piling and Diaphragm Walling

NG 1601 General

1 British Standard 8004 : 'Code of Practice for Foundations' provides guidance on preliminary investigation, design, materials, workmanship and control of piling.

2 The Specification has been prepared on the assumption that the information from a site investigation report/ground investigation report will enable the Engineer to consider the type of pile, e.g. precast or cast-in-place, to estimate the lengths and to decide whether there are any special requirements, e.g. permanent casings or sulphate-resisting cement.

3 Generally, in cohesive soils, all types of friction pile should be driven or excavated to length and, in non-cohesive soils, all types other than bored piles should be driven to a set. Should ground conditions vary from those predicted in the site investigations then the set should be used for determination of founding level and then only after further investigation.

4 For a scheme requiring a considerable expenditure on piling, the construction and proof loading of trial piles is recommended either in advance of the Contract (where a nonproprietary system is envisaged), as an aid to its preparation, or at an early stage of the Works, to prove their suitability. Trial piles should be located so that they do not interfere with the Works.

5 Where the Engineer prepares a design, the piling type he has selected must be based upon the use of a non-proprietary system.

6 Where piles are designed by the Contractor, the Engineer should consider the need for pile proof loading. For example, driven piling in non-cohesive soil may not require proof loading whereas it may be necessary for bored cast-in-place piling.

7 The Instructions for Tendering require the Contractor to submit with the Tender the name of any piling sub-contractor he proposes to employ. This is to enable the Engineer to assess the suitability of the sub-contractor's method of installation. In general, if the Contractor wishes to change his sub-contractor after the Contract has been awarded, the Engineer should be prepared to agree if he is satisfied that the alternative method of installation is technically acceptable.

8 Some specialist piling sub-contractors will install their type of pile to a performance specification. In this event details should be agreed (see 9 below). The minimum length of pile shown on the Drawings may subsequently be adjusted in the light of information from a trial pile.

9 Where piling is offered to meet a performance specification, the Engineer should obtain from the Contractor full details of the type of pile offered, the standards of control he intends to use, how the calculation and checking of the load-carrying capacity and settlement of the piles will be carried out and the proof loading or other testing he proposes to undertake on the Site.

10 Completed piles may be subjected to lateral loading due to consolidation of sub-soil because of adjacent earthworks operations.

11 The purpose of requiring the Contractor to give early warning of ground conditions different from those expected from his interpretation of the ground investigation report is to enable the Engineer to determine without delay the need for changes in design or construction or for any remedial measures. When such differences are reported during work on bored cast-in-place piles, the Engineer should obtain confirmation, if possible by, having soil tests made in accordance with BS 5930.

12 The following information should be shown on the Drawings, as appropriate (cross-referenced in Appendix 16/1):

• Location of trial piles.

• Timing of installation and testing of trial piles.

• Working load.

• Class of concrete.

• Minimum cement content.

• Cross-sectional dimensions and tolerances.

• Estimated length.

• Minimum length of pile.

• Reinforcement, including pile shoe.

• Prestress and cube strength at transfer.

• Handling points.

• Concrete cube strength to be attained before lifting.

March 2000 200


• Proof loading details: - Proof load; - Number of increments; - Limits of permissible movement and

recovery.

• Method of lengthening piles.

• Method of incorporating the pile head into the substructure (e.g. a minimum of 75 mm of pile and an anchorage length of prestressing tendon or reinforcement might be incorporated).

• Details of permanent casings.

• Any other information (see NG 1602.5 and NG 1605.11).

This information should not be based upon any proprietary system.

13 Timber bearing piles are seldom used in Permanent Works and are not specially mentioned. Where they are required and sufficient description cannot be included on the Drawings, Substitute or Additional Clauses should be based on 'Piling - Model procedures and Specifications' published by ICE.

14 The Engineer should complete Appendix 16/1 and include cross-references to Drawings which give further information.

NG 1602 Precast Concrete Piles

1 The concrete should be not inferior to Grade 30 for normal reinforced precast concrete piles and Grade 50 for prestressed precast concrete piles.

2 Sub-contracting of the manufacture of precast concrete piles requires the Engineers written consent under Clause 4 of the Conditions of Contract. If their manufacture differs in any respect from that described in Appendix 16/1, the Contractor should be asked for complete details of his proposed alternative if these were not submitted at tender stage.

3 When sides of piles are used as formwork for casting adjacent piles, the method used to prevent adhesion between concrete surfaces should be to the approval of the Engineer.

4 The Engineer should require the Contractor to submit his detailed proposals for pile driving for approval in compliance with Clause 14 of the Conditions of Contract. When the plant and procedure have been agreed, the Engineer should state any particular requirements such as the set or length to be obtained.


The Engineer may permit the suspension of driving if he is satisfied that the rate of penetration before the suspension of driving will be substantially re-established on its resumption.

."> In certain types of soil, the set obtained using a diesel hammer may not reliably indicate the bearing capacity of the pile. Any limitations on the type of driving should be stated on the Drawings.

6 The length of pile required should be shown on the Drawings. Any variation in length should be approved only after the installation and, where necessary, testing of a trial pile.

7 During installation of the piles the Engineer should ensure that the Contractor records pile head levels. The Engineer should look for any signs of rising of, or damage to, completed piles resulting from ground heave. If uplift or damage does occur, the Engineer should agree appropriate remedial measures.

8 Where prestressed concrete piles may require lengthening, splicing steel should be included in the pile head. Welding of reinforcement in prestressed concrete piles is subject to the prior approval of the Engineer to comply with sub-Clause 1716.1. Guidance on various methods of lengthening can be found in Concrete Society Technical Report No. 12, 'Segmental Precast Prestressed Concrete Piles'.

March 2000 201



NG 1603 Cast-in-place Piles

1 For cast-in-place piles the slump values of fresh concrete measured at the time of discharge shown in Table NG 16/1 are given to guide the Engineer in his assessment of the Contractor's proposals. After agreement, they may be varied at the discretion of the Engineer following due consideration of conditions of mixing, transport and placing.

2 As it is seldom possible to vibrate the concrete in small diameter cast-in-place piles, workability is of equal importance to cube strength. A 28-day cube strength of 20 N/mm 2

is adequate in most cases, but a minimum cement content of 375 kg/m 1 should be maintained. It may be desirable to vibrate the concrete in large diameter piles but, as this may involve special heavy vibrational equipment, the Engineer should satisfy himself that this will not cause segregation.

3 Any type of cast-in-place pile which is considered unsatisfactory for the particular site should be excluded but otherwise the Contractor's freedom to propose an alternative piling system should not be inhibited.

4 If the proposed system is a cast-in-place pile where a casing is driven and subsequently withdrawn, the Engineer should ensure that the Contractor's proposals to avoid damage to unfilled pile excavations or completed piles are acceptable having regard to the ground conditions, sequence of piling and the time interval between the construction of successive piles.

The Engineer may permit the suspension of driving if he is satisfied that the rate of penetration before the suspension of driving will be substantially re-established on its resumption.

5 Piles which are formed with zero slump concrete and hammered into place (especially those with enlarged bases) should not be driven in an alternate sequence because the increased resistance to driving might result in the infilling piles being founded at a higher level. The risk of damage from driving in sequence is less for these types of piles than for driven cast-in-place piles.

6 With all driven piles there is a risk, especially for closely spaced piles in stiff clays, that the upward displacement of soil may tend to lift adjacent piles. Recently placed concrete in driven cast-in-place piles can also be damaged by horizontal and vertical soil movements due to the installation of nearby piles. It has not been found possible to give firm rules regarding the sequence and distance between piles as the correct procedure will vary for different types of pile and ground conditions. In some circumstances a spacing of 3 pile diameters may be satisfactory while in others it may be as much as 6 pile diameters. Because redriving of cast-in-place piles is generally impracticable, it is essential that the Engineer should require the Contractor to satisfy him that the working procedure will avoid these difficulties.

7 During installation of the piles the Engineer should ensure that the Contractor records pile head levels. The Engineer should look for any signs of rising of, or damage to, completed piles resulting from ground heave. If uplift or damage does occur the Engineer should agree appropriate remedial measures.

8 Reinforcement should be openly spaced to facilitate the placing of concrete, lateral or spiral binding should be spaced no closer than 150 mm and spacer blocks should be used to ensure correct cover throughout the length of the pile.

TABLE NG 16/1: PELING C O N C R E T E MDC WORKABILITY

Piling Mix Workability

Slump Typical Conditions of Use

Minimum mm

Maximum

mm

A 75 125 Placed into water-free unlined hole. Widely spaced reinforcement leaving ample room for free movement between bars.

B 100 175 Where reinforcement is not spaced widely enough to give free movement between bars. Where casting level of concrete is within the casing. Where pile diameter is less than 600 mm.

C 150 — Where concrete is to be placed by tremie under water or drilling fluid.

March 2000 202


9 Inspection of pile borings and/or casings should be carried out immediately before concrete is placed. The method and type of apparatus proposed to be used should be agreed by the Engineer. It will normally be sufficient to lower a light down the shaft to check that the alignment and full cross-section are maintained within acceptable limits, but if more sophisticated methods are required they should be described in Appendix 16/1. In the case of large diameter bored piles, adequate safety precautions to comply with the codes and statutory regulations must be taken to protect personnel lowered into the shaft.

10 Where casings are damaged, or water or other foreign matter has entered the casing, the casing should be withdrawn and repaired or other action taken to ensure the soundness of the pile. Any damaged permanent casings should be assessed as to their acceptability as part of the working piles. Should water in the excavations be unpolluted then the pile may be concreted using a tremie pipe.

11 Pumping from a boring, or dewatering operations should not be permitted unless the Contractor has satisfied the Engineer that these operations will not have a detrimental effect on the surrounding soil or property, or cause damage to concrete during and after concreting operations.

12 Where standing groundwater level is higher than the required pile head level shown on the Drawings, the Contractor should submit his proposals for the approval of the Engineer before placing concrete. The pile head should not be left below groundwater level unless approved precautions are taken.

13 Temporary casings should be extracted while the concrete within remains sufficiently workable to ensure that it is not lifted.

14 Should the Contractor propose to drive any specialist type of pile to carry a specified load, the details of how this is to be achieved should be submitted to and receive the consent of the Engineer. The pile lengths shown on the Drawings may be adjusted in the light of information from a trial pile.

15 If the Engineer wishes to design on the basis of continuous flight auger cast-in-place piles, he should insert an appropriate additional clause.


NG 1604 Steel Piles

1 Radiographic tests on steel casings and piles may be carried out. While satisfactory results are being obtained, one radiograph 300 mm long should be made for not less than 10% of the number of welded connections in the case of a pile where the load is carried by the wall or section of a pile, and for not greater than 10% of the number of welded connections in the case of a pile where the load is to be carried by a concrete core.

2 For a pile where the load will be carried by the wall or section of the pile, and where the pile will be subjected to loads that induce reversal of stress during or after construction, the acceptance standard for radiographs should comply with ASME Boiler and Pressure Vessel Code, Section VIII. Division 1, Part UW-51. For a pile where the loads will be static and will not be carried by the wall of the pile, and where the pile will have a long length without lateral support, the acceptance standard for radiographs should comply with API 1104. For a pile where the loads will be static and where the pile will receive lateral support or where the load will be carried by a concrete core, radiographs will not normally be required, but welds must be capable of withstanding handling, driving and design load stresses.

3 Where radiographic testing is to be carried out, full details should be included in an Additional Clause and scheduled in Appendix 1/5.

4 Where the Contractor proposes to use proprietary steel pile sections for which there are no requirements in Series 1800, the Engineer should ensure that the manufacturers materials specification and rolling and fabrication tolerances are adequate for the purpose.

5 Reference should be made to NG 1602.4 to 1602.7 inclusive, as these are also applicable to steel piles.

6 The Engineer may permit the suspension of driving if he is satisfied that the rate of penetration before the suspension of driving will be substantially re-established on its resumption.

NG 1605 Proof Loading of Piles

1 The Specification deals with the proof loading of a pile by the application of an axial force, and covers the testing of both vertical and raking piles loaded in compression or tension.

March 2000 203


2 Where trial piles are required, the object should be to have them constructed prior to the installation of working piles and to allow time for the test and the adoption of modifications if these prove necessary. If it is necessary to specify a more precise timing for the construction and testing of trial piles this should be included as an alteration to sub-Clause 1605.3 in Appendix 0/2.

3 Subject to the approval of the Engineer, main piles may be tested at any time. Although a more favourable result will often be obtained by delaying the testing of any pile, this should be balanced against the risk of delaying the remainder of the Works if the pile proves to be unsatisfactory. However, for some strata, e.g. soft chalk, it is essential to delay the testing for up to 28 days after pile construction.

4 The method of loading, i.e. under kentledge, against anchor piles or against ground anchors, should not be specified but is subject to the Engineer's approval.

5 The Contractor should satisfy the Engineer that the load measuring equipment he proposes to use is capable of indicating the full value of the test load and the incremental values in which it is to be applied.

6 The Maintained Load Test may provide a workable means for accepting piles and for determining remedial measures, lb prevent delays, a shorter Maintained Load Test, as described in 'Piling - Model Procedures and Specifications' published by the Institution of Civil Engineers, may be used with the approval of the Engineer. This may be considered appropriate in situations where most of the settlement is expected to take place relatively quickly, e.g. in free draining granular soils.

7 When testing a main pile, a Maintained Load Test would normally be applied and the maximum test load should be 1.5 times the working load. The value of the test load and the number of increments, which should be not less than 4, together with the limits of permissible movement and recovery, should be shown on the Drawings. Where a large number of piles are used, it may be advantageous to test trial piles to failure to achieve optimum design.

8 The failure of a pile under a Maintained Load Test may be due to faulty workmanship or material, or to the failure of the ground supporting the pile. Where the pile itself has failed, e.g. sudden excessive deflection under load caused by collapse due to necking of a cast-in-place pile, remedial measures are required. Where the supporting ground has


failed then, as the Engineer will have determined the diameter and length of the pile or accepted the Contractor's proposals, the cost of remedial measures will normally be borne by the Employer. The test failure criterion is normally accepted as a pile movement of 10% of its equivalent diameter.

9 Subject to the agreement of the Engineer, the Contractor may carry out integrity testing of piles where there is some doubt as to the soundness of a pile. Integrity testing should not generally be used to assess the load carrying capacity of a pile. Where integrity testing is to be specified for quality control of cast-in-place piles, an Additional or Substitute Clause will be required, cross-reference in Appendix 1/5.

10 Where the Engineer wishes to determine the ultimate capacity of a pile, the loading in the Maintained Load Test may be increased progressively by increments in order to reach the ultimate bearing capacity, or failure, of the pile. The point at which the soil fails to support the pile may not be clearly shown by the results obtained and for this reason a Constant Rate of Penetration or Constant Rate of Uplift Test is more suitable. Tests to failure should not be carried out on main piles. Maximum applied loads should be limited to avoid physical breakage of the pile.

11 For continuous structures, values for movement and recovery should be stated under working load as these are of prime importance in the design. Where they are required they should be stated on the Drawings.

12 For further information on the type of pile test and test procedure see British Standard 8004 : 'Code of Practice for Foundations', 'Piling -Model Procedures and Specifications' published by ICE, and DOE and CIRIA Report PG7 (1980) : Tile Load Testing Procedures'.

March 2000 204

Volume 2 Notes for Guidance on the Specification for Road Works Piling and Diaphragm Walling

Series NG 1600

NG 1607 Diaphragm Wall Construction

1 The tremie pipe used for placing concrete in diaphragm walls should be clean, watertight, without projecting flanges and extend to the bottom of the trench excavation before concreting. All drilling fluid should be expelled from the pipe during the initial charging process. Sufficient embedment of the tremie pipe in the concrete should be maintained throughout the concreting to prevent re-entry of drilling fluid and at no time should the foot of the pipe be lifted clear of the placed concrete.

2 The Contractor's proposals for concrete cast under drilling fluid should be checked to ensure that they meet the following:

(i) Aggregates should preferably be naturally rounded, well graded gravels and sands when they are readily available in the locality. The maximum aggregate size should be 20 mm. The sand should conform with Grading M of IS 5. The use of other aggregates may be permitted subject to the suitability of the diameter of the tremie pipe used for placing the concrete.

(ii) A cement content of not less than 400 kg/m 1 should be maintained.

(iii) The slump value of fresh concrete measured at the time of discharge should be between 150 mm and 200 mm and the water/cement ratio should not exceed 0.6.

(iv) The mix should be designed to give the required high workability and specified characteristic strength.

3 Where diaphragm walling is subsequently to receive a finish, this should be detailed on the Drawings and any treatment of the diaphragm walling concrete should be stated.

March 2000 205



N G S A M P L E A P P E N D I X 16/1: R E Q U I R E M E N T S F O R P I L I N G A N D D I A P H R A G M

W A L L I N G


Piling

1 Requirements for piling if different from the requirements of sub-Clause 1601.2.

2 Requirements for time of stressing if different from the requirements of sub-Clause 1602.3.

3 Whether there is a requirement for demonstrating that final set is maintained [1603.10].

4 Requirements for inspection of pile borings and/or casings [1603.13].

5 Full details of piling required including proof loading tests, etc. and cross-references to appropriate Drawing Numbers [1605.3, 1605.4].

Diaphragm Walling

1 Full details of diaphragm walling required including cross-references to appropriate Drawing Numbers

[1607.1].

2 Requirements for the Contractor to provide drawings showing full details of wall panel sizes, recesses and reinforcement [1607.1J. [Requirements for working drawings, if required, should be scheduled in Appendix 1.4]

March 2000 206


Specification for Road Works Structural Concrete

October 2009

STRUCTURAL CONCRETE

Contents

Clause

Title

Page

NG 1701 Concrete – General ......................................................................................................................... 1

NG 1702 Concrete – Consistent Materials ................................................................................................... 1

NG 1703 Concrete – Exposure Classes ......................................................................................................... 3

NG 1704 Concrete – General Requirements ................................................................................................ 3

NG 1705 Concrete – Requirements for Designed Concrete ......................................................................... 8

NG 1706 Concrete – Production .................................................................................................................... 9

NG 1707 Concrete – Conformity and Identity Testing ................................................................................ 9

NG 1708 Concrete – Surface Finish .............................................................................................................. 11

NG 1709 Concrete – Surface Impregnation.................................................................................................. 12

NG 1710 Concrete – Construction General .................................................................................................. 14

NG 1711 Concrete – Grouting and Duct Systems For

Post-tensioned Tendons .................................................................................................................

22

NG 1712 Reinforcement – Materials ............................................................................................................ 25

NG 1713 Carbon Steel Reinforcement and Stainless Steel Reinforcement – Bar

Schedule Dimensions – Cutting and Bending ..............................................................................

25

NG 1714 Reinforcement – Fixing .................................................................................................................. 25

NG 1715 Reinforcement – Surface Condition .............................................................................................. 26

NG 1716 Reinforcement – Laps and Joints .................................................................................................. 26

NG 1717 Reinforcement – Welding ............................................................................................................... 26

NG 1718 Prestressing Tendons – Materials ................................................................................................. 28

Contents – continued on next page



October 2009

Structural Concrete

Contents - continued

NG 1720 Prestressing Tendons – Surface Condition ................................................................................... 28

NG 1722 Prestressing Tendons – Cutting .................................................................................................... 28

NG 1723 Prestressing Tendons – Positioning of Tendons, Sheaths and Duct Formers............................ 28

NG 1724 Prestressing Tendons – Tensioning .............................................................................................. 28

NG 1725 Prestressing Tendons – Protection and Bond ............................................................................... 29

NG 1727 Inspection and Testing of Structures and Components ............................................................... 30



October 2009 1

STRUCTURAL CONCRETE

NG 1701 Concrete - General

Specification of Concrete

1 In the Specification the concept of concrete

as a single material has been adopted. It

is therefore the responsibility of the

designer to specify in Appendix 17/1 the

type of concrete required to ensure both

the strength and the durability of the

finished structure. By the definitions

given in Clause 1702 limitations on the

constituent materials are already

established.

Designed Concrete

2 Note that I.S. EN 206-1 and the Irish

National Annex to I.S. EN 206-1 cover

prescribed and standardized prescribed

concretes. Guidance on the specification of

designed concrete is given in 6.2 of I.S. EN

206-1. The Contractor should be

responsible for selecting the constituent

material proportions in accordance with

Clause 1705 to achieve the required

strength and consistence, but the designer

is responsible for specifying the minimum

cement content, maximum water/cement

ratio, the Exposure Class, and other

properties required to ensure durability in

accordance with Clauses 1703 and 1704.

Designed Concrete Specification

sub-Clause

Compressive strength class

of concrete

Minimum cement content

Required type and class of

cement

Maximum water/cement

ratio

1704.1

1704.2

1702.1

1704.2

In appropriate circumstances any of the

information listed in Appendix 17/1 may be

included, but great care should be taken to

ensure the requirements specified do not

conflict with each other.

Requirements for Fresh Concrete

3 Unless specified otherwise the

requirements for the concrete in the fresh

or plastic state, particularly its

consistence, should be selected by the

Contractor/Producer who should inform

the designer of the requirements. The

designer should add this requirement to

the Specification.

It may be necessary when working in cold

or hot weather to control the temperature

of fresh concrete (see sub-Clause 1710.6 or

1710.7).

Where the minimum dimension of concrete

to be placed at a single time is greater

than 600mm and especially where the

cement content is likely to be 400 kg/m3 or

more, measures to reduce the adverse

affects of temperature, such as the

selection of aggregates with low

coefficients of thermal expansion or of a

cement type with a slower release of heat

of hydration, should be considered. In

exceptional cases other measures to reduce

the temperature or to remove evolved heat

may be necessary.

NG 1702 Concrete – Constituent

Materials

Cement

1 In addition to the cements listed, CEMI

cement conforming to I.S. EN 197-1 with a

mass fraction of 66% to 80% of combination

of ggbs conforming to IS EN 15167-1, or

CEMIII/B cement may be used for special

applications such as sulphate resistance of

buried concrete, but it should not be used

in the surfaces of exposed concrete where

there is a risk of surface scaling under

conditions of freezing and thawing.

The use of blended cements containing

pulverized-fuel ash or ground granulated

blastfurnace slag may increase concrete

durability and resistance to both chloride

ingress and sulphate attack. However,

care should be taken due to possible

delayed strength development and

particular attention should be paid to



October 2009 2

curing in accordance with sub-Clause

1710.5.

Cements containing other pozzolanic

materials such as silica fume and

metakaolin are excluded from the

Specification for the present time until

more widespread experience is gained of

their use to confer long term durability to

structures exposed in aggressive

environments.

Aggregates

2 (i) General. In general the aggregates

specified in sub-Clause 1702.2 of the

Specification should be used. In

exceptional circumstances and for

particular special applications the

designer may specify the use of

aggregates other than those specified

in sub-Clause 1702.2, including types

of gradings not covered by the

appropriate Irish Standards, provided

that there are satisfactory data on the

properties of concrete made with

them. Recycled concrete aggregate

(RCA) and recycled aggregate (RC)

are excluded from the Specification

for the present time until ongoing

research is completed to establish the

long term durability to structures

exposed in aggressive environments,

especially chloride-bearing

environments.

When high strength concrete is

required, the source as well as the

type of aggregate may need careful

selection based on the results of

initial testing.

Where it is known that the property

of any aggregate is likely to have an

unusual effect on the strength,

density, shrinkage, moisture

movement, thermal properties, creep,

modulus of elasticity or durability of

concrete made with it, the designer

should take account of these factors in

the design and workmanship

requirements.

The ten per cent fines test for

resistance of coarse aggregate to

fragmentation has been replaced by

the Los Angeles test given in I.S. EN

1097-2 but there is no direct

correlation between the test methods.

The Los Angeles coefficient is

declared in accordance with the

relevant category specified in Table

12 of I.S. EN 12620. The Los Angeles

coefficient category should be the

category specified in the project

specification or, where a category has

not been specified, it should meet the

requirements of LA40. However, this

limitation may exclude perfectly

usable materials and aggregates with

LA coefficient values above 40 may

also perform satisfactorily in normal

concrete but it is recommended that

their strength performance be

established in concrete trials before

use. A note stating this is included in

the Specification (see sub-Clause

1702.2).

Aggregates having a high drying

shrinkage, such as some dolerites and

whinstones, and gravels containing

these rocks produce concrete having a

higher drying shrinkage than that

normally expected. This can result in

deterioration of exposed concrete

unless special measures are taken.

For further information refer to BRE

Digest 357.

When air cooled blastfurnace

aggregate conforming to I.S. EN

12620 is used, sampling and testing

should be carried out at sufficiently

frequent intervals to conform the bulk

density.

Despite initial compliance with the

minimum density, substantial

variation above this minimum can

change the characteristics of the

concrete mix if the weights of the

aggregates are kept constant. If such

variations occur, the mix should be

adjusted to allow for them. Further

advice on this subject can be obtained

form the UK Building Research

Establishment.

(ii) Maximum aggregate size. The

preferred maximum aggregate sizes

of an aggregate are 40mm and 20mm,

but if a smaller size is necessary it

should be 10mm.

Admixtures and Pigments

3 (i) General. Admixtures should be

specified by type and effect.



October 2009 3

Many admixtures are highly active

chemicals and may impart

undesirable as well as desirable

properties to the hardened concrete;

their suitability should generally be

verified by initial testing. The initial

testing should contain cement of the

same make and type and from the

same source as that intended to be

used for the permanent Works. If two

or more admixtures are thought to be

required in any one mix, the

manufacturer of each should be

consulted. The trials should confirm

that the admixture is compatible with

all the other constituents of the

concrete and show whether it

accelerates or retards the setting time

and results in any loss of consistence.

Only in exceptional circumstances, for

example in hot weather, should

retarders be used in structural

concrete. Consideration may be given

to their use in grouts for prestressing

tendons, especially in hot weather

(see NG 1711.1).

(ii) When a concrete of Class 32/40 or

lower is subject to freezing when wet

and/or subject to the effects of salt

used for de-icing, it should contain

entrained air.

The carbon contained in pulverized-

fuel ash and certain pigments can

substantially reduce the effectiveness

of some air-entraining agents. This

does not usually create a problem but

care may have to be taken when

using these materials. In some cases

it may be necessary to increase

appreciably the amount of admixture

used. The amount of air entrained in

a designed concrete can also be affected by many other factors, among

which are:

(i) Type and amount of admixture

used.

(ii) Consistency of the concrete.

(iii) Concrete proportions.

(iv) Type and grading of the

aggregate.

(v) The length of time for which the

concrete is mixed.

(vi) Temperature. In the range of

10oC to 30oC an increase of 10oC

can reduce the amount of

entrained air by about 25%.

(vii) The cement type, source,

fineness and cement content of

the concrete.

NG 1703 Concrete – Exposure

Classes

1 Environmental and ground conditions are

classified as exposure classes in Tables 1

and 2 of I.S. EN 206-1. Table 1 gives a

non-exhaustive list of examples applicable

in Ireland. All relevant exposure classes

pertaining to the structure or structural

element should be identified. There can be

specific structures or elements where the

exposure does not readily fit the

descriptions given in the exposure classes.

In such situations, designers should use

design judgement for that application.

Since the final concrete requirements are

dependent on the exposure classes,

Appendix 17/1 makes allowance for the

relevant exposure classes to be listed.

NG1704 Concrete – General

Requirements

General Considerations

1 The minimum requirements for the

strength and durability of the concrete in

the hardened state should be decided by

the designer from consideration of EN

1992-1 and the guidance in NG 1704.2 but

if in addition a special property or a

particular surface finish is required, these

minimum requirements may have to be

considerably exceeded.

The strength class of concrete required

depend partly on the particular use and

the characteristic strength needed to

provide the structure with adequate

ultimate strength and partly on the

exposure conditions and the cover provided

to any reinforcement or tendons (see EN

1992-1 and the Irish National Annex).



October 2009 4

Compressive Strength Class of Concrete

2 Compressive strength is specified

according to I.S. EN 206-1 by a dual

classification comprising the characteristic

strength of 150mm diameter by 300mm

length cylinders followed by the

characteristic strength of 150mm cubes,

e.g. C20/25. Table NA. 1 of the Irish

National Annex to I.S. EN 206-1 gives

recommended strength classes to be used

in specifications in Ireland. Note that this

Table contains some extra classes

compared with Table 7 of I.S. EN 206-1.

Intended Working Life

3 Table NA. 5 of the Irish National Annex to

I.S. EN 206-1 gives recommended limiting

values for composition and properties of

concrete for an intended working life of at

least 50 years. Road bridge and other

structures are normally designed for a

working life of 120 years, which might

require more onerous requirements than

those given in Table NA. 5. However, it is

preferred to provide increased concrete

cover instead of increasing concrete quality

in order to achieve increases in working

life. In some situations it might be

appropriate to achieve increased intended

working life by reducing contact between

chloride and the concrete or the use of

stainless steel reinforcement – examples of

this approach are the provision of bridge

deck waterproofing and surfacing on decks,

and the provision of stainless steel

reinforcement in parapet edge beams.

Road bridges and other structures

designed in accordance with IS EN 1992-1

for a service life of 100 years, which

corresponds to an “intended working life of

at least 100 years” in I.S. EN 206-1, may

be deemed to satisfy the requirements to

design for 120 years.

Cover to Reinforcement

4 The concept of Structural Class in IS EN

1992-1-1 (and / or the appropriate Irish

National Annex) allows for the designer to

determine the minimum cover (cmin) based

on exposure class, service life, strength

class, member geometry and quality

control. The nominal cover is generally

given by the sum of cmin + ∆cdev where ∆cdev

(the allowance for deviation) should be

taken as 15mm (or such other value as

may be given by the appropriate National

Annex). In some applications such as

precast concrete and thin concrete sections

where the design is sensitive to cover

variation, the design issues and practical

fixing considerations may dictate that the

allowance for cover deviation (or tolerance)

should be reduced to 5mm. However, the

default value of 15mm should be used

unless there is clear evidence that a lower

value is appropriate. The nominal cover,

including the allowance for cover deviation

(fixing tolerance) should be clearly stated

on the drawings.

Selection of Limiting Values for Concrete

Composition and Properties

5 Having identified the limiting values for

concrete composition and properties

relevant to all identified exposure classes

pertaining to the particular structure

element, these values should be compared

and the most onerous values selected and

specified. Values selected should be the

highest strength class, the lowest

maximum w/c ratio, the highest minimum

cement/combination content and

cement/combination types that are suitable

for all the identified exposure classes.

Minimum Cement Content and Maximum

Water/Cement Ratio

6 The designer should state in Appendix 17/1

the minimum cement content required for

each concrete. One of the main

characteristics influencing the durability of

any concrete is its ability to absorb water.

With strong dense aggregates, a suitably

low absorption is achieved by having a

sufficiently low water/cement ratio, by

ensuring sufficient hydration of the cement

through proper curing methods, and by

ensuring maximum compaction of the

concrete. Therefore for given aggregates

the cement content should be sufficient to

provide adequate consistence with a low

water/cement ratio so that the concrete can

be fully compacted with the means

available.

Water reducing admixtures conforming to

I.S EN 934-2 can be beneficial in reducing

the free water/cement ratio.

Table NA. 5 of the Irish National Annex to

I.S. EN 206-1 applies to concrete made

with cements described in sub-Clause

1702.1. The cement content may need to

be greater than the minimum values given



October 2009 5

in Table NA. 5 when trial mixes (see NG

1705.2) indicate that this is necessary for:

(i) the consistent production of a

concrete with a maximum free

water/cement ratio not greater than

that given for a particular condition;

and

(ii) the conditions of pacing and

compaction.

Maximum Cement Content

7 Cement contents in excess of 550 kg/m3

should not be used unless special

consideration has been given in design of

the increased creep, risk of cracking due to

drying shrinkage in thin sections, and

higher thermal stresses in thicker sections.

For higher strength classes of lightweight

aggregate concrete, cement contents in

excess of 550 kg/m3 may be used provided

that the concrete produced is suitable in all

respects.

Maximum Chloride Content

8 The maximum chloride content of concrete

is specified by means of a chloride class.

Relevant classes are given in Table 17/1.

Maximum Sulfate Content

9 Sulfates are present in most cements and

in some aggregates; excessive amounts can

cause expansion and disruption in the

concrete. However, as no tests exist to

determine mobile sulphate content, it is

usual to measure the acid soluble sulphate

content of cements and aggregates. The

relationship between such measurements

and the mobile sulfate content of the

hardened concrete is variable and

therefore no universal sulphate limit can

sensibly be applied to concrete.

Control of Alkali-Silica Reaction

10 (i) It is generally accepted that alkali-

silica reaction can only occur if

reactive minerals are present, the

alkali level of the concrete is above a

certain level and a sufficient supply of

water is available. For concrete road

bridges and other structures it must

be assumed that sufficient water will

be available so that aggregate types

and alkali levels must be controlled.

Most cases of alkali-silica reaction

appear to be associated with the use

of high alkali cements.

(ii) Requirements to minimise the

occurrence of alkali-silica reaction are

part of the general requirements of

Clause 1704. These are based on the

guidance given in IEI/ICS Report

„Alkali-Silica Reaction: General

Recommendations and Guidance in

the Specification of Buildings and

Engineering Works; 2002‟.

(iii) Extremely reactive aggregates,

comprising those aggregates

containing detectable quantities of

opal, glass and calcined flint, should

not be used alone or in combination

with other aggregates.

Buried Concrete Exposed to Sulfates

11 (i) Recommended limiting values for

compositions and properties of

concrete are given in Table NA. 5 of

the Irish National Annex to I.S. EN

206-1, which include concrete exposed

to aggressive chemical environments

(including buried concrete exposed to

sulfates). The recommendations in

Table NA. 5 are only valid for the

limiting values for exposure classes

for chemical attack from natural soil

and ground water given in Table 2 of

I.S. EN 206-1. It is considered that in

most cases, in Ireland, of buried

concrete exposed to chemical attack

(including sulfates) from natural

ground and ground water, that the

exposure class designation as given

by Table 1 of I.S. EN 206-1 (i.e. XA1

or XA2 or XA3) is appropriate and

that the recommendations of Table

NA. 5 are valid. However, in cases

where the assumptions stated in

Table 1 of I.S. EN 206-1 for chemical

attack are suspected of not being

valid then a special study may be

needed to establish the relevant

exposure conditions where the

following conditions apply either

singly or collectively;

(a) limits outside of Table 2 of I.S.

EN 206-1;



October 2009 6

(b) other aggressive chemicals are

present;

(c) the ground or water is polluted

chemically;

(d) there is high water velocity in

combination with the chemicals

in Table 2 of I.S. EN 206-1.

In practice, where the assumptions of

Table 1 of I.S. EN 206-1 for chemical

attack are not satisfied, then the

designer may specify one or more of

the following additional protective

measures:

(a) enhanced concrete quality;

(b) controlled permeability

formwork;

(c) provision of surface protection;

(d) provision of a sacrificial layer;

(e) address drainage of site.

Recommendations on the protection of

buried concrete exposed to sulfates

can be found in Building Research

Establishment Special Digest SD1

„Concrete in Aggressive Ground‟

(published in four parts by BRE),

which covers a wider range of

environmental actions than I.S. EN

206-1 and includes mobile ground

water, acids and brown field sites.

BRE Special Digest SD1 uses the

concept of „structural performance

level‟; foundations and other buried

structural elements of road bridges

and other structures should be

classed as high performance level.

Where buried concrete is exposed to

sulfates on the earth face and to de-

icing salts on the exposed face then

the use of CEMI SR cement (i.e.

SRPC to BS 4027) might not be

appropriate where the exposure class

is both XA3 and XD3 or XD4 in

accordance with Table 1 of I.S. EN

206-1. In such circumstances the

designer should consider specifying

CEMI cement in combination with a

Type II addition, as follows:

(a) CEMI cement conforming to I.S.

EN 197-1 with a mass fraction of

21% to 35% of combination of pfa

conforming to IS EN 450-1 (CII

B-V) but provided that the pfa

content is a mass fraction of not

less than 25% of cement or

combination;

(b) CEMI cement conforming to I.S.


36% to 55% of combinations of

pfa conforming to IS EN 450-1

(CIVB-V) but provided that pfa

contents is a mass fraction of not

more than 40% of cement or

combination;

(c) CEMI cement conforming to I.S.


36% to 65% of combination of

ggbs conforming to IS EN 15167-

1 (CIIIA);

(d) CEMI cement conforming to I.S.


66% to 80% of combination of

ggbs conforming to IS EN 15167-

1 (CIIB + SR).

Where a CEMI cement in

combination with a Type II addition

is specified by the designer in order to

provide concrete with sulphate

resisting properties then this should

be clearly stated in Appendix 17/1.

Design of Concrete for Piles

(ii) Design of concrete for piles will need

careful consideration if ground

assessment indicates highly

aggressive ground or water,

particularly so if required for high

performance structures in which the

piles are required to resist tension

forces or horizontal loads which

create bending moments. In adverse

situations the design of the piles must

be carefully appraised, and additional

precautionary measures such as the

use of Range C aggregate concrete

(refer to BRE SD1) or sleeving

considered.

In general, precast and in-situ

concrete piles through natural

undisturbed unweathered

sulphide/sulfate-bearing ground



October 2009 7

appear to carry little risk or

deterioration by sulfate attack. An

exception may be cases where the

unweathered ground has seepage

paths through discontinuities or more

preamble zones and there is a flow of

groundwater through these which has

a high concentration of sulfate

derived from a source such as

deposits of gypsum.

In the case of concrete piles in contact

with well-weathered sulfate-bearing

clay (such clay is generally free from

sulfides such as pyrite), the outer

surface should be regarded as at some

risk of sulfate attack particularly if

ground conditions are wet. Such

attack could potentially reduce the

skin friction component of pile load-

bearing capacity. The concrete design

should be based on the results of a

thorough ground appraisal that

determines sulfate concentrations at

appropriate close vertical intervals

(say 1 metre apart).

In-situ concrete piles through „made‟

ground may be especially vulnerable

to sulfate attack. Waste materials

from mining and industry are often

rich in sulfides and sulfates. Also,

made ground composed of formerly

unweathered pyrite-rich clay may

potentially have high sulfate contents

due to oxidation and bacterial

processes. Thorough ground

appraisal is needed prior to concrete

design. Appropriate procedures are

given in BRE Special Digest SD1

(Part 1). Effects on inadequately

specified concrete piles could include

significant reduction in pile section

and corrosion of reinforcement, as

well as loss of skin friction.

Drainage Considerations

(iii) Sulfate and/or acid bearing

groundwater should be intercepted, if

possible, before coming into contact

with buried concrete, and backfill

must be adequately drained.

Structure-specific and carrier drains

in proximity to the structure or

building foundations should be

designed to ensure that they have

sufficient capacity and that they can

be maintained. Detailing of the

design of drainage and its

construction should be undertaken

with care to avoid accidental

discharge of contaminated water into

backfill to structures, or on to buried

concrete surfaces.

Specifically designed groundwater

drainage is the preferred additional

protective measure where a

hydrostatic head of groundwater

greater than five times the concrete

section thickness is present.

Sulfates Resulting from Sulfides in

the Ground

(iv) The risk of deterioration due to

sulfate attack, including the

thaumasite form of sulfate attack

(TSA), is worse where clays or other

sulphide bearing materials have been

excavated, reworked and replaced

adjacent to buried concrete. The

rapid oxidation of sulfides,

particularly pyrites, in disturbed

ground, results in enhanced levels of

sulfates in the soil and groundwater.

Careful consideration must be given

to the choice of materials surrounding

buried concrete. They must be

assessed in relation to the presence

and sources of sulfates, the prevailing

groundwater conditions, the provision

and location of drainage, the proposed

usage of the structure, and coatings

and other protective measures to be

used. Though there may be benefits

in considering the use of non-

sulphate/sulphide bearing backfills in

proximity to structures, designers

would need to assess the potential for

sulfate migration from remote sources

through the backfill.

Large excavations to deep

foundations create sumps around

buried concrete. If they are

unavoidable then account should be

taken of the more aggressive

groundwater conditions and steps

taken to provide adequate drainage to

the backfilled excavation and to

prevent groundwater entering from

the surrounding area. On no account

should such excavations be refilled

with clays containing high

concentrations of sulfates and

sulfides.



October 2009 8

Irrespective of the type of backfill,

designers should try to ensure that

groundwater is intercepted by drains

or other means to prevent

groundwater reaching buried

concrete.

Surface Protection

(v) At present there is little information

available on the protection afforded

by commercially available coatings

and tanking against sulfate attack.

Traditional methods of using bitumen

emulsion based coatings have not

been fully effective in all the cases of

TSA investigated so far. However,

such coatings, properly applied,

appear to offer some measure of

additional protection, and are an

acceptable additional protective

measure.

The main requirements of coatings

and tanking are listed below:

provide an impermeable barrier;

be resistant to sulfates and other

deleterious chemicals;

have a neutral effect on the

concrete substrate;

be resistant to envisaged

mechanical damage;

be easy to apply correctly;

have long term durability;

be cost effective.

Such coatings and tanking must be

applied in accordance with the

manufacturer‟s instructions, and the

workmanship must be of a high

standard to maintain their integrity.

As an alternative to commercial

coatings and tanking, there appears

to be some merit in considering the

use of additional „sacrificial‟ concrete

in buried construction. This could be

achieved by providing an additional

sacrificial thickness of cover concrete

integral with a parent concrete or by

constructing a separate layer of

concrete made from range C

aggregates.

A sacrificial concrete layer is one of

the additional protective measures

given in BRE SD1. The quality of

such a layer should be at least equal

to that of the inner concrete.

Although service data are scarce,

BRE Special Digest SD1 (Part 2,

Section 5.6) suggests an additional

sacrificial layer of 50mm thickness.

The design of the concrete element

would need to be reappraised to

reflect the additional concrete.

Where TSA is considered possible, the

need to exercise good control over the

maintenance of the design cover in

reinforced concrete construction is

emphasised to minimise the risk of,

and delay the onset of, reinforcement

corrosion.

NG 1705 Concrete –

Requirements for Designed

Concrete

Conformity Criteria

1 Conformity criteria for compressive

strength are given in 8.2.1.3 of I.S. EN 206-1.

Suitability of Proposed Constituent

Material Proportions

2 Initial tests should establish a concrete

that satisfies all specified requirements for

fresh and hardened concrete. Where the

specifier or producer can demonstrate an

adequate design, based on data from

previous tests or long-term experience, this

may be considered as an alternative to

initial tests. Details of initial testing are

given in Annex A of I.S. EN 206-1.



October 2009 9

1706 Concrete – Production

General

1 In a significant change from previous Irish

practice, I.S EN 206-1 contains detailed

provisions for production control. It

requires the concrete producer to have a

documented production control system and

it sets out a list of general requirements,

followed by procedures that amplify some

aspects of these general requirements.

These procedures are allowed to be varied

to take account of:

the kind and size of the production;

the works;

the particular equipment being used;

procedures and rules in use at the

place of production;

the use of the concrete.

What is not specifically stated, but is

understood, is that any alternative procedure

should achieve effective control of that aspect of

production and be documented.

Every reasonable opportunity and facility

should be taken to inspect the materials and the

manufacture of concrete and to take any

samples or to make any tests. All such

inspection, sampling and testing should be

carried out with the minimum of interference

with the process of manufacture and delivery.

Consistence at Delivery

2 Additional Water. In general water or

admixtures should not be added to

delivered concrete and is forbidden by I.S.

EN 206-1. The addition if extra water to a

designed concrete will not only increase

the slump, but will also increase the

shrinkage potential and permeability of

the hardened concrete. The extra water

will also reduce the final compressive

strength of the concrete and its durability.

NOTE: If more water or admixtures are

added to the concrete in a truck mixer on

site than is permitted by the specification,

the concrete batch or load should be

recorded as “non-conforming” on the

delivery ticket. The party who authorized

this addition is responsible for the

consequences and this party should be

recorded on the delivery ticket. “Non-

conforming” concrete should not be

included in the Permanent Works.

NG 1707 Concrete – Conformity

and Identity Testing

Conformity

1 In a further significant change from

previous Irish practice, I.S. EN 206-1

requires the concrete producer to

determine conformity. This is logical as

only the producer has sufficient data to be

able to declare statistical conformity with

the specification. Where the producer

detects non-conformity that was not

obvious at the time of delivery, this non-

conformity has to be declared to the

relevant specifiers and users. Some

independent re-assurance that this has

been done as required is one of the

strongest reasons why concrete should be

subject to product certification, and

reference should be made to the product

certification scheme for ready mixed

concrete, see NG Sample Appendix 1/25:

Product Certification Schemes. The

conformity test results and associated

analysis should be provided by the

concrete producer at least every 3 months.

Non-conformity

2 The action to be taken in respect of the

concrete that is represented by the test

results that fail to meet the requirements

of I.S. EN 206-1 may range from qualified

acceptance in less severe cases to rejection

and removal in the most severe cases. In

determining the action to be taken, due

regard should be given to the technical

consequences of the kind and degree of

non-compliance, and to the economic

consequences of alternative remedial

measures either to replace the

substandard concrete or to ensure the

integrity of any structure in which the

concrete has been placed.



October 2009 10

In estimating the concrete quality and in

determining the action to be taken when

the tests indicate non-compliance, the

following should be established wherever

possible:

(a) the validity of the test results, and

confirmation that specimen sampling

and testing have been carried out in

accordance with the appropriate parts

of I.S. EN 12350 and I.S. EN 12390;

(b) the constituent materials proportions

actually used in the concrete under

investigation;

(c) the actual section of the structure

represented by the test cubes;

(d) the possible influence of any

reduction in concrete quality on the

strength and durability of this section

of the structure.

Additional tests may be carried out on the

hardened concrete in the structure to confirm

its integrity or otherwise. These may include

non-destructive testing methods or the taking of

cored samples (see NG 1727) for laboratory

examination and testing.

Identity Testing

3 (i) The specifier or user of the concrete

has the right to check the concrete

supplied to them. This does not form

part of conformity testing, but the

producer may opt to use such data in

the assessment of conformity. Such

testing is called “identity testing”, not

“acceptance testing” although in

reality its purpose is to decide if a

particular batch or batches are

acceptable to the specifier or user.

(ii) Identity testing identifies with a high

level of probability whether a

particular batch or batches come from

a conforming population. I.S. EN

206-1, Annex B provides rules for the

assessment of strength for one or

more batches of concrete.

(iii) The Irish National Annex to I.S. EN

206-1 gives identity test criteria for

slump and air content of single

batches of concrete. These are the

same as the conformity criteria for

single batches of concrete. Such

testing will determine if the

particular batch is accepted or

rejected.

(iv) The specifier is responsible for

organising any identity testing, see

Appendices 1/5 and 1/6.

Identity Testing Rates

4 The need for identity testing and the rate

of testing should be matched to the use of

the concrete. Low strength class concrete

usage and concrete used in less critical

structural elements usually will not

require identity testing to be undertaken,

unless there is a specific cause for doubt

over quality. High strength class concrete

and concrete used in structurally critical

elements will usually always require

identity testing, to confirm that the

supplied concrete conforms to the required

characteristics of the specified concrete.

5 Where identity testing for compressive

strength is required, it should be described

in Appendix 17/4, and be in accordance

with the requirements given in Annex B of

I.S. EN 206-1.

6 Where identity testing for slump and air

content is required on individual batches of

concrete, it should be described in

Appendix 17/4, and it should be in

accordance with the requirements given in

the Irish National Annex to I.S. EN 206-1.

7 Where identity testing is not restricted to

cases of doubt or random spot checks, the

type to be carried out, the volume of

concrete should be described in Appendix

17/4.

8 Typical rates of sampling for identity

testing are given in Table NG 17/1 below,

but not less than one sample should be

taken on each day for each concrete class

used.

9 Higher rates of sampling and testing may

be required at the start of work or if the

level of quality is in doubt; conversely,

rates may be reduced when high quality

has been established.



October 2009 11

TABLE NG 17/1: Typical Rates of Sampling

and Testing

Use of concrete Sample from one

batch selected

randomly to

represent an average

volume of not more

than the lesser of

(assumes batches of

6m3)

Prestressed

concrete

12m3 or 2 batches

Reinforced concrete From 24m3or 4 batches

to 96m3 or 16 batches

depending on

application

Mass concrete May not be required

10 For special reinforced concrete such as end

blocks, half-joints or other highly stressed

areas the rates of sampling for prestressed

concrete may be considered more

appropriate.

Air Content of Fresh Concrete

11 It should be noted that the method of

measuring air content described in I.S. EN

12350-7 is not applicable to concrete made

with lightweight aggregate.

Additional Tests on Concrete for Special

Purposes

12 Additional cubes may be required for

various purposes. These should be made

and tested in accordance with I.S. EN

12390, but the methods of sampling and

the conditions under which the cubes are

stored should be varied according to the

purpose for which they are required. For

determining the cube strength of

prestrssed concrete before transfer or of

concrete in a member before striking

formwork or removing cold weather

protection, sampling should preferably be

at the point of placing, and the cubes

should be stored as far as possible under

the same conditions as the concrete in the

members. The extra cubes should be

identified at the time of making and

should not be used for the normal

conformity or identity testing procedures.

NG 1708 Concrete – Surface

Finish

General

1 The type of surface finish required depends

on the nature of the member, its final

position in the structure, and whether or

not it is to receive an applied finish. The

appropriate finish, which may vary from

face to face, should be carefully chosen and

clearly specified.

Wherever possible, samples of surfaces of

adequate size (preferably incorporating a

horizontal and vertical joint and

reinforcement representative of heavily

congested zones of reinforcement) should

be agreed before work commences. All the

factors affecting the quality of the surface

finish from formwork should be carefully

studied. For detailed descriptions of these

factors and their interrelationship,

attention is directed to the pamphlet

„Appearance Matters 3 The Control of

Blemishes in Concrete‟, Cement and

Concrete Association.

Texture, colour and durability are affected

by curing (see NG 1710.5). Where

appearance is important, curing methods

and conditions including the time of

removal of formwork require careful

consideration. Components that are

intended to have the same surface finish

should receive the same treatment.

Control of Colour

2 Where uniformity of colour is important,

all materials should be obtained from

single consistent sources. In formwork the

replacement of individual plywood sheets

or sections of timber in large panels should

be avoided.

Colour can be affected by curing.

Release Agents

3 Release agents for formwork should be

carefully chosen for the particular



October 2009 12

conditions they are required to fulfil.

Where the surface is to receive an applied

finish, or it is to be impregnated, care

should be taken to ensure the

compatibility of the release agent with the

subsequent treatment process, for example

no deleterious residue should be left.

Surface Finishes for Concrete

4 (i) The class of finish should be shown on

the drawings. Class F1 finish should

be specified for unexposed formed

surfaces and Class F2 finish normally

for exposed surfaces. F3 finish is very

costly and should only be used for

small areas. F4 is appropriate where

large areas are required to have a

first-class appearance. Although

metal parts should never be

permanently embedded within the

cover depth from the surface of the

concrete, internal ties can be used in

ways which will not detract from the

appearance. For instance, if made

coincident with certain types of

surface features (e.g. vertical grooves

formed to break up large areas or

features which create shadow effects)

the holes are practically indiscernible

and an economical design of formwork

ensues. The designer is urged to be

flexible in his requirements for

surface features bearing such facts in

mind. For Class F3 and F4 finishes,

it is recommended that trial panels

should be made. Class F5 finish is

primarily intended for precast

pretensioned beams. The position of

the exposed surfaces in the finished

structure should be taken into

account in determining the extent of

making good. In cases where beams

are of the same design it is possible,

within practical limits, to minimise

the extent of making good by

selecting beams with the best surface

finish for positions of maximum

exposure.

(ii) Class U2 finish should normally be

specified for exposed concrete; Class

U3 being reserved for positions where

the surface is required to be

especially smooth for function or

aesthetic reasons; Class U4 finish is

to be used for bridge decks that are to

receive waterproofing systems; Class

U5 finish is reserved for footbridge

surfaces that are to receive either

separate or combined systems, or

coatings of waterproofing and

surfacing materials. The method

adopted for finishing a surface which

is to receive deck waterproofing

should be such that a layer of laitance

is not left on the surface nor the

course aggregated exposed.

(iii) Other classes of finish should be fully

specified and scheduled in Appendix

17/3 and should, if possible, be related

to samples that are readily available

for comparison. Included under this

heading is any finish that requires

the coarse aggregate to be

permanently exposed, the use of

special forms or linings, the use of a

different concrete mix near the

surface, grinding brush-hammering

or other treatment.

Protection

5 High quality surface finishes are

susceptible to subsequent damage, and

special protection may have to be provided

in vulnerable areas.

This is particularly relevant for precast

elements (especially facing elements for

reinforced walls) where careful

consideration needs to be given to the

handling and storage of these to prevent

marking of the surface by timber supports,

plastic spacers etc.

NG 1709 Concrete – Protection

Systems

General

1 Impregnation is carried out by spraying

concrete surfaces with a hydrophobising

material that penetrates the concrete and

reacts with the silicates and moisture

present. This produces a water repellant

but vapour permeable layer that inhibits

the ingress of water and/or chloride and

sulfate ions. Effectiveness of this layer is

determined by the quality of the

hydrophobisation and the strength and

permanence of the bond between the silane

molecule and the concrete substrate. The

depth of penetration will vary depending

on concrete quality and moisture content.

Impregnation is known to be effective for

at least 15 years provided it has been

applied correctly. Longer service lives are

anticipated. However, it is considered

advisable until further experience is



October 2009 13

gained to assume that reapplication will be

necessary after about 20 years.

2 Because of the wide variety of structural

types and span arrangements, etc. all

parts of a structure are not equally at risk

from attack. Generally the risk depends

upon the degree of exposure to water and

salts which in turn will depend on the

geometry, design and location of individual

members. It is highly desirable to treat all

exposed reinforced and prestressed

concrete surfaces subjected to spray and/or

possible leakage from deck joints. The

following is intended as a guide when

completing Appendix 17/2:

(i) piers, columns, crossheads and

abutments subjected to spray;

(ii) piers, columns, crossheads and

abutments with a deck joint above

but with no provision for positive

drainage. The tops of these members

should also be treated where possible;

(iii) bearing shelves, ballast walls and

deck ends with a deck joint above,

where possible;

(iv) structures in marine environments

and columns and soffits over brackish

water. A marine environment is

usually experienced within 1 km of

the coast or tidal waters unless there

are special local conditions.

(v) where possible, concrete parapets and

parapet plinths (all inclinations) and

those areas not protected with deck

waterproofing;

(vi) deck beams and soffits;

(vii) wing walls within 8 metres of the

edge of the carriageway;

(viii) retaining walls within 8 metres of the

edge of the carriageway;

(ix) „M‟ beams (webs and tops of bottom

flanges should be treated before

erection).

Material

3 (i) Silane is a toxic material and is an

irritant to human tissue. Containers

must be retained in a safe and secure

facility and quantities used must be

carefully monitored. Access for

sampling of opened containers and at

the spraying equipment must be

provided for the Employer‟s

Personnel.

(ii) Silane hydrolyses with moisture in the

atmosphere. The contents of any

opened containers should be used in

accordance with sub-Clause 8 of this

Clause within 48 hours or discarded

(iii) Silane can be contaminated with

substances such as paraffin or white

spirit without any visual indications.

It is important to test for such

contamination by measuring the

refractive index of the silane and

taking the necessary actions as

indicated in sub-Clause 1709.2.

Spraying Equipment

4 The type of nozzle used and spraying

distance should be in accordance with the

manufacturer‟s instructions.

Protective Measures

5 (i) Silane may have deleterious effects

that need to be controlled during the

application of the material. Prior to

application, protective measures must

be implemented to prevent

contamination of watercourses and

damage to humans, animals,

vegetation and vehicles.

(ii) Impregnation over or adjacent to

watercourses will require protective

sheeting or complete encapsulation

beneath the structure to be

impregnated.

(iii) Impregnation on structures over or

adjacent to roads will require

protective sheeting or complete

encapsulation. Consideration should

also be given to the introduction of

appropriate traffic management and

safety measures.

(iv) Vegetation that could be subject to

spray, needs to be covered or

otherwise protected, and the

protective covering must be

maintained in position and in good

condition.

(v) Silane has a softening effect when it

comes into contact with elastomeric

bearings, painted steel surfaces,

bituminous materials and joint

sealants, and these items should be

protected during application. The



October 2009 14

protective measures must be

maintained in position and in good

condition. On completion of the

impregnation process the masking

materials should be removed and

disposed of in accordance with sub-

Clause 8 of this Clause.

Surface Condition

6 (i) It should be ensured that curing

membranes and release agents,

where they have been used, have fully

degraded before impregnation is

carried out. This is particularly

important to check when silane is to

be applied less than a month after the

concrete was placed.

(ii) Water jetting or steam cleaning

should not in general be used to

remove contamination, solid deposits

or curing membranes. In exceptional

circumstances, where there is

substantial contamination, these

methods may be used with care,

subject to a satisfactory trial being

undertaken. However, impregnation

should not commence for a minimum

of 48 hrs from completion of the

cleaning works, and remains subject

to the other application and surface

condition requirements, particularly

the need for a period of surface

dryness of the concrete substrate for a

period of 24 hours in advance of the

impregnation operation.

(iii) Silane should not be applied until the

concrete surface has been dry for 24

hours because absorption of silane

will be restricted if damp, reducing its

effectiveness. Artificial drying of the

concrete surface is not permitted, as

this may lead to increased moisture

at the surface by capillary action from

within the concrete, when the drying

equipment is removed.

Application

7 (i) Depending on climatic conditions, it

may be necessary to protect surfaces

to be treated to ensure that they are

surface dry before impregnation.

(ii) The required coverage of each coat at

300 ml/m2 must be regularly

monitored by determining the

quantities of silane material used on

particular areas of each structure.

Achieving the required rate may

result in some loss of material, by run

down and evaporation. Application of

silane can be judged by a

characteristic „wet look‟ to the

concrete.

(iii) It is important to apply the silane

before the concrete receives its first

exposure to salts, subject to the prior

degradation of any curing

membranes, because a substantial

amount of contaminants can enter the

concrete by capillary adsorption

during this initial exposure. This may

be particularly important in a marine

environment.

Disposal

8 Given the toxic nature of silane, the

contents of all containers that have been opened

for more than 48 hrs, contaminated materials,

sheeting etc, must be disposed of appropriately

at an approved disposal facility.

Quantities of materials must be monitored on

site and materials kept in safe and secure

facilities.

Materials Testing

9 (i) It is essential that volumes of

impregnation material delivered to

site, used on site and for disposal, are

accurately monitored.

(ii) Samples of impregnation material

(refer to sub-Clause 1709. 2(vi))

should be tested to confirm

compliance with the requirements of

sub-Clause 1709. 2(ii).

NG 1710 Concrete –

Construction General

Construction Joints

1 The number of construction joints should

be kept as few as possible consistent with

reasonable precautions against shrinkage

and early thermal movement. Concreting



October 2009 15

should be carried out continuously up to

construction joints.

Where it is necessary to introduce

construction joints, careful consideration

should be given to their exact location,

which should be shown either on the

drawings or determined by the Contractor

in accordance with the specified criteria.

Construction joints should be at right

angles to the general direction of the

member and should take due account of

shear and other stresses.

The use of retarding agents painted onto

formwork is not permitted because they

tend to migrate into the concrete under the

action of vibration.

When open mesh permanent formwork is

proposed, its suitability should be

supported by sufficient information about

its stiffness, strength, method of use and

performance.

Concrete should not be allowed to run to a

feather edge and vertical joints should be

formed against a stop end. The top surface

of a layer of concrete should be level and

reasonably flat unless design requirements

are otherwise. Joint lines should be so

arranged that they coincide with features

of the finished work.

If a kicker (i.e. a starter stub) is used, it

should be at least 70mm high and carefully

constructed. Where possible, the formwork

should be designed to facilitate the

preparation of the joint surface, as the

optimum time for treatment is usually a

few hours after placing.

Particular care should be taken in the

placing of the new concrete close to the

joint. This concrete should be particularly

well compacted.

Formwork

2 (i) Design and construction. It should be

ensured that all permanent or

temporary formwork, including

supports, is adequate for the proper

construction of the Works.

Before any formwork is constructed,

the Contractor should prepare detail

drawings, including details of

external vibrators where proposed

and the depth of lifts to be concreted

where appropriate. The drawings

should be supported by calculations

which show the adequacy of the

proposals.

Requirements for permanent

formwork, for either internal or

external use, should be described in

Appendix 17/4; due regard being

given to the conditions to which it is

likely to be exposed and to its

function in the structure. The

material selected for external use

must be durable, particularly at

exposed edges or joints.

(ii) Projecting reinforcement. Special

care should be taken when formwork

is struck to avoid the risk of breaking

off the edge of concrete adjacent to

any projecting reinforcement.

Transporting, Placing and Compacting

3 Concrete should be transported from the

mixer to the formwork as rapidly as

practicable by methods that will prevent

the segregation or loss of any of the

ingredients and maintain the required

workability. It should be deposited as near

as practicable to its final position to avoid

rehandling.

All placing and compacting should be

carried out under the direct supervision of

a competent member of the Contractor‟s

(or manufacturer‟s) staff. Concrete should

normally be placed and compacted soon

after mixing, but short delays in placing

may be permitted provided that the

concrete can still be placed and effectively

compacted without the addition of further

water.

A cohesive concrete mix that does not

segregate may be allowed to fall freely

provided that special care is taken to avoid

displacement of reinforcement or

movement of formwork, and damage to

faces of formwork. In massive sections it is

necessary to consider the effect of lift

height on the temperature rise due to the

heat of hydration.

Concrete should be thoroughly compacted

by vibration, pressure, shock or other



October 2009 16

means during the operation of placing to

produce a dense mass having the required

surface finish when the formwork is

removed.

Whenever vibration has to be applied

externally, the design of formwork and

disposition of vibrators should receive

special consideration to ensure efficient

compaction and to avoid surface blemishes.

The mix should be such that there will not

be excess water on the top surface on

completion of compaction. It may be

necessary to reduce the water content of

batches at the top of deep lifts to

compensate for water gain from the lower

levels, but this can be avoided by designing

the mix, checking with preliminary trials

and accurately controlling the mix

proportions throughout the work.

Spillages of concrete onto other parts of the

permanent structure, e.g. structural

steelwork, should be removed immediately

they occur to avoid damage to finishes.

When air entrained concrete is used,

reference should also be made to NG

1702.3(ii).

For the time being it should be noted that

self-compacting concrete (SCC) is not

explicitly permitted under the

Specification, as concrete is required to be

compacted. However, where SCC is

considered to be the preferred option then

agreement should be sought under NRA

BD 2 Technical Acceptance of Structures

on Motorways and Other Roads and

amendments agreed to Specification

Clauses, dealing with quality control,

materials, testing and construction

requirements. In particular attention

should be given to the type of testing

proposed, such as slump flow table, and

setting target flow values, to be used as

part of the quality control procedures. Also

important are specification and limitation

of admixture dosage rates, both at the

batching plant and at the point of delivery.

From experience it may be necessary to

undertake trial panels to ensure that the

specified concrete finishes are achieved

and that any necessary controls over the

method and rate of placement of SCC can

be assessed and instigated.

Striking of Formwork

4 (i) General. The time at which

formwork is struck is influenced by

the following factors:

(a) concrete strength;

(b) stresses in the concrete at any

stage in the construction period,

which in the case of precast

units includes the stresses

induced by disturbance at the

casting position and subsequent

handling;

(c) curing (see NG 1710.5);

(d) subsequent surface treatment

requirements;

(e) presence of re-entrant angles

requiring formwork to be

removed as soon as possible

after concrete has set to avoid

shrinkage cracks;

(f) requirements of any deflection

profile.

The formwork should be removed

slowly, as the sudden removal of

wedges is equivalent to a shock load

on the partly hardened concrete.

(ii) Striking period for cast in situ

concrete.

Field conditions for control cubes may

be simulated by temperature-

matching curing or other methods. In

the absence of control cubes, reference

should be made to the specialist

literature, e.g. “Formwork Striking

Times-Methods of Assessment”

prepared by CIRIA (Report No. 67) for

appropriate guidance.

The periods given in Table 17/5 of the

Specification are not intended to

apply where accelerated curing or slip

forms are used. Where it is not

practicable to ascertain the surface

temperature of concrete, air

temperatures may be used though

these are less precise. In cold

weather the period should be

increased according to the reduced

maturity. For example, for soffit

formwork it would be appropriate to

increase the value by half a day for

each day on which the concrete



October 2009 17

temperature was between 2OC and

7OC, and by a whole day for each day

on which the concrete temperature

was below 2OC.

When formwork to vertical surfaces

such as beam sides, walls and

columns is removed in less than 12

hours, care should be exercised to

avoid damage to the concrete,

especially to arrises and features.

The provision of suitable curing

methods should immediately follow

the removal of the vertical formwork

at such early ages, and the concrete

should be protected from low or high

temperatures by means of suitable

insulation (see NG 1710.5).

Curing

5 (i) Curing Methods. The method of

curing and its duration should be

such that the concrete will have

satisfactory durability and strength

and the member will suffer a

minimum of distortion, be free from

excessive efflorescence and undue

cracking. To achieve these objectives

it may be necessary to insulate the

concrete so that it is maintained at a

suitable temperature, or so that the

rates of evaporation of water from the

surfaces are kept to appropriate

values, or both. Different curing or

drying treatments are appropriate to

different members and products.

Where necessary, special care should

be taken to ensure that similar

components are cured as far as

possible under the same conditions.

Curing usually consists of

maintaining the formwork in place

and covering the concrete with a

material such as polythene sheet or a

curing compound or with an

absorbent material that is kept damp

for a period of time.

Where formwork is struck before

curing is complete some other form of

protection should be used.

Where structural members are of

considerable depth or bulk or have an

unusually high proportion of cement

or are precast units subjected to

special or accelerated curing methods,

the method of curing should be

specified in detail in Appendix 17/4.

Some special cases are cited as

examples in NG 1710.5(iii).

The higher the rate of development of

strength in concrete, the greater the

need to prevent excessive differences

in temperature within the member

and too rapid a loss of moisture from

the surface. Alternate wetting and

drying should be avoided, especially

in the form of cold water applied to

hot concrete surfaces. In order to

avoid surface cracking, cold water

should not be applied to relatively

massive members immediately after

striking the formwork while the

concrete is still hot.

(ii) Accelerated curing. Accelerated

curing (which includes steam curing)

consists of curing the concrete in an

artificially controlled environment, in

which the humidity and the rate of

temperature rise and fall are

controlled, to speed up the rate of

increase in strength.

(iii) Additional Considerations. The

principal reasons and

recommendations for curing concrete

are given in (i) and (ii) above. The

following parts of this sub-Clause are

intended to amplify the factors that

should be considered. The

recommendations are based on the

assumption that the concrete

temperature during the curing period

will not fall below 2OC. Particular

precautions to be taken when

concreting at low air temperatures

are given in NG 1710.6.

(a) Strength of concrete. The effect

of admixtures on curing should

be considered. The higher the

rate of development of strength

of the concrete (and hence of

heat of hydration of the cement),

the more care should be taken

during the early period after

casting to prevent excessive

differences in temperature

within the concrete and

excessive loss of moisture from

the pour.

The rate of gain of strength is

also increased if the temperature

of the concrete is raised. An



October 2009 18

approximate guide of the

development of strength at

different temperatures can be

obtained by using the concept of

„maturity‟, which may be defined

as the area under a curve of the

concrete temperature (in degree

Celsius) plotted against time (in

hours) calculated from a basis of

–10OC. Curing by means of

damp absorbent materials is

likely to cause a lowering of the

temperature of the concrete as a

result of the evaporation from

the material, and in some

circumstances the effect can be

significant.

The rate of development of

strength diminishes as the

concrete dries out; hence

excessive evaporation of water

from all surfaces may need to be

prevented.

(b) Distortion and cracking. The

concrete should b cured so that

internal stresses within the

member, whether due to

differences in temperature or

differences in moisture content

within the concrete, are not

sufficient to cause distortion or

cracking. The disposition of

reinforcement will affect the

restraint to the strains, and

hence it will have an effect on

any distortion and cracking.

In assessing the likely

temperature variation within

the concrete, the following

factors apply:

rate of heat evolution

(related to rate of

development of strength);

size and shape of member;

different insulation values

of curing media (e.g.

wooden moulds or water

spray);

external temperature.

For example, surface cracking

may occur as a result of

variation in temperatures due to

applying a cold water spray to a

relatively massive member

immediately after stripping the

moulds while the concrete is still

hot.

In assessing the likely variation

in moisture content within the

concrete. The rate of evaporation

will be higher with atmospheric

conditions encouraging

evaporation (e.g. low relative

humidity, high wind speed,

concrete surface hotter than air),

especially if the rate of

migration of water through the

concrete is greater than the rate

of evaporation from the surface,

e.g. for:

members of high

surface/volume ratio;

concrete at early age or

lower strength class of

concrete.

For example, cracking may occur

due to varying shrinkage in

members with sudden changes

in section that affect the

surface/volume ratio

appreciably; especially if the

more massive section is

reinforced and the more slender

section is not.

Further information can be

obtained from CIRIA Report No.

91, “Early-age Thermal Crack

Control in Concrete”.

If the shrinkage of units after

they are built into the structure

is likely to lead to undesirable

cracking at the ends of the unit,

curing aimed at preventing the

loss of water from the unit

should be continued no longer

than is necessary to obtain the

desired durability and strength;

thereafter the concrete should be

given the maximum opportunity

to dry out consistent with the

limitation of the variation in

moisture content as already

outlined.



October 2009 19

(c) Durability and appearance. As

deterioration is most likely to

occur as a result of the concrete

providing inadequate protection

for the reinforcement, or because

of frost attacking the surface

concrete, all vulnerable surfaces

of concrete should be protected

against excessive loss of water

by evaporation that would result

in a weak, porous surface layer.

Where it is important to prevent

the formation of efflorescence,

especially in cold weather, the

atmosphere adjacent to the

surface of the concrete should be

maintained at a constant

relative humidity approaching

100% for the time given in Table

17/5 of the Specification.

Concrete should be protected

from wetting and drying cycles.

(iv) Curing liquids, compounds and

membranes. Before curing liquids,

compounds and membranes are

accepted for use on surfaces on which

waterproofing systems are to be laid

they should be shown to be

completely removable by natural or

mechanical means.

It should be noted that proprietary

liquid curing membranes may take a

long time to disintegrate and may

affect the appearance of permanently

visible surfaces as well as the bond of

any waterproofing layer.

Only film type membranes that fully

degrade by exposure to ultra-violet

light should be used where concrete

surface impregnation is specified, as

other curing liquids, compounds or

membranes may leave residues which

prevent satisfactory application of the

treatment. Sufficient interval should

be allowed for the film to fully

decompose before impregnation

commences (see NG 1709.6). To

achieve optimum breakdown of the

membrane the manufacturer‟s

recommendations for prior wetting or

dampening of the concrete surfaces

and the rate of application of the

membrane material should be closely

followed.

Cold Weather Work

6 (i) General. Before placing concrete, the

formwork, reinforcement,

prestressing steel and any surface

with which the fresh concrete will be

in contact should preferably be at a

temperature close to that of the

freshly placed concrete. Special care

should be taken where small

quantities of fresh concrete are placed

in contact with larger quantities of

previously cast concrete at a lower

temperature. Any concrete damaged

by frost should be removed from the

work.

Concrete temperatures should be

measured at the surface at the most

unfavourable position.

(ii) Concrete Temperature.

The raising of the temperature of the

concrete may be achieved in a number

of ways including the following:

(a) By heating the mixing water and

aggregate. If the water is heated

above 60OC, it is advisable to

mix the water with the

aggregate before adding the

cement.

(b) By increasing the top cement

content of the mix or by using a

more rapid hardening cement.

(c) By covering the top face of slabs

and beams with adequate

insulating material.

(d) By providing wind breaks to

protect newly placed concrete

from cold winds.

(e) By using a heated enclosure,

completely surrounding the

freshly placed concrete or using

heated formwork panels. In

either event care should be

taken to prevent excessive

evaporation of water from the

concrete.

Formwork should be left in place

as long as possible to provide

thermal insulation; timber



October 2009 20

formwork provides better

insulation than steel. Further

guidance on this subject can be

obtained from the Cement and

Concrete Association Publication

No. 45.007 “Winter Concreting”.

Hot Weather Work

7 In hot weather, the incidence of cracking

and loss of workability may be reduced if

measures are taken to cool the constituent

materials. Aggregates can be kept cool by

protecting them from direct sunlight and

by spraying with water, making due

allowance for the moisture content of the

mix. Water pipes particularly if long

should preferably be shaded and if possible

insulated.

Surface Preparation of Precast Concrete

Units

8 Laitance is the dusty milky cement

compound which can be removed after the

concrete has hardened using a stiff brush.

Handling and Erection of Precast Concrete

Units

9 (i) Manufacture off the Site. The

designer should show on the drawings

the type of preparation of the surfaces

of concrete members which will

subsequently receive in situ concrete.

Supervision of workmanship and

materials for factory-made concrete

units is as important for Site work

and is most satisfactorily carried out

by a resident inspector or by making

frequent visits during manufacture.

To monitor control during production,

test results should be readily

available. This should help to

encourage careful manufacture.

Where exceptional circumstances

prevent proper supervision being

exercised, visual inspection and

measurement of the completed units

can determine some of the important

properties. Reference should also be

made to NG 1727. To benefit from

manufacturer‟s normal practice, it is

recommended that for factory-made

pretensioned beams, the designer

should be prepared to accept

alternative types and positions of

tendons. Where the size and position

of the tendons is shown on the

drawings, the words “or equivalent”

should be added and the force before

transfer and its eccentricity should be

given. The designer should ensure

that the losses from the type of

tendons proposed are not greater

than those taken into account in the

design.

(ii) Storage. Indelible identity, location

and orientation marks should be put

on the member end where necessary.

The designer should in all cases

specify the points of support during

storage, and these should be chosen to

prevent unacceptable permanent

distortion and lack of fit of the units.

In order to minimise the stresses

induced, supporting arrangements

that permit only small settlements

are to be preferred.

The accumulation of trapped water

and rubbish in the units should be

prevented. The freezing of trapped

water can cause severe damage.

Where necessary, precautions should

be taken to avoid rust stains from

projecting reinforcement and to

minimise efflorescence.

(iii) Handling and transport. Precast

units should resist, without

permanent damage, all stresses

induced by handling and transport.

The minimum age for handling and

transport should be related to the

concrete strength, the type of unit

and other relevant factors.

The position of lifting and supporting

points, the method of lifting, the type

of equipment, the minimum age for

handling, and transport to be used

should be as specified by the designer.

Care should be taken to ensure that

lifting details are practicable and can

be used safely, and that no damage

results from the lifting equipment.

During transport the following

additional factors require

consideration



October 2009 21

(a) Distortion of the transporting

vehicles.

(b) Centrifugal force due to

cornering.

(c) Oscillation. A slim member may

flex vertically or horizontally

sufficiently to cause damage.

(d) The possibility of damage due to

chafing.

(iv) Assembly and erection. Where the

method of assembly and erection is

part of the design, it should be stated

in Appendix 17/4.

In order to ensure compliance with

sub-Clause 1710.8(iv)(a) of the

Specification, it may be advisable to

have the camber of precast beams

measured at the factory so that they

can be placed in the correct order.

The object of preventing lateral

movement of precast beams in

composite slab bridges is to prevent

differential movement between

beams, which may occur if the

concrete is placed in longitudinal

strips. This is particularly important

when the beams are supported on

flexible bearings.

(v) Forming structural connections. The

precast units should be inspected to

ensure that the design requirements

of the structural connection can be

met.

The precast units should be free from

irregularities which may cause

damaging stress concentrations.

When reliance is placed on bond

between the precast and in situ

concretes, the contact surface of the

precast units should have been

suitably prepared. If frictional

resistance is assumed to be developed

at a bearing, the construction should

be such that this assumption can be

realised. Particular care should be

given to checking the accurate

location of reinforcement and any

structural steel sections in the ends of

precast members, and to introducing

any additional reinforcement needed

to complete the connection.

(a) Concrete or mortar packing.

When joints between units,

particularly the horizontal joints

between successive vertical lifts

are load-bearing and are to be

packed with mortar or concrete,

tests should be carried out to

prove that the material is

suitable for the purpose and the

proposed method of filling

results in a solid joint (for

bedding mortar see Clause

2601).

(b) Other packing materials. Where

epoxy resin bonding agents for

segmental deck construction are

to be used the designer should

prepare additional specification

requirements based on the

manufacturer‟s

recommendations. Reference

should also be made to

Federation Intrernatinoale de la

Precontrainte (FIP) publication

FIP/9/2, available from the

British Cement Association.

The composition and

water/cement ratio of the in situ

concrete or mortar used in any

connection should be as

specified.

Care should be taken to ensure

that the in situ material is

thoroughly compacted.

The manufacturer‟s

recommendations as to the

application and method should

be strictly followed.

Careful consideration should be

given to the proposed methods

for removing levelling devices

such as nuts and wedges.

(vi) Protection. The degree and extent of

the protection to be provided should

be sufficient for the surface finish and

profile being protected, bearing in

mind its position and importance.

This is particularly important in the

case of permanently exposed concrete

surfaces, especially arrises and



October 2009 22

decorative features. The protection

can be provided by timber strips,

hessian, etc. but should not be such as

will damage, mark or otherwise

disfigure the concrete.

Measurement of Precast Concrete

10 Units may be measured at any convenient

time but not less than 7 days after casting,

provided that the alternative time

proposed by the Contractor is supported by

calculations to demonstrate the

dimensions predicted for 28 + 2 days.

NG 1711 Concrete – Grouting

and Duct Systems for Post-

tensioned Tendons

General

1 The Specification allows for the designer to

call for full-scale trials to be carried out to

demonstrate that the grouting will provide

adequate protection to the tendons. This

requirement should be specified in

Appendix 17/6 and fully detailed on the

Contract drawing, including trial beam

size, concrete strength class, cover to

reinforcement and tendons, reinforcement

for testing and investigation. The designer

should recognise that the purpose of the

trial is to test the Contractor‟s systems and

methods and personnel proposed for the

permanent works and should incorporate

any particular requirements pertaining to

the construction sequence and duct

configurations. Requirements for

subsequent disposal of the trial beam

should be specified.

Feedback from previous Contracts has

shown that there are very significant

benefits for all parties in undertaking a

full-scale trial. In the circumstances it is

advocated in all but very minor post-

tensioning and grouting operations.

The trials should be carried out well in

advance of the planned need for use of

post-tensioning in the permanent works

(56 days is the default period in the

Specification). In particular, any proposals

for untried systems should be given due

time for acceptance.

Successful completion of the trials and

materials tests will allow commencement

of the grouting in the permanent Works.

Grouting techniques such as vacuum

grouting and void grouting (undertaken as

a remedial measure) are available from

some suppliers and can be considered

either to be demonstrated as suitable in

trials or for remedial works as appropriate.

Grout Material

2 Composition of the grout is classified in

sub-Clause 1711.2. The grout may be

supplied as a proprietary manufactured

pre-bagged material, to which water must

be added, or as a designed site batched

blend of cement, admixtures and water.

Both materials have identical performance

requirements. Performance of the grout

will in all cases be assured by suitability

testing, irrespective of whether full-scale

grouting trials have been specified.

Where bagged cement is used in site

batched grout the Employer‟s

Representative should be aware that

variations in cement type, age, chemical

composition, fineness and temperature can

have significant effects on the performance

of the grout.

Ducting

3 Sub-Clause 1711.3 requires the ducting to

form an air and water resistant protective

barrier as an additional defence against

corrosive contaminants. This follows the

philosophy adopted in Concrete Society

Technical Report TR47 „Durable Bonded

Post-tensioned Concrete Bridges‟ 2nd

edition, of multi-layer corrosion protection.

The duct system should comply, as a

minimum with the International

Federation for Structural Concrete (fib)

recommendations (Technical Report,

Bulletin No. 7) for „Corrugated plastic

ducts for internal bonded post-tensioning‟.

Polyethylene and polypropylene are

suitable materials for ducting but other

materials may also be suitable.

Debate continues over the minimum wall

thickness of ducting, and over the air-

pressure test requirements.

The minimum manufactured wall

thickness of ducting for internal tendons



October 2009 23

should be 2mm. The duct rigidity and type

and spacing of fixings and supports should

be such as to maintain line, position and

cross section shape during concreting.

Local deformation of the duct at supports

should be avoided.

For external tendons the minimum wall

thickness should be 4mm for durability, or

such thicker wall as required to withstand

grouting pressures of the particular duct

configuration. It is important to anticipate

any sagging of the duct due to the weight

of grout, particularly for tendons stressed

after grouting, and appropriate temporary

duct support should be provided during the

grouting operation.

Minimum wall thickness of the ducting

after tensioning should be considered by

the designer and appropriate requirements

specified in Appendix 17/6, taking account

of minimum radii of curvature of the

tendons which will tend to bite into the

duct wall. Type and spacing of duct

supports also need careful attention to

avoid this. Manufacturers‟ and suppliers‟

data should be referred to.

The internal diameter of vents should be

as large as possible but designers should

bear in mind the sizes included within

available systems. The vents, connections

and taps should be sufficiently robust to

withstand full grouting pressure.

For most applications a minimum vent

height of 500mm above the highest point

on a duct is recommended to help

entrapped air and water to escape. For

some configurations of tendons this will

not be appropriate and the designer should

specify an alternative in Appendix 17/6.

There are circumstances where the

requirement for a sealed ducting system

will be difficult e.g. in segmental

construction. The designer should consider

the options. Sealing of ducts at joints in

segmental construction is an issue which

remains to be satisfactorily resolved, and

consequently such a form of construction

using internal grouted tendons is not

currently permitted.

The purpose of air testing is to

demonstrate, first, that the system

provides an adequate degree of resistance

to contaminants and, second, that the

system is correctly assembled and has no

significant leaks. The pressure testing

requirements make reference to

compliance testing before installation and

duct assembly verification testing. It is

expected that all currently available

systems can pass the latter test, but

designers should seek the prestressing

supplier‟s guidance before completing

Appendix 17/6.

Grouting Equipment

4 The mixing equipment should be of a type

capable of producing a homogeneous grout

by means of high local turbulence while

imparting only a slow motion to the body of

the grout.

Injecting Grout

5 The volume of the spaces to be filled by the

injected grout should be compared with the

quantity of grout injected.

Grouting should be undertaken from one

end of the duct only, to avoid the risk of

voids. In exceptional situations such as

looped vertical ducts this may be

undertaken from both ends, but the

methods should be assessed in full scale

trials.

The rate of grout injection should be

defined in Appendix 17/6. Grout injection

should not normally result in more than

10m of duct being grouted per minute. For

certain applications where ducts are

outside the normal range of size (i.e. not

multi-strand tendons in 80mm – 125mm

ducts), this limit may be increased to 15m

of duct per minute.

Grouting During Cold Weather

6 The grout materials may be warmed

within the limits recommended for

concrete (see NG 1710.6).

Testing

7 The requirement for bond length is given

as 50-100 diameters of the duct in line

with fib recommendations. If the designer

wishes to give an alternative, this should

be specified in Appendix 17/6.



October 2009 24

The mandatory Duct Assembly

Verification Test included in the

Specification is intended to demonstrate

that the system has been correctly

assembled. If the system fails to meet the

criteria required by the Test, it should be

dismantled, any damaged items replaced,

and the system reassembled and re-tested.

If it still fails to comply, sealing of joints

with the addition of a suitable sealant may

improve matters. Acceptance would then

be subject to the results of re-testing.

Appendix A of TR47 describes additional

tests to measure the effectiveness of seal

provided by the duct system, which the

designer may wish to consider adopting in

appropriate circumstances. These methods

require further experience and

development before adoption as a

specification requirement.

The fluidity of the grout during the

injection period should be sufficiently high

for it to be pumped effectively and

adequately to fill the duct, but sufficiently

low to expel the air and any water in the

duct. The time during which fluidity is

maintained will need to be assessed but a

target of 90 minutes is a sensible upper

limit.

The grout should be sufficiently stable to

bleed very little and so the materials

segregate and settle to a minimal extent.

The Employer‟s Representative should

adopt a pragmatic approach to the size of

acceptable voids in ducts. The limits given

in sub-Clause 1711.1 would normally be

acceptable at a crest in the duct where the

steel tendons are embedded in grout in the

lower part of the duct and the vents are

properly filled and sealed, and the surface

is waterproofed.

It is recommended that where the system

includes end caps at anchorages intended

to be left in place, these are left

undisturbed and completeness of grouting

is tested by sounding and visual

examination of vent holes in order to avoid

disturbing the seals.

It has been observed that the type of belled

test currently specified in most national

codes, and in the first edition of TR47,

failed to identify potentially unstable

grouts. The important feature missing

from these tests is the destabilising effect

of the „wick action‟ caused by the strands.

This shortfall has been addressed by LCPC

Appendix A, clause A7 in France by the

development of an inclined tube test,

which is included in Appendix A7 of TR47

as an acceptable alternative test. It has

also been addressed in a BRITE Euram

Project „QA of grouting‟, clause 9.3 by the

development of a 1.5m vertical test. The

latter test is simpler, quicker and more

economical, and is incorporated in TR47,

and is recommended for general use.

It has also become evident that

specifications that require bleed water to

be reabsorbed in 24 hours have no logical

basis. If bleed water develops,

reabsorption will merely create an air void.

Likewise, requirements to measure the

bleed water after three hours are not

necessarily relevant to modern thixotropic

grouts.

Admixtures

8 Expanding grout admixtures are supplied

as powders which expand to ensure that

there is no overall decrease in the volume

of grout at the end of the hardening period.

Non-expanding grout admixtures are

supplied in liquid or powder form.

Both types of grout admixture may also

permit a reduction in water/cement ratio,

improve fluidity, reduce bleeding and

retard the set of the grout.

Grouting

9 Normally, grout injection should not

exceed the rate of 10m of duct per minute.

For certain applications, where ducts are

outside the normal range of size (i.e. not

multi-strand tendons in 80-125mm ducts0,

this may be increased to 15m of duct per

minute.

To minimise the risk of blockages of

pumping equipment or delivery hoses or of

lumps forming in the grout, it is advisable

to wash out equipment with water at least

every three hours. This is especially

recommended before grouting very long

tendons and in warm weather.



October 2009 25

In cold weather it is necessary to measure

the temperature of the concrete structure

(for internal tendons) or the air void

around the ducts (for external tendons) to

comply with specifications to avoid freezing

the grout. Air temperature measurement

is straightforward but measuring the

temperature of the structure can be more

difficult.

Recommended procedures are to seal the

ducts, say, 12 hours before grouting and

measure the air temperature inside the

ducts, or to form a small pocket in the

concrete, fill it with water, again, say 12

hours before grouting and measure the

temperature of this water.

Grouting plant should be located as close

as practical to the point of injection to keep

supply lines short.

NG 1712 Reinforcement –

Materials

Stainless Steel Reinforcement

1 Advice on stainless steel reinforcement is

given in BA 84 (DMRB 1.3). Since there

are a multiplicity of grades of stainless

steel, it is essential that supplied steel is

clearly designated with its strength and

chemical grade, and that care is taken to

ensure that the correct materials are

utilised.

NG 1713 Carbon Steel

Reinforcement and Stainless

Steel Reinforcement – Bar

Schedule Dimensions – Cutting

and Bending

1 Bending of reinforcement should not be

carried out when the temperature of the

steel is below 5OC. If necessary,

reinforcement may be warmed to a

temperature not exceeding 100OC.

Where it is necessary to bend

reinforcement projecting from concrete, the

radius of the bend should be not less than

that specified in BS 8666, and there should

be a clear distance of 4d between the

concrete face and the start of the bend.

Embedded couplers should be used

wherever practicable to avoid damage to

concrete and reinforcement.

2 Where the Contractor or precast

manufacturer opts to cut and bend

reinforcement on the Site, or in the

precasting works respectively, even

through the CARES fabricators offer this

service, it should be ensured that any

fabricated reinforcement not covered by a

third party certified product certification

scheme such as CARES is assessed by

acceptance tests carried out by an

independent testing laboratory as specified

in BS 8666.

NG 1714 Reinforcement – Fixing

1 Cover blocks and spacers should be of such

materials and designs that they will be

durable, will not lead to corrosion of the

reinforcement, and will not cause spalling

of the concrete cover.

Cover and spacer blocks made from

cement, sand and fine aggregate should

match the mix proportions of the

surrounding concrete as far as is

practicable with a view to being

comparable in strength, durability and

appearance. The Concrete Society Report

CS 101 “SPACERS” provides standardised

methods of achieving the specified nominal

cover and gives standard performance

requirements and methods of testing

spacers and chairs.

Non-structural connections for the

positioning of reinforcement should be

made with stainless steel wire or tying

devices or by welding (see NG 1717). Care

should be taken to ensure that projecting

ends of ties or clips do not encroach into

the concrete cover.

The cover and position of reinforcement

should be checked before and during

concreting; particular attention being paid

to the position of top reinforcement in

cantilever sections. The support of

reinforcement to achieve the correct

location, cover and spacing is the

Contractor‟s responsibility and supports

should not be shown on the drawings and

bar schedules.



October 2009 26

The concrete cover to reinforcement should

be confirmed as soon as possible after the

removal of formwork by the use of non-

destructive methods of testing (see NG

1727.2(ii)(d)). A record of this survey

should be retained for inclusion in the as-

build drawings.


Surface Condition

1 Normally handling prior to embedment in

the concrete is usually sufficient for the

removal of loose rust and scale from

reinforcement; otherwise wire-brushing of

sand-blasting should be used. The sand

used for blasting should comply with BS

1199 and BS 1200.

NG 1716 Reinforcement – Laps

and Joints

General Requirements

1 Where continuity of reinforcement is

required through the connection, the

jointing method used should be such that

the assumptions made in analysing the

structure and critical sections are realised.

The following methods may be used to

achieve continuity of reinforcement:

(i) lapping bars;

(ii) mechanical joints;

(iii) threaded reinforcing bars;

(iv) welding (see NG 1717).

Such connections should occur, where

possible, away from points of high stress

and should be staggered. The use of any

other jointing method not listed should be

confirmed by test evidence.

Lapping of Bars

2 Where straight bars passing through the

joint are lapped, the requirements of BS

5400 : Part 4 apply. When reinforcement

is grouted into a pocket or recess, an

adequate shear key should be provided on

the inside of the pocket.

Where continuity over a support is

achieved by having dowel bars passing

through overlapping loops of

reinforcement, which project from each

supported member, the bearing stresses

inside the loops should be in accordance

with BS 5400 : Part 4.

Jointing of Bars

3 A number of systems are available for

jointing reinforcing bars, which are

capable of transmitting the tensile and

compressive forces in the bar; these are as

follows:

(i) swaged couplers;

(ii) tapered threaded bars and couplers;

(iii) upset bar ends with parallel threads

and couplers;

(iv) couplers fixed to the bars with studs

for transmitting compressive forces

only;

(v) sleeves with tapered closers that

align the square sawn ends of bars for

transmitting compressive forces only.

Mechanical Joints should have a current

British Board of Agrément Roads and

Bridges or CARES Certificates.

Mechanical joints for stainless steel

reinforcement should have equivalent

durability to the reinforcement itself.

They require specific approval from the

Engineer in respect of the technical design

requirements.


Welding

General

1 Welding should be avoided whenever

possible. Very significant loss in fatigue

strength of reinforcement can occur as a

result of welding. Location welds (track

welds used for locating bars) pose a



October 2009 27

particular fatigue risk (see BS 5400 : Part

10) and any welding to shear stirrups

requires careful assessment.

Welding may only be undertaken where

suitable safeguards, supervision and

techniques are to be employed. Where it is

acceptable in the design and to BS 5400 :

Part 4 and Part 10 it should be checked

that where cyclic loading occurs, the Class

of weld given in Table 17 of BS 5400 : Part

10 has been achieved.

Where, notwithstanding the above,

welding is to be used, and the fatigue

effects of the welds have been taken into

account in the design it should if possible

be carried out under controlled conditions

in a factory or workshop. The competence

of the operators should be demonstrated

prior to, and periodically during, welding

operations.

In such circumstances welding may be

considered for:

(i) Fixing in position, e.g. by welding

between crossing or lapping

reinforcement or between bars

and other steel members. Metal-

arc welding or electric-resistance

welding may be used on suitable

steels.

(ii) Structural welds involving

transfer of load between

reinforcement or between bars

and other steel members. Butt

welds may be carried out by flash

butt welding or metal-arc welding.

The manual metal-arc process is used on

Site or in fabrication shops for making

joints of every configuration. In particular

it is the only process available for making

tee joints between bars and anchorage

plates and lapped joints between bars. It

is emphasised that operators should be

trained and possess sufficient skill for

producing good welded joints. The flash

butt welding process is restricted to

fabrication shops where it can produce

sound butt welds more rapidly than

manual metal arc welding. The resistance

welding process for cross bar joints can be

used on Site or in fabrication shops,

through for work on Site it is more usual to

use manual metal-arc welding. Further

guidance on metal-arc welding of

reinforcing bars is given in BS 7123.

2 Flash butt welding is carried out by

clamping the reinforcing steel bars in

water-cooled copper shoes which introduce

a large current to the bars. The bar faces

are moved slowly towards each other and,

when in close proximity, arcing of flashing

occurs at those parts of the two faces in

closest contact. The arcing or flashing

results in intense heating of the bars. This

flashing period can be extended to further

preheat the joint before completing the

weld which is performed by forcing the hot

faces together, metal being forced from the

hot faces during the actual welding stage

to form a collar. Advice on the correct

combination of flashing, heating, upsetting

and annealing should be obtained from the

reinforcement manufacturer.

3 Manual metal-arc welding is a form of

fusion welding in which heat for welding is

obtained from an arc struck between a

consumable stick electrode and the joint

faces. The stick electrode consists of a

metal core and a flux covering, the flux

forming a protective shield for the molten

metal in the weld pool, protecting it from

atmospheric contamination. In addition

the flux includes constituents that can slag

off some harmful contaminants that may

present in the joint prior to welding.

4 Other methods such as resistance welding

may be used for forming butt welds. This

is a similar operation to flash butt welding,

contact of the bar faces creating intense

heat due to electrical resistance at the

interface. After a predetermined period,

sufficient to heat the bar faces into a

plastic state, the current is turned off, the

bars faces are pressed together under great

pressure and a welded joint made, with

less material upset than arises in flash

butt welding. It is, however, necessary to

have cleaner bar faces for resistance butt

welding than for flash butt welding.

Resistance welding is rarely used for butt

welding of reinforcing steel bars, but

resistance spot welding finds wide

application for joining wire bars in cross

welds configurations. Large automatic

machines with multiple pairs of electrodes

are used for simultaneously welding many

wires and smaller diameter bars to form

mesh. In addition portable guns with

single pairs of electrodes are used for tack

welding bars of smaller diameter.



October 2009 28

Should fabricators wish to use other

processes, reference should be made to the

reinforcement manufacturer for guidelines

in developing satisfactory procedures.

NG 1718 Prestressing Tendons –

Materials

1 The characteristic strengths of

prestressing tendons are given in the

appropriate British Standards.


Surface Condition

1 All prestressing tendons and internal and

external surfaces of sheaths or ducts

should be free from loose mill scale, loose

rust, oil, paint, grease, soap or other

lubricants, or other harmful matter at the

time of incorporation in the structural

member. Slight surface rusting is not

necessarily harmful and may improve the

bond. It may, however, increase the loss

due to friction.

Cleaning of tendons may be carried out by

wire brushing or by passing them through

a pressure box containing carborundum

powder. Solvent solutions should not be

used for cleaning.


Cutting

1 In post-tensioning systems the heating

effect on the tendon due to cutting should

be kept to a minimum both to avoid

damage to the anchorage or bond of the

tendon, and to avoid any undesirable

metallurgical effects in the tendon steel

within the concrete member. Where

tendons between beams on long line

prestressing beds are to be cut, the

yielding of steel in burning imparts less of

a shock load to the beam ends than any

cold cutting method and is, therefore, to be

preferred.


Positioning of Tendons, Sheaths

and Duct Formers

1 The method of supporting and fixing the

tendons (or the sheaths or duct formers) in

position should be such that they will not

be displaced by heavy or prolonged

vibration, by pressure of the wet concrete,

by workmen or by construction traffic. The

means of locating prestressing tendons

should not unnecessarily increase the

friction where they are being tensioned.

Sheaths and extractable cores should

retain their correct cross section and

profile and should be handled carefully to

avoid damage. Extractable cores may be

coated with release agent and should not

be extracted until the concrete has

hardened sufficiently to prevent it being

damaged.

Damage can occur during the concreting

operation, and if the tendon is to be

inserted later, the duct should be dollied

during the concreting process to ensure a

clear passage for the tendon. Inflatable

rubber duct formers are not suitable for

this purpose.

Should the profile of any empty duct be in

doubt after the concrete has been cast a

technique has been developed of drawing a

radioactive source through the duct and

plotting its path.


Tensioning

General

1 Tendons may be stressed either by

pretensioning or by post-tensioning

according to the particular needs of the

form of construction. In each system

different procedures and types of

equipment are used, and these govern the

method of tensioning, the form of

anchorage and, in post-tensioning, the

protection of the tendons.

Safety Precautions

2 A tendon when tensioned contains a

considerable amount of stored energy

which, in the event of any failure of

tendon, anchorage or jack, may be released

violently. All possible precautions should

be taken during and after tensioning to



October 2009 29

safeguard persons from injury, and

equipment from damage, that may be

caused by the sudden release of this

energy. Guidance on the precautions

which should be taken is given in

Appendix C to BS 5400 : Part 8.

Pretensioning

3 The transfer of stress should take place

slowly to avoid shock that would adversely

affect the transmission length.

Post-tensioning

4 (i) Arrangement of tendons. Tendons,

whether in anchorage systems or

elsewhere should be so arranged that

they do not pass around sharp bends

or corners likely to provoke rupture

when the tendons are under stress.

(ii) Anchorage system. The anchorage

system in general comprises the

anchorage itself and the arrangement

of tendons and reinforcement

designed to act with the anchorage.

The form of anchorage system should

facilitate the even distribution of

stress in the concrete at the end of the

member, and should be capable of

maintaining the prestressing force

under sustained and fluctuating load

and under the effect of shock.

Provision should be made for the

protection of the anchorage against

corrosion.

(iii) Tensioning procedure. The measured

tendon force should be compared with

that calculated from the extension,

using the Youngs Modulus (E) value

for the tendon obtained by measuring

the load-extension relationship in a

calibrated testing machine with an

extensometer of 1m gauge length.

This provides a check on the accuracy

of the assumption made for the

frictional losses at the design stage; if

the difference is significant, corrective

action should be taken.

Where a large number of tendons or

tendon elements are being tensioned

and the full force cannot be achieved

in an element because of breakage,

slip or blockage of a duct, and if the

replacement of that element is not

practicable, the designer should

consider whether a modification in

the stress levels can still comply with

the design requirements.

The designer should specify the order

of loading and the magnitude of the

load for each tendon.


Protection and Bond

General

1 It is essential to protect prestressing

tendons from both mechanical damage and

corrosion. Protection may also be required

against fire damage.

It may also be an important design

requirement for the stressed tendon to be

bonded to the structure.

Protection and Bond of Internal Tendons

2 Internal tendons may be protected and

bonded to the member by cement grout in

accordance with Clause 1711.

Alternatively the tendons may be protected

by other materials such as bitumen or

petroleum-based compounds, epoxy resins,

plastics and the like, provided that bond is

not important.

Protection and Bond of External Tendons

3 A tendon is considered external when,

after stressing and incorporation in the

work but before protection, it is outside the

concrete section. It does not apply, for

example to a slab comprising a series of

precast beams themselves stressed with

external tendons and subsequently

concreted or grouted in so that the

prestressing tendons are finally contained

in that filling with adequate cover.

Protection of external prestressing tendons

against mechanical damage and corrosion

from the atmosphere or other aspects of

the environment, should generally be

provided by an encasement of dense

concrete or dense mortar of adequate

thickness. It may also be provided by

other materials hard enough and stable

enough in the particular environment.

In determining the type and quality of the

material to be used for the encasement,



October 2009 30

full consideration should be given to the

differential movement between the

structure and the applied protection that

arises from changes of load and stress,

creep, relaxation, drying shrinkage,

humidity and temperature. If the applied

protection is dense concrete or mortar and

investigations show the possibility of

undesirable cracking, then a primary

corrosion protection system should be used

that will be unimpaired by differential

movement.

If it is required that external prestressing

tendons be bonded to the structure, this

should be achieved by suitable

reinforcement of the concrete encasement

to the structure.

NG 1727 Inspection and Testing

of Structures and Components

General

1 This Clause indicates methods for

inspecting, and where necessary, testing

whole structures, finished parts of a

structure, or structural components to

ensure that they have the required

components to ensure that they have the

required standards of finish dimensional

accuracy, serviceability and strength.

Where inspection or results of other tests

(see NG 1727.2) lead to doubt regarding

the adequacy of the structure, loading tests

may be made following the procedure set

out in NG 1727.6.

In this Clause, deflection means the

maximum amount of movement under load

of the component being tested, relative to a

straight line connecting its points of

support. The load tests described in this

Clause may not be suitable for:

(i) model testing when used as a basis of

design;

(ii) development testing of prototype

structures;

(iii) testing to prove the adequacy of a

structure owing to change of use or

loading.

Where the Contractor or manufacturer

uses a quality control method, and

maintains records of the entire process of

manufacture (subject to these records

being certified by a Chartered Engineer or

a person who has a recognised equivalent

qualification of another state of the

European Economic Area) which show that

the products meet the requirements of the

Specification, such records may be

accepted as confirming that the required

quality has been reached. This in no way

precludes the designer specifying such

tests as he requires.

Testing requirements should be fully

described in Appendix 17/4 and scheduled

in Appendix 1/5 and/or Appendix 1/6.

Check Tests on Structural Concrete

2 (i) General. The testing of concrete

specimens to establish whether the

concrete used in the structure

complies with the Specification as a

structural material is described in

Clause 1707 and the additional cube

tests for special purposes are dealt

with in NG 1707.6. The tests

described in sub-Clause (ii) below are

applicable to hardened concrete in the

finished parts of a structure or in

precast units. They may be used in

routine inspection and for quality

control. They are also of use when

concrete is found defective from visual

inspection and when assessing the

strength of the concrete used. Details

of procedures are contained in British

Standards and advice is provided in

the Concrete Bridge Development

Group Technical Guide No. 2 “Testing

and Monitoring the Durability of

Concrete Structures” (TG2).

(ii) Types of check tests

(a) Cutting cores. In suitable

circumstances the compressive

strength of the concrete in the

structure may be assessed by

drilling and testing cores from the

concrete. The procedure used

should comply with BS 1881 : Part

201. Such cores may also be cut to

investigate the presence of voids

in the compacted concrete. Core

cutting should, whenever possible,

avoid reinforcement.



October 2009 31

(b) Gamma radiography. Gamma

radiography has been used to test

concrete up to 450mm thick for

the presence of local voids in the

concrete and the efficiency of the

grouting of ducts in prestressed

members; the presence and

location of embedded metal may

also be determined. The testing

should be carried out in

accordance with the

recommendations in BS 1881 :

Part 205. Further information

about gamma radiography testing

is contained in Post-tensioned

Concrete Bridges published in

1999 by Thomas Telford,

specifically Chapter 8. Special

precautions are necessary to avoid

contamination from the

radioactive source.

(c) Ultrasonic test. If an ultrasonic

apparatus is regularly used by

trained personnel and if

continuously maintained

individual charts are kept that

show, for a large number of

readings and the strength of cubes

made from the same batch of

concrete, such charts may be used

to obtain approximate indications

of the strength of the concrete in

the structure.

In the cases of suspected lack of

compaction or low cube strengths,

ultrasonic tests carried out on

adjacent suspect and acceptable

sections of the structure may

provide useful comparative data.

(d) Electromagnetic cover measuring

devices. The position of

reinforcement or tendons may be

verified to depths of about 70mm

by an electromagnetic cover

measuring devices as described in

BS 1881 : Part 204. The position

of reinforcement and

ducts/tendons may be verified to

depths of up to 500mm using an

inductive probe as described in

TG2.

(e) Rebound hammer test. If a

rebound hammer is regularly used

by trained personnel and if

continuously maintained

individual charts are kept that

show, for a large number of

readings, the relation between the

readings and the strength of cubes

made from the same batch of

concrete, such charts may be used

in conjunction with hammer

readings to obtain an approximate

indication of the strength of the

concrete in a structure or element.

An accuracy of + 3 N/mm2 could be

expected when used by trained

personnel in these circumstances.

Rebound hammer tests are

usually preformed on a grid over a

defined test area. 12

measurements are obtained

around each grid point. Abnormal

readings should be discarded and

the rebound number determined

as the mean of the remaining

numbers. (TG2). Readings should

not be taken within 25mm of the

edge of concrete members. It may

be necessary to distinguish

between readings taken on a

trowelled face and those taken on

a moulded face. When making the

test on precast units, special care

should be taken to bed them

firmly against the impact of the

hammer.

Surface Finish

3 The surface of the concrete should be

inspected for defects, for conformity with

the Specification and, where appropriate,

for comparison with approved sample

finishes.

Subject to the strength and durability of

the concrete being unimpaired, the making

good of surface defects may be permitted,

but the standard of acceptance should be

appropriate to the strength class and

quality of the finish specified and should

ensure satisfactory performance and

durability. On permanently exposed

surfaces great care is essential in selecting

the mix proportions to ensure that the

final colour of the faced area blends with

the parent concrete in the finished

structure.

Dimensional Accuracy

4 The methods of measurement of

dimensional accuracy, making allowance

for specified tolerances, if any, should be

agreed in advance of manufacture.



October 2009 32

The effect of temperature, shrinkage and

imposed load should be taken into account.

The positions of bars, tendons or ducts

should be checked where these are visible

or ascertainable by simple means

(reference sub-Clause 2(ii) (d) of this

Clause).

In the case of precast units, the checking of

twist, bow squareness and flatness may

entail removal of the unit from its stacked

position to a special measuring frame.

Extensive checking of units in this manner

may materially affect the cost. The

frequency and scope of measurement

checks should therefore be strictly related

to the production method, the standard of

quality control at the place of casting, and

the function that the unit has to fulfil.

When checking the camber or upward

deflection due to prestress, the precast unit

should be placed on proper bearings at full

span and a central reference point should

be provided level with the bearings. The

amount of upward deflection to be expected

at any stage should be assessed as

described in BS 5400 : Part 4. Alternative

methods of checking include the use of dial

gauges or measurements from a thin wire

stretched across the bearings and

tensioned sufficiently to take out the sag.

Upward deflection is preferably measured

on the underside.

Load Tests on Individual Precast Units

5 (i) General. The load tests described in

this Clause are intended as checks on

the quality of the units and should

not be used as a substitute for normal

design procedures. Where members

require special testing, such special

testing procedures should be

described in Appendix 17/4 and

scheduled in Appendix 1/5.

Test loads should be applied and

removed incrementally.

(ii) Non-destructive test. The unit should

be supported at its designed points of

support and loaded for 5 minutes with

a load equivalent to the sum of the

nominal dead load plus 1.25 times the

nominal imposed load. The deflection

should then be recorded. The

maximum deflection measured after

application of the load should be in

accordance with the requirements

defined by the designer. The recovery

should be measured 5 minutes after

the removal of the applied load and

the load then reimposed. The

percentage recovery after the second

loading should be not less than that

after the first loading nor less than

90% of the deflection recorded during

the second loading. At no time during

the test should the unit show any sign

of weakness or faulty construction in

the light of a reasonable

interpretation of relevant data.

(iii) Destructive test. The unit should be

loaded while supported at its design

points of support and should not fail

at its ultimate design load within 15

minutes of the time when the test

load becomes operative. A deflection

exceeding one-fortieth of the span is

regarded as a failure of the unit.

(iv) Special test. For very large units or

units not readily amenable to tests

(such as columns, the precast parts of

composite beams, and members

designed for continuity or fixity) the

testing arrangements should be

agreed before such units are cast.

(v) Load testing of pretensioned beams.

Load testing is not normally required

and should only be embarked upon

when the adequacy of the beams is in

serious doubt. When testing is

required, the appropriate loading

should be agreed with both the

Employer‟s Representative and

Specialist responsible for the design,

taking account of any composite

action in the permanent works.

Load Tests of Structures or Parts of

Structures

6 (i) General. The tests described in this

Clause are intended as a check on

structures other than those covered

by NG 1727.5 where there is doubt

regarding serviceability of strength.

Test loads should be applied and

removed incrementally.



October 2009 33

(ii) Age at test. The test should be

carried out as soon as possible after

the expiry of 28 days from the time of

placing the concrete. When the test is

for a reason other than the quality of

the concrete in the structure being in

doubt, the test may be carried out

earlier provided that the concrete has

already reached its specified

characteristic strength.

When testing prestressed concrete,

allowance should be made for the

effect of prestress at the time of

testing being above its final value.

(iii) Test loads. The test loads to be

applied for deflection and local

damage are the appropriate design

loads, i.e. the nominal dead and

imposed loads. When the ultimate

limit state is being considered, the

test load should be equivalent to the

sum of the nominal dead load plus

1.25 times the nominal imposed load

and should be maintained for a period

of 24 hours. If any of the final deal

load is not in position on the

structure, compensating loads should

be added as necessary.

During the tests, struts and bracing

strong enough to support the whole

load should be placed in position,

leaving a gap under the members to

be tested, and adequate precautions

should be taken to safeguard persons

in the vicinity of the structure.

(iv) Measurements during the tests.

Measurements of deflections and

crack width should be taken

immediately after the application of

load and, in the case of the 24-hour

sustained load test, at the end of the

24-hour loading period, after removal

of the load and after 24-hour recovery

period. Sufficient measurement

should be taken to enable side effects

to be taken into account.

Temperature and weather conditions

should be recorded during the test.

(v) Assessment of results. In assessing

the serviceability of a structure or

part of a structure following a loading

test, the possible effects of variation

in temperature and humidity during

the period of the test should be

considered.

The following recommendations

should be met

(a) For reinforced concrete structures

the maximum width of any crack

measured immediately on

application of the test load for

local damage should not be more

than two thirds of the value for

the serviceability limit state of

cracking given in BS 5400 : Part

4. For prestressed concrete

structures or elements considered

under Class 1 of Class 2, no

visible cracks should occur under

the test load for local damage.

(b) For members spanning between

two supports, the deflection

measured immediately after

application of the test load for

deflection should be not more

than the specified value. Limits

should be agreed before testing

cantilevered portions of

structures.

(c) If, within 24 hours of the removal

of the test load for the ultimate

limit state as calculated in NG

1727.6(iii), a reinforced concrete

structure does not show a

recovery of at least 75% of the

maximum deflection shown

during the 24 hours under load,

the loading should be repeated.

The structure should be

considered to have failed to pass

the test if the recovery after the

second loading is not at least 75%

of the maximum deflection shown

during the second loading.

(d) If, within 24 hours of the removal

of the test load for the ultimate

limit state as calculated in NG

1727.6(iii), a prestressed concrete

structure or member, considered

under Class 1 or Class 2 does not

show a recovery of at least 85% of

the maximum deflection shown

during the 24 hours under load,

the loading should be repeated.

The structure or member should

be considered to have failed to

pass the test if the recovery after

the second loading is not at least



October 2009 34

85% of the maximum deflection

shown during the second loading.



October 2009 35

NG SAMPLE APPENDIX 17/1: SCHEDULE FOR THE SPECIFICATION OF

DESIGNED CONCRETE

These mixes below shall be supplied as designed mixes in accordance with the relevant clauses of I.S. EN

206-1

1. Mix reference

2. Strength class

3. Nominal maximum size of aggregate, in mm

(D)

4. Types of aggregate

Coarse

IS EN 12620

Other [specify

requirements]

Fine

IS EN 12620

Other [specify

requirements]

5. Sulphate class [ring as appropriate] XA 1

XA 2

XA 3

6. Cement type(s) or combinations complying with

[ring those permitted]

CEM I N IS EN 197-1

CEM I R IS EN 197-1

CEM I SR B.S. 4027

Others [specify requirements]

CEM I N

CEM I R

CEM I SR

7. Exposure Class (As in IS EN 206-1)

(or combinations)

X0

XC1, XC2, XC3,

X

C

4

XS1, XS2, XS3,

X

S

4

XD1, XD2, XD3,

X

D

4

XF1, XF2, XF3

XA1, XA2, XA3

8. Chloride Class Cl 1,0

C1 0,30

Cl 0,20

Cl 0,10

9. Minimum cement content, kg/m3

10. Maximum free water/cement ratio

11. Quality assurance requirements (1) (1) (1)

12. Rate of sampling intended by the purchaser for

strength testing (for information)

(2) (2) (2)

13. Other requirements [alkali, colour, etc. as

appropriate]



October 2009 36

In the case of fresh concrete the following shall be completed by the purchaser

14. Consistence [Choose one method]

Slump Class

Vebe Class

Compaction Class

Flow Class

S1, S2, S3, S4, S5

V0, V1, V2, V3,

V

4

C0, C1, C2, C3

F1, F2, F3, F4,

F

5

,

F

6

15. Method of placing (for information)

16. Other requirements by the purchaser of fresh

concrete [only if appropriate]

[Notes to compiler:

(1) Cross-reference should be made to Appendix 1/24 and /or 1/25 as appropriate.

(2) Cross-reference should be made to Appendix 1/5 and/or 1/6 as appropriate.]



October 2009 37

NG SAMPLE APPENDIX 17/2: CONCRETE – IMPREGNATION AND COATING

SCHEDULE

[Notes to compiler: Areas to be impregnated, or impregnated and coated should be scheduled. If

considered preferable the schedule can be placed on a drawing and this Appendix

should cross-refer].

NG SAMPLE APPENDIX 17/3: CONCRETE – SURFACE FINISHES

[Note to compiler: Include here]

1. Requirements for trial panels [1708.1].

2. Requirements for Contract-specific surface finishes [1708.4] [cross-referring to the drawings as

appropriate].

3. Positions where internal ties are permitted (other than in rebates) for Class F4 finish [1708.4(i)].

4. Locations where a regular pattern of formwork joints is unnecessary [1708.4(i)].



October 2009 38

NG SAMPLE APPENDIX 17/4: CONCRETE – GENERAL


1. Requirements for concrete if different from the requirements of sub-Clause 1701.1.

2. Whether the use of cement other than to Clause 1702.1 is permitted.

3. Requirements for lightweight aggregate if different from the requirements of sub-Clause 1702.2.

4. Requirements for admixtures if different from the requirements of sub-Clause 1702.3.

5. Requirements for sampling and testing if different from the requirements of sub-Clause 1707.1.

Whether identity testing is required [1707.2]. [Cross-reference should be made in Appendix 1/5

and/or Appendix 1/6 as appropriate].

6. Requirements for construction joints [1710.1].

7. Whether retarding agents may be used [1710.1(ii)].

8. Requirements for permanent formwork [1710.2(iv].

9. References to drawings which show lifting and support points [1710.8(ii) and (iii)].

10. Requirements for assembly and erection of precast concrete members [1710.8(iv].

11. Whether welding or reinforcement other than steel fabric reinforcement is permitted [1717.1].

12. Requirements for tolerance if different from the requirements of sub-Clause 1723.1.

13. Requirements for time of stressing if different from the requirements of sub-Clauses 1724.3(ii) and

1724.4(iv).

14. Requirements for protection of prestressing tendons [1725.1].

15. Requirements for inspection and testing of structures and components [1727.1]. [Guidance is given

in NG 1727. Tests should be scheduled in Appendix 1/5 and Appendix 1/6].

16. Requirements for particular curing methods for deep / bulky elements, elements containing

unusually high proportion of cement or precast units subject to special or accelerated curing

methods. [1710.5 and NG1710.5].



October 2009 39

NG SAMPLE APPENDIX 17/5: NOT USED

NG SAMPLE APPENDIX 17/6: GROUTING AND DUCT SYSTEMS FOR POST-

TENSIONED TENDONS

TENDON REFERENCE:

[Note to compiler: complete this for each different group or type of tendons]

GROUT DEFINITION:

Grout type: Grout [Common] [Special]

Maximum water/cement ratio: Not specified [0.40] [0.35]

REQUIREMENTS FOR TRIALS/TESTS:

Drawing Reference:

[full details including location of cuts should be defined on drawing]

Time at which trials are to be carried out (days before planned use in the permanent works: [56 days]

[Note to compiler: Optional additional testing requirements to prove protection against ingress of

contaminants are given in Section 8 of the Concrete Society Technical Report 47, 2nd

Edition – Durable Bonded Post-Tensioned Concrete Bridges. Availability of

compliant duct components should be discussed with manufacturers, and tests

interpreted in accordance with Section 3.2A of the report].

Required duct assembly testing pressure: [0.01 N/mm2]

Minimum duct wall thickness as manufactured: [2.0mm] [4.0mm for external tendons]

Minimum duct wall thickness after tensioning: [1.5mm]

Minimum duct to concrete ultimate bond length: [50-100 diameters]

REQUIREMENTS FOR DUCT SYSTEM:

Distance beyond crests to next vent: [Horizontally, to the point where the duct is half the

diameter lower than at the crest, or 1m, whichever is the

lesser]

Maximum vent spacing [15m]

Minimum vent height above highest point [500mm]

Other requirements [-]

Requirements for Grouting:

Maximum rate of grouting of ducts [10m/min]

Minimum volume of grout expelled after visual test [5 litres]

[Note: Default values shown in brackets]

Volume 2


Structural Steelwork

STRUCTURAL STEELWORK

Contents C l a u s e mi*

N G 1 8 0 1 General 2 4 f J

Sample Append ix 243

March 2000 239


Series NG 1800 Structural Steelwork

Structural Steelwork

NG 1801 General

1 The Notes for Guidance should be read in conjunction with Clause 5.3 of BS 5400 : Part 10 : 1980 where appropriate and BS 5400 : Part 6 : 1999. With regard to the latter document, the following amendments and additions shall apply to Annex B, Guidance Clauses:

3.1.4 Delete heading of clause and insert the following:

"3.1.4 Internal imperfections".

3.1.4, paragraph 1, lines 2, 7 & 9

Delete 'laminations' and insert 'internal imperfections".

Page 23

3.1, line 3

Delete 'without obtaining the specific approval of the Engineer.'

3.1, line 5

Delete 'the Engineer requires material', insert "material is required".

3.1.4, paragraph 1, line 4

Delete 'the Engineer should clearly indicate', insert "clear indication should be given to".


Delete Any material found to be defective due to laminations may still be used at the discretion of the Engineer'.

3.1.1 Delete heading and text of clause and insert the following:

"The carbon equivalent value of steel is one of the factors affecting the need for preheat treatment (see Appendix E of BS 5135 : 1984). This is important for the larger thicknesses and/or higher strength steels, and consideration should be given to specifying the maximum carbon equivalent value for such material.

Where the details of the ladle analysis of additional elements are required e.g. for calculation of carbon equivalent values, the relevant option should be specified. Product analysis is more costly than ladle analysis and should only be invoked with the prior agreement of the National Roads Authority.

Specifying of maximum carbon equivalent values should be considered for the following materials, when welding is involved:

(a) Grade S275 steels over 50 mm thick.

(b) Grade S355 steels over 30 mm thick.

(c) Grade S420 or S460 steels, all thicknesses."


Delete 'the Engineer should consider', insert "consideration should be given to".


Delete 'the Engineer should consider', insert "consideration should be given to".

3.1.5 Delete clause and substitute:

"In determining the scope of any additional marking requirements, the ease of identification of different material grades (including suffixes) by variations in sectional shape or dimensions should be taken into account."

Insert additional clause 3.4.4 as follows:

"3.4.4 Stainless steel bolts, nuts and washers. A4-80 stainless steel bolts and nuts to BS 6105 should normally be specified but in certain bridge parapet applications (other than attachment systems) the proprietary system may recommend A4-70 or equivalent."

3.9, line 1

Add to end of first sentence "or equivalent in later editions of BS."

3.1.2 Delete clause.

March 2000 240


3.10.2, line 1

Delete 'The Engineer should specify the appropriate', insert "Appropriate".

Add "should be specified" at the end of the paragraph.


Delete 'by the Engineer'.

4.2.3. line 2

Delete 'the Engineer should specify'.


Page 24


Delete "the Engineer should specify'.



"4.4.5 High strength friction grip bolts, nuts and washers. Attention is drawn to the need for tightening to a pattern, generally by working from the centre of a group of bolts to the outside. This procedure should be followed both for the preliminary and final tightening. As layers are drawn together during the application of the preliminary bedding torque, the first bolts tightened in a group may be found to relax and require further tightening until the specified bedding torque is achieved.

Load indicating bolts and washers should not normally be used with improved atmospheric corrosion resistant steels because they may permit the ingress of water."


"4.4.6 Washers. The extension of the threaded portion of a bolt within the thickness of the connected parts may affect the design strength of the bolt (see BS 5400 : Part 3)."

4.7.1, after paragraph 1

Insert additional paragraphs as follows:

"Electro slag and Fusarc type welding should not be used where fracture toughness is a critical design parameter,


e.g. joints in areas of high applied tensile stress or severe restraint.

Welds for temporary attachments can act as stress raisers and increase the risk of fatigue. Critical areas where such welding is not permitted should be specified.

Where in addition to specifying that a weld be dressed flush, it is required that the finish machining be in a particular direction, e.g. for certain fatigue considerations, this requirement should also be specified.

Where partial penetration butt welds are required, their throat thickness should be specified (see BS 5135 and BS 5400 : Part 3).

Where it is required for major butt welds to be traced to particular welders, these welds should be so specified (see BS 5135).

For improved atmospheric corrosion resistant steels, alloys increase the hardness and this has to be taken into account in selecting welding procedures. The carbon equivalent value may be calculated from the ladle analysis on the mill sheets if the percentages of all the relevant elements necessary for the calculation of carbon equivalent values are also included in the analysis. Otherwise either special chemical analysis should be undertaken to ascertain the percentage of all the relevant elements necessary for the calculation of the carbon equivalent value, or the maximum permissible carbon equivalent value should be assumed for this purpose. Pre-heat requirements should then be determined in accordance with the provisions of BS 5135. Attention is drawn to the facts that BS 5135 provisions do not fully cover the requirements for carbon equivalent values higher than 0.54 and special consultation and procedure trials are required when sufficient previous experience is not available. For butt welds in material 12 mm thick or less, the degree of weld metal dilution is normally sufficient to ensure uniform weathering and colour without the need for electrodes with improved atmospheric corrosion resisting properties. For fillet welds, the degree of weld metal dilution is insufficient to ensure uniform weathering and therefore electrodes of matching chemical

March 2000 241



composition should be used in all single run fillet welds and capping runs of multi-run fillet welds. All electrodes should be chosen such that after a reasonable period the surface colour of the resultant welds matches that of the connected plates. Special care is necessary to ensure that the electrodes are stored and handled strictly in accordance with BS 5135."

4.7.3, line 1

Delete 'The Engineer should give consideration', insert "Consideration should be given".



"Provision should be made in Appendix 18/1 for procedure trials to arrive at approved procedures before the fabrication of the item concerned.

Samples of materials for welding, flame cutting and shearing procedure trials should as far as possible be selected from available material having the highest carbon equivalent value as determined from ladle analysis. For thick plates in critical areas, product analysis may be necessary to establish the carbon equivalent value of the samples."


"4.7.4 Stud shear connectors: welding and procedure trials. See paragraphs 2 and 3 above of 4.7.3."

Insert additional clause 4.17 as follows:

"4.17 Improved atmospheric corrosion resistant steel. Areas requiring special protection during construction should be shown on the Drawings."

5.4.1.1, paragraph 2, line 1

Delete 'The Engineer may use the hardness tests on procedure test macrosections', insert "The hardness tests on procedure test macrosections may be used".

Page 26

5.4.1.2

Delete 5th paragraph

5.4.1.2, paragraph 7, line 2

Delete 'the Engineer may give consideration', insert "consideration may be given".

Page 27

5.5.2, line 6

Delete 'by the Engineer', insert "on the Drawings".

5.5.2, Delete text following paragraph 1.



"The methods of testing may include combinations of:

(a) Visual.

(b) Radiographic.

(c) Ultrasonic.

(d) Penetrant dye.

(e) Magnetic particle.

Reference may be made to the following British Standards for non-destructive methods of examining and testing welds: BS EN 571, BS EN 970, BS EN 1435, BS 3923 and BS 6072."

2 Requirements for structural steelwork should be described in Appendix 18/1.

Further guidance and advice on the preparation of an Appendix 18/1 can be found in The Steel Construction Institute Publication 170.

March 2000 242



N G S A M P L E A P P E N D I X 18/1: R E Q U I R E M E N T S F O R S T R U C T U R A L S T E E L W O R K

[The compiler should include here:]

1 The drawing numbers of all drawings which give related structural steelwork requirements [1801.1 J.

2 Requirements for Materials, Workmanship, Inspection and Testing, Handling, Transport and Erection, Supply, Measurement and Weighing if different from the requirements of sub-Clause 1801.2.

3 Requirements for surface preparation and corrosion protection if different from the requirements of sub-Clause 1802.1.

4 Particular requirements for Materials, Workmanship, Inspection and Testing, Handling, Transport and Erection, Supply, Measurement and Weighing, as required by BS 5400 : Part 6 : 1999 as amended by Clause 1803, including the following as appropriate.

(a) application of Standards other than BS EN 10025, BS EN 10113, BS EN 10137, BS EN 10155, BS EN 10210 or BS 7668 [3.1.1]

(b) option requirements of relevant Standards [3.1.1, 3.1.6]

(c) chemical analysis and carbon equivalent values [3.1.1]

(d) grades of steel for notch toughness [3.1.3J

(e) internal imperfections [3.1.4.3]

(f) inspection documents [3.1.6]

(g) rivet steels [3.2]

(h) steel for shear connectors [3.3/

(i) bolts, nuts and washers [3.4.1, 3.4.3, 3.4.4, 4.4, 4.4.4]

(j) welding consumables and procedures [3.5/

(k) cast iron [3.10]

(1) interchangeability of parts 14.1]

(m) fabrication tolerances [4.2.2, 4.2.3]

(n) plate edge grinding or machining /4.3.3J

(o) HSFG connection surface treatment [4.3.6[

(p) holes for rivets and bolts [4.5.1, 4.5.3/

(q) rivet heads [4.6]

(r) welding processes and procedures [4.7.1, 4.7.2]

(s) welding procedure trials [4.7.3, 4.7.4]

(t) bending and pressing 14.8]; straightening and flattening [4.9]

(u) tie rod fabrication [4.11]

(v) pin hole fabrication [4.13]

(w) formation of camber [4.14]

(x) marking for erection 14.15]

(y) rectification and testing of defects [4.16, 5.3]

(z) improved atmospheric corrosion resistant steel [4.17]

(aa) procedure trial weld testing (5.4.1.1, 5.4.1.2]

(bb) production weld testing [5.5.1.1, 5.5.1.2, 5.5.2]

(cc) checking of deviations [Table 7, 5.6.6]

(dd) temporary erection [5.9]

(ee) lines and levels of completed structure [6.3.1]

(ff) spare bolt supply [7.3]

March 2000 243

Volume 2 Series NG 1800 Notes for Guidance on the Specification for Road Works Structural Steelwork

March 2000 2 4 4


Series NG 1900 Protection of Steelwork Against Corrosion


Contents

Clause Title Page

N G 1 9 0 1 General 246

NG 1902 Surface Preparation - General Requirements 260

NG 1903 Surface Preparation - Materials and Methods 260

NG 1904 Procedures for Treatment at Joints 262

NG 1905 Procedures for Treatment at Areas of Mechanical Damage or

Other Surface Defects 264

NG 1906 Procedures for Treatment of Local Failure in Protective Coat ings 265

NG 1907 Workmanship Standards for the Surface Preparation of Steel by Blast Cleaning, Abrading, Gr inding and Cleaning 265

NG 1908 Workmanship Standards for the Surface Preparation of Coated Steelwork

by Blast Cleaning, Abrading, Gr inding and Cleaning 266

NG 1909 Paint and Similar Protective Coat ings 267

N G 1 9 1 0 Testing of Paints 267

N G 1 9 1 1 Metal Coat ings 269

NG 1912 Testing of Metal Spray Coat ings 269

NG 1913 Storage Requirements and Keep ing Periods for Paints 269

NG 1914 Applicat ion of Paint 270

N G 1 9 1 5 Procedure TVials 271

NG 1916 Storage and Transport of Steel and Fabricated Steelwork 271

NG 1917 Surfaces in Contac t with Concrete 272

NG 1918 Form BE/P2 (New Works) Paint System Sheet (Appendix 19/5)

Form BE/P5 Paint Data Sheet (Appendix 19/8) 272

NG 1919 Acces s and Light ing 273

NG 1920 Addit ional Requirements for the Protection of Steel in Br idge Bear ings . . . 273

NG 1921 Addi t ional Requirements for the Protection of Steel Light ing Co lumns and Bracket A r m s 273

NG Sample Append ice s 274

Append ices (Forms BE/P2 to BE/P5)

March 2000 245

Volume 2 Notes for' Guidance on the Specification for Road Works


Protection of Steelwork Against Corrosion

NG 1901 General

1 The 1900 Series Clauses cater for shop and site surface preparation and protective coating requirements for new steel in highway structures, from the start of fabrication to the completion of erection. Separate requirements exist for subsequent maintenance painting of steel highway structures.

The Clauses are applicable to steel sections and fabricated steelwork in bridges, parapets, gantries and other highway structures, including bearings and lighting columns which are to be protected with the basic systems described in NG 1901.9 to 18. Clause 1920 is concerned with requirements particular to steel in bearings only, and Clause 1921 is concerned similarly with steel lighting columns.

Reference has also been made, in other Series, to certain Clauses in the 1900 Series when appropriate, e.g. Clauses 1902 and 1903 for surface preparation and Clause 1911 for hot dip galvanizing.

The main surface preparation work, usually by dry blast cleaning, together with local surface treatment will be carried out within the fabricators works. After erection however, all surfaces of the shop applied systems which protect the steelwork during delivery and erection, and the surfaces of patch coatings applied during erection will require cleaning before the application of the final overall coat(s); site connections and welded joints will require special treatment, also areas of mechanical damage will need to be made good. On small structures e.g sign/signal gantries all paint coats, including the finish coat, may be applied in the works in order to reduce access time for completion at site. This may be necessary where, say, a new gantry is to be erected over a motorway during a night-time possession. In such cases the Contractor will need to ensure that damage to the paint system during handling and erection is kept to a minimum and that any minor damage is satisfactorily restored. On large structures, final site painting may not be undertaken for as long as two or even three years, and in these cases wet blast cleaning may be the most effective method of removing contamination.

2 The choice of protective systems will depend mainly on the environment and accessibility for maintenance painting. The detailed requirements for surface preparation, the coatings and

their application are specified by means of appropriate 1900 Series Appendices . A consistent format should be adopted for the Appendices and the layout of the sample Appendices should be followed. The format is flexible and can cater for a single component contract, e.g. from a length of parapet, up to the involved requirements of a bridge strengthening and widening scheme.

Item numbers in the Basic Protective Systems and 1900 Series Sample Appendices are listed in the Manual of Paints for Structural Steelwork at Annex A of UK Department of Transport Standard BD 35. A current list of paint manufacturers whose paints have been registered with the UK Department of Transport is published in UK Department of Transport Advice Note SAl . Requirements for the registration of paints are given in UK Department of Transport Advice Note BA 27 Quality Assurance Scheme for Paints and Similar Protective Coatings.

Aluminium is the preferred metal spray coating. Zinc metal spray is not advised for highway structures and is excluded from the basic systems.

Hot dip galvanizing is viable for components such as parapets and lighting columns. For larger components and structures, the validity of hot dip galvanizing, whether painted or not, shall be assessed, and may be restricted by the size and weight of steel fabrication.

3 The information on environment, accessibility and durability provided in the Appendices will aid the Contractor in assessing the extent of, the cleaning likely to be necessary on site. The 'Required Durability' is not a contractual requirement but is a means of alerting the paint manufacturer as to the performance expected from the system he is offering. It is also useful information for the maintenance of the structures.

Substitute and Additional Clauses

4 Clauses 1901 to 1921, the basic systems described in NG 1901.9 to 18 and the sample 1900 Series Appendices should be scrutinised to ensure that all aspects of the Contract can be covered satisfactorily. When, exceptionally, Substitute or Additional Clauses are required, the alterations should be made after agreement with the National Roads Authority.

March 2000 246



A p p e n d i c e s 19/1 to 19/4 - Sec t ions 1 to 3

5 The environment, accessibility and required durability of the systems for the Permanent Works, should be described in Sections 1 to 3 of the Appendices, and should also be written into Appendix 19/5, Form BE/P2 (New Works) Paint System Sheet (parts 3 and 4): see Clause 1918 and NG 1918. The factors to be taken into account in determining the descriptions for Sections 1 to 3 of the Appendices are described below.

(i) Section 1, Environment

Location of structures

Two locations are considered; 'Inland' and

'Marine'.

Structures out of reach of sea salt spray are considered as being 'Inland'. Structures which can be affected by sea salt spray are considered as being 'Marine'.

(ii) Section 2, Accessibility

For maintenance painting purposes, new structures are described as having either Ready Access or Difficult Access.

The description Ready Access would apply to structures where future restrictions on working time due to road or rail traffic are likely to be minimal and where future access on site is unlikely to be a problem.

The description Difficult Access would apply, for example, to a bridge or sign gantry over a motorway or to a bridge over a railway where painting is likely to be restricted to one section at a time or halted completely at certain periods when traffic is heavy.

It would also apply on two counts to a high bridge, say, without painting gantries and built over difficult terrain or a river where movement on the ground would be difficult and because extensive scaffolding would be required.

(iii) Section 3, Required Durability

(a) For the basic systems (except for lighting columns), the periods 'No maintenance up to 12 years', 'Minor maintenance from 12 years' and 'Major maintenance after 20 years' will be sufficiently accurate for both access situations and the environments described in this sub-Clause. However when access is especially difficult, e.g. when dismantling of cover plates is necessary, a special system may be required. In such a case the usual periods for 'No

maintenance' and 'Minor maintenance' would not be applicable (N/A); 'Major maintenance' being given as, say, 20 years, or even 25 years.

The choice of system will depend finally on the following:

Type of structure, especially in the case of a bridge;

Expected service life of structure based on its use;

Environment;

Accessibility.

(b) The types of basic systems for steelwork in NG 1901.10 are designed to cover three main Environment/ Accessibility situations, viz:

Type 4. Inland Environment Ready Access

Type 4. Alternative Inland Environment Ready Access

Type 8. Marine Environment Ready Access

Type 8. Alternative Marine Environment Ready Access

Type 10. Inland or Marine Environment Difficult Access

Type 10. Alternative Inland or Marine Environment Difficult Access

Type 13. All environments

Acrylated Rubber system

High build, quick drying Epoxy (2 pack) system

Acrylated Rubber system

High build, quick drying Epoxy (2 pack) system

Aluminium Metal Spray plus Acrylated Rubber system

Aluminium Metal Spray plus high build, quick drying Epoxy (2 pack) system

Galvanizing and Acrylated Rubber system

Basic system types 1,2,3,5,6,7 and 9 are not used.

Other basic systems are given for inside of box girders and parapets.

Basic systems for bridge bearings and lighting columns are also given.

March 2000 247



(c) The basic systems described should be detailed in Appendices 19/1, 19/2 and 19/3 respectively for bridge steelwork and parapets, gantries and other structures; bearings; lighting columns and bracket arms. An Appendix 19/4 may be incorporated for other works requiring protection.

Examples:

Red Oxide/Zinc Chromate Blast Primer, red.

Zinc Phosphate AR Blast Primer, pink.

Zinc Chromate Etch Primer (2 pack), vellow. (Medium not stated).

Standard Terminology for the Description of Paints

6 Standard Terminology enables paints to be described in generic terms and without specifying trade names. It is used for the Registered Description in Paint System Sheets, in Data Sheets and in the Specification and should convey the following information in the order given:

(i) Name of Pigment: where a pigment provides inhibitive or structural properties it must be named, e.g. MIO, Zinc Phosphate. Zinc Chromate. Where pigments provide colour, opacity or act as extenders etc. the pigments should not be named.

(ii) Type of Medium: except for acid type Etch and Blast Primers the type of medium should be stated, e.g. Vinyl Alkyd. M/Phenolic, Phenolic (i.e. pure Phenolic), Silicone Alkyd, Polyurethane, Epoxy (2 pack), AR. (See (iv) below for meaning of abbreviations.)

(iii) Use: i.e. Blast Primer, Etch Primer, Primer, Undercoat or Finish. If two pack, add '(2 pack)'.

The first coat only of a new system is described as a Blast Primer, Etch Primer or Primer, all subsequent intermediate coats are described as Undercoats, the last coat being the Finish. A Primer or Primer/Undercoat (i.e. a dual purpose paint) may be specified when it is desirable to obtain a relatively high film build in the first coat, usually for small areas on site.

(iv) Colour: a descriptive colour must always be stated as part of the Registered Description in Appendix 19/5, Form BE/P2 (New Works) Paint System Sheet. If a BS colour is specified in the 1900 Series Appendices, the BS 4800 reference should follow the descriptive colour, e.g. green-yellow 12 B 21.

Zinc Phosphate Epoxy Primer (2 pack).

Zinc Phosphate Epoxy Ester Undercoat, yellow.

MIO Phenolic Finish, natural grey (i.e. with pure phenolic resin).

MIO M/Phenolic Finish, medium grey (i.e. with modified phenolic resin).

MIO Epoxy (2 pack) Undercoat, medium grey.

Silicone Alkyd Finish, white (Pigment not stated).

Zinc Phosphate AR Undercoat, blue.

AR Undercoat, green-yellow (Pigment not stated).

MIO AR Finish, medium grey.

Zinc Phosphate High Build, quick drying Epoxy Blast Primer (2 pack).

MIO High Build, quick drying Epoxy Undercoat (2 pack).

Polyurethane (2 pack) Finish, 18 B 25.

MIO MC/Polyurethane Undercoat, natural grey.

Polyurethane (2 pack) Finish, green-yellow 12 B 21 to BS 4800 (Pigment not stated).

Convenient abbreviations have been introduced where these can be readily understood and used in Specifications, e.g.:

MIO Micaceous Iron Oxide M/Phenolic Modified Phenolic AR Acrylated Rubber MC Polyurethane Moisture cured

Polyurethane

March 2000 2 4 8


Terminology Used in Painting Practice

7 For definitions of terms used in painting practice reference should be made to BS 2015. Specific meanings of the descriptions of workmanship standards for surface preparation of steel and coated steelwork are given in Clauses 1907 and 1908 respectively.

Consultations on Health Hazards and Environmental Restrictions

8 Health hazards associated with pollution of the atmospheric environment have to be taken into account during surface preparation and the application of protective coatings. Unless necessary precautions are taken and any limitations on the Contractor's method of working (Appendix 1723) are observed, people may be adversely affected, also the site ground area and waterways may become contaminated to an unacceptable extent. In the shops the avoidance of hazards arising from blast cleaning steel with abrasives is usually a matter of protection against dust. The precautions to be taken during the application of protective coatings are usually stated by the suppliers, e.g. ventilation to remove strong solvent vapour. On site, in the case of blast cleaning with non-metallic abrasives, particularly if large surface areas are involved, plans should be discussed with the Environmental Health Officer, the Health and Safety Authority, Water Authority and other interested parties and clearance obtained in writing for the proposals. The debris produced by combined wet and dry blast cleaning (see sub-Clauses 1903.14 and 15) can usually be contained satisfactorily. However in some cases it may be necessary to use dry blast cleaning only, e.g. to clean up a metal spray based system. This method is usually acceptable for a structure in an unpopulated area, even over a road.

However for a structure near or over a river, particularly near a water supply take off point or where fish stock is maintained, it may be necessary to prevent any debris from falling into the water or even on the ground nearby. In other areas, for example near a dust sensitive industrial process, the spreading of any dust in the atmosphere near the plant would be unacceptable.

On site also, although operators can usually be protected from the effects of spray application, it may be necessary in some cases to protect the immediate environment from overspray (see NG 124); it may even be expedient to specify brush application only.

If as a result of investigation it is clear that side sheeting or close boarded scaffolding is


required to reduce or prevent dust and debris being released into the atmosphere or from falling into a river, say, this should be stated in Appendix 19/9.

Basic Protective Systems for Steelwork Except Bearings and Lighting Columns

9 General

(i) The basic systems for bridge and other highway structures include systems which are satisfactory for sign gantries, footbridges, parapets and also for structures such as towers and buildings. Systems for structures which have to withstand especially aggressive conditions, salt hoppers for example, are not listed. Systems for plastic coated items such as sign posts are covered in Series 1200 and fencing in Series 2600.

(ii) Types 4, 8 and 10 basic systems, including alternative systems, should not require major maintenance up to 20 years. Type 10 and Type 10 alternative basic systems should require maintenance of paint coats only at the time of the first and second planned maintenance subject to the metal spraying of all welded or bolted site joints and to the avoidance of mechanical damage during erection. Treatment of site joints during erection requires particular care, e.g. selection of a satisfactory abrasive, achieving the required standard of cleanliness, avoiding damage to adjacent metal spray and ensuring that site metal spraying and sealing is completed immediately after blast cleaning;the required thickness of metal spray being obtained in one continuous operation [see sub-Clause 1911.2(iv)]. Site paint coats should be applied as soon as practicable over the sealed aluminium metal spray and in any case given within the timescale in sub-Clause 1914.27.

(iii) Item 159 is an Aluminium Epoxy Sealer for use when aluminium metal spray plus Sealer is to be overcoated with AR or Epoxy paints.

(iv) Acrylated Rubber (AR) paints are listed in the Manual of Paints for Structural Steelwork. AR paints have replaced Chlorinated Rubber paints in all situations. Although AR paints are thermoplastic, they have an increased degradation temperature and will generally recover completely from the effects of above normal temperatures e.g. when applied on the underside of a steel

249 March 2000



deck which is to be asphalted. However a check should be made with the paint manufacturer before using AR or other paints in areas subject to high temperature.

Acrylated Rubber systems can be applied by brush (B) as well as by airless spray (AS) and may be specified for structures situated in areas where airless spray application during the erection stage or during maintenance would not be acceptable, e.g. in built up areas, or for structures more suited to brush application, e.g. parapets. Alternative brushing quality Item Numbers are given in brackets for all AR paints although in the shops a fabricator is more likely to apply AR paints by airless spray.

(v) Colours of finishing paints. Where the appearance of the structure is of particular importance, colours for gloss finishes and matt finishes should be selected as in (a) and (b) below:

(a) Gloss Finishes

From the following colours in BS 4800:

Light Grey 00 A 05 Medium Grey 18 B 21

Dark Grey 18 B 25 Green-yellow 12 B 21

White 00 E 55

(b) Matt Finishes

When a matt finish is acceptable, or is specifically required such as for sign gantry steelwork, MIO paints should be used. Because these paints contain a comparatively high percentage of MIO, colour matching is not precise and colours are restricted to the following in BS 4800:

Medium grey Natural grey Dark blue Dark green

approximately 00 A 09 approximately 00 A 13 approximately 18 C 39 approximately 14 C 39

Complete matching of the above MIO paints from batch to batch is not feasible. Pigment size, orientation in coating and application method all have an effect on the finish appearance. In areas where appearance is particularly important the finish should be supplied from one batch. See sub-Clause 1914.9.

When there is a need for other colours, for example in the case of a large bridge or one which is in an

environmentally sensitive area and visually dominant the matter should be referred to the National Roads Authority, describing the structure, its location and the proposed alternative BS 4800 colour and the reasons for selecting it. Advice on the choice and use of colour is available in the UK Department of Transport Highways Agency publication 'The Appearance of Bridges and other Highway Structures' Chapter 21.

Details of Basic Protective Systems for Steelwork Except Bearings and Lighting Columns

10 Basic Systems

Note: mdft = minimum dry film thickness B = apply by brush

AS s apply by airless spray

Type 1 not used.

Type 2 not used.

Type 3 not used.

Type 4 (AR)

Inland Environment. Ready Access.

Shop. 1st Coat: Item 170(170), Zinc Phosphate

AR Blast Primer.

Shop. 2nd and 3rd Coats: Item 172(171), Zinc Phosphate AR Undercoat

Site. 4th Coat: Item 174(173), MIO AR

Undercoat.

Site. 5th Coat: Item 176(175), AR Finish, mdft 50 microns.

Minimum total dry film thickness : 250

microns.

Type 4 Alternative (Epoxy)

Shop. 1st Coat: Item 111, Zinc Phosphate High

Build Quick Drying Epoxy Blast Primer (2

pack).

Shop. 2nd Coat: Item 112, MIO High Build

Quick Drying Epoxy (2 pack).

Site. 3rd Coat: Item 168, Polyurethane Finish (2 pack), mdft 50 microns

or

March 2000 250


Site. 3rd Coat: Item 164, Moisture Cured Polyurethane Finish, mdft 40 microns.

Minimum total dry film thickness: 300 microns.

Type 5 not used.

Type 6 not used.

Type 7 not used.

Type 8 (AR)

Marine Environment. Ready Access.

Shop. 1st Coat: Item 170(170), Zinc Phosphate AR Blast Primer.

Shop. 2nd and 3rd Coats: Item 172(171), Zinc Phosphate AR Undercoat.

Shop. 4th Coat: Item 174(173), MIO AR Undercoat.

Site. 5th Coat: Item 176(175), AR Undercoat, mdft 50 microns.


Minimum total dry film thickness : 300 microns,

or


Shop. 1st Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Blast Primer (2 pack).

Shop. 2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack).

Site. 3rd Coat: Item 168, Polyurethane Finish (2 pack), mdft 50 microns

or

Site. 3rd Coat: Item 164, Moisture Cured Polyurethane Finish, mdft 40 microns.


Type 9 not used.

Type 10 (AR)

Inland or Marine Environment. Difficult Access.


Shop. 1st Coat: Item 159, Aluminium Epoxy Sealer (2 pack) B or AS.

Application rate: 12 - 20 m-/litre.

Shop. 2nd Coat: Item 172(171), Zinc Phosphate AR Undercoat.

Shop. 3rd Coat: Item 174(173), MIO AR Undercoat.

Site. 4th Coat: Item 174(173), MIO AR Undercoat.


Minimum total dry film thickness : 250 microns.

or


Metal coating: Aluminium metal spray.

Shop. 1st Coat: Item 159, Aluminium Epoxy Sealer (2 pack), B or AS.

Application rate: 12 - 20 m'Tlitre.

Shop. 2nd Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Undercoat (2 pack).

Shop. 3rd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack).

Site. 4th Coat: Item 168, Polyurethane Finish (2 pack), mdft 50 microns

ear

Site. 4th Coat: Item 164, Moisture Cured Polyurethane Finish, mdft 40 microns.


Type 11 (Interior of box girders)

All Environments. Ready or Difficult Access.

Shop. 1st Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Blast Primer (2 pack), mdft 100 microns.

Shop or Site. 2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Finish (2 pack).

Minimum total dry film thickness : 200 microns.


March 2000 251


Two stripe coats are required for AR systems, one applied in the shop in Item 172(171) paint and one applied at site in Item 172(171) or 174( 173) paint.

One stripe coat is required for Alternative (Epoxy) systems, to be applied in the shop in Item 112 paint, at mdft 75 microns.

Type 12 not used.

Type 13 (AR) (for galvanized surfaces, e.g. parapets)

All Environments. Ready or Difficult Access.

Metal coating: Galvanizing.

1st Coat: Item 155, T' Wash.

2nd Coat: Item 172(171). Zinc Phosphate AR

Undercoat.

3rd Coat: Item 174(173), MIO AR Undercoat.

4th Coat: Item 174(173), MIO AR Finish,

medium grey.

Miriimum total dry film thickness : 150 microns.

For parapets to be erected in a Marine environment, the T' Wash, the 2nd and 3rd coats shall be applied in the shops; the 4th Coat may be applied in the shops or on site at the Contractor's option. For parapets in an Inland environment, the T Wash and coats of paint may be applied in the shops or on site at the Contractor's option.

When a semi gloss, medium to dark finish, is required, an extra coat in Item 176(175) AR Finish should be applied. For a light colour finish the final MIO coat should be replaced by an AR Undercoat and AR Finish of Item 176( 175).

Notes:

1. The finish coats in Types 4, 8 and 10 basic systems above are semi gloss coats. When a gloss finish is required the semi gloss finish should be replaced by Item 180 (179).

2. The finish coats in Type 4 Alternative, 8 Alternative and 10 Alternative basic systems above are either gloss coats (Item 168) or semi-gloss coats (Item 164). When a matt finish is required, e.g. fascia of a sign gantry, the semi-gloss or gloss finish should be replaced by Item 112.


3. Only the details of coatings have been given in the above Basic Systems and not the surface preparation requirements.

4. Advice on the specifying of abrasives for shop work is given in NG 1907.1. For site work see sub-Clause 1903.11 and NG 1903.11.

Basic Protective Systems for Steel in Bridge Bearings

11 General

(i) The 'required durability' of Type 2 basic system which consists of aluminium metal spray plus a paint system, is no maintenance up to 12 years, minor maintenance from 12 years and major maintenance after 20 years. The protective coatings on bridge bearings are likely to require repair of mechanical damage sustained during erection. The periods of 12 and 20 years are considered to be adequate for both environments.

(ii) Type 2 basic system is suitable for bearings of bridges with Ready Access or Difficult Access.

(iii) MIO Epoxy paints have been selected for the basic system to provide quick drying and impact resistant coatings which can be applied by either brush or airless spray. The Contractor may opt to apply the last two MIO Epoxy coats on site at the same time as he is painting the site fasteners and remedying any erection damage. Medium or dark grey MIO Epoxy Finish is usually suitable for bearings for concrete bridges, and hence special finish coats will be required less frequently than in the case of steel bridges where the colour of the bearings may be required to match the finishing paint on the steelwork. Provision has been made for replacing the last MIO Epoxy coat with a Polyurethane finish coat in case a different colour is required, e.g. to match main steelwork system. Details are shown in Sample Appendix 19/2.

(iv) The use of MIO Epoxy (2 pack) paints is standard, and the fact that the Contractor applies the site coats and carries out any remedial work, should make it unnecessary for the bearing manufacturer to visit the site. See Application Instructions in the basic system below. It should be ensured, however that at each stage the bearing protective system is in good condition and that site coats are properly applied. See NG 1920.1.

March 2000 252


Details of Basic Systems for Steel in Bridge Bearings (and Metal Coated Fasteners)

12 Basic System

Type 2 (Type 1 basic system not used)

(i) Surface preparation.

All Environments. Ready or Difficult

Access.

Area A

Exterior surfaces, excepting wearing surfaces but including a 25 mm minimum return on areas of top bearing plates or base plates in contact with grout or mortar.

Method: Blast clean with chilled cast iron grit.

Standard: Clean steel, 1st Quality, Medium

profile.

Area B

Central area of top bearing plates or base

plates in contact with grout or mortar.

Method: Blast clean with metallic abrasive.

Standard: Clean steel. 2nd Quality. Medium

profile.

Area C

Areas of top bearing plates or base plates in contact with structural steel components.

Method: As Area A.

Standard: As Area A.

Area D

Exposed shop fasteners in components to be coated after assembly.

Method: As Area A.


Area E

Concealed shop fasteners.

Method: No requirement.

Standard: No requirement.


Area F

Site fasteners for fixing bearings to piers or abutments and for fixing bridge components to bearings.

Restore metal coating as necessary to specified standard of cleanliness.

(ii) Protective system.

Area A

Aluminium metal spray minimum thickness

150 microns.

1st Coat: Item 159, Aluminium Epoxy Sealer (2

pack) B or AS. Application rate: 12 — 20 m'-'/litre.

2nd Coat: Item 118, MIO Epoxy Primer

(2 pack), B or AS mdft 50 microns.

3rd Coat: Item 120, MIO Epoxy Undercoat/

Finish (2 pack), B or AS mdft 50 microns.

Minimum combined dry film thickness for 2nd

and 3rd coats 115 microns.

Additional coats for bearings for steel or

concrete bridge beams.

Over Area A

4th Coat: Item 120, MIO Epoxy Undercoat/ Finish (2 pack), B or AS mdft 50 microns.

5th Coat: Item 120, MIO Epoxy Undercoat/

Finish (2 pack), B or AS mdft 50 microns.

Minimum total dry film thickness for paint

system 225 microns.

Alternative 5th coat for bearings for steel bridge beams, applied on site.

Over Area A

5th Coat: Item 164, MC Polyurethane Finish, B. mdft 40 microns or Item 168, Polyurethane (2 pack) Finish, B. mdft 40 microns.

Colour to match finish on main steelwork.

Minimum total dry film thickness for paint

system 225 microns.

Aluminium metal spray plus Item 159, Aluminium Epoxy Sealer (2 pack) only, are required on interfaces of machined surfaces of spreader plates and of bearing.

March 2000 253



Area B

Item 118, MIO Epoxy Primer (2 pack) mdft 50 microns.

Area A

Item 120 (4th and 5th coats) shall be applied at the bearing manufacturer's works or on site by the Contractor.

Area C

Aluminium metal spray minimum thickness

150 microns.

Sealer: Item 159, Aluminium Epoxy Sealer (2

pack) B or AS. Application rate: 12 - 20 m2/litre.

Area D

As Area A.

Area E

Fasteners unprotected by grease shall be zinc electroplated.

Area F

Metal Coating: Zinc electroplating.

1st Coat: Item 155, 'T' Wash.

2nd Coat: Item 118, MIO Epoxy Primer (2

pack), B or AS. mdft 50 microns.

3rd Coat: Item 120, MIO Epoxy Undercoat/

Finish (2 pack), B or AS. mdft 50 microns.

4th Coat: Item 120, MIO Epoxy Undercoat/ Finish (2 pack), B or AS. mdft 50 microns.

Items 164 or 168 (alternative 5th coat) shall be applied on site.

Area F

Item 155, T Wash shall be applied on site, either before or after erection, to surfaces to be painted. T Wash coming into contact with adjacent paint coats shall be removed immediately.

The remaining site coats shall be applied to

exposed surfaces after erection.

Stripe coats for bearings only: (stripe coats are not required for bearing site fasteners).

A 1st stripe coat of undercoat shall be applied over the MIO Epoxy Primer at the bearing manufacturer's works.

A 2nd stripe coat of last undercoat shall be

applied on site. MIO Epoxy coats shall be in

contrasting colours, e.g. medium grey, dark

grey.

Site coats shall be applied by the Contractor.

Note: When compiling Appendix 19/2, the appropriate finish paints should be selected from the basic system. The letter references, A, B, C etc. should be varied as appropriate, and the application instructions arranged to suit.

5th Coat: Item 120, MIO Epoxy Undercoat/ Finish (2 pack), B or AS. mdft 50 microns.

Minimum total dry film thickness 225 microns.

Alternative 5th coat.

As Area A.

(iii) Application instructions.

Areas A, B or C, and D

The aluminium metal spray and Items 155, 118 and 120 (3rd coat) shall be applied at the bearing manufacturer's works.

Basic Protective Systems for Steel Lighting Columns and Bracket Arms

13 General

(i) The six basic systems and the setting out of the typical Sample Appendix 19/3 should be studied. For motorways and other trunk roads the basic system most appropriate to the environment, see (ii) and (iii) below should be selected, and then Appendix 19/3 compiled on the lines of the Sample Appendix, bearing in mind that lighting columns of 3 mm section thickness or less are to be galvanized.

The 'required durability' of the exterior coatings, which consist of aluminium metal spray plus sealer, galvanizing only or one of these metal coatings plus a paint system, is no maintenance up to 8 years, minor maintenance after 8 years and major maintenance after 15 years.

March 2000 254


(ii) The simplest (and cheapest) protection will be either aluminium metal spray plus sealer or galvanizing only (see Type Al and Gl basic systems). These systems will be suitable for columns in an inland environment with ready access for maintenance. Columns situated in an inland environment with difficult access or marine environment with ready or difficult access will require a metal coating plus paint coats. See Type A2a, A2b (Alternative), G2a and G2b (Alternative) basic systems.

(iii) The choice of metal coating and paint system [i.e. Type A2a, A2b (Alternative), G2a or G2b (Alternative)] may be left to the Contractor, in which case each type of system should be included in Appendix 19/3. Planted columns protected with A2b (Alternative) or G2b (Alternative) protective systems must have an additional sacrificial steel thickness of a minimum 1.0 mm above that needed in the design, from the bottom of the column to at least 250 mm above ground level.

(iv) The policy for the protection at column

bases is as follows:

(a) Columns, which have been aluminium metal sprayed externally, require internal protection for the ground section and door area. Blast cleaning, to 2nd Quality, medium profile, followed by application of Pitch Epoxy (2 pack) paints, extending from the bottom to 300 mm above the door opening, has been specified for internal protection of these columns.

(b) Galvanized columns do not require additional internal protection.

(c) External surfaces of the ground section of all rooted columns are protected by Pitch Epoxy (2 pack).

(d) External surfaces of flange mounted columns do not require special treatment at the base unless the flange is below ground level or built over, e.g. covered by a plinth. In this case Pitch Epoxy (2 pack) should be specified. See Sample Appendix 19/3 for details.

Note: So that the Contractor will know how far to extend the Pitch Epoxy (2 pack) a nominal 'ground' or 'plinth level' should be stated in Appendix 19/3 as being at a fixed distance below the door opening. A value of 600 mm will usually be appropriate.


Details of Basic Protective Systems for Steel Lighting Columns and Bracket Arms

14 General

(i) In the case of basic system A2a, G2a, A2b (Alternative) and G2b (Alternative), the Contractor may opt to apply the finishes in the shop or at site, unless otherwise specified.

(ii) The colour of the finish coat of paint in systems A2a and G2a in the sample Appendix 19/3 is blue/black 18 B 29 to BS 4800. When a white or pale tint finish is to be specified, an additional coat of Item 164 or 168 may be required to ensure complete obliteration of the MIO high build Epoxy (2 pack) Undercoat.

Before specifying white or pale tint finishes, any requirement for an additional coat of paint should be checked with the paint suppliers listed in section 7 of Appendix 19/3.

(iii) Item 150, Pitch Epoxy (2 pack) polyamide cured has been specified. However Item 152, Pitch Epoxy (2 pack) isocyanate cured will be acceptable as an alternative if offered by the Contractor and subject to his taking the necessary health and safety precautions during application.

(iv) Type A l , A2a and A2b (Alternative) basic systems are based on aluminium metal spray.

(v) Type G l , G2a and G2b (Alternative) basic systems are based on galvanizing.

Note: In these basic systems the protection for the ends of flange mounted columns which are built over or protected by a plinth is assumed to be the same as for the ground section of planted columns. Appendix 19/3 should be written accordingly.

System Al for Columns in an Inland Environment with Ready Access

15 Basic System

Type A1

(i) External surface.

Flange mounted and planted columns,

overall treatment.

Surface preparation.

Method: Blast clean with chilled cast iron

grit or aluminium oxide grit.

March 2000 255



Standard: Clean steel, 1st Quality, medium profile.

Protective system.

Aluminium metal spray.

Item 159. Aluminium Epoxy Sealer (2 pack) B or AS. Application rate: 12 - 20 mVlitre.

Ground section, additional coat.

Item 150, Pitch Epoxy (2 pack) AS. mdft 100 microns.


(ii) Internal surfaces.

Flange mounted columns, flange to door area.

Planted columns, ground section to door area.


Method: Blast clean.

Standard: Clean steel, 2nd Quality, Medium profile.

Protective system.

1st Coat: Item 110, Zinc Phosphate Epoxy Primer (2 pack), AS. mdft 30 microns.

2nd Coat: Item 150, Pitch Epoxy (2 pack), AS. mdft 100 microns.


On internal surfaces Items 110 and 150 shall be applied from the bottom to 300 mm above the door opening.

Systems A2a and A2b (Alternative) for Columns in an Inland Environment with Difficult Access or in a Marine Environment with Ready or Difficult Access

16 Basic Systems

Type A2a


Flange mounted and planted columns, overall treatment.


Method: Blast clean with chilled cast iron grit or aluminium oxide grit.

Standard: Clean steel, 1st Quality. Medium profile.

Protective system.



2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack), AS. mdft 100 microns.

Flange mounted columns, additional overall coat. Planted columns, additional coat for upper section only.

Item 164, Moisture Cured Polyurethane Finish, B or AS. mdft 50 microns


Blast cleaning, aluminium metal spray and all shop paint coats on external surfaces shall be returned on to edges at ends, at door and other openings and 25 mm under base flange.

All paint coats shall be applied in the shops.

Item 159 shall be overcoated within 96 hours.

On external surfaces Item 150 shall be applied from the bottom to 250 mm above ground level.

Item 168, Polyurethane Finish (2 pack), B or AS. mdft 50 microns.


Planted Columns, additional coat for ground section.



March 2000 2 5 6


(ii) Internal surface.

Flange mounted columns, flange to door area. Planted columns, ground section to door area.




Protective system.


2nd Coat: Item 150, Pitch Epoxy (2 pack) AS. mdft 100 microns.

Minimum total dry film thickness 150

microns.


Blast cleaning, aluminium metal spray and all shop paint coats on external surfaces and site paint coats where access permits shall be returned on to edges at ends, at door and other openings and 25 mm under base flange.

All paint coats except Items 164 and 168 shall be applied in the shops. Items 164 and 168 may be applied in the shops or on site.

Item 110 shall be overcoated within 96

hours.

On internal surfaces Items 110 and 150 shall be applied from the bottom to 300 mm above the door opening.

For planted columns:

On external surfaces Item 150 shall be applied from the bottom to 250 mm above ground level.

Item 164 or 168 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

T)rpe A2b (Alternative)

Planted columns shall have an additional sacrificial steel section thickness of a minimum 1.0 mm, above that needed in the design, from the bottom of the column


to at least 250 mm above ground level; additional thickness to be recorded in Part A of Appendix 13/2, Column and Bracket Data Sheet.





Standard: Clean steel, 1st Quality, Medium profile.

Protective system.


Item 159, Aluminium Epoxy Sealer (2

pack). B or AS. Application rate: 12 - 20 m-/litre.

Flange mounted columns, additional overall coats. Planted columns, additional coats for upper section only.

1st Coat: Item 130, Vinyl/Vinyl Copolymer Primer. B or AS. mdft 75 microns.

2nd Coat: Item 131, Vinyl/Vinyl Copolymer Finish. B or AS. mdft 75 microns.


Planted columns, additional coat, for ground section only.

Item 150, Pitch Epoxy (2 pack). B or AS. mdft 100 microns.

Minimum total dry film thickness 110

microns.


Flange mounted columns, flange to door area. Planted columns, ground section to door area.




Protective system.

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1st Coat: Item 110 Zinc Phosphate Epoxy Primer (2 pack). AS. mdft 30 microns.

2nd Coat: Item 150, Pitch Epoxy (2 pack). AS. mdft 100 microns.



Blast cleaning, aluminium metal spray and all shop paint coats on external surfaces, and site paint coats where access permits, shall be returned on to edges and 25 mm inside at ends, at door and other openings and 25 mm under base flange.

On internal surfaces, Items 110 and 150 shall be applied from the bottom to 300 mm above the door opening.



On external surfaces, Item 150 shall be applied over Item 159 from the bottom to 250 mm above ground level.

On external upper section, Items 130 and 131 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm. Item 131 may be applied in the shops or on site, to overlap Item 150 by 25 mm.

System Gl for Columns in an Inland Environment with Ready Access

17 Basic System

Type Gl

(i) External and internal surfaces.


Galvanize.

(ii) External surface.

Ground section, additional coats.

1st coat: Item 155, 'T Wash.

2nd Coat: Item 110, Zinc Phosphate Epoxy Primer (2 pack) AS. mdft 30 microns.


3rd Coat: Item 150, Pitch Epoxy (2 pack) AS. mdft 100 microns.



The requirements of sub-Clause 1914.21 need not apply for lighting columns which remain in a shop environment after galvanizing.

T Wash and shop paint coats on external surfaces shall be returned on to edges and 25 mm inside at ends and under base flange.

All paint coats shall be applied in the shops.


Items 155, 110 and 150 shall be applied from the bottom to 250 mm above ground level.

Systems G2a and G2b (Alternative) for Columns in an Inland Environment with Difficult Access or in a Marine Environment with Ready or Difficult Access

18 Basic Systems

Type G2a



Galvanize.


Flange mounted and planted columns, additional overall coats.

1st Coat: Item 155, T Wash.

2nd Coat: Item 110, Zinc Phosphate Epoxy Primer (2 pack) AS. mdft 30 microns.

3rd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack), AS. mdft 100 microns.

Flange mounted columns, additional overall coat.

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Planted columns, additional coat for upper section only.

Item 164, Moisture Cured Polyurethane Finish, B or AS. mdft 50 microns, or Item 168, Polyurethane Finish (2 pack), B or AS. mdft 50 microns.

Minimum total dry film thickness, including Primer, 200 microns.

Planted columns, additional coat for ground section only.




The requirement of sub-Clause 1914.21 need not apply for lighting columns which remain in a shop environment after galvanizing.

T' Wash, all shop paint coats on external surfaces and site paint coats where access permits shall be returned on to edges and 25 mm inside at ends, at door and other openings and under base flange.

All paint coats except Items 164 and 168 shall be applied in the shops. Items 164 and 168 may be applied in the shops or on site.



Item 150 shall be applied over Item 110 from the bottom to 250 mm above ground level.

Item 164 or 168 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

Type G2b (Alternative)

Planted Columns shall have an additional sacrificial steel section thickness of a minimum 1.0 mm, above that needed in the design, from the bottom of the column to at least 250 mm above ground level; additional thickness to be recorded in Part A of Appendix 13/2, Column and Bracket Data Sheet.




Galvanize.

(ii) External surfaces.



Flange mounted columns, additional overall coats. Planted columns, additional coats for upper section only.

1st Coat: Item 130, Vinyl/Vinyl Copolymer Primer. B or AS. mdft 60 microns.

2nd Coat: Item 131, Vinyl/Vinyl Copolymer Finish. B or AS. mdft 60 microns.


Planted columns, additional coats, for ground section only.

1st Coat: Item 110, Zinc Phosphate Epoxy Primer (2 pack). B or AS. mdft 30 microns.

2nd Coat: Item 150, Pitch Epoxy (2 pack). B or AS. mdft 100 microns.



The requirements of sub-Clause 1914.21 need not apply for lighting columns which remain in a shop environment after galvanizing.

T Wash and shop paint coats on external surfaces, and site paint coats where access permits, shall be returned on to edges and 25 mm inside at ends, at door and other openings and 25 mm under base flange.

Items 110 and 150 shall be applied from the bottom to 250 mm above ground level.

Items 130 and 131 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

Item 131 may be applied in the shops or

on site.

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NG 1902 Surface Preparation -General Requirements

Shop and Site Work

1 In most cases the use of a cleaning agent followed by rinsing is considered to be more effective than the use of a solvent. If traces of oil or grease remain after the first attempt, further cleaning may be necessary. However if wetting of the surface is not permissible, use of a solvent may be necessary.

2 It should be ensured that, throughout the duration of the work, clean water is used for wet cleaning and rinsing. Generally, potable water will be satisfactory, but there should be a check that the water (or the cleaning agent) does not leave harmful residues on the surface. Warm water may be used where appropriate.

3 There should also be a check that the cleaning agents offered do clean satisfactorily and do not themselves leave harmful residues on the surface after final rinsing. Abrasives should be checked for freedom from impurities which could contaminate the surface to be cleaned.

4 Dry blast cleaning in particular may have to be repeated if the steel to be used for the Permanent Works has become rusted and contaminated before fabrication as a result of being stored in the open in an industrial environment. In some cases the site coats may not be applied for a considerable time and repeated cleaning down may be required.

5 Blast cleaning will not remove all weld spatter; it should therefore be ensured that firmly adhering spatter is removed before blast cleaning. In most cases weld spatter can be removed before the application of a protective system. It will not, however, be possible inside some hollow sections, e.g. tubes, even if these are to be galvanized internally.

6 Except at site welded joints, dry methods of surface preparation should be specified for the inside of box girders otherwise excessive water will accumulate on the bottom surfaces especially between stiffeners, also surfaces may remain wet for some time and delay painting. The internal surfaces of hollow sections which are to be coated should be free from dust and debris as far as practicable.

7 Although the initial surface preparation may have been satisfactory, and all dust and debris removed, further dust may well collect on the cleaned surface. In harsh environments further pollutants may also be deposited. It is essential therefore to check surfaces immediately.before painting.


8 If particles of abrasive are allowed to fall onto a freshly painted surface they are likely to become embedded in the wet paint. Shop coats in particular may also become contaminated by metallic dust from badly contained metal spraying operations. Embedded abrasive in fresh paint should be removed, and if necessary, the affected coat restored. Wet paint which has been contaminated by metal spray dust should be removed completely. If dried films only have been affected, wet cleaning may prove effective in removing such surface dust, however careful checks should be made. Metal spray dust remaining on an MIO pigmented coat, for example, would be difficult to remove later and could cause early failure of site coats.

9 Cleaning of the shop coats before painting on site will usually be necessary as it is not possible to check that all areas are free from contamination.

NG 1903 Surface Preparation -Materials and Methods

Dry Blast Cleaning in the Shops

1 There should be a check that the grading and hardness of the abrasive used for the work complies with Clause 1903. It is important to realise that the restrictions on abrasive sizes necessary to keep the blast cleaning profile within the ranges covered by the Surface Profile Comparator will also reduce the number of i'ogue peaks'.

2 Samples should be taken from abrasive stored in the blast cleaning plant before the start and during the work to ensure that there are no oversize particles in the mix. All fresh supplies should also be checked before they are used to replenish abrasive in use. The inspector should have the necessary sieves in his possession in the shops. Abrasive which does not comply with the Specification should be rejected. Oversize particles in excess of that allowed by the relevant standard, for example, are unacceptable. The performance of equipment and the technique of the operator can affect the attainment of a satisfactory profile or cleaning rate. A working mix with oversize particles will increase the frequency and size of rogue peaks and affect the cover provided by the subsequent painting.

3 Contamination of abrasives is not generally a problem in the shops when new steel is being blast cleaned. However the whole mix may well have become contaminated if steel, which has been exposed to, say, sulphates or chlorides, has been put through the plant. Hence the importance of early and subsequent checks.

March 2000 260


Abrading in the Shops or on Site

4 Power wire brushing, whether or not preceded by chipping or scraping, is unlikely to achieve a satisfactory standard of cleanliness and is therefore considered as no more than an aid prior to abrading.

5 Abrading will be used mainly to repair mechanical damage and during restoration of local failure in the shop paint system. Water should not be allowed to come into contact with exposed metal spray coatings which are porous, nor if possible with bright steel. However, wet abrading can be usefully employed where galvanizing is present.

6 Only power tools which rotate at the relatively fast speeds necessary for power wire brushing or abrading should be used. Deposits of concrete are difficult to remove if allowed to harden, hence it is important that appropriate chipping and scraping tools are used otherwise the paint system is likely to be damaged. The use of hard grinding wheels is not permitted for abrading as their edges can easily cut into the surface.

7 Electric drill speeds are relatively slow, the use of hand-held drills as a power source for wire brushing often results in a polished appearance due to the formation of a patina of pollutants and corrosion products.

8 Sub-Clause 1903.8 caters for the protection of exposed areas of cleaned steel substrate or metal spray coatings before they can be adversely affected by wetting or debris from adjacent surface preparation.

Wet Cleaning in the Shops or on Site

9 Shop coats which may have been exposed on site for a considerable time, particularly in an Inland or Marine environment, should be thoroughly cleaned. Scrubbing of flat surfaces is usually satisfactory, however light wet blast cleaning may be necessary to remove harmful contamination from areas difficult to clean. The selected cleaning agent should be used as recommended.

Dry Cleaning in the Shops or on Site

10 Dry cleaning is usually satisfactory for internal surfaces as these are less likely to have become contaminated. Nevertheless these surfaces should be checked before painting and further cleaning carried out if necessary. If this is unsatisfactory, advice should be sought from the National Roads Authority.


Dry Blast Cleaning on Site

11 Copper slag can be used to blast clean steel surfaces which are to be painted only, also to remove unsound paint; however if surfaces have become heavily contaminated, dry blast cleaning may not be adequate and wet blast cleaning may be necessary. Modern and efficient blast cleaning equipment which will recirculate metallic abrasive is available. The requirements for fasteners are covered in Clause 1904.

Sand (or other substance) containing free silica may not be used as an abrasive for blast cleaning.

Wet Blast Cleaning on Site

12 The main advantages of wet blast cleaning on site are that it keeps dust down and that it is the best method of removing heavy contamination. It should not be used to clean up metal spray coatings because they are porous. Wet blast cleaning as a first time method will not produce a satisfactory profile for the application of metal spray. It should only be used on bolted connections if dry blast cleaning is impractical, otherwise water will penetrate into the joint . It is, however, satisfactory for welded joints which are to be painted, also for cleaning up or removing paint over a steel substrate. It can also be used to clean up the surface only of a paint system applied over metal spray, but no further, as wetting of metal spray should be avoided.

13 Unless blast cleaned and adjacent surfaces are cleared of abrasive and debris within a short period, re-contamination is likely.

Combined Wet/Dry Blast Cleaning on Site

14 When wet blast cleaning is used to prepare steel surfaces, flash rusting may occur if painting is delayed. The required standard of cleanliness should be restored by light dry blast cleaning and paint should be applied while the surfaces are still clean.

15 As already mentioned, one of the main advantages of wet blast cleaning is its effectiveness in removing contamination; however, if this is not achieved using wet blast cleaning any subsequent light dry blast cleaning, although it may restore a clean appearance, is unlikely to remove contamination remaining on the surface or in the blast cleaned profile.

March 2000 261


Other Requirements

16 Sub-Clause 1903.16 is an important sub-Clause as it informs the Contractor of the sequence of operations necessary to keep contamination of adjacent surfaces to a minimum when different methods of surface preparation are used.

Grinding After Surface Preparation in the Shops or on Site

17 Visible surface defects should have been rectified by grinding during fabrication and before blast cleaning in the shops. Blast cleaning may reveal further defects and these should be dealt with before shop painting. Heavy mechanical damage or scoring caused during transport or during erection should also be rectified by grinding but subject to thickness limitations specified in 1800 Series. Grinding has to be carried out with minimum damage to the surface and only skilled operators should be allowed to carry out this work.

NG 1904 Procedures for Treatment at Joints

General

1 The treatment specified at joints prior to assembly or welding, covers both shop and site

t conditions.

Most erection joints are prepared in the shops for completion later on site. In these cases particular attention has to be given to limiting the application of the primers and to stepping back the undercoats on the parent material.

Treatment at completed joints includes sealing against the ingress of water, this should be carried out concurrently with the painting of either shop or site joints.

The requirements are also adequate in the case of joints which have to be prepared and made entirely on site e.g. in permanent strengthening of steelwork. Generally, contact surfaces at HSFG bolted joints are blast cleaned only or blast cleaned and aluminium sprayed.

Any metal coatings to be applied to fasteners in painted only joints, metal sprayed joints or metal sprayed and painted joints or where uncoated fasteners are to be provided, should be specified in Appendix 19/1. (see NG 1904.4).


Fasteners, Joint Material and Parent Material in Joints, Before Assembly or Welding in the Shops or on Site

Fasteners, Including Bolts, Nuts and Washers

2 Uncoated HSFG fasteners are usually delivered with oiled threads or with all the surfaces lightly oiled. Blast cleaning should remove traces of light oil remaining after assembly of the joint. Heavier oil or grease should be removed before assembly.

3 Hot dip galvanized fasteners should generally be specified for joints in hot dip galvanized and painted steelwork. However stainless steel fasteners may have an application in some cases.

4 The usual metal coatings for fasteners are galvanizing, zinc electro-plating and sherardiz-ing. In order to prevent rust staining of fasteners to be aluminium metal sprayed after assembly either in the shops or on site, zinc electroplating, as a temporary coating, should be specified, but this will be blast cleaned off preparatory to metal spraying. In the case of small structures stainless steel fasteners may be considered as an alternative. Hot dip galvanizing applied before assembly (seldom after), and metal spray coats applied to fasteners after assembly provide long term protection. Other than hot dip galvanizing, metal coatings applied before assembly, including zinc electro-plating and sherardizing, only provide short term protection and will require a full protective paint system. T Wash should not be applied to fasteners in assembled site joints as it is likely to penetrate into the joint. It can also run down on to painted surfaces, and cause problems if splashed on to other surfaces as it is a weak acid

5 Coated fasteners are usually delivered free of oil. As the threads are dry, difficulty in tightening may occur if the fasteners have been exposed outside in conditions where the nut and bolt threads have become corroded, this applies particularly to galvanized fasteners. Fasteners affected to this extent should be replaced.

Joint Material and Parent Material in Joints

6 Steel contact surfaces or steel surfaces which are to be painted on site need only be restored to 2nd Quality. Surfaces of metal spray should be restored by blast cleaning to sound metal. Galvanized surfaces are only likely to need wet cleaning. The Contractor may opt to use abrading, grinding or sometimes blast cleaning to restore a clean surface at weld preparation areas.

Wire brushing of even lightly rusted previously

blast cleaned surfaces is not acceptable.

March 2000 262


At Joints Made with HSFG Bolts

7 It is important that paints other than a primer or sealer should not be taken into the contact surface area, and that the primer should not be applied further than specified. HSFG bolted joints in galvanized steelwork are unusual.

8 When paint is applied to the outer faces of joint material at HSFG bolted joints, a check should be made that joint plates are not reversed during assembly; also if the maximum of 20 microns of paint is exceeded the whole coat should be taken off before the joint is made, otherwise the load carrying capacity of the joint may not be achieved. This also applies to sealer.

At Non Friction Bolted Joints

9 There are instances where HSFG or other high tensile fasteners may be used in shear and bearing rather than the more usual mild steel fasteners. As friction is not a criterion, paint may be taken over the joint surfaces. It is usually impracticable to apply the full shop system to the contact surfaces, but at least the primer and first undercoat should be applied.

10 Sealing of joints by assembling the plies on wet paint is not necessary for galvanized steelwork.

At Welded Joints

11 It is only necessary that surfaces to be welded should have a bright clean appearance. A check should be made however to ensure that they are free of metal coating, and other protective coatings, otherwise the weld could be impaired.

Parent Material, Shop Treatment Adjacent to Joints Which Are to be Assembled or Welded Later at Site

At HSFG Bolted Joints

12 Paint coats should be stepped back at breaks in the system, viz. at joints, otherwise the break will show on completion and a potential weakness in the protective coating may result.

At Non Friction Bolted Joints

13 It will usually be practical to take the full shop system over the joint surfaces.

At Welded Joints

14 Metal spray and paint should be kept back from weld areas not only to avoid degradation of the weld, but also to prevent damage to the


coating by heat and the possible production of toxic fumes. Galvanizing must be removed from the prepared joint area otherwise fumes and spatter may be excessive.

At Completed Joints

15 It should be checked that bad weather conditions or a severe environment have not affected unprotected bolted joints adversely; if adverse conditions are likely the Contractor should seal any gaps and apply sufficient protection within 48 hours, or earlier if possible, of a joint being made.

The protective system on adjacent parent material will usually be satisfactory for all types of joints. However because of varying requirements for the protection of welded site joints, e.g. internal welds and joints in metal sprayed or galvanized steelwork, the appropriate surface preparation for site welded joints should be specified in Appendix 19/1. See NG 1904.18 below. Advice on the treatment for site welds, including the use of phosphating agents may be sought from the National Roads Authority.

At Bolted Joints

16 Dry blast cleaning is preferable at newly-made joints as wet cleaning and wet blast cleaning in particular will lead to difficulties if water penetrates into the joints. If the registered priming coat on the outer surfaces is sound, dry cleaning may be adequate provided that the surfaces are checked finally for freedom from detrimental contamination.

17 Wet cleaning is usually suitable for galvanizing. It does not damage the surface and has been found to be satisfactory, for example for the type of joints used in parapets.

At Welded Joints

18 Site welds may be difficult to free from detrimental contamination by dry blast cleaning to 2nd Quality. After an external weld has been freed of slag and wire brushed, wet cleaning should be specified before dry blast cleaning.

Alternatively combined wet/dry blast cleaning can be used as this method is effective in removing contamination. When any form of blast cleaning is impracticable for external welds in painted only steelwork, wet cleaning should be followed by phosphating and a coat of Item 110, Zinc Phosphate Epoxy Primer, (2 pack). In most box girders, the water and debris from wet blast cleaning of internal surfaces would be difficult to clear up

263 March 2000


satisfactorily and hence removal of slag, wire brushing and wet cleaning followed by phosphating and Item 109 should also be specified. Item 109 should be followed by the first undercoat of the system.

When a metal spray coating is to be applied over a welded joint, blast cleaning will be necessary.

The removal or stepping back of coatings (e.g. galvanizing) from the prepared joint area should prevent damage to the protective system. The protective treatment of welds and weld areas in galvanized steelwork should be dealt with separately in Appendix 19/1.

Sealing at Joints, Plies and Fasteners

19 If joints or steel plies have been exposed to water it should be ensured that they are free from moisture before gaps are sealed and the paint system applied.

20 There should be a check that paint penetrates the fine gaps sufficiently to provide an effective seal and that other gaps are painted in sufficient depth to maintain the seal in position.

NG 1905 Procedures for Treatment at Areas of Mechanical Damage or Other Surface Defects

1 Damaged coatings may require different treatment in the shops than on site. Reference should be made to Clauses 1907 and 1908 and related NG for requirements and guidance on workmanship standards for remedial treatment.

2 Damage in the shops to unprepared surfaces should be treated before blast cleaning. However minor areas of repair to blast cleaned surfaces which are to be painted need not be re-blast cleaned. Generally, most damage to coated surfaces is caused during transport and erection, often due to inadequate handling or stacking. Abrading is an effective method for dressing minor damage in steel surfaces or in metal coatings or for smoothing more heavily damaged areas after grinding. Fissures in the surface caused by the removal of 'hackles' or inclusions may need to be ground out, and when a metal spray is to be applied the area should be blast cleaned; however it should be ensured that mechanical damage or grinding, even if smoothed out does not reduce the thickness of the steel below specified limits.


3 Abrading is also an effective means of preparing small areas of damage in hard dry paintwork.

4 Blast primers less than 30 microns dry film thickness need not be replaced. However, other primers, e.g. AR and Epoxy (2 pack) Primers, which are usually applied at film thicknesses as greater than 30 microns, are an essential part of the protective system and should be replaced.

5 After surface preparation of a metal sprayed area by abrading or grinding, the whole of the affected area should be dry blast cleaned to ensure overall adhesion of the re-application of metal spray. There will be no clear demarcation between exposed steel substrate and the metal spray.

6 It is generally possible to restore metal spray coatings in the shops and replacement by paint should not be allowed.

7 When a metal spray coating together with any sealer is being restored on site during repairs to a damaged area the minimum thickness of metal coating should be increased to 150 microns. This is to ensure the required durability from the application on site.

It should be ensured that adhesion checks in accordance with ISO 2063, Annex A, method Al are made at a representative number of repaired areas.

8 It would be uneconomical as well as unreasonable to expect metal spray coatings to be restored in every case of minor mechanical damage occurring on site, particularly on large components. However the extent of repairs by painting should be strictly limited.

9 The term 'in the shops' includes the galvanizer's works. A large proportion of hot dip galvanized components are delivered direct to site from the galvanizer, and generally any component with damaged hot dip galvanizing should be re-galvanized before despatch.

10 The incidence of damage is related to the type of component, care in storing and positioning for erection. For example a length of parapet laid out on a roadway for an unnecessarily long period is likely to be damaged. Minimum damage commensurate with proper care in handling only should be accepted. The relaxation at site applies to hot dip galvanized-only components (such as lighting columns) as well as to hot dip galvanized components protected by a paint system. Marking of the surface or light bruising of hot dip galvanizing should not be considered as damage referred to in Clause 1905.

March 2000


11 The bevelling back of edges of adjacent, and apparently unaffected paint coatings, or metal coatings, into sound coatings will not only improve appearance but may also show up unsuspected adhesion defects. Only dry methods of surface preparation should be used when removing damaged or faulty paint from the surface of metal sprayed coatings (see NG 1903.5). Galvanizing on the other hand is not porous, either wet or dry methods may be used to remove paint and prepare the surface before coating.

12 T' Wash contains a weak acid and should be wiped off immediately if it has been applied over paint. Affected paint should then be wet cleaned.

13 It should be ensured that the Contractor does not extend the specified overcoating times, otherwise local failure early in the life of the system is likely.

NG 1906 Procedures for Treatment of Local Failure in Protective Coatings

1 Local failure of coatings may also require different treatment in the shops than on site. Remedial work is likely to be more extensive than in the case of repair to mechanical damage; this is because contamination or other cause of failure may affect a relatively wide area. Reference should be made to Clauses 1907 and 1908 and related NG for requirements and guidance on workmanship standards for remedial treatment.

2 Achieving adequate standards of surface preparation, including freedom from harmful residues and detrimental contamination, is most important when remedying areas of local failure in paint coats or metal spray coatings. Local failure, early in the life of the shop coats or after completion of a system on site, is usually due to painting in adverse conditions or inadequate surface preparation initially e.g. ineffective removal of contamination including oil or grease prior to painting. Early failure of a metal spray coating is often due to poor adhesion, the usual causes being delay in application, say overnight, excessive spraying distance or even steel at too low a temperature. The causes of local failure should be investigated as soon as possible so that the fault can be corrected. It should be ensured that all protective coatings are up to standard before steelwork leaves the shops.

3 Although site blast cleaning to 2nd Quality will be acceptable as far as visible residues are concerned, equivalent relaxation in the


standard of chemical cleanliness is not permissible. Particular attention should be paid to checking the latter as contamination may have caused the local failure.

4 Local failure of galvanizing, e.g. detachment of the coating, may be indicative of extensive unsound galvanizing. In all cases the component should be regalvanized.

5 It should be ensured that the full extent of the failure has been cleared of unsound paint and checked that any abrading of paint coats has not damaged any underlying galvanizing by reducing its thickness unduly.

6 The cause of any failure should be ascertained and it should be ensured that the Contractor achieves the required standard of surface preparation, including the removal of contamination, before overcoating. The expertise to mount tests to verify that surfaces have been cleaned adequately should be available.

NG 1907 Workmanship Standards for the Surface Preparation of Steel by Blast Cleaning, Abrading, Grinding and Cleaning

1 The method of surface preparation required, e.g. blast clean, and when appropriate the abrasive to be used, e.g. chilled cast iron grit or aluminium oxide (for metal spray in the shops) should always be specified in Appendices 19/1 to 19/4. The standard, e.g. clean steel, 1st Quality medium profile should also be specified. If the type of abrasive is not specified the Contractor may use any of the abrasives described in sub-Clause 1903.1 in the shops. Steel shot is satisfactory for blast cleaning surfaces to be painted only.

2 The Surface Profile Comparator is an 80 mm square stainless steel plate showing agreed ranges for fine, medium and coarse blast cleaning profiles. There are separate Comparators for assessing profiles produced by grit and by shot abrasives. The NSAI or BSI should be contacted for details and names of suppliers.

3 The amplitude of the blast cleaning profile on new steel is largely controllable by the size of abrasive used. Although the size and incidence of rogue peaks are also related to the size of abrasive, faulty manual blast cleaning techniques can greatly increase the problem. Regular use should be made of the Comparator

March 2000 265


and frequent checks of the abrasive should be carried out to ensure compliance with sub-Clauses 1903.1 and 2.

4 'Hackles' ranging from small spikes, some just visible to the unaided eye to those which have to be pulled from the surface and leave fissures which require treatment by grinding, show up as a result of blast cleaning, even when fine grades of abrasive are used. It is difficult to distinguish between rogue peaks and small hackles, and because the latter can appear at any time during blast cleaning, even if the process is well controlled, continuous checking is necessary. If metal spray, in particular, is to be applied, then the remainder of the component as well as the dressed areas may have to be blast cleaned in order to comply with ISO 2063.

Even if paint only is to be applied, re-blast cleaning may be required if the dressed areas are large, viz. such that the surface preparation by blast cleaning overall can no longer be claimed to exist.

5 Generally, dry blast cleaning to 1st or 2nd Quality, of lightly rusted surfaces which may be contaminated to a minor extent, will reduce contamination to negligible quantities. However, as the levels of rust and contamination on stock steel increase, so will the quantity of soluble salts remaining after blast cleaning increase; these will be unevenly distributed, making inspection difficult. The abrasive in use is also likely to become contaminated and may spread salts over otherwise clean surfaces.

Surfaces should therefore be checked for contamination before and after blast cleaning particularly in the case of more heavily rusted stock steel. If blast cleaned steel is still contaminated to an unacceptable level it should be rejected immediately; the abrasive should also be checked, see sub-Clause 1903.3. The Contractor may decide to pre-clean steel so that it can be finally dry blast cleaned satisfactorily; some blast cleaning plants include a washing stage for this purpose.

6 The requirements for 'clean steel' and 'bare steel' to be achieved by blast cleaning are described in sub-Clause 1907.5, those for freedom from 'harmful residues' or 'detrimental contamination' are described in sub-Clause 1907.7. See also Clause 1908.

It will be seen that 'clean steel' can only be achieved by blast cleaning the surface to 1st or 2nd Qualities. 'Bright steel' can be chemically clean if the steel surface was chemically clean originally. However there may be cases where an 'overall bright appearance' will be obtained


in a contaminated area, in which case any remaining detrimental contamination will have to be removed. 'Bright steel' however can be accepted for final dressing of small areas, such as sharp corners and other surface defects prior to painting or galvanizing.

Blast cleaning to clean steel 1st Quality with chilled cast iron grit or aluminium oxide grit is necessary for the successful overall adhesion of metal spray coatings. 1st Quality should also be specified for exposed steelwork when minimum maintenance is required, that is without any rusting through from the substrate having occurred.

Note: For the extent and depth of surface defects permitted in steel, reference should be made to the thickness limitations specified in the 1800 Series.

7 At present, BSI or ISO specifications or accepted Codes of Practice setting limits on embediment of particles of abrasive are not available. Some small particles may remain embedded in the profile. Faulty blast cleaning techniques, e.g. too high an air pressure, and large sharp particles, will exacerbate the problem. Sharp particles projecting above the blast cleaning profile will be harmful, as will large quantities of abrasive particles lodged in the profile. However experience has shown that agreement on acceptable limits is reached without difficulty.

8 For systems for difficult access structures the limits for harmful residues and detrimental contamination will be 'virtually nil'. Where 'bare steel' has been specified, checking surfaces for detrimental contamination is most unlikely to be necessary.

The same principle also applies to protective

coatings.

NG 1908 Workmanship Standards for the Surface Preparation of Coated Steelwork by Blast Cleaning, Abrading, Grinding and Cleaning

1 The standards of workmanship described in sub-Clause 1908.1 are for remedial work carried out in accordance with Clauses 1905 and 1906.

2 The terms listed in sub-Clause 1908.2 are in

use for maintenance contracts as well as for

new works.

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3 The term 'restored' is now a defined term; lower standards for replaced coatings are not acceptable.

4 In the shops, the most frequent cause for having to remove a metal spray coating is lack of adhesion. Subject to proper control, dry blast cleaning will remove a metal spray coating completely, this being necessary in the case of adhesion failure. Wetting of the surface, over say 1.0 m 2, at regular intervals is a practical method of checking that the metal spray is being removed. The wetted area should show even rusting.

On site, prolonged exposure in a harsh environment is likely to cause corrosion of a metal spray coating. In severe cases all but traces of the coating allowed under sub-Clause 1908.4 should be removed, wet blast cleaning may have to be used in such cases followed finally by dry blast cleaning. Only dry blast cleaning should be used to remove a damaged or failed paint system over metal spray or to clean up the surface of the metal coating itself: this is because metal spray coatings are porous, retained moisture may cause early failure of a restored paint system.

NG 1909 Paint and Similar Protective Coatings

1 Grease paints are protective coatings based on Calcium Soaps of Oxidized Petroleum Wax and are applied by brush or airless spray and are similar in appearance to ordinary paints but do not harden completely. When the solvent has evaporated grease paints are hard enough to walk on. Epoxy Pitch (2 pack) coatings and bitumens are also covered by Clause 1909 requirements.

2 Appendix 19/5 should be checked to ensure that the registered dates have been entered by the Contractor. Late registrations will not be permitted.

The fact that paints have been registered does not imply approval and the Contractor remains responsible for the adequacy of the paints he has selected. It has been found, for example that the film thickness claimed by a paint manufacturer for high build brushing paints cannot always be attained where applied directly on a blast cleaned surface, even by a skilled applicator.

3 Tins should show all the specified markings and the required standard should be insisted on at the outset. Omission of the Item Number for example, can lead to delay in checking the


specific gravity on site and the despatch of A and B samples. A check of the batch numbers will enable the inspector to verify whether the first batch of paint consists of less than 200 litres. If so, the batch should be discarded as required under sub-Clause 1910.3.

4 In practice, a paint manufacturer issues Appendix 19/8, Form BE/P5 Paint Data Sheet, to the Contractor. The Data Sheets should be examined and any special stipulation as to application which may cause problems or delays during the work should be noted and brought to the attention of the Contractor. If, for example, the weather is likely to be unfavourable the Contractor should be fully aware of any relevant restrictions on the application of the paints.

5 A source of supply should only be rejected after consultation with the National Roads Authority. Rejection would be considered in circumstances such as late or non-registration, unusable paint or closing down of the paint manufacturer's works.

NG 1910 Testing of Paints

Provision of Samples

1 Quality assurance of paint as delivered, that is verification of the composit ion data and application characteristics given in paint manufacturers' registered formulations can only be carried out on paint samples taken from previously unopened tins; these are known as 'A' Samples.

Before the Contractor despatches the 'A' Samples to the address given in NG 1910.5 for testing in accordance with sub-Clause 1910.4, the checks referred to in NG 1910.3 below should be carried out but on paint taken from other tins of the same batch.

'B' Samples, on the other hand, should be taken from paint in use to ensure that it is as supplied. See sub-Clause 1910.8 and NG 1910.8.

'A' Samples

2 Although A' samples are not required in the case of certain bridge and other highway structures described in sub-Clause 1910.2, 'B' samples should still be taken as these make an effective contribution to quality control.

3 Special deliveries of single tins of paint arranged by the Contractor, to the site or to the testing authority, are not acceptable as A'

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samples. Samples should be selected from fully representative batches at the shops or on site. As a minimum, the condition of the paint in the tins should be examined and, after mixing, the specific gravity checked; matching of finish colours to BS 4800 should also be checked. Paint found to be faulty, especially in the case of appreciably incorrect specific gravity should be rejected on site. For guidance on specific gravity tolerances reference should be made to the Notes Section in the Manual of Paints for Structural Steelwork. It should be ensured that the cause of any unsatisfactory application during the procedure trial is remedied before the start of the main painting.

4 After submission of the first A' samples of each type of paint, further A' samples should be submitted for testing as painting proceeds depending on the weight of structural steel in the Permanent Works.

The Contractor may deliver paint to the shops or site in containers up to 25 litres providing that the tops are of the completely removable clip-on type and that the contents are thoroughly stirred using a mechanical mixer when taking samples and prior to use. A' samples must be correctly labelled before despatching for testing.

5 Details of each set of samples despatched should be listed in Appendix 19/6, Form BE/P3 Paint Sample Despatch List. A copy of each form should be forwarded immediately to the National Roads Authority and a further copy to the Coatings Section, Materials Technology Department, Enterprise Ireland, Glasnevin, Dublin 9, which is the testing authority.

Single copies of completed Appendix 19/5, Form BE/P2 (New Works) Paint System Sheet should be sent to the National Roads Authority, and to the testing authority, at the same time that Appendix 19/6 is forwarded for the first A' samples or first 'B' samples (if A' samples are not required).

The testing authority will notify the results of tests on Form BE/P4 Paint Sample Analysis Report (Appendix 19/7).

6 It should be noted that at the height of the painting season, testing and assessment of the first A' samples may take up to ten weeks. Unless therefore special arrangements can be made with the testing authority, for priority in testing samples, the Contractor cannot be expected to start painting under ten weeks from the time of awarding the Contract.

Once the Contract has been awarded, the Contractor should order paint early enough to


enable the first A' samples to arrive at the testing authority at least ten weeks before painting is due to start, or sooner if possible, so that the results of the analysis can be assessed in time. Also, throughout the work, the remaining paint should be ordered sufficiently in advance to allow time for testing subsequent A' samples.

About 2 weeks is required for testing 'B' samples.

7 Painting may be permitted to be started before the results of testing A' samples have been received only if postponing the painting would mean an unacceptable delay in the work; however it should be made clear to the Contractor that such permission shall not relieve him of his obligations under the Contract. When a first A' sample is rejected, an A' sample of the replacement batch of paint should be submitted for testing as soon as possible. If painting is allowed to proceed with a replacement batch or a subsequent batch still under test, it should also be made clear to the Contractor, that such permission shall not relieve him of his obligations under the Contract.

'B ' Samples

8 Control or 'B' samples are to be taken from a painter's kettle or from the airless spray gun nozzle, in order to ensure that paint actually being applied will be tested. 'B' samples are a check on the applicator rather than on the paint manufacturer, the main fault being lack of proper mixing; samples should be taken as spot checks on the thoroughness of the Contractor, with a minimum of, say, one batch in three being sampled. *B' samples of mixed two pack materials can only be tested in situ and before any reaction has taken place.

Provis ion of 500 ml Tins, Pack ing and Transport o f ' A ' a n d 'B ' Samples

9 It should be ensured that the Contractor has provided an adequate number of tins, lids and lid clips at the start of the work, to enable samples to be taken.

10 Unless tin lids are clipped down securely, and the tins properly packed, the contents may be spilled. Even if only one tin leaks, the spilled contents may obliterate markings on other tins, testing thus being delayed until new samples are checked and delivered.

11 The selected A' or 'B' samples should be labelled correctly as described in Appendix 19/6

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steels, e.g. steels with a tensile strength over 827 N/mm 2, possible defects caused by any hydrogen absorption or other adverse effects should be investigated.

and despatched promptly throughout the Contract. Not only should the Contractor despatch samples promptly, but his transport arrangements should be such that the samples reach the testing laboratory without delay, particularly in the case of the first A' or 'B' samples.

NG 1911 Metal Coatings

1 Adequate control of the pickling process is important otherwise the properties of higher grade steels can be affected. However the requirements in Clause 1911 are precautionary and should prevent difficulties.

Passivation by chromating of galvanized surfaces should not be permitted if painting is intended, as this treatment, on lighting columns for instance, may prevent the action of T W a s h .

2 Effective protection is unlikely in areas where the thickness of a sprayed metal coating is less than 100 microns. The terms nominal or average are not used in the Specification. Although zinc metal spray is referred to in sub-Clause 1911.2. experience has shown that it is not suitable for overall application to highway structures such as bridges, gantries, lighting columns or parapets. Zinc metal spray will, however, have an application for other components, e.g. temporary structures in a mild environment.

It is now known that many failures of metal spray coatings have been due to unsatisfactory surface preparation leading to poor adhesion. Application in two layers and poor application technique have also caused problems. Particular close inspection at all stages is essential. The standard of blast cleaning must be clean steel, 1st Quality, medium profile using chilled cast iron grit or aluminium oxide grit.

3 Sherardized coatings offer temporary protection only, if fasteners cannot be free from detrimental contamination by dry methods, e.g. by dry cleaning or dry blast cleaning, they should be replaced.

4 The advice on sherardized coatings applies to zinc electroplated coatings.

5 The hot dip galvanizing of steelwork should only proceed when the procedure to be adopted by the Contractor will produce satisfactory workmanship complying with the Specification. In the case where acid pickling or fluxing is required prior to metal coating of higher grade HSFG bolts or components of higher grade

NG 1912 Testing of Metal Spray Coatings

1 It is to be expected that contractors undertaking metal spraying have the necessary expertise, particularly in respect to understanding the importance of a clean sharp blast cleaning profile and of being able to check adhesion with modern equipment. Nevertheless it should be ensured that all the requirements are being met. otherwise experience has shown that early and very expensive failures can occur. Adhesion tests should be made in accordance with recommendations of the manufacturer of the testing equipment, for example the pull-off force must be normal to the surface. Usual reasons for lack of adhesion are bad application techniques or blast cleaned surfaces which have been exposed, even for a short time, in a damp environment and have lost their initial bright finish. When the overall adhesion is suspect, all the metal spray must be blast cleaned off the area in question as obviously any residual metal spray may also be defective. In the excepted areas, adhesion cannot be checked by the test panel method; the only practical method being the grid test described in ISO 2063, Annex A, carried out as the work proceeds.

NG 1913 Storage Requirements and Keeping Periods for Paint

1 It should be ensured that a suitable store has been provided and that paini is unloaded directly into it. The store temperature should be controlled within the limits specified. Extremes of temperature, freezing conditions in particular, can affect the properties of the paint. The paint store should be as near as practicable to the painting areas. If the paint store is at a considerable distance from the work area, paint is unlikely to be returned to the store at the end of the working day, or several tins may well be kept out on site to be ready for use and thus may be damaged by extremes of temperature; also if the inspector has to waste time in journeying to and from the paint store to check deliveries and select samples, his supervision of the work will be less effective.

2 The date of manufacture in particular must be marked on the tins, see sub-Clause 1909.3. If

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Volume 2 Notes for~ Guidance on the Specification for Road Works


the date of manufacture is not indicated the paint should always be rejected.

The requirement that paint in use should be returned to store and kept in sealed containers should be enforced for both brushing and airless spray grades. Paints with fast evaporating solvents will be adversely affected if the containers are left open in hot weather.

Only the types of paint referred to in sub-Clause 1913.4 should be considered for extended keeping times. The performance of other paints can be permanently affected if their keeping times are exceeded. The paint manufacturer's checks will include the following:

Property

Condition in tin

Viscosity Drying time Fineness of grind

Colour

Likely fault

Settlement, skinning, separation Tendency to body Absorption of dryers Pigment agglomeration, resin "seeding" Flocculation, agglomeration of colour pigments

Lastly, the paint manufacturer will verify that the specific gravity of paint about to be returned after any necessary reconstitution is correct.

Paints which have exceeded the keeping period before delivery, or during storage before or after testing under Clause 1910, should not be used. These paints should not be tested or retested until the requirements of sub-Clauses 1913.4 and 5 have been complied with.

NG 1914 Application of Paint

1 Up to an additional 5% solvent may be required when painting is carried out at extremes of temperature or to correct a minor deviation from the normal viscosity.

2 It should not only be checked that surface preparation has been carried out in accordance with the Specification but also that the standard has been maintained up to the time of application.

3 Paints and other protective coatings in the Manual of Paints for Structural Steelwork are generally applied either by brush or airless spray or by both. However, for paints with lower viscosities, e.g. etch primer, good use can be

made of air pressure spray equipment to avoid over application, flooding and overspray of paint.

Work should not be allowed to proceed outside the limits specified in Clause 1914. Records should be kept as these will be required should any premature failure occur.

Difficulties may arise on site in deciding when a surface is dry enough to paint. Most types of paint are intolerant of moisture at the time of application and during the curing period. At present, there is no method for checking the amount of moisture deposited on a surface, or advice on how much moisture types of paints will tolerate. Generally, the rule should be, if moisture is present or may be expected to be present at the time of application or during the curing period, then painting should not go ahead.

In winter or when weather conditions are unfavourable, it should be ensured that workshops, in which structural steelwork is to be painted, are properly enclosed.

A check on the amount of paint used after allowing for waste is a useful verification of film thickness. Notes on theoretical and actual quantities and cost comparison, also on attaining the required thickness of paint systems are available in the Manual of Paints for Structural Steelwork.

A record of wet film thickness checks should be kept. This is particularly important in the case of site painting; non-destructive checks of total mdft are unlikely to be conclusive although they are useful as a guide. If there is any doubt about the mdft of the shop or complete system it is possible to cut out 10 mm x 10 mm samples and have these checked. The usual practice however is to make a 90° 'V cut into the system and to check the thickness of each coat with a small viewing microscope fitted with a graticule. A proprietary instrument of this type is available. Equipment necessary to carry out these checks should be kept on site. Reference should be made to the Notes Section of the Manual of Paints for Structural Steelwork for further information on paint coating thicknesses.

Defects are, as often as not, due to inadequate surface preparation rather than application of faulty paints. Compliance with the Specification, especially the requirement for satisfactory adhesion, should be checked from the time work starts and not left until the steelwork is about to be despatched from the shops or until the Contractor has dismantled

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his scaffolding and is about to leave the site. Remedying faults in a difficult access situation, such as over a motorway, is usually time consuming and expensive. See NG 1901.91 v) regarding matching of MIO finishes.

Stripe Coats

9 Paint has a tendency to pull away from corners and even if the specified minimum total dft can be attained by careful application, it is unlikely to be maintained and stripe coating is always necessary. Excepting for alternative basic system Types 4, 8 and 10 and basic system Type 11 (see NG 1901.10) for which only one stripe coat in Item 112 paint is to be applied over Item 111 in the works, all other basic systems are to include two stripe coats. The first stripe coat is applied at the works to reinforce the shop system and the second on site to reinforce the site coats. When the whole system is applied at the works or on site, e.g. at connections, two stripe coats will still be required. It should be ensured that the first stripe coat on 'T Washed fasteners is brush applied carefully, any final traces of grease should be removed beforehand using a solvent, and not by wet cleaning down. On small square bars a single extra undercoat, applied in the shop or on site, replaces both the stripe coats.

Except for the above, application of stripe coats by airless spray is acceptable, and in most cases gives better and more uniform results. However in areas where space is restricted or when the system itself is brush applied, the Contractor will usually opt for brush application of stripe coats. 'Brushing out' of stripe coats should be avoided otherwise little paint will remain on the corners.

Exposure Times for Prepared Steel Surfaces and for Metal Coatings. Exposure Times and Treatment of'T' Wash and Overcoating Times for Paints

10 The times quoted in sub-Clauses 1914.15 to 20 and 23 to 27 are basic requirements when painting is carried out in average conditions in the shops or on site. However longer or shorter exposure times may be permissible depending on conditions. For example in an environment where the relative humidity is low, clean steel which has been dry blast cleaned in the shops or on site, can be left for longer than 4 hours provided that there will be no adverse effect.

Exposure times on site for sealed metal spray coatings may also be extended in good conditions. Components will be considered as not having been exposed, as described in sub-


Clause 1914.20, if they are fully protected during the short time which may be required for transport from shop to shop.

Transport should not be allowed during unfavourable weather, e.g. heavy rain, and should be restricted to a mile or so at the most.

11 Because of the variations in the surface condition of galvanizing and the lack of uniformity following the application and drying of T Wash with the exception of assembled T Washed fasteners, it has been found expedient to wash all T Wash treated surfaces before painting.

12 In a mild environment the time after delivery to site for the application of T Wash may be increased to allow painting to suit weather conditions or the work programme. In all cases the requirements of sub-Clause 1902.7 for removing dust and debris should not be overlooked.

NG 1915 Procedure Trials

1 The procedure trials are to ensure that the Contractor has the necessary knowledge and expertise, and that with the supervision, labour and equipment proposed to be used, the Contractor is capable of carrying out the work in accordance with the Specification.

2 The National Roads Authority attach considerable importance to procedure trials and permission to omit them should only be given in exceptional circumstances.

3 If changes in any paint formulation other than adding up to bl7e by volume of solvent appear to be necessary, the Contractor should arrange for the paint manufacturer to forward the revised formulation to the Coatings Section, Materials Technology Department, Enterprise Ireland, Glasnevin, Dublin 9 and verify that the revised formulation has been registered before agreeing to the changes.

4 The requirement for further trials may be relaxed providing the Contractor can furnish evidence to demonstrate that replacement labour has the necessary skill and experience and that new equipment is suitable.

NG 1916 Storage and Transport of Steel and Fabricated Steelwork

1 It should be ensured that steel earmarked for the Works and held in stock for any length of time is adequately protected, e.g. stored under

March 2000 271


cover. However if it is decided provisionally to accept rusted and possibly pitted steel as structurally satisfactory, checks should be made on the depth of corrosion defects and freedom from contamination, after blast cleaning. Dry blast cleaning may have to be repeated or air/water/abrasive blast cleaning employed in order to achieve the required standard of cleanliness.

2 Although relatively fast drying paints which keep down handling times for steelwork painted in the shops have been listed in the Basic Systems in NG 1901, overlapping of coats and cold weather may result in areas where the shop system takes longer to dry, thus delaying the handling and loading.

3 If at any time the Contractor has not complied with the requirements of sub-Clause 1916.3, the badly stored steelwork should be re-stacked immediately.

It is important, for example, that water is not allowed to pond inside box girders awaiting erection because restoring the specified standard of surface preparation by blast cleaning inside box girders after erection will be difficult to achieve.

4 Tf light steelwork is stored in the erection area it will be liable to damage during the handling of heavier components or from site traffic; it should therefore be stored out of the way until required.

5 Bridge parapets especially, and lighting columns tend to be laid out in position along the roadside for considerable periods where they are liable to site traffic damage and contamination. Therefore the requirements of sub-Clause 1916.5 must be complied with.

6 Damage to protective coatings can be avoided or kept to a minimum by careful slinging, stacking and general handling of steelwork. If preventable and excessive damage has been caused the Contractor should restore the coatings before undertaking further work. Such damage to protective coatings on lighting columns, for example, should be restored before erection.

NG 1917 Surfaces in Contact with Concrete

1 Steel surfaces in contact with concrete will usually be adequately protected from corrosion and therefore overall protective paint or other coatings are not normally required.


In areas where a steel/concrete bond is not required the adjacent primer and first undercoat, or the primer only if applied at a mdft of 40 microns, may be specified for the contact area to reduce rust staining before and during the erection stage. Uncoated aluminium metal spray is particularly reactive to wet concrete and, even when sealed, should not extend into the concrete/steelwork contact area when not protected by paint. Item 109 or 110, Zinc Phosphate Epoxy (2 pack) sealer applied at 25 microns mdft should cover the peaks of the aluminium metal spray and provide a barrier coat between the metal spray and concrete contact surfaces.

2 In areas such as the underside of galvanized base plates or in concrete/galvanised steel contact areas in composite construction, it is generally accepted that galvanizing does not react harmfully with concrete, and as selective galvanizing is impractical, the concrete may come into contact with galvanized surfaces. The 25 mm return for paint coats is still required.

Concrete or grout spatter or runs must however be cleaned off, see sub-Clause 1902.9. In higher risk areas, particularly in the presence of high humidity, the use of a protective membrane or sheathing should be considered.

NG 1918 Form BE/P2 (New Works) Paint System Sheet (Appendix 19/5)

Form BE/P5 Paint Data Sheet (Append ix 19/8)

1 Normally, a copy or copies of Appendix 19/5, Form BE/P2 (New Works) Paint System Sheet will be provided in the tender documentation, of which parts 1, 2, 3 and 4 (which are common to the various protective systems in the Contract) will have been completed. It should be ensured that in part 1 of Appendix 19/5 the National Grid reference required for the National Roads Authority's records has been included.

Grid references are not required for parapets only, or for lighting columns (other than high masts).

2 As soon as the Contract has been awarded the Contractor is required to prepare a copy or copies of Appendix 19/5 of which he will have completed parts 5 to 9 for each of the systems specified in Appendices 19/1 to 19/4. At the same time, the Contractor is required to provide relevant copies of Appendix 19/8, Form BE/P5 Paint Data Sheet, containing data which is required for checking paints before and after

March 2000 272


application. Full application instructions are also given. The information provided in Appendix 19/8 is the responsibility of the Contractor.

Approved copies of Appendix 19/5 should be forwarded to the testing laboratory, together with the first Appendix 19/6, Form BE/P3 Paint Sample Despatch List. See NG 1910 for details of checks on samples and despatch requirements, also the instructions to the inspector in Appendix 19/6.

NG 1919 Access and Lighting

1 For surface preparation and coating application to be carried out satisfactorily, it is important that the working area and access should permit, wherever possible, unrestricted access to the workface by the operators. For example, if the blast cleaning nozzle or the airless spray gun cannot be held at the correct angle or be moved freely, then good uniform work will be difficult to attain. It is equally important that the supervisory staff and inspectors should feel secure when carrying out checks.

2 If lighting is inadequate, workmanship will also be adversely affected and thorough inspection difficult. It should therefore be ensured that natural lighting is supplemented by temporary lighting as necessary to maintain an intensity of illumination at the workface of at least the specified 500 lux during work and inspection. Spot lighting of small areas is not acceptable and hence the requirement that the lighting should cover at least 1.0 m'.

NG 1920 Additional Requirements for the Protection of Steel in Bridge Bearings

Applicable Clauses

1 The testing of A' samples will seldom apply but 'B' samples should be taken and checked immediately in the shops for compliance. Also, as the procedure trials are unlikely to be necessary, it should be checked that the correct abrasive is being used and that the standard of blast cleaning and application of metal spray comply with the Specification.

It should be ensured that the Contractor complies with the requirements of Clause 1918 regarding the provision of Appendices 19/5 and 19/8.


Supply of Coatings

2 In order to minimise costs the bearing manufacturer may stock two-pack epoxy coatings supplied by a single manufacturer of his choice.

It should be checked that the 'T' Wash and other coatings are supplied by the paint manufacturer listed in the approved Appendix 19/5.

NG 1921 Additional Requirements for the Protection of Steel Lighting Columns and Bracket Arms

Applicable Clauses

1 The testing of A' samples is not required for lighting columns but 'B' samples should be taken and checked immediately for compliance. Also, as the procedure trials are unlikely to be necessary, it should be checked that the correct abrasive is being used and that the standard of blast cleaning and application of metal spray comply with the Specification. A separate Appendix 19/5 must be provided for each different system on each area of the columns in accordance with Clause 1918. For example, in the case of a Type A2b (Alternative) basic protective system for planted columns, the Contractor will need to complete three Appendices 19/5, one for the treatment of external upper surfaces, one for the treatment of external ground surfaces and one for the treatment of internal surfaces.

Surface Preparation

2 Because lighting columns are made of relatively thin steel the level of rusting of steel offered for the work should be limited as described in Clause 1921. Pitting inside columns, particularly those which have not been galvanized, will shorten the useful life of the column.

Stripe Coats

3 Lighting columns are manufactured on a production line, and to reduce the time required for painting only one stripe coat has been specified. When the last two coats are site coats, the stripe coat may also be applied on site.

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APPENDICES

Appendix 19/1 Protective requirements for bridges, parapets and other structures excluding bearings & lighting columns

Appendix 19/2 Protective requirements for bearings

Appendix 19/3 Protective requirements for lighting columns and bracket arms

Appendix 19/4 Protective requirements for other work

Appendix 19/5 Form BE/P2 (New Works) Paint System Sheet

Appendix 19/6 Form BE/P3 Paint Sample Despatch List

Appendix 19/7 Form BE/P4 Paint Sample Analysis Report

Appendix 19/8 Form BE/P5 Paint Data Sheet

Appendix 19/9 General Requirements

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CLAUSES AND APPENDICES

Register paint formulations i.e. component specifications (UK Department of Transport Standard BA 27 Methodology)

Appendix Appendix Appendix Appendix

19/1

SURFACE PREPARATION


19/2 19/3 19/4

Clauses 1902-1908


19/2 19/3 19/4

Appendix 19/9

Clause 1909 Register Paints with

Registration Authority Form BE/P2

Appendix 19/5 Appendix 19/9

Provision of samples of the actual contract paint for testing and comparison with registered and approved formulations. Testing to UK Department of Transport Standard BD 35, by testing authority (Clause NG 1910).

Clause 1910 Provision of samples A' &

'B' from contract paint

METAL COATINGS Clauses 1911-1912

Appendix 19/9

Appendix 19/9

PAINT STORAGE REQUIREMENTS

Clause 1913

PROCEDURE TRIALS Clause 1915

STORAGE & TRANSPORT Clause 1916

CONTACT WITH CONCRETE Clause 1917

FORM BE/P2 & BE/P5

Clause 1918 ACCESS & LIGHTING

Clause 1919 BRIDGE BEARINGS

Clause 1920 STEEL LIGHTING COLUMNS

Clause 1921

Appendix 19/1 Appendix 19/2 Appendix 19/3 Appendix 19/4

APPLICATION OF PAINT


Clause 1914


Appendix 19/5

Appendix 19/1 Appendix 19/2 Appendix 19/3 Appendix 19/4 Appendix 19/9

Appendix 19/1 Appendix 19/2 Appendix 19/3 Appendix 19/4 Appendix 19/5 Appendix 19/8 Appendix 19/9

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N G S A M P L E A P P E N D I X 19/1: R E Q U I R E M E N T S F O R B R I D G E S , P A R A P E T S A N D O T H E R

H I G H W A Y S T R U C T U R E S E X C E P T B E A R I N G S A N D L I G H T I N G C O L U M N S

1 Environment: Inland.

2 Accessibility: Difficult Access.

3 Required durability:

No maintenance up to 12 years.

Minor maintenance from 12 years.

Major maintenance after 20 years.

4 Surface preparation and protective systems.

(i) Surface preparation. Bridge steelwork, fabrication stage.

Area A

Exterior main surfaces, including shop welds.


Standard: clean steel, 1st Quality, Medium profile.

Area B

Interior of box girder surfaces, except area C, but including shop welds.


Standard: clean steel, 2nd Quality, Medium profile.

Area C

Contact surfaces of parent material at HSFG bolted joints.

Method: As Area A.


Area D

HSFG bolted joints.

Contact and outer surfaces of joint material.

Method: As Area A.


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H I G H W A Y S T R U C T U R E S E X C E P T B E A R I N G S A N D L I G H T I N G C O L U M N S (continued)

(ii) Surface preparation. Bridge steelwork, erection stage.

Area E

Exterior surfaces of site welds and weld affected areas.

Method: Remove slag, wire brush, wet clean and blast clean as Area A.


Area F

Interior surfaces of site welds and weld affected areas.

Method: Remove slag, wire brush and wet clean.

Standard: Bare steel.

(iii) Surface preparation. Parapets.

Area G

All surfaces, subject to accessibility.

Method: Pickling for galvanizing.

Standard: In accordance with Clause 1911.

(iv) Protective systems.

Area A


Shop. 1st Coat: Item 159, Aluminium Epoxy Sealer (2 pack), B or AS.

Application rate: 12 - 20 m'Vlitre.

Shop. 2nd Coat: Item 172, Zinc Phosphate AR Undercoat.

Shop. 3rd Coat: Item 174, MIO AR Undercoat.

Site. 4th Coat: Item 174, MIO AR Undercoat.

5th Coat: Item 176, AR Finish, mdft 50 microns.

Colour of Finish: green-yellow 12 B 21 BS 4800.


Area B

Shop. 1st Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Blast Primer (2 pack), mdft 100

microns.

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N G S A M P L E A P P E N D I X 19/1: R E Q U I R E M E N T S F O R BRIDGES, P A R A P E T S A N D O T H E R H I G H W A Y S T R U C T U R E S E X C E P T B E A R I N G S A N D LIGHTING C O L U M N S (continued)

Shop or Site. 2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Finish (2 pack)


Area C


Area D

Contact surfaces. Metal coating: Aluminium metal spray.

Outer surfaces. As Area A.

Area E

As Area A.

Area F

1st Coat: Phosphating solution.

2nd and 3rd Coats: As Area B, 1st and 2nd coats.

Area G



2nd Coat: Item 172, Zinc Phosphate AR Undercoat.

3rd Coat: Iteml74, MIO AR Undercoat.

4th Coat: Item 174, MIO AR Undercoat.




Alternat ive protect ive systems

The Contractor may offer the following alternative protective system:

Area A


Shop. 1st Coat: Item 159, Aluminium Epoxy Sealer (2 pack), B or AS. 12 - 20 mVlitre.

Shop. 2nd Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Undercoat (2 pack)

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Volume 2 Notes for Guidance on the Specification for Road Works Protection of Steelwork Against Corrosion

Series NG 1900


HIGHWAY S T R U C T U R E S E X C E P T B E A R I N G S A N D L I G H T I N G C O L U M N S (continued)

Shop. 3rd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack).

Site. 4th Coat: Item 168, Polyurethane (2 pack) Finish, mdft 50 microns,

Site. 4th Coat: Item 164, Moisture Cured Polyurethane Finish, mdft 40 microns.

Colour of Finish: green - yellow 12 B 21 BS 4800.


Area B

Shop. 1st Coat: Item 111, Zinc Phosphate High Build Quick Drying Epoxy Blast Primer (2 pack), mdft 100 microns.

Shop or Site. 2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Finish (2 pack), medium grey.


Area C


Area D

Contact surfaces. Metal coating: Aluminium metal spray.

Outer surfaces. As Area A.

Area E

As Area A.

Area F

1st Coat: Phosphating solution.

2nd and 3rd Coats: As Area B 1st and 2nd coats.

Area G



2nd Coat: Item 172, Zinc Phospahte AR Undercoat.

3rd Coat: Item 174, MIO AR Undercoat.

4th Coat: Item 174, MIO AR Undercoat


Colour of Finish: green - yellow 12 B 21 BS 4800.


or

March 2000 279




H I G H W A Y S T R U C T U R E S E X C E P T B E A R I N G S A N D L I G H T I N G C O L U M N S (continued)

(v) Application Instructions.

(a) All surfaces to receive protective coatings.

The method of application indicated by the Item No. and / or the number of paint coats may be changed by the Contractor, the new Item Nos. and/or additional paint coats being entered in Appendix 19/5 by the Contractor's paint supplier.

(b) Parapets.

The 'T' Wash and coats of paint may be applied in the shops or on site at the Contractor's option.

(c) Areas A, C, D and E.

Aluminium Epoxy Sealer (2 pack), Item 159, should not be over-applied and should not be

included in the overall thickness of the protective paint system.

(vi) Fasteners.

Unless otherwise specified on the Drawings, bolts nuts and washers in bridge steelwork shall be supplied zinc electroplated or hot dip galvanized. After the joint is made, they shall be prepared and protected as for the joint material.

5 Paint suppliers.

Paints for any one system shall be obtained from the same manufacturer.

[Notes to compiler:

(i) The above is a sample Appendix 19/1 for the protection against corrosion for bridge steelwork and parapets. Further sheets of Appendix 1911 may be included, e.g. for structures where the areas listed above may not be appropriate. In some cases it may be necessary to provide one Appendix 19/1 slieet for each structure. Sheets should be numbered for easy identification.

(ii) The surface preparation and protection for joint material and at welds should also be specified in Appendix 19/1, as should any metal coating on fasteners unless defined clearly on the Drawings. See NG 1904 and Clause 1904.

(iii) The Appendices for steel bridge bearings should follow if required, see NG 1901.11. It would not be necessary to repeat the descriptions for Environment or Accessibility if already given for the Bridgework Appendices. The Appendices for Lighting Columns should also be included if appropriate. Because rooted and flange mounted columns are dealt with simultaneously, the standard method of specifying Area A, Area B, etc has not been used.

(iv) Paint coats may be applied by brush or airless spray. Application by brush is denoted by the letter B, application by airless spray is denoted by the letters AS, following the paint description. Acrylated Rubber (AR) paints are particularly amenable to brush application and may be brushed or airless sprayed. To facilitate compiling the 1900 Series Appendices both AS and B quality Item Nos are given in the AR Basic Systems. The two-pack Epoxy paints in the alternative basic system for the main steelwork and the two-pack Epoxy paints listed in the Basic Systems for bearings may be applied either by brush or air-less spray and hence there is only one Item Number for each paint of this type.

(v) When a white or pale tint Moisture Cured Polyurethane Finish or Polyurethane Finish (2 pack) is to be specified, an additional coat of Item 164 or 168 may be required to ensure complete obliteration of the MIO Epoxy Undercoat.

Before specifying white or pale tint finishes, any requirement for an additional coat of paint should be checked with the paint suppliers listed in section 7 of the relevant Appendix.]

March 2000 280



N G S A M P L E A P P E N D I X 19/2: R E Q U I R E M E N T S F O R B E A R I N G S

(Basic system with site finish coats to match main steelwork paint system.)

1 Environment: All Environments.






4 Surface preparation and protective systems,

(i) Surface preparation.

Area A

Exterior surfaces, excepting wearing surfaces but including a 25 mm return on surfaces of top bearing plates and base plates in contact with grout or mortar.


Standard: clean steel, 1st Quality, Medium profile.

Area B

Central area of base plate in contact with grout or mortar.


Standard: clean steel, 2nd Quality, Medium profile.

Area C

Central area of top bearing plate in contact with structural steel components.

Method: As Area A.


Area D

Exposed shop fasteners in components to be coated after assembly.

Method: As Area A.


Area E

Concealed shop fasteners.

Method: No requirement.

March 2000 281



N G S A M P L E A P P E N D I X 19/2: R E Q U I R E M E N T S F O R B E A R I N G S (continued)

Standard: No requirement.

Site fasteners for fixing bearings to piers or abutments and for fixing bridge components to bearings.

Restore metal coating as necessary to specified standard of cleanliness.

(ii) Protective systems.

Area A

Aluminium metal spray minimum thickness 150 microns.

1st Coat: Item 159, Aluminium Epoxy Sealer (2 pack), B or AS. Application rate: 12 - 20 mVlitre

2nd Coat: Item 118, MIO Epoxy Primer (2 pack), B or AS. mdft 50 microns.

3rd Coat: Item 120, MIO Epoxy Undercoat/Finish (2 pack), B or AS. mdft 50 microns.

Minimum combined dft for 2nd and 3rd coats 115 microns.

Additional site coats on exposed surfaces of Area A.

4th Coat: Item 168, Polyurethane Finish (2 pack) mdft. 50 microns

4th Coat: Item 164, Moisture Cured Polyurethane Finish, mdft 40 microns.


Minimum total dft for paint system 175 microns.

Aluminium metal spray plus Item 159, Aluminium Epoxy Sealer (2 pack) only, are required on interfaces of machined surfaces of spreader plates and of bearing.

Area B

Item 118, MIO Epoxy Primer (2 pack), B or AS. mdft 50 microns.

Area C

Aluminium metal spray minimum thickness 150 microns. Item 159, Aluminium Epoxy Sealer (2 pack), B or AS. Application rate: 12 - 20 mVlitre.

Area D

As Area A.

Area E

Fasteners unprotected by grease shall be zinc electroplated.

Area F

or

March 2000 282



N G S A M P L E A P P E N D I X 19/2: R E Q U I R E M E N T S F O R B E A R I N G S (continued)

Area F

Metal coating: Zinc electroplating or galvanizing.


2nd Coat: Item 118, MIO Epoxy Primer (2 pack), B or AS. mdft 50 microns.

3rd Coat: Item 120, MIO Epoxy Undercoat/Finish (2 pack), B or AS. mdft 50 microns.

4th Coat: Item 168, Polyurethane Finish (2 pack), mdft 50 microns

4th Coat: Iteml64, Moisture Cured Polyurethane Finish, mdft 40 microns.


Minimum total dft 175 microns.


(a) Areas A, B, C and D.

Aluminium metal spray, Items 159, 118 and 120 shall be applied at the bearing manufacturers works. Item 164 or 168 shall be applied on site.

Aluminium Epoxy Sealer (2 pack) should not be over-applied and should not be included in the overall thickness of the protective paint system.

(b) AreaF

Item 155, 'T' Wash shall be applied on site, either before or after erection, to surfaces to be

painted.

T' Wash coming into contact with adjacent paint coats shall be removed immediately.

The remaining site coats shall be applied to exposed surfaces after erection.

(c) Stripe coats for bearings only: (stripe coats are not required for bearing site fasteners).

A single stripe coat in Item 120 paint shall be applied over the MIO Epoxy Primer (2 pack) at the bearing manufacturer's works. A second stripe coat is not required.

(d) MIO Epoxy (2 pack) coats shall be in contrasting shades, e.g. medium grey, dark grey.

(e) Site coats shall be applied by the Contractor.

5 Paint suppliers.

[The requirements of Clause 1920 should be noted.]

[Note to compiler:

See Note (iv) and (v) in NG Sample Appendix 19/1.]

or

March 2000 283



N G S A M P L E A P P E N D I X 19/3: R E Q U I R E M E N T S F O R L I G H T I N G C O L U M N S A N D B R A C K E T A R M S

(Type A2a and G2a basic systems.)







4 'Ground level' shall be taken as being 600 mm below the door opening /Note to compiler: Amend this definition where appropriate].

5 Type of columns: Planted columns.

6 Surface preparation and protective systems (Type A2a basic system),

(i) External surfaces.

(a) Overall treatment.




Item 159, Aluminium Epoxy Sealer (2 pack), B or AS, Application rate: 12 - 20 mVlitre.


2nd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack), AS. mdft 100

microns.

(b) Upper section, additional coat.

Item 164, Moisture Cured Polyurethane Finish, AS. mdft 50 microns or

Item 168, Polyurethane (2 pack) Finish, AS. mdft 50 microns.

Colour of finish: Medium grey, 00.A.09.


(c) Ground section, additional coat.

Item 150. Pitch Epoxy (2 pack), AS. mdft 100 microns.

March 2000 284



N G S A M P L E A P P E N D I X 19/3: R E Q U I R E M E N T S F O R L I G H T I N G C O L U M N S A N D

B R A C K E T A R M S (continued)



Ground section to door area.







(a) Blast cleaning, aluminium metal spray and all shop paint coats on external surfaces and site paint coats where access permits, shall be returned on to edges at ends, at door and other openings.

(b) All paint coats except Item 164 or 168 shall be applied in the shops.

(c) Item 159 shall be overcoated within 96 hours.

(d) On external surfaces, Item 150 shall be applied from the bottom to 250 mm above ground level.

(e) Item 164 or 168 shall be applied on site and shall be taken down to 225 mm above ground level,

overlapping Item 150 by 25 mm.

(f) On internal surfaces, Item 110 and 150 shall be applied from the bottom to 300 mm above the door opening.

(g) Brushing grade paints may be used at the option of the Contractor.

(h) Aluminium Epoxy Sealer, Item 159, should not be over-applied and should not be included in the overall thickness of the protective paint system.

7 Paint suppliers.


8 Alternative protective system (Type G2a basic system).

The Contractor may offer the following:

Surface preparation and protective system.

(i) External and internal surfaces, overall treatment.

Galvanize.


(a) Additional overall coats.


2nd Coat: Item 110, Zinc Phosphate Epoxy Primer (2 pack), AS. mdft 30 microns.

3rd Coat: Item 112, MIO High Build Quick Drying Epoxy Undercoat (2 pack), AS. mdft 100 microns.

March 2000 285



N G S A M P L E A P P E N D I X 19/3: R E Q U I R E M E N T S F O R L I G H T I N G C O L U M N S A N D

B R A C K E T A R M S (continued)

(b) Upper section, additional coat.

Item 164, Moisture Cured Polyurethane Finish, AS. mdft 50 microns or

Item 168, Polyurethane Finish (2 pack), AS. mdft 50 microns.

Colour of finish: Medium grey, OO.A.09.

Minimum total dry film thickness, including Primer 200 microns.

(c) Ground section, additional coat.

Item 150, Pitch Epoxy (2 pack), AS. mdft 100 microns.

Minimum total dry film thickness, including Primer, 275 microns.


(a) T Wash, all shop paint coats on external surfaces and site paint coats where access permits,

shall be returned on edges and 25 mm inside at ends, at door and other openings.

(b) All paint coats except Item 164 or 168 shall be applied in the shops.


(d) Item 150 shall be applied from the bottom to 250 mm above ground.

(e) Item 164 or 168 shall be applied on site and shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

(f) Brushing grade paints may be used at the option of the Contractor.

(g) Sub-Clause 1914.21 need not be applied to lighting columns which remain in a shop environment after galvanizing.

9 Paint suppliers.


March 2000 286



N G S A M P L E A P P E N D I X 19/3 (ALTERNATPvTE): R E Q U I R E M E N T S F O R L I G H T I N G

C O L U M N S A N D B R A C K E T A R M S

(Type A2b and G2b alternative basic systems.)


3 Required Durability:




4 'Ground level' shall be taken as being 600 mm below the door opening I Note to compiler: Amend this definition where appropriate].

5 'fype of columns: Planted columns.

Columns shall have an additional sacrificial steel section thickness of a minimum 1.0 mm, above that needed in the design, from the bottom of the column to at least 250 mm above ground level.

6 Surface preparation and protective systems (Type A2b (Alternative) basic system),

(i) External surfaces.

(a) Overall treatment.




Item 159, Aluminium Epoxy Sealer (2 pack). B or AS Application rate: 1 2 - 2 0 mVlitre.

(b) Upper section, additional coats.

1st Coat: Item 130, Vinyl/Vinyl Copolymer Primer, AS. mdft 60 microns.

2nd Coat: Item 131, Vinyl/Vinyl Copolymer Finish, AS. mdft 60 microns.



(c) Ground section, additional coats.





March 2000 287



N G S A M P L E A P P E N D I X 19/3 (ALTERNATIVE) : R E Q U I R E M E N T S F O R L I G H T I N G

C O L U M N S A N D B R A C K E T A R M S (continued)

(ii) Internal surfaee.

Ground section to door area.







(a) Blast cleaning, aluminium metal spray and all shop paint coats on external surfaces and site paint coats where access permits, shall be returned on to edges and 25 mm inside at ends, at door and other openings.

(b) All paint coats except Item 131 shall be applied in the shops.


(d) On external surfaces, Item 150 shall be applied from the bottom to 250 mm above ground level.

(e) On internal surfaces, Items 110 and 150 shall be applied from the bottom to 300 mm above the door opening.

(0 On external upper section, Items 130 and 131 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

(g) Aluminium Epoxy Sealer, Item 159, should not be included in the overall thickness of the protective paint system.

(h) Item 131 may be applied in the shops or on site, to overlap Item 150 by 25 mm and shall be the last applied coat.

(i) Brushing grades may be used at the option of the Contractor.

7 Paint suppliers.


8 Alternative protective system (Type G2b (Alternative) basic system).

The Contractor may offer the following:

Surface preparation and protective system.


Galvanize.




March 2000 288

Volume 2 Notes for Guidance on the Specification for Road Works Protection of Steelwork Against Corrosion

Series NG 1900

N G S A M P L E A P P E N D I X 19/3 (ALTERNATP/E) : R E Q U I R E M E N T S F O R L I G H T I N G

C O L U M N S A N D B R A C K E T A R M S (continued)



(b) Upper section only, additional coats.





(c) Ground section, additional coats.





(a) The requirements of sub-Clause 1914.21 need not apply for lighting columns which remain in a shop environment after galvanizing.

(b) T' Wash, all shop paint coats on external surfaces and site paint coats where access permits, shall be returned on to edges and 25 mm inside at ends, at door and other openings.

(c) On external upper section, Items 130 and 131 shall be applied down to 225 mm above ground level, overlapping Item 150 by 25 mm.

(d) All paint coats except Item 131 shall be applied in the shops. Item 131 may be applied in the shops or on site, to overlap Item 150 by 25 mm and shall be the last applied coat.

(e) Items 110 and 150 shall be applied from the bottom to 250 mm above ground level.

(f) Brushing grades may be used at the option of the Contractor.

9 Paint suppliers.


March 2000 289



N G S A M P L E A P P E N D I X 19/3 (ALTERNATIVE) : G 2 b S Y S T E M F O R F L A N G E M O U N T E D

C O L U M N S W I T H A P L I N T H BUILT O V E R T H E F L A N G E

[Compiler to complete 1 to 5 as appropriate!

6 Surface preparation and protective system.


Galvanize.




(b) Upper section only, additional coats.





(c) Plinth area, additional coats.





(a) The requirements of sub-Clause 1914.21 need not apply for lighting columns which remain in a shop environment after galvanizing.

(b) T' Wash, all shop paint coats on external surfaces and site paint coats where access permits shall be returned on to edges and 25 mm inside at ends, at door openings and under base flange.

(c) All paint coats except Item 131 shall be applied in the shops. Item 131 may be applied in the shops or on site, to overlap Item 150 by 25 mm and shall be the last applied coat.

(d) Item 110 shall be overcoated within 96 hours.

(e) Item 150 shall be applied over Item 110 from the bottom to 150 mm above plinth level.

(f) Brushing grade paints may be used at the option of the Contractor.

7 Paint suppliers.


March 2000 290



N G S A M P L E A P P E N D I X 19/4: R E Q U I R E M E N T S F O R O T H E R W O R K

[Notes to compiler:

1 This Appendix should he in a similar format to Appendices 1911 to 19/3 as appropriate.

2 Refer to NG 1901.5(iii)(c).J

March 2000 291

A P P E N D I X 19/5 (SPECIFICATION FOR ROAD WORKS) FORM BE/P2 (NEW WORKS) PAINT SYSTEM SHEET Sheet No.

1. CONTRACT TITLE: STRUCT. No.: GRID REE: 2. DATE OF ISSUE OF DOCUMENTS TO TENDERERS:

* 3 "3> s i to

Q S i .

I I 5 I f i "Si 8 a-. a

B

a.

r

3. ENVIRONMENT AND ACCESSIBILITY:

5. PAINT SYSTEM TO BE APPLIED OVER:

4. REQUIRED DURABILITY OF SYSTEM NO MAINTENANCE: MINOR MAINTENANCE: MAJOR MAINTENANCE:

6. DETAILS 1st Coat 2nd Coat 3rd Coat 4th Coat 5th Coat 6th Coat

Registered Description

Item No. and Colour

Date Registered

Brand Name and Manufacturers Ref. No.

Date Sheet No.

Where applied

How applied

Min dry film thickness (mdft)

Max local dft (See CI. 1914.7)

5

I | a Co a- f«i

3 "1 r CO

7. STRIPE COAT DESCRIPTION (Including Item No. and colour)

Shop: Site:

8. PAINT MANUFACTURER'S OFFICIAL STAMP:

to x to

9. MINIMUM TOTAL DRY THICKNESS OF PAINT SYSTEM:.... microns (See Note) NOTE: The minimum total dry film thickness of the paint system, neglecting primers and sealers under 30 microns, shall be Wvi, greater (to the nearest 25 microns) than the sum of the mdfts of the individual paint coats.

10. APPROVED BY:

DATE



A P P E N D I X 19/6

(SPECIFICATION F O R ROAD WORKS) F O R M BE/P3 PAINT S A M P L E DESPATCH LIST: SHEET 1

Contract Title

Structure Name or No.

Supervising Engineer's Firm

Supervising Engineer's Name Tel No.

Address

Inspecting Firm

Paint Manufacturer

Inspector's Name:

Samples Despatched From:

Inspector's Signature

(Note 1) Date Despatched

SAMPLES: (Numbered A l , A2 etc. o r B l , B2 etc.) (Note 2 )

Sample

No. Item No. Manufacturer's Reference No. Batch No.

Sp. G. (Note 3 & 4)

March 2000 293




(SPECIFICATION F O R ROAD WORKS) F O R M BE/P3 PAINT S A M P L E DESPATCH LIST: SHEET 2

INSPECTOR to complete Form BE/P3 and to forward single copies to each of the following within 24 hours of despatch of samples by the Contractor to Enterprise Ireland:

INSPECTOR to forward Form(s) BE/P2 Paint System Sheet! s) with the first Form BE/P3 to both addresses. INSPECTOR to select A' samples and to ensure that manufacturers labels on tins comply with the Specification. INSPECTOR to take and mark each 'B' sample tin with Item No., manufacturer's name and brand reference No., batch No. and sample No. (NOTE 2).

CONTRACTOR to CLIP DOWN LIDS of all tins and to pack, address and despatch samples. In addition to address. CONTRACTOR to label each case (or tin sent loose): 'NRA (State structure name) and DATE (date of despatch as noted above)'.

Note 1. State whether from shop (give name and address) or site.

Note 2. Batch samples comprising unopened tins to be marked A l , A2, etc. Control samples in 0.5 litre tins to be marked B l , B2, etc. Samples No. to run consecutively, i.e. Al and Bl onwards.

Note 3. For 'A samples specific gravity (Sp.G.) to be measured by Inspector from separate tins of the same batch. For 'B' samples Sp.G. to be measured by Inspector when taking samples. Samples will be rejected unless Sp.G. is filled in above by Inspector.

Note 4. If Sp.G. differs appreciably from data sheet do not despatch A' or 'B' samples.

1. National Roads Authority, St. Martin's House, Waterloo Road, Dublin 4.

2. Coatings Section, Materials Technology Department, Enterprise Ireland, Glasnevin, Dublin 9.

March 2000 294




(SPECIFICATION FOR ROAD WORKS) FORM BE/P4 PAINT SAMPLE ANALYSIS REPORT

From: Coatings Section, Materials Technology Department, Enterprise Ireland, Glasnevin, Dublin 9.

Tb: (Name of Supervising Engineer for Project)

Address:

Telephone confirmation:

Contract Title

Bridge Name and/or No.

Samples Despatched from

Despatch Date on BE/P3

Samples and BE/P3 Received at Enterprise Ireland

Paint Manufacturer

Satisfactory Samples

Sample No. Reference No. Batch No.

Unsatisfactory Samples and Technical Comment

Sample No. Reference No. Batch No.

Signed: (Enterprise Ireland) Date:

March 2000 295




(SPECIFICATION FOR ROAD WORKS) FORM BE/P5 PAINT DATA SHEET

Sheet No.

Manufacturer :

Item No. :

Registered Description :

Brand Name and Reference No. :

Consistency and Method of Application :

Weight per 5 Litres (kg) :

Volume Solids % :

Manufacturer's Minimum Dry Film Thickness Range

Recommended lower mdft : Recommended upper mdft :

Full Application Instructions :

Flash Point :

5°C 10°C 20°C 30°C

Drying Times Surface dry Drying Times

Hard dry

Overcoating Times Minimum Overcoating Times

Maximum

Cleaning Solvent

Effect on Drying Times of Temperatures below 20°C

Manufacturer's Application Restrictions, e.g. for Temperatures or Humidity

Manufacturer's General Recommendations

March 2000 296



N G S A M P L E A P P E N D I X 19/9: G E N E R A L R E Q U I R E M E N T S

/Note to compiler: This should include:/

1 Whether solvents may be used to remove oil or grease /1902.1j.

2 Requirements for cleaning final shop coat if different from the requirements of sub-Clause 1902.10.

3 Requirements for:

(i) abrasive if different from the requirements of sub-Clause 1903.1;

(ii) wet blast cleaning if different from the requirements of sub-Clause 1903.12.

4 Requirements for treatment to threaded fasteners if different from the requirements of sub-Clause 1904.2.

5 Requirements for metal spray at joints if different from the requirements of sub-Clauses 1904.7 and

6 Requirements for stepping back shop paint coats if required at non-friction bolted joints [1904.16].

7 Requirements for surface preparation and material for 'restored' coatings if different from the requirements of sub-Clauses 1908.3 (i) and (ii).

8 Requirements for procurement of paints if different from the requirements of sub-Clause 1909.5.

9 Requirements for provision of samples if different from the requirements of sub-Clause 1910.1.

10 Requirements for galvanized coatings if different from the requirements of sub-Clause 1911.1.

11 Requirements for:

(i) sprayed metal coatings if different from the requirements of sub-Clause 1911.2;

(ii) sherardized coatings if different from the requirements of sub-Clause 1911.3;

(iii) electroplated coatings if different from the requirements of sub-Clause 1911.4.

12 Requirements for stripe coats if different from the requirements of sub-Clause 1914.13.

13 Requirements for shop and site procedure trials if different from the requirements of sub-Clause 1915.1.

14 Requirements at concrete/steelwork contact areas if different from the requirements of sub-Clauses 1917.1

15 Requirements for the protection of steel in bridge bearings if different from the requirements of Clause

16 Requirements for the protection of steel lighting columns and bracket arms if different from the requirements of Clause 1921.

17 Measures to contain plant, materials, dust and debris [1901.3].

[Cross-reference should be made in Appendix 1/23].

1904.8.

and 1917.3.

1920.

March 2000 297

Volume 2 Series NG 1900 Notes for Guidance on the Specification for Road Works Protection of Steelwork Against Corrosion

March 2000 298

Volume 2 Series NG 2000 Notes for Guidance on tlie Specification for Road Works Waterproofing for Concrete Structures

WATERPROOFING FOR CONCRETE STRUCTURES

Contents

Clause Title Page

N G 2 0 0 1 General 300

NG 2002 Protect ion of Br idge Deck Waterproofing Dur ing Construct ion 300

NG 2003 Materials for Waterproofing Concrete Bridge Decks 300

NG 2004 Materials for Waterproofing Below Ground Concrete Surfaces 301

NG 2005 Workmanship for Waterproofing Concrete Br idge Decks 301

NG Append ix 20/1 (Form P W S ) 303

NG Sample Append ix 20/2 305

March 2000 299


Series NG 2000 Waterproofing for Concrete Structures

Waterproofing for Concrete Structures

NG 2001 General

1 The most opportune periods for installing waterproofing systems are the spring, summer and autumn when climatic conditions are most favourable.

2 Specification requirements for unformed finishes to concrete bridge decks are given in sub-Clause 1708.4.

3 Specification requirements for restrictions on curing liquids, compounds and membranes are given in sub-Clause 1710.5.

4 The use of ventilating layers, partial bonding or bond breakers is not permitted in the Specification as they provide an easy passage for water to pass under the membrane. The pumping action produced by the passage of vehicle wheels exacerbates the problem and leads rapidly to the general failure of the adhesion and disruption of the surfacing.

5 Fillets are generally formed in sharp internal angles to ensure the fitting and shaping of prefabricated sheet and minimum thickness of sprayed membrane in the angle.

NG 2002 Protection of Bridge Deck Waterproofing During Construction

1 Before granting permission for rubber tyred plant and equipment to travel on bridge deck waterproofing, the Engineer should satisfy himself that the surface is and remains free of all loose materials and stable enough to withstand traction forces.

NG 2003 Materials for Waterproofing Concrete Bridge Decks

Proprietary Waterproofing Systems

1 As soon as possible after the Contract has been awarded, the Engineer should ensure that the Contractor provides the PWS (Proprietary Waterproofing System) Data Sheets.

2 Should the Engineer call for tests, it is important that uniform methods of testing be used. Details of the tests, test methods and criteria can be obtained from the LAB.

Outgassing

6 The design of many bridge decks includes voids, which contain air, and air may be held within the concrete itself. This contained air can move in and out of voids with temperature and barometric pressure changes and such air movement through pores in the bridge deck top surface can cause pinholes in primers and thence blister the membrane. It is less likely to affect sheet membranes, but can cause pinholes, blowholes or blisters in liquid applied membranes whilst in the partially cured condition.

7 The greatest risk of outgassing occurs following rainfall and during early summer mornings.

3 A bonding agent or liquid waterproofing membrane/adhesive has set or cured when it has become sufficiently stabilized to prevent movement of the waterproofing system during the laying of an additional protective layer or surfacing.

4 Unless otherwise described in the particular PWS Data Sheet, the primer should be thoroughly dry or cured before the membrane is applied. Where solvent based primers are used, any excess primer that has not been removed is likely to 'skin over' but give the appearance of being dry. The trapped solvent will expand rapidly under the application of hot bitumen and lead to failure of the membrane.

March 2000 300


NG 2004 Materials for Waterproofing Below Ground Concrete Surfaces

1 The Engineer should consider whether the upper surface of buried concrete structures such as subways should be waterproofed with a material complying with Clause 2003 or whether materials complying with Clause 2004 are suitable for the purpose.

2 Buried concrete structures which need to be waterproofed with a material complying with Clause 2003 should be identified on the Drawings.

3 The Engineer should specify in Appendix 20/2 any restrictions on the materials in Clause 2004 which may be used for any particular structure.

NG 2005 Workmanship for Waterproofing Concrete Bridge Decks

General

1 Prior to laying the waterproofing, the primed surface should be inspected and any entrapped aggregate or debris removed. Should the primed area be damaged it should be made good using the appropriate primer and allowing the necessary evaporation or cure time.

Blistering and Blowholes

2 Moisture in the concrete deck, incomplete coverage by primer, unevaporated solvents in primers and general outgassing can lead to blistering of prefabricated sheet waterproofing, together with blowholes in mastic asphalt and liquid applied membranes. The waterproofing system and the additional protective layer should be covered as quickly as possible with the road surfacing in order to minimize the risk of blistering which is usually more prevalent in the late spring and early summer, during clear sunny weather.

Application of Waterproofing Into Angles, Including Chases

Sheet Membranes

3 Efforts by the operative to seat the sheet into a sharp angle can result in weakening or hidden damage to the membrane. There is also a


tendency for the sheet to resist bending sharply into an angle and to draw away leaving a hollow which may give rise to blistering and puncturing when the surfacing is applied.

Spray Applied Membranes

4 With inadequate equipment or poor application technique there can be a tendency for sprayed coatings not to enter right into the angle but to build up thickness on the adjacent margins resulting in a thinning of the membrane in the angle. Spraying technique, material rheology and equipment can be selected to minimize these faults.

Vacuoles and pin/blow holes can also be caused by the above inadequacies.

Priming for Mastic Asphalt

5 When using mastic asphalt it is necessary that the concrete is first primed before the mastic asphalt is applied to the clean primed surface.

6 As a guide, for the evaporation of solvent from a spirit based primer, 20 hours should elapse when the temperature is between 10°C and 16°C before mastic asphalt is applied.

Mastic Asphalt

7 Satisfactory results for waterproofing have been obtained with mastic asphalt complying with BS 6925, types R988 and T1097. The former may prove slightly more economical and less susceptible to blistering. The latter is generally preferred for use in service bays as it is more likely to retain an adequate resistance to impact damage. It will usually be more economical to specify one type for the whole of the work. The type required should be shown on the Drawings and cross-referenced in Appendix 20/2.

8 Mastic asphalt complying with BS 1447 (Mastic asphalt for roads and footways) is unsuitable for waterproofing bridge decks.

9 The use of ventilating layers, isolating membranes and bond breakers to avoid blistering and blow holes is an established practice in roofing and building work but is not appropriate for bridge decks. Notwithstanding the Specification, asphalt paviors may on their own initiative wish to use some form of bond breaker, e.g. lightly dusting with sand, limestone dust or dry cement but this practice should not be permitted.

March 2000 301


10 Blistering of mastic asphalt can occur and blow holes commonly appear during laying. Both effects can usually be attributed to moisture, but can often be prevented by working to the lower limit of the temperature range.

11 Mastic asphalt is laid in 2 or 3 coats and in multi-coat work it is not permitted to leave any blow holes to be made good by the application of the next coat. The Specification expressly precludes this practice and all blow holes should be made good before laying a subsequent coat. The making good of blisters or 'blows' is covered in CP 144 : Part 4 : 1970.

12 An acceptable method of intimately bonding the two mating edges of a joint is to prepare a clean vertical edge to the material already laid and overlap it with a minimum of 50 mm with the new material. When the heat has penetrated the original material the overlap should be struck off and the fused joint completed with the edge of a float.

Proprietary Waterproofing Systems

13 The method of sealing the edges of the waterproofing system and around interruptions such as gullies should be shown on the Drawings. Most manufacturers of proprietary systems show examples in their marketing literature.

14 Before commencing each stage of installation the surface should be inspected, using the guide lines given in NG 2005.1, to check the complete evaporation of solvent, the removal of any entrapped aggregate or debris and that necessary repairs have been carried out.

15 Where oxidised bitumen is used as a bonding agent for sheet material it should not be heated to a temperature in excess of that necessary to secure an effective bond. The required temperature of the bitumen will depend on the air and deck temperature at the time of laying. It should not be heated above 260°C and it is normally suitable for application at a temperature of approximately 240°C. Overheating and prolonged heating of the bitumen compound will drive off volatile oils leaving the residue hard and brittle and unsuitable for bonding layers together. A suitable thermometer should be used to monitor the temperature of the bonding bitumen.

16 Proprietary waterproofing systems, including where necessary a tack coat and also the additional protective layer, should be covered without undue delay with road surfacing materials in order to minimise the risk of blistering. Should blistering occur, repairs


should be in accordance with the PWS Data Sheets and the manufacturer's installation procedure, to the satisfaction of the Engineer.

17 In considering the Contractor's additional information submitted with the PWS Data Sheet to cater for site conditions, the Engineer may need to call for a site procedure trial.

Additional Bituminous Protection

18 Where the waterproofing system is to be overlaid with hot rolled surfacing materials, additional protection consisting of red tinted bituminous protection complying with sub-Clause 2003.4 is required. When it is necessary for the additional protective layer to be trafficked by plant and equipment, e.g. where there is delay in surfacing, any damage is to be made good before surfacing is laid. The areas and thickness, normally 20 mm ± 2 mm, should be shown on the Drawings.

March 2000 302




(SPECIFICATION FOR ROAD WORKS) FORM PWS PROPRIETARY WATERPROOFING SYSTEM DATA SHEET

1. Manufacturer or Marketing Group

2. Product

co" Irish Agrement Board Roads and Bridges Certificate No. Date

4. Concrete Deck Surface Finish Class U4

5. Manufacturers maximum and minimum application temperatures at respective relative humidities.

6. Application Temp, of Bonding Agent To comply with Clause 2005

7. Life of Mixed Liquid Materials

8. Recommended Minimum Depth of Flexible Surfacing and Waterproofing 120 mm

9. Manufacturer's Recommended Minimum Depth of Flexible Surfacing and Waterproofing

10. Preparation and Installation See Annex A

11. Form PWS with Annex A cleared through IAB. Date

12. Description of Materials Thickness mm

Weight kg/m 2

Nominal width

Nominal length

March 2000 303

Volume 2 Notes for Guidance on. the Specification for Road Works Waterproofing for Concrete Structures

Series NG 2000


(SPECIFICATION F O R ROAD WORKS)

F O R M PWS PROPRIETARY WATERPROOFING SYSTEM DATA SHEET

ANNEX'A'

Manufacturer or Marketing Group:

Product:

TAB Certificate No.:

P reamble

This waterproofing system is to be installed in accordance with this Annex and the Specification.

Should there be any contradiction between the requirements of this Annex and the Specification, the Specification requirement shall take precedence unless otherwise agreed by the Engineer.

All materials of the waterproofing system are to be as stated on the PWS (Proprietary Waterproofing System) Data Sheet.

No substitution of any of the stated materials is permitted.

General Requ i rements

Immediately before the application of the primer or laying of the waterproofing system or protective layer, the concrete surface or primed surface shall be clean, dry and free from ice, frost, laitance, loose aggregate, dust and other debris and also where the adhesion to the concrete would be impaired, free from curing liquids, compounds and membranes.

On any structure, providing no damage results, plant and equipment all fitted only with rubber tyres may stand or travel on the waterproofing system solely for the purposes of laying an additional protective layer or surfacing material on that structure. All such plant and equipment shall have its tyre treads regularly inspected and any embedded stones removed.

The permission of the Engineer shall be obtained before the plant, equipment, and traffic is permitted onto the waterproofing system.

Rollers shall not be permitted to stand or travel directly on the waterproofing system.

Where it is necessary for plant, equipment or traffic to stand or travel on the waterproofing system, suitable temporary protection is to be provided to the satisfaction of the Engineer.

Part icular Requ i rements

March 2000 304



N G S A M P L E A P P E N D I X 20/2: W A T E R P R O O F I N G F O R C O N C R E T E S T R U C T U R E S

/Note to compiler: This should include:]

1 Requirements for mastic asphalt if different from the requirements of sub-Clause 2003.2.

2 Any restrictions on the use of proprietary materials for waterproofing below-ground concrete surfaces [2004.4].

3 Where sealing with primer is not required prior to the application of tar or bitumen waterproofing

[2006.1].

4 Type of mastic asphalt (see NG2005.7)

5 List of waterproofing materials for waterproofing below-ground concrete structures (the Engineer should

complete a list of acceptable waterproofing materials)

March 2000 305



March 2000 306

Volume 2


Bridge Bearings

BRIDGE BEARINGS

Contents

Clause Title Page

N G 2 1 0 1 General 308


March 2000 307


Series NG 2100 Bridge Bearings

Bridge Bearings

NG 2101 General

1 A bearing schedule should be included either on a drawing or in Appendix 21/1.

2 The advice given in the Guidance Clauses of BS 5400 : Part 9 : Section 9.2 : 1983 (except sub-Clauses 7.2(b) and (c) which are included in the Specification) should be used, together with the following:

Page 10

7.2 (a) paragraph 1, line 6

Delete 'to the satisfaction of the Engineer'.

7.2 (a)(3) line 3

Delete 'or when required by the Engineer' and insert "in Appendix 21/1".

Page 11

7.2 Insert additional sub-clause as follows:

"(d) Number of tests required. These tests should be inserted in the bridge bearing schedule. Unless otherwise required by a special feature of the design, the number and type of acceptance tests should be as follows:

(1) Bearings other than elastomeric bearings. One complete bearing of each type should be subjected to a combined vertical and horizontal load test at the serviceability limit state. A load test to ultimate limit state need only be carried out when the design of the bearing or any of its components, made from materials other than structural steel, is governed by an ultimate criterion; design of structural steel components of a bearing need not be verified by load tests at ultimate limit state. Well attested and documented evidence of previous independently supervised tests on similar bearings may be accepted as an alternative to the specified tests.

(2) Laminated elastomeric bearings. A 'quick production test' should be carried out for each bearing. One in every twenty bearings of the same type should be subjected to shear

stiffness tests. In addition, where the vertical deflection of the bearing under load is critical to the design of the structure, compressive stiffness tests should be carried out on one in every twenty bearings of the same type."

8.3 (a) paragraph 4, line 2

Delete 'by the Engineer provided he allows for the relaxed tolerances in his design' and insert "provided that the relaxed tolerances are allowable within the design".

paragraph 4, line 6

Delete 'by the Engineer'.

3 Where proprietary bearings are to be used, the Contractor should design the bearings. A Bridge Bearing Schedule shall be provided and a statement included thereon that "The bearings shall be designed in accordance with the requirements of UK Department of Transport Standard BD 20".

Where bearing design is not covered by UK Department of Transport Standard BD 20 any particular requirements for the bearings should be included in Appendix 21/1.

March 2000 308

Volume 2


Series NG 2100 Bridge Bearings

N G S A M P L E A P P E N D L X 21/1: B R I D G E B E A R I N G S C H E D U L E

/Notes to compiler:

1 This schedule is to be prepared in accordance with that in BS 5400 Section 9.1 : 1983 Table 9 as implemented by UK Department of Transport Standard BD 20. If considered preferable, the schedule can be placed on a Drawing and Appendix 21/1 would cross-refer.

2 This schedule should state the bearing design requirements, including method of fixing, where design is to

be carried out by the Contractor (see NG 2101). Appendix 1/11 should cross-refer.

3 List the bearings which are not required to comply with Clause 2101 and state the requirements to be

complied with.

4 Steel components of bearings are to have their surface preparation and protection requirements stated in

Appendix 19/2 individually for different treatments. See Basic Systems sub-Clause ofNG 1901.

Where surface preparation and corrosion protection is not to be as given in the 1900 Series the requirements should be given including those for the protection of aluminium alloy and ferrous components where permanently exposed (2102, 2104).

5 The maximum stress in the bedding mortar at the time of loading should be stated (2103).

6 List the bearings which are to be tested by the Contractor and any special requirements of the tests (2104),

and cross-refer with Appendix 115.

7 The requirements for quality of material should be given where there is a choice (2104).

8. The requirements for vibration resistant bolts or screws should be given (2104).

9 The requirements for presetting sliding or roller bearings at time of clamping should be given (2104).

10 Tolerances where different from those specified in Clause 2104 should be given.

11 Requirements for installation of bearings should be given (2104).

12 Interchangeability of corresponding parts should be stated (2104).J

March 2000 309

Volume 2 Series NG 2100 Notes for Guidance on the Specification for Road Works Bridge Bearings

March 2000 310

Volume 2 Series NG 2200 Notes for Guidance on the Specification for Road Works Parapets

PARAPETS

Conten ts

Clause Title Page

N G 2 2 0 1 General 312

N G 2 2 0 2 Metal Parapets 312

NG 2203 Anchorages and At tachment Systems for Metal Parapets

for Vehicle Conta inment 312


NG 2207 Inspect ion and Testing of Parapet Posts 313

NG 2208 Site Tests on Anchorages in Drilled Holes 313


March 2000 3 1 1


Parapets

NG 2201 General

1 A schedule of metal parapets is to be placed in Appendix 22/1.

2 The schedule should list those parapets, anchorages and attachment systems which are to be designed by the Contractor or, where appropriate, by the manufacturer and proposed by the Contractor. This schedule should state that such parapets shall comply with BS 6779 : Part 1 : 1992 and the UK Department of Transport Standard BD 52. When adopted this schedule should be placed in Appendix 22/1.

3 Full height concrete parapets for vehicle containment are covered by BS 6779 : Part 2. Combined concrete and metal parapets will be contained in BS 6779 : Part 3 and for this type, at present reference should be made to UK Department of Transport Standard BD 52.

4 Concrete parapets are normally designed and included within the contract documents. Where the Contractor is required to carry out the design, the requirements should be given in Appendix 22/1 and details should be completed in Appendix 1/11.

NG 2202 Metal Parapets

Aesthetic Approval

1 The parapet systems given in Appendix G of BS 6779 : Part 1 : 1992 will normally be deemed to be aesthetically acceptable. The Engineer should state in Appendix 22/1 whether or not this is the case.

2 Where other systems are proposed they shall

be submitted to the National Roads Authority

for aesthetic approval.

NG 2203 Anchorages and Attachment Systems for Metal Parapets for Vehicle Containment

1 Failures of anchorages in drilled holes are known to occur due to either the lack of cleanliness of the hole or excessive tolerance in the size of the hole. Manufacturers of the anchorages should give details of the maximum

Series NG 2200 Parapets

tolerance permitted and test evidence that they are satisfactory when installed in holes having these tolerances.

2 Where attachment systems are used, the Engineer should ensure that the bolts or nuts are tightened adequately in accordance with the manufacturers recommendations to ensure that effective shear transfer will occur between the post baseplate and the base. In addition, it is important to ensure an adequate length of thread engagement.


1 Sealing of voids in anchorages, attachment systems and base plates with a non-setting passive filler is important to prevent ingress of water and to avoid corrosion.

2 Prior to the anticipated start of manufacture of parapet components the Engineer should request copies of the most recent certified destructive test reports covering those component types to be supplied under the Contract.

3 The Engineer should arrange for sample components and/or joints for destructive testing to be selected at the works and on site. Selection should be made taking into account the manufacturer's inspection reports, previous destructive test reports and observations of current production practice on similar component types. Samples should be selected on the basis that they represent the lower end of quality in the production batch. Particular attention should be given to any features which could adversely affect the true throat size or the mechanical properties of the materials.

4 For the purposes of defining component types in sub-clause 19.2.5.2 of BS 6779 : Part 1 : 1992, differences in either member cross-sectional shape, joint configuration or weld type, constitute a change in component type. Variations in cross-section size or member length need not constitute a change in component type. Variations in parent metal thickness or weld throat dimension from the specified sizes on the sample selected for destructive test may be included within the same type up to a limit of ±40%.

March 2000 3 1 2


5 Sample components and/or joints selected for destructive testing in accordance with subclause 19.2.5.2 of BS 6779 : Part 1 : 1992 should be indelibly marked by the Engineer who should dispatch them to a testing laboratory appropriately accredited by ILAB for weld testing and, in the case of aluminium alloy posts, for static load testing in accordance with BS 6779 : Part 1 : 1992 Appendix F.

6 The Engineer should consider the following points when ascertaining the acceptability of components subject to destructive testing:

(aJ Aluminium alloy posts should be static load tested in accordance with BS 6779 : Part 1 : 1992 clause Fl and F.2 prior to destructive examination.

(b) When conducting destructive examination each length of weld between weld ends or changes of direction should be sectioned at intervals not exceeding 100 mm. One side of each section should be ground, filed, finished or machined to a finish equivalent to that produced by a 120 grit paper complying with BS 871, so that the actual throat and leg dimensions can be measured and any discontinuities exposed. One nick break test in accordance with BS 709 on a length of weld of not less than 50 mm should be made for each joint type on each component. Additional sections and nick break tests may be required in cases of borderline acceptance. Noncompliances with ISEN 288 : Part 3 should be recorded. Non-conformance with the requirements of clause 19.2.4 should be cause for rejection, except that in 19.2.4.2 the throat and leg dimensions should be the true rather than the apparent dimensions.

(c) One representative section from each joint type for each type of component should be prepared for macro-examination. A hardness survey should be done where any of the parent material is 20 mm thick or greater. An additional macro-examination should be made of each non-conforming weld.

7 The results of the destructive tests, including macrographs and load deflection history where relevant, should be reported and a certified copy sent to the manufacturer. In the event of non-conformances being found, the Contractor and the manufacturer should be notified as soon as possible. The test specimens, uniquely identified by hard stamped marks, should be returned to the manufacturer's works.


NG 2207 Inspection and Testing of Parapet Posts

1 Provided the Engineer is satisfied with a test certificate and the time limit relating to a test previously carried out, this may be used in relation to current work.

NG 2208 Site Tests on Anchorages in Drilled Holes

1 The Contractor is responsible for designing the anchorages and carrying out Site tests at the frequency given in Appendix 1/5. Any particular requirements should be included in Appendix 22/1.

2 The Engineer should satisfy himself that the Contractor's calculations for the nominal tensile load have been correctly carried out and have been checked, before selecting the anchorages for testing.

3 The Contractor's test record documents should be included in the as-built records.

March 2000 313



N G S A M P L E A P P E N D I X 22/1: P A R A P E T S C H E D U L E

[Note to compiler: This should list the following and cross-refer to Appendix 1/5 and Appendix 1/11 as necessary:]

Concrete Parapets

1 Those structures where concrete parapets are required and any special requirements [cross-refer to the Drawings as necessary].

Metal Parapets

1 Group designation for parapets and pedestrian/equestrian parapet requirements for each structure /cross-refer to the Drawings as necessary].

2 Requirements for parapets if different from the requirements of sub-Clause 2202.1.

3 Requirements for pedestrian parapets if different from the requirements of sub-Clause 2202.3.

4 Requirements for anchorage and attachment systems if different from the requirements of sub-Clause 2203.1.

5 Whether the parapet systems in Appendix G of BS 6779 : Part 1 : 1992 are deemed to have aesthetic approval [2202.4].

Special Parapets [e.g. non-standard parapets including all-metal or a combination of metal and concrete]

1 Requirements for special parapets designed by the Engineer [cross-refer to the Drawings as necessary].

2 Requirements for special parapets designed by the Contractor including requirement to comply with UK

Department of Transport Standard BD 52 Isee NG 2201].

Inspection and Testing of Parapet Posts

1 Requirements for inspection if different from the requirements of sub-Clause 2207.1.

2 Requirements for static testing of posts if different from the requirements of sub-Clause 2207.2.

Site Tests on Anchorages in Drilled Holes

1 Requirements for testing of anchorages [2208.3].

Destructive Testing

1 Requirements for provision of copies of certified reports of destructive tests [2204, 19.2.5.1], and requirements for supply of test components [2204, 19.2.5.2].

March 2000 314

Volume 2 Series NG 2300 Notes for Guidance on the Specification for Road Works Bridge Expansion Joints and Sealing of Gaps

BRIDGE EXPANSION JOINTS AND SEALING OF GAPS

Contents

Clause Title Page

N G 2 3 0 1 General 316

NG 2302 Installation of Bridge Deck Expansion Joints 316

N G 2 3 0 3 In Situ Nosings 316


March 2000 315


Series NG 2300 Bridge Expansion Joints and Sealing of Gaps

Bridge Expansion Joints and Sealing of Gaps

NG 2301 General

1 A schedule of expansion joints should be included in Appendix 23/1, cross referring to the Drawings where appropriate. Where the use of proprietary joints or materials is envisaged, or the joint is not fully detailed on the Drawings, Appendix 23/1 should also give details of the design movements, to enable the Contractor to propose appropriate joints. Particular requirements for subsurface drainage should be described in Appendix 23/1, cross-referring to the Drawings where appropriate.

2 The Engineer should check that all bridge deck expansion joints proposed by the Contractor for use in the Works have a current IAB certificate.

3 Where gap sealing is required, e.g. between wing walls and abutments, the details should be shown on the Drawings, with cross references to them and a schedule, if applicable, in Appendix 23/2.

NG 2302 Installation of Bridge Deck Expansion Joints

1 The installation of expansion joints requires a very high standard of workmanship and supervision if premature failure is to be avoided.

5 Where constituent parts of a joint system are required to be cured, the manufacturer's advice should be considered in conjunction with the actual mean air temperature when determining the curing time before the joint can be trafficked.

6 Specific requirements for the protection of newly installed joints (complementary, and without prejudice to, the safeguard afforded by Clause 20 of the Conditions of Contract) should be shown on the Drawings.

NG 2303 In Situ Nosings

1 Nosings should be dimensioned on the Drawings. They should only be applied to sound concrete and it is imperative that concrete affected by cracking or deterioration be replaced.

2 It is emphasised that satisfactory in situ resin based mixes can only be achieved with completely dry aggregates.

3 Resin based materials of any composition when placed in thin layers, say 12 mm thick, do not generate sufficient heat to cure satisfactorily below 10°C. A temperature of 10°C or above may be obtained by means of artificial heating to a constant temperature over the whole area.

2 The width of the expansion joint gap and, where appropriate, the deck joint gap to be provided should be related to the amount of residual creep, shrinkage, structural rotation and temperature movements that may be expected in the deck and to the prevailing deck temperature at the time of setting the joint gap. Where a preformed compression seal is to be incorporated in the gap, the gap setting should ensure that the seal does not lock up solid before full expansion has taken place.

3 Hardboard has proved to be effective in preventing surfacing materials, where they are to be cut back, adhering to the deck or the waterproofing.

4 Holding down bolts installed at an early stage of the deck construction are particularly vulnerable to damage. Care should be taken to protect threads from damage as any slight imperfections may prevent the pre-determined torque load being achieved.

March 2000 3 1 6

Volume 2


Bridge Expansion Joints and Sealing of Gaps

N G S A M P L E A P P E N D I X 23/1: B R I D G E D E C K E X P A N S I O N J O I N T S C H E D U L E

All bridge deck expansion joints shall satisfy the requirements of UK Department of Transport Standard BD 33/88 'Expansion Joints for Use in Highway Bridge Decks'.

[Notes to compiler: This schedule should list all bridge expansion joints in the Contract by type as described in Table 1 of BD 33/88 and give a cross-reference to the Drawing Number where the joint location is shown. The movement fringes of each joint should be given to enable the Contractor to propose an appropriate joint. Particular requirements for subsurface drainage, including the position and invert level of connections to surface water drains or soakaways should be given. Requirements for surface preparation and protection of metal components against corrosion should also be given/.

March 2000 317


Series NG 2300 Bridge Expansion Joints and Sealing of Gaps

N G S A M P L E A P P E N D I X 23/2: S E A L I N G O F G A P S S C H E D U L E ( O T H E R T H A N I N B R I D G E

D E C K E X P A N S I O N J O I N T S )

[Note to compiler: This schedule should include all gap sealing such as joints between wing wall and abutment, etc. Typical aspects to be included are:]

(i) Joint types and references

(ii) Filler requirements

(iii) Sealant requirements

(iv) Water stop requirements

(v) A cross-reference to the Drawing Number giving this or further information.

March 2000 3 1 8


Series NG 2400 Brickwork, Blockwork and Stonework

BRICKWORK, BLOCKWORK AND STONEWORK

Contents

Clause Title Page

N G 2 4 0 1 C e m e n t 320

N G 2 4 0 4 Mortar 320

N G 2 4 0 5 Lime Mortar 320

N G 2 4 0 6 Br icks 320

N G 2 4 0 7 Blocks 321

N G 2 4 0 8 Recons t ruc ted Stone 321

NG 2409 Natural Stone 321

N G 2 4 1 2 Br ickwork and Blockwork 321

N G 2 4 1 3 Stonework 321

N G 2 4 1 4 Cold Weather Working 322

N G 2 4 1 5 Protect ion o f New Work 322

N G 2 4 1 6 Brick, Block and Stone Facework Fixed to Concrete 322


March 2000 319



Brickwork, Blockwork and Stonework

NG 2401 Cement

1 Sulphate-resisting Portland cement should be specified where there is a risk of sulphate attack; guidance is given in Table NG 17/2. The cement to be used in different locations should be shown in Appendix 24/1.

NG 2404 Mortar

1 Table 24/1 in the Specification is confined to the more durable mortars which can withstand exposure to severe weather. Further guidance is given in IS 325 and BS 5628 : Part 3.

2 An important consideration besides durability when selecting a mortar for a particular use is that increasing strength is accompanied by decreasing ability to accommodate movements such as drying shrinkage, expansion or settlement.

3 Generally for brickwork, blockwork or stonework in bridgework, mortar designation (i) or (ii) will be appropriate except for reconstructed stone, concrete and calcium silicate bricks and blocks, when mortar designation (iii) should be specified to allow for their relatively high shrinkage. Details of the mortar required for use in the Works should be shown in Appendix 24/1.

4 Extensive use of loadbearing brickwork, blockwork and masonry is not envisaged in new bridge construction but when these are required, reference should be made to IS 325, and the Specification should contain an Additional Clause which should include 28-day mean compressive strengths.

5 The approximate 28-day mean compressive strengths of the mixes in Table 24/1 based on six 75 mm cubes, 100 mm cubes or 100 mm x 25 mm x 25 mm prisms are shown in Table NG 24/1.

6 Where a plasticiser is to be used the recommendations of the admixture manufacturer should be followed. Where previous evidence of the suitability of the mixer and time of mixing is not available the Engineer should conduct trials.

TABLE NG 24/1: Mortar Compressive Strengths

Mortar designation

28-day mean compressive strength Mortar designation

Laboratory tests N/mm 2

Works tests N/mm 2

(i) 16.0 11.0

(ii) 6.5 4.5

(iii) 3.6 2.5

NG 2405 Lime Mortar

1 Lime mortars have good working qualities but develop strength very slowly. For this reason such mortars are rarely suited to present day needs and should only be used for renovating existing lime mortar joints.

NG 2406 Bricks

1 Consideration should be given to the quality of brick and mortar to enable water/sand blasting to be used to remove graffiti.

2 Full details of the bricks required for use in the Works should be shown in Appendix 24/1. The terms of IS 91 should be used for the description of the bricks.

3 Frost resistant bricks classified in IS 91 should be specified for facework, and it should be specified that no sample of a brick intended for use in facework should develop efflorescence worse than 'slight' when tested in accordance with IS 91. Bricks manufactured to the requirements of BS 3921 should have a minimum strength of 7 N/mm 2, which will normally be sufficient for non-structural facework fixed to concrete as described in Clause 2416. If a higher strength is required, e.g. where the facework is loadbearing, this should be shown in Appendix 24/1.

March 2000 3 2 0


NG 2407 Blocks

1 Full details of the blocks required for use in the Works should be shown in Appendix 24/1. The terms of IS 20 with regard to type and designation should be used for the description of the blocks.

NG 2408 Reconstructed Stone

1 Reconstructed stone is alternatively referred to as cast stone, or reconstituted stone.

2 Special requirements such as colour, special mixes, texture, and casting in stainless steel ties should be shown in Appendix 24/1.

NG 2409 Natural Stone

1 In some quarries the durability of stone is well known while in others the variations are such that each individual block has to be considered separately. The performance of the stone used in the area should be studied to gauge the effects of exposure. Samples of selected stones should be taken and these should represent the range of variations that are acceptable. Further guidance on choice of stone is given in BS 5390.

NG 2412 Brickwork and Blockwork

1 Different bricks and blocks including reconstructed stone possess different suction properties and any requirements regarding wetting before laying should be given on the Drawings.

2 The bond and type of mortar required for jointing, and pointing where necessary, should be shown in Appendix 24/1 and for all visible work the coursing should be described, e.g. brickwork, 4 courses to 300 mm.

3 The Drawings should also include information regarding the use of purpose-made bricks or blocks, e.g. in quoins, copings or string courses, and of any sample panels of brickwork or blockwork which the Engineer will require to be built.

4 Reinforcement laps and cover should be detailed on the Drawings. This is particularly important if the joints are raked out and left open.


5 The type of pointing required in exposed joints should be described in Appendix 24/1. Reference should be made to BS 5628 : Part 3 for the correct definitions.

NG 2413 Stonework

1 The selection of stone to be used for masonry will involve aesthetic as well as technical consideration.

2 Where required, directions should be shown in Appendix 24/1 regarding:

(i) the amount and type of dressing the stones require on the face and sides;

(ii) the minimum and maximum size of the stones;

(iii) the treatment of the pointing;

(iv) in the case of coursed work, the depth of the course;

(v) stonework fixings including dowels, cramps, joggles, etc.;

(vi) stones which must be laid damp;

(vii) the limit of projection of any part of the exposed face of stones;

(viii) the minimum and maximum thickness of joints.

3 Except in the case of the finest ashlar, joints should not normally be less than 6 mm thick in any part of the bed.

4 The Engineer should refer to BS 5390 for guidance on walling type, finishes and other relevant details.

5 When special stones are required for quoins, copings or other similar purposes, they should be detailed separately on the Drawings. Special care should be taken in the choice of stone for parapets, cornices, string courses and places where more than one face of the stone is exposed. Such stones should have good weathering characteristics and be able to withstand frost.

6 The use of block-in-course stonework is limited to heavy engineering works and requires the use of power-driven plant to lift the heavy stones.

March 2000 321



NG 2414 Cold Weather Working

1 The precautions to be adopted if bricks, blocks or stonework are to be laid in cold weather should accord with BS 5628 : Part 3. The precautions to be taken may also include:

(i) storing materials in a heated shed or covering them with waterproof sheets;

(ii) warming fine aggregate and water but

not the cement or lime;

(iii) not wetting the bricks, blocks or stonework, but if necessary using a little more water for mixing the mortar;

(iv) protecting the working areas and the site where mortar is mixed from frost, snow and rain;

(v) ensuring compliance with Clause 2414 if

special precautions are not taken.

NG 2416 Brick, Block and Stone Facework Fixed to Concrete

1 Brick, block and stone facework should normally be built after the concrete has hardened. Brickwork built by this method is less liable to discoloration from efflorescence than that used as formwork.

2 Full details of the method of construction and spacing of ties should be shown on the Drawings. An adequate support should be provided so that the sole function of the ties is to hold the facework back to the concrete and not to carry its weight.

3 It is essential that there should be no voids between the facework and the backing so that damage will not be caused by water collecting behind the facework and subsequently freezing. The gap to be filled should be a minimum of 30 mm.

NG 2415 Protection of New Work

The acceptable variation in depth from front to back of stones for masonry facework should be shown in Appendix 24/1.

1 The Engineer should refer to BS 5628 : Part 3 for advice on the avoidance of efflorescence.

March 2000 322



N G S A M P L E A P P E N D I X 24/1: B R I C K W O R K , B L O C K W O R K A N D S T O N E W O R K


1 Locations where sulphate-resisting Portland cement is to be used 12401.1].

2 Mortar designations for brickwork, blockwork and stonework [2401.1, 2412.5].

3 Strength and frost resistance requirements for clay bricks to IS 91 [2406.1].

4 Requirements for bricks for chambers if different from the requirements of sub-Clause 2406.4.

5 Particular requirements for concrete blocks to IS 20 [2407.1, 2407.2].

6 Details of the type and quality of natural building stone [2409.1].

7 Particular requirements such as colour, special mixes, texture and casting-in stainless steel ties for reconstructed stone [2408].

8 TVpe of bonding for brickwork and blockwork [2412.1].

9 Locations where pointing is required and the type of pointing [2412.5].

10 Locations where jointing is required and the type of finish to be used [2412.6].

11 Requirements for dimensions of stones if different from the requirements of sub-Clause 2413.1.

12 Requirements for tooling stonework [2413.6, 2413.7].

13 Requirements for dimensions of bond stones if different from the requirements of sub-Clause 2413.9.

14 Details of the requirements for levelling squared random rubble coursed and uncoursed stonework

[2413.9].

15 The variation in depth, front to back for masonry facework [2416.4].

March 2000 323


Notes for Guidance on the Specification for Road Works Brickwork, Blockwork and Stonework

March 2000 324


Series NG 2500 Special Structures

SPECIAL STRUCTURES

Contents

Clause Title Page

N G 2 5 0 1 Corrugated Steel Bur ied Structures 326

NG 2502 Reinforced Earth and Anchored Earth Structures 326


March 2000 325



Special Structures

NG 2501 Corrugated Steel Buried Structures

1 Any special drainage requirements associated with corrugated steel buried structures, such as the need for watertight jointing or lining of trenches with impervious membranes, should be shown on the Drawings or given in Appendix 25/1.

2 The Engineer should also complete other details in Appendix 25/1 to enable the Contractor to produce a design and submit details to the Engineer for checking and acceptance.

3 The Engineer should check that bolts and nuts

are tightened to a torque within the range

stated on the Certificate.

NG 2502 Reinforced Earth and Anchored Earth Structures

1 The Engineer should include design requirements in Appendix 25/2 to enable the Contractor to produce a design and submit details to the Engineer for checking and acceptance.

March 2000 326

Volume 2


Series NG 2500

Special Structures

N G S A M P L E APPENDLX 25/1: R E Q U I R E M E N T S F O R C O R R U G A T E D S T E E L B U R I E D

S T R U C T U R E S

1 Design Requirements

[Note to compiler: This should include all relevant information required to enable the Contractor to complete and submit to the Engineer a detailed design using any bolted or helically wound segmental structure system, having a current IAB Certificate.J

2 Other Information.

[To be included as required]

(a) Roughness coefficient.

(b) Special needs for watertight jointing.

(c) Special needs for lining of trenches with impervious linings.

(d) Need for paved invert.

(e) Special requirements, if any. for the protection of exposed surfaces after erection.

[Acceptability limits for MCV, if required, for Class 6K and 6M fills should be stated in Appendix 611.]

March 2000 327



N G S A M P L E A P P E N D I X 25/2: R E Q U I R E M E N T S F O R R E I N F O R C E D E A R T H A N D

A N C H O R E D E A R T H S T R U C T U R E S

[Note to compiler: Include here:/

1 Design requirements.

[Where the design retained height exceeds 1.5 m, include the requirement for the design to comply with UK Department of Transport Standard BD 2/89 : Part I and all other relevant requirements.]

2 References to drawings showing locations and outlines.

3 Other information.

[Contract-specific earthworks requirements should he included in Appendix 6/1; see NG 622./

March 2000 328



N G S A M P L E A P P E N D I X 25/3: R E Q U I R E M E N T S F O R P O C K E T T Y P E R E I N F O R C E D

B R I C K W O R K R E T A I N I N G W A L L S T R U C T U R E S


1 Requirements for concrete if different from the requirements of sub-Clause 2503.3.

2 Requirements for wall ties [2503.5].

3 Requirements for damp proof courses [2503.6].

4 Requirements for additives or admixtures [2503.18/. [See sub-Clause 1703.4.]

5 Requirements for trial panels [2503.31]

March 2000 329


Notes for Guidance on the Specification for Road Works Special Structures

March 2000 330


Series NG 2600 Miscellaneous

MISCELLANEOUS

Contents

Clause Title Page

N G 2 6 0 1 Bedding Mortar 332

N G 2 6 0 2 Concrete for Anci l lary Purposes 333


March 2000 331



Miscellaneous

NG 2601 Bedding Mortar

General

1 Great importance is attached to the material having flow characteristics sufficient for it to occupy all the spaces between base plates and the surrounding sub-strata completely, including around all holding down bolts. The Specification for Road Works does not cover non-flowing mortars or dry pack mortars.

Where the Engineer requires a higher strength, this should be specified in Appendix 26/2. Materials with higher strengths may be more temperature sensitive and variable.

Mortar test cubes required in connection with early loading should be cured under conditions which simulate as far as possible those of the mortar in the Works.

holding down bolts. Packers and washers should be made of materials which will not corrode. Adequate bedding cover should also be provided to the packers and washers to ensure that they are fully protected from the weather and any road and traffic contaminants. Packers and washers should be compatible with the materials used in the base plates or bolts.

(iii) Addition of mortar may be required to form a finished plinth. Voids may occur under the base plate if this operation is carried out incorrectly.

(iv) The quantity of mortar in the plinth extending beyond the base plate should be kept to a minimum to reduce cracking. Forming of large plinths to support two or more base plates is not recommended.

Materials

2 (i) The minimum thickness of bedding mortar should be 10 mm and the maximum thickness without reinforcement should be 30 mm. This will allow sufficient space to enable filling yet reduce creep and shrinkage effects. The nominal thickness, with tolerances, should be shown on the Drawings.

(ii) A purpose-made portable insulated store, equipped with thermostatically controlled heaters, would be suitable for complying with sub-Clause 2601.21 ii)( a). It may be convenient to include provision for storage of the mixing water at 20°C.

Approval Tests

4 (i) It is important that the various temperatures required in the flow tests are accurately maintained within the tolerances specified. The testing laboratory appointed should be able to demonstrate that it has the facilities for accurate cold testing.

(ii) Where different methods of placing the mortar are proposed, e.g. pumping, or where the geometry of the base plate is significantly different from that shown on UK Department of Transport Highway Construction Detail (HCD) Drawing No. K2, then the glass plate test, specified in sub-Clause 2601.4(iii), should be modified to the Engineer's approval.

Site Mixing, Placing and Curing

3 (i) It is common practice to add the dry material to the water in the mixer. If the material does not flow correctly the addition of extra water or dry mortar to the sample is not permissible. In order to control the amount of water accurately it is good practice to use a proprietary graduated container. A bucket with a mark is not suitable.

Batch Acceptance Tests

5 The tests on Site should be conducted by a competent person. Proof of ability to carry out the flow cone test method consistently may be checked by trials using water.

(ii) Where permanent shims are used underneath base plates to align or support parapet posts etc. they should take the form of either central packers or slotted washers placed around the shanks of the

March 2000 332



NG 2602 Concrete for Ancillary Purposes

1 Concrete mixes complying with Clause 2602 will normally be suitable for the purposes described in Table 26/3 and need not be shown on the Drawings for these purposes. Standard mixes from BS 5328 may also be suitable for other purposes and should be called up on Drawings where necessary. Sub-Clause 1 of Clause 2602 makes it unnecessary to do more than show "ST4 concrete" (for example) on the Drawings. The relationship between concrete mix and strength of the concrete is given in BS 5328 : Part 2.

2 Where additional requirements are necessary, for example the use of sulfate-resisting cement in ground containing sulfates (see 1704.2), or resistance to alkali-silica reaction, these requirements should be specified in Appendix 26/1. Air entrainment will not normally be necessary but if it is required, this should also be specified in Appendix 26/1. Alkali-silica reaction will not normally be a risk because cement contents are comparatively low but in some areas where aggregates are known to be highly reactive, it may be necessary to state in Appendix 26/1 that ancillary concrete is to comply with sub-Clause 1704.5 for ST4 and ST5 mixes.

3 Foundations for traffic sign supports, lighting columns and safety fence anchors, should, where necessary, be structural concrete complying with the 1700 Series and be shown on the Drawings accordingly.

March 2000 333


Series NG 2600

Miscellaneous

N G S A M P L E A P P E N D I X 26/1: A N C I L L A R Y C O N C R E T E

[Note to compiler: Special requirements for Ancillary Concrete, e.g. sulphate-resisting cement, etc. should be listed here. Also to distinguish different mix designs, mix references should be listed here but differentiated from those for structural concrete in Appendix 1711J

March 2000

Volume 2


Miscellaneous

N G S A M P L E APPENDLX 26/2: B E D D I N G M O R T A R


1 Compressive strength requirements. [Where different from 2601. l(i)]

2 Locations at which permanent metal shims are acceptable.

3 Early loading requirements [For bridge bearings, cross-reference should be made to Appendix 2111}.

March 2000 335



N G S A M P L E A P P E N D I X 26/3: C O R E D T H E R M O P L A S T I C N O D E M A R K E R S


1 Locations of node markers [2606.1].

2 Copies of existing site records.

3 References for the re-establishment of existing node markers.

March 2000 336

Volume 2 Series NG 2800 NRA Notes for Guidance on the Specification for Road Works Trenchless Installation of Road Drainage & Service Ducts

January 2009

TRENCHLESS INSTALLATION OF ROAD DRAINAGE AND SERVICE DUCTS Contents Clause

Title Page

NG 2801 Scope ................................................................................................................... 1

NG 2802 Information ......................................................................................................... 1

NG 2803 Techniques .......................................................................................................... 2

NG 2804 General Requirements ....................................................................................... 2 NG 2805 Pipes for Drainage and Service Ducts .............................................................. 10

NG 2806 Specific Requirements for On-line Replacement Techniques ......................... 10

NG Sample Appendix 28/1 ....................................................................................... 11


January 2009 1

Trenchless Installation of Road Drainage & Service Ducts

NG 2801 Scope

1 These notes for guidance convey as appropriate the reasoning behind the requirements in the Specification where this is considered necessary. The information required from the designer/compiler that will detail the performance required from the trenchless installation is given in Appendix 28/1.

NG 2802 Information

General

1 Trenchless techniques should be considered for crossing environmentally sensitive areas, roads, railways, airfield runways, taxiways, urban developments and as a means of limiting damage to trees. The techniques have been shown to be a positive means of reducing indirect and social costs, particularly those arising out of traffic delays caused by disruptive installation methods. Trenchless installation also offers the benefits of rapid installation, minimal environmental disturbance and little disruption to an existing pavement and adjacent infrastructure.

2 Trenchless installation of pipes is a

continuously evolving technology and developments in industry may overtake this edition of the Specification. The techniques listed in this Specification are not exhaustive and approval of the use of other techniques should not be withheld if they are capable of meeting the performance requirements.

3 In many cases there will be more than one method of installation that could provide an appropriate solution and the designer should allow the Contractor to select from the range of alternative techniques. The

performance requirements are specified in Appendix 28/1 and these should influence the Contractor’s choice of installation method.

4 In addition to the information required in

Appendix 28/1, the designer should provide drawings showing the following information:

• Identification of pipe runs to be constructed using trenchless, minimum dig or rehabilitation techniques;

• Existing pipes to be replaced;

• Existing chambers which may be used as launch/reception pits and reinstated;

• Existing chambers which may be used as launch reception pits and abandoned;

• Launch/reception pits to be converted to permanent chambers;

• Existing pipes to be connected to new pipes;

• Working areas;

• Areas of contaminated land;

• Carriageway levels and sections;

• Information on underground structures and foundations;

• Location of Statutory Utilities and other authorised users plant;

• Motorway communication cables;

• Road lighting and power cables.

5 The Contractor’s chosen solution may be a

proprietary system. All elements to be designed by the Contractor should be listed in Appendix 1/11.


January 2009 2

6 Series NG 000 (MCDRW Vol. 2) should be consulted on the preparation of Contract-specific information and requirements.

NG 2803 Techniques

General

1 Guidance on the various methods and their suitability for different applications is given in Tables NG 2803/1 to 2803/5. The Tables show typical pipe sizes and lengths of drives. This information should only be considered as a guide.

NG 2804 General Requirements Method Statements

1 Specific requirements for information to be provided in the Contractor’s Method Statement should be entered in Appendix 28/1. The following list includes examples of items that may need to be provided:

• Site staff and organisation;

• The experience of the Contractor and his staff, with the installation type and the identified ground conditions;

• The details of the plant should be sufficient to demonstrate its suitability for achieving the requirements and to work within any noise and vibration limits where these are restricted;

• Setting out method and means of achieving specified tolerances;

• Location and construction details of drive and reception pits;

• Method of spoil removal and storage;

• Methods of dealing with ground water and existing pipe flows;

• Design loads for pipes;

• Design information for Cured in Place Liners;

• Maximum permitted draw and angular deflection for the pipes;

• The use of support fluids, lubricants and drilling fluids;

• Risk Assessments;

• Pit access;

• Emergency procedures;

• Geotechnical Certifications;

• Working hours.

Records

2 Records to be kept by the Contractor and supplied to the Employer’s Representative should be entered in Appendix 28/1. Table NG 2804/1 includes examples of items that may need to be provided.

Ground Movement

3 Where trenchless installations are undertaken beneath motorways and national roads no heave or settlement should be allowable. If the designer considers this is too onerous, values of acceptable heave or settlement should be entered in Appendix 28/1. For installations in other areas the designer should consider the allowable values for heave and settlement and enter these in Appendix 28/1.

4 In order to monitor any heave or

settlement caused by the pipe installation, the Contractor should take measurements of levels at the locations and frequencies specified in Appendix 28/1. The designer should choose the locations with a view to the practicality of taking the readings. Existing levels at the locations should be agreed with the Contractor prior to work commencing.

Monitoring Adjacent Structures and Services

5 The Employer’s designer [Specialist responsible for the design of the Works] should determine the location and condition of adjacent structures and services that are likely to be affected by the Works. Certain structures may be particularly susceptible to noise, vibration or ground movement and, prior to inviting tenders, the Employer’s designer [the


January 2009 3

Specialist responsible for the design of the Works] should assess where special measures are likely to be required for protecting these structures. The information on location and condition of these structures together with the restrictions to be imposed and the monitoring requirements should be presented on the drawings and in Appendix 28/1. The Contractor is required to confirm the information on site and provide proposals to meet the specified requirements in respect of these structures and services.

Machinery

6 All machinery should be checked for electromagnetic compatibility to ensure that there are no conflicts of operational frequency between the trenchless installation plant and any motorway communications system. This is particularly important due to the sophistication of the motorway and other control systems now in use.

Contaminated Land

7 All areas of contaminated and potentially contaminated land should be thoroughly investigated prior to the design. The results of the investigation should be included in Appendix 28/1 and the accompanying drawings and schedules.


January 2009 4

Table NG 2803/1 - Trenchless New Installation Techniques

Technique Pipe Diameter

(mm)

Pipe material Soil Types Typical Installation

Length

Limitations/comments

Microtunnelling 150 – 900 C, Co, GRP, S, RC

Any up to 150 m Boulders and obstructions can halt machine. Installations above 900 mm internal diameter are outside the scope of this document although the technique may be appropriate for larger diameter pipes

Pipe Jacking =900 C, Co, GRP, S, RC

Any up to 250 m Not suitable for working under water at diameters less than 900 mm. Installations above 900 mm internal diameter are outside the scope of this document

Directional Drilling

300 – 900 S, PE Not gravels, rock or soil with a large number of boulders or cobbles

up to 1500 m Only suitable for gravity sewers if they have a significant fall, as tolerances cannot be guaranteed. Many systems require tracking of the drill head from the surface above it and are, therefore, unlikely to be

suitable for motorway crossings unless equipped with the remote tracking system. Installations above

900 mm internal diameter are outside the scope of this document although the technique may be appropriate for larger diameter pipes

Thrust Boring 50 – 500 S, PE Cohesive is most

suitable,

avoid cobbles, boulders or soft ground

up to 50 m Only suitable for small diameter, flexible pipe. Recommended minimum cover = 10 x pipe diameter

Key

C Clay GRP Glass Reinforced Plastic Co Concrete UPVC Unplasticised Polyvinyl Chloride S Steel PE Polyethylene

RC Reinforced Concrete

Further details of pipes can be found in Tables 5/1 and 5/2 (MCDRW Vol 1, 500 series)


January 2009 5

Table NG 2803/2 - Non Steerable New Installation Techniques

Technique Pipe Diameter (mm)

Pipe material

Soil Types Typical Installation

Length


Auger Boring

50 – 900 Various inside Steel casing

Cohesive. Avoid cobbles, boulders or soft ground

60 m Boulders, cobbles and soft ground can halt/deflect the bore. Installations above 900 mm i.d. are outside the scope of this

document although the technique may be appropriate for larger diameter pipes

Pipe Ramming

50 – 900 Various inside

Steel casing

Not soil containing boulders

Up to 80 m Boulders and cobbles can halt/deflect the casing off-line. Installations above 900 mm i.d. are outside the scope of this document although the technique may be appropriate for larger diameter pipes

Impact Moling

40 – 250 PE, UPVC Cohesive is most suitable, avoid cobbles, boulders or soft ground

Up to 30 m Boulders, cobbles and soft ground can halt/deflect the bore. Granular soils may provide insufficient friction against the mole. Recommended minimum cover = 10 x pipe diameter

Key


RC Reinforced Concrete

Further details of pipes can be found in Tables 5/1 and 5/2 (MCDRW Vol 1, series 500)


January 2009 6

Table NG 2803/3 - On-Line Replacement Techniques


Existing Pipe Material

Upsize

Possible

New Pipe Material

Soil Types

Typical Installation

Length


Pipe Bursting

50 – 800 Co, C, AC, UPVC, CI, PF, S, PE

Up to 800 mm diameter

C, PE, GRP, PP

Continuous or segmental

Avoid narrow rock trenches, concrete surround or densely

packed

granular soil

100 m

Maximum 400 m

Cannot handle ductile iron collars or valves. Curves can be negotiated using continuous pipe. Burster can deal with localised pipe collapses. Existing flows must be diverted. Lateral connections must be disconnected before replacement starts

Pipe Eating 200 – 600 C, Co, AC, GRP, RC

Up to

600 mm

diameter

GRP, Co, C

Any

Continuous

or segmental

150 m Some can operate in live drainage conditions but care must be taken to avoid polluting flows during replacement

Key

C Clay CI Cast iron PE Polyethylene Co Concrete GRP Glass Reinforced Plastic UPVC Unplasticised Polyvinyl Chloride

S Steel S Steel PP Polypropylene RC Reinforced Concrete PF Pitch Fibre

Further details of pipes can be found in Tables 5/1 and 5/2 (MCDRW Vol 1, series500)


January 2009 7

Table NG 2803/4 - Minimum Dig New Installation Techniques


Pipe Material

Soil Types Typical Installation

Length


Narrow Trenching

90 – 5900 PE, UPVC, C

Cohesive and

selfsupporting

150 m/day Maximum depth to invert is 3 m. Can be difficult to achieve compaction in a narrow trench, self-compacting backfill is recommended

Mole Ploughing

45 – 300 Continuous

flexible PE

Most. Avoid very hard ground, very soft ground and

soft/hard layers

150 – 300 m/day

Maximum depth to invert is 2 m

Only suitable for verges, fields, etc

Table NG 28038/5 – Rehabilitation


Pipe Material Soil Types

Typical Installation

Length


Cured in Place

Lining

75 – 900 – 1200

In accordance with WIS 4-34-04

(UK)

Any Manhole to manhole

Long-term strength depends on type of resin used and method of curing. Should be designed in accordance with WIS 4-34-04 (UK)

Sliplining 20 – 900 – 2500

PE, C, Co, RC, GRP

Any Manhole to

manhole

Reduction in cross sectional area of pipeline may significantly reduce

flow capacity of pipeline

Key


RC Reinforced Concrete WIS 4-34-04 Renovation of gravity sewers by lining with cured-in-place pipes (11/06)

Further details of pipes can be found in Tables 5/1 and 5/2 (MCDRW Vol 1, series500)

Volume 2 Series NG 2800 NRA Notes for Guidance on the Specification for Road Works Trenchless Installation of Highway Drainage & Service Ducts

January 2009 8

Table NG 2804/1: Records to be kept (As indicated by an asterisk)

Micro

Tunnelling & Pipe Eating

Pipe

Jacking

Directional

Drilling

Thrust

Boring

Auger

Boring

Pipe

Ramming

Impact

Moling

Pipe

Bursting

Narrow

Trenching

Mole

Ploughing

Cured in Place

Lining

Sliplining

Contract * * * * * * * * * * * * Reference of pipe

run * * * * * * * * * * * *

Date of work * * * * * * * * * * * * Start time * * * * * * * * * * * *

Finish time * * * * * * * * * * * * Details of any

stoppages * * * * * * * * * * * *

Diameter of bore * * * * * * * * * * * * Pipe material * * * * * * * * * * * * Pipe diameter * * * * * * * * * * * * Joint packing * * * * * *

Length installed * * * * * * * * * * * * Main survey checks * * * * * * * * * *

Soil conditions * * * *

Ground water level * * * * * * Line and level

achieved * * * * * * * * * * *

Lubrication * * * *

Support Fluid * *

Jacking & winch * * * * * * * *


January 2009 9

loads w.r.t. progress

Slurry pressures viscosity, discharge,

flow rate

* * *

Shield role, pitching, steering

adjustment

* * *

Thrust rate, cutting torque, soil discharge

* * *

Intervals at which measurements should be taken

Grout materials andvolumes

*


January 2009 10

NG 2805 Pipes for Drainage and Service Ducts Pipes

1 The pipes used will depend on several factors including ground conditions, method of installation and intended use. Many trenchless methods can use standard pipes but microtunnelling and jacked methods require specially constructed pipes. Apart from meeting its in-service performance requirements the pipe has to have a structural wall section adequate to meet the forces imposed when it is jacked.

2 If the Contractor intends to use plastic

pipes (even if they have a Irish Agrement Board Certificate) he should demonstrate that there will be sufficient side support from the trench to retainthe design section of the pipeline.

3 Where a trenchless method has been used

to create the bore but the pipe is to be installed by hand then the standard pipes and service ducts given in MCDRW Tables 5/1 and 5/2 can be used. Where pipe installation is to be by towing or jacking then the pipes should be capable of accommodating the increased forces as a result of the installation technique.

Tolerances

4 If the designer/compiler wishes to relax the tolerances given in sub-Clause 2805.10 then the revised acceptable tolerances to true line and level for each bore should be entered in Appendix 28/1. Determination of tolerances should take account of the gradient requirements and the proposed purpose of the bore. This will have a bearing on the number and types of trenchless techniques that can be used to install the bore.

Steering of Rigidly Jointed Pipes

5 If rigidly jointed polyethylene and steel pipes are subjected to bends exceeding those in Clause 2805.13 there is a risk of the pipe collapsing or flattening out.

Connecting to Existing Drains, Chambers and Channels

6 When pipes have been drawn into the bore it is possible, depending on pipe material, that the service pipe will have stretched. It is important to allow the material to recover from this imposed stretch before cutting to fit between manholes, sealing at manholes or manhole invert shaping. Polyethylene pipes usually take at least 12 hours to recover.

NG 2806 Specific Requirements for On-Line Replacement Techniques Specific Requirements for Pipe Bursting

1 Where the existing pipe has deviations in line or level over a length in excess of 5 m, that section of pipe should be replaced by non-trenchless techniques.

Specific Requirements for Cured in Place Lining

1 The thickness and composition of the liner is designed in accordance with the WIS 4-34-04 (UK).

2 Details of the liner design should be given

to the Employers Representative along with the results of testing on the samples from the installation. This is the only control on the structural capabilities of the liner.

Specific Requirements for Sliplining

3 Where grouting of the annulus is undertaken extra care should be exercised to ensure flotation does not occur as this could put the finished pipeline out of tolerance.


January 2009 11

NG SAMPLE APPENDIX 28/1: TRENCHLESS AND MINIMUM DIG TECHNIQUES


1 Identification of those drainage or service duct installations from Series 500 Appendix 5/1 and 5/2 that are to be constructed using trenchless or minimum dig techniques and schedule of permitted techniques; Product certificate requirements, for example, Irish Agrement Board certificate etc. [2804.1];

2 Information to be included in Contractor’s method statement including directions of bores or sequence of works, if to be specified [2804.2];

3 Records of installation required (refer to Table NG 2804.1 plus any additional requirements) [2804.5];

4 Allowable ground movements if different from those specified in sub-Clause 2804.7 and the locations and periods when ground levels should be measured [ 2807.7,2804.8];

5 Requirements for monitoring adjacent structures, pavements and services including conditions, line and level surveys and restrictions, if to be specified [2804.9];

6 Information on the presence and nature of known areas of contaminated ground including soil profile information [2804.16];

7 Requirements for existing manholes or chambers that are not to be reinstated [2804.21];

8 Permitted tolerances on alignment of pipeline if different from sub-Clauses 2805.10 and 2805.11 [2805.10, 2805.11];

9 The locations where existing drains, chambers or channels are to be connected to new drains, chambers or channels [2805.19];

10 Details of reinstatement requirements for Minimum Dig Techniques, if to be specified [2807.1];

11 Details of sampling and testing required for cured in place lining technique [2808.4];

12 The content of the survey report, including number of copies and types should be specified [2806.1, 2808.7 and 2808.9].

Volume 2 Series NG 2900 NRA Notes for Guidance on the Specification for Road Works CCTV Survey of Road Drainage Systems

January 2009

CCTV SURVEY OF ROAD DRAINAGE SYSTEMS Contents Clause

Title Page

NG 2901 Scope ................................................................................................................... 1 NG 2902 Information ......................................................................................................... 1

NG 2903 Definitions .......................................................................................................... 1

NG 2904 General Requirements ....................................................................................... 1

NG 2905 Survey Reporting ................................................................................................ 2 NG 2906 Quality ................................................................................................................ 3

NG 2907 Health and Safety Issues ................................................................................... 4

NG 2908 Coding of Survey Information ........................................................................... 4

NG 2909 Drain Condition Inspection ............................................................................... 5 NG Sample Appendix ............................................................................................... 6


January 2009 1

CCTV Survey of Road Drainage Systems NG 2901 Scope General

1 Closed Circuit Television (CCTV) survey of road drainage systems is the remote inspection of these systems by the insertion of a camera connected to a monitor and recording apparatus.

NG 2902 Information General

1 The visual inspection of a drain pipeline by manentry is a potentially hazardous, time consuming and labour intensive operation, hence the use of CCTV survey offers a practical alternative. In practice, the vast majority of road drainage systems are of diameters too small to gain access by man-entry and thus can only be inspected using remote techniques, of which CCTV survey is the most obvious.

2 The use of CCTV survey has been widely

practiced in the water industry for many years and the apparatus and techniques have been refined and developed. There is now an increasing use of CCTV for the inspection of road drainage systems as a maintenance tool and identified benefits in terms of future expenditure to using this technique during the construction process.

3 The UK Highways Agency’s (HA) research

has shown there to be an unacceptable number of defects within the road drainage system in the UK and this is likely to be the case in the Republic of Ireland as well. The HA has also identified the need for more complete and accurate recording of the drain positions, sizes and condition. The use of CCTV survey can greatly assist in the collation of the record data and the programming of road drainage maintenance. Identifying sections of drain in poor structural condition and the consequent remedial works can have a significant effect

on the longevity of the pavement construction.

NG 2903 Definitions 1 Definitions relating to CCTV survey of road

drainage systems are formally defined in Clause 2903.

2 It is important that a distinction is made

between the Contractor engaged to undertake the survey and the individual who will perform the inspection. This is because only the individual Surveyor can hold the required current certification.

NG 2904 General Requirements General

1 The extent of the drainage system comprising the survey should be marked on plans and detailed in Appendix 29/1.

2 The access points should have unique

reference numbers and individual drains to be surveyed should be referenced. The unique reference numbers will be inserted in to the Header Sheet, by the Contractor, at the start of each survey.

3 The location of each survey should be stated

in Appendix 29/1. Pre-cleanising

4 Where pre-cleansing is to form part of the contract this should be specified in Appendix 29/1 and itemised in the Bill of Quantities.

5 Guidance on pre-cleansing can be found in

Clause 520 of the UK MCHW Vol. 1 6 Drains that have been pre-cleansed should

be identified in Appendix 29/1. 7 Where the Contractor is required to

undertake pre-cleansing this should be identified in Appendix 29/1.

8 Pre-cleansing can remove evidence of

siltation problems that affect the performance of the drain and hence consideration should be given to only removing silt from those drains where it is known that the silt level will prevent access


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by CCTV camera. It is important to record the location of the silt prior to its removal and the location and depths of silt removed should be reported.

Traffic

9 The CCTV survey of road drainage systems should usually be carried out in conjunction with other road works or programmed maintenance contracts. In these instances the contract shall be arranged so that the traffic management for the other works should afford the CCTV Surveyor the facilities to undertake the survey works within the confines of the traffic management control.

10 Where the survey works are to be

undertaken separately from any other works, the complier should determine the traffic management measures appropriate for the classification of road and the locations of the surveys. These requirements should be inserted into Appendix 1/17 irrespective of whether or not the Contractor will be required to provide the traffic management.

11 Where the Contractor is to provide the

traffic management, this will be stated in the Appendix 1/17 and identified in the pricing document.

Chambers

12 It will be the Contractor’s responsibility to raise all the access (manhole) covers necessary for gaining access to the drains for the survey. The Employer [Contractor] should endeavour to ensure that all chambers within the survey are accessible. Where any covers are found to be broken, damaged or fast, these should be replaced prior to the commencement of the survey. Where, during the course of the survey, covers are found to be broken, damaged or fast, the Contractor should notify the Employer’s Representative who should arrange for the covers to be replaced.

Flows and blockages

13 Except where responsibility for clearing blockages is stated in Appendix 29/1 as being that of the Contractor any blockages identified during the course of the survey should be promptly addressed by the Employer’s Representative as appropriate and the Contractor notified accordingly.

14 The Survey Contactor should be responsible for dealing with the flows within the drains to be surveyed. Where survey is suspended due to temporary excessive flows within the drain, this should be the Contractor’s liability and the Employer should not incur any additional costs in this respect.

Site Availability

15 Where the Contractor’s working hours are to be restricted during certain parts of the day or night, or where there are any other restrictions on access to the site, a schedule of restrictions should be provided in Appendix 1/7 and in the Schedule of Constraints in Appendix 1/13.

NG 2905 Survey Reporting General

1 Where any changes to the IS EN 13508-2:2001 format of the Report are required, these should be stated in Appendix 29/1.

2 Where the Employer requires some items of

the Survey Report to be supplied during the course of the survey, this should be made clear in the Instructions to Tenderers and these items should be stated in Appendix 29/1.

CCTV Photographs

3 Where the size of the photographs required is different to those specified in sub-Clause 2905.13, the required dimensions should be stated in Appendix 29/1.

4 The frequency of condition photographs

should be specified in Appendix 29/1. The spacing between general condition photographs should not be more than 10 metres.

5 The format that the Contractor is required

to submit the record photographs should be entered in Appendix 29/1 by the compiler.

6 Where the requirement for the provision of

negatives is different from the specification sub-Clause 2905.19, the compiler should insert the requirements into Appendix 29/1.

Condition Grade

7 As part of the assessment of the survey it is good practice to develop a proposed survey


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programme for future surveying. The programme should be based on the condition grade from Table NG2904/1 below and this will identify the need for work. A risk assessment should be used to set the time limit between surveys.

• Grade 1 and 2 then the survey

frequency should not be more than once in 10 years and not less than once in 15 years

• Grade 3 then the survey frequency

should be no less than once in 10 years

• Grade 4, the survey frequency should

be once in 5 years

• Grade 5, the survey frequency should be once in 1 year.

8 The frequency may be increased where the drain gradient or the connection of land drains may affect the performance of the drain.

Table NG 2904/1: Application of Condition Grade to piped drainage systems Internal condition grade

Typical defect descriptions

5

Already collapsed Deformation > 10% and broken Extensive areas of fabric missing Fracture with deformation > 10%

4 Broken Deformation up to 10% and broken Fracture with deformation 6-10% Multiple fracture Serious loss of level Serious joint defects with voids or soil visible (open joint with >50mm soil or void visible or joint displacement >25% of diameter) Surface damage – spalling large Surface damage – wear large

3 Fracture with no deformation or deformation < 5% Longitudinal cracking or multiple cracking Minor loss of level

Severe joint defects, ie open joint (large) or joint displaced (large) Surface damage – spalling medium Surface damage – wear medium

2 Circumferential crack Moderate joint defects ie open joint (medium) or joint displaced (medium) Surface damage – spalling slight Surface damage – wear slight

1 No structural defects Notes 1: Deformed pipes that have subsequently been relined with a structural lining can normally be considered to have no deformation. 2: Exercise caution when assessing open joints since this may be a feature of pipelines for filter drains. 3: The Employer should be consulted where the condition of brickwork drains is to be assessed.

NG 2906 Quality General

1 The Employer’s Representative should ensure that the Surveyor who is to undertake the survey has current valid certification. The compiler should ensure that The Instruction for Tendering require the Tenderers to name the Surveyors proposed and to provide evidence that they hold the appropriate qualification.

2 All defects should be recorded on site,

however, the technical judgement as to the significance of the defect in respect of road drainage systems should be made by the Employers designer [Specialist responsible for the design of the Works].

Quality control procedures

3 The 5% sample survey for quality control is to be selected by the use of randomly generated numbers.

4 Each Surveyor should have a different set of

random numbers, which should be generated


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at the end of each week and applied to the previous week’s surveys.

5 On site, the Surveyor logs certain

information about the surveys being undertaken and the order in which they are carried out. The Contractor’s office staff then counts through the surveys that have taken place and selects the reports that coincide with the random numbers.

6 The derivation of Header accuracy is the

proportion of entries made in the header fields, which are correctly entered using the correct symbols or codes.

7 The derivation of the Detail accuracy is the proportion of entries that are correct. A missing entry should be regarded as incorrect. The results are plotted on the Surveyor’s accuracy graph.

8 The continued accuracy of the Surveyor is

calculated by taking the mean of 5 percentage results. Both the individual survey percentages and the mean results are entered on to the Surveyors’ accuracy graph.

9 If either two lines fall below the tolerances

given in sub-Clause 2906.5 then the action is taken in accordance with sub-Clause 2906.8.

CCTV Picture quality – camera, video tape and monitor

10 The test device for the camera shall utilise the Marconi Resolution Chart No 1 or equivalent. Where the Contractor proposes the use of an equivalent, the details of the chart should be supplied to the Employer’s Representative.

11 The Contractor is required in sub-Clause

2906.10 to submit the test devices for the video tape recorder and monitor to the Employer for approval.

12 The performance of the camera is to be

demonstrated by the recording of the approved test device for a minimum of 30 seconds at the commencement of each day. The Employer’s Representative [Specialist responsible for the design of the Works] should ensure that the demonstration recordings are reviewed on a daily basis.

13 It may be necessary to vary the illumination to accommodate changes in drain fabric or environment. This should be undertaken prior to the setup as the illumination,

generally, should not be varied during the survey.

NG 2907 Health and Safety Issues General

1 All chambers and pipelines comprising roaddrainage systems should be treated as confined spaces. A confined space is defined as a workplace that does not have the benefit of natural ventilation. They are potentially dangerous because of the possible existence of toxic or flammable gases, deficiencies in oxygen, or the build-up of fumes due to the operations being undertaken. Where physical exertion is necessary to gain access or egress due to confinement can define a confined space.

2 The presence of known hazards should be

stated in the preliminary Safety and Health Plan .

Zone Classification

3 All electrical equipment shall be suitable for use in potentially explosive atmospheres.

4 Unless otherwise specified in Appendix 28/1

all road drainage systems are to be classified as a place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only. The Contractor shall confirm the classification with the Employer ’s Representative.

Known Hazards

5 Any known hazards associated with the sections of drain to be surveyed shall be stated in the preliminary Health and Safety file and be incorporated into the Contractor’s Health and Safety Plan. This information shall be used in the Risk Assessment before each survey is commenced.

NG 2908 Coding of Survey Information General

1 The coding of survey information shall comply with IS EN 13508-2:2001 Condition of Drain and Sewer Systems Outside


January 2009 5

Buildings, Part 2 Visual Inspection Coding Systems.

Header Information

2 The pipe or manhole reference shall be unique. The reference numbering shall be supplied to the Contractor by the Employer’s Representative [Specialist responsible for the design of the Works]. The use of a numbering system that identifies the access points (chambers) by reference to the Irish Ordnance Survey grid will enable the unique numbering system to be maintained when new reference numbers are applied to chambers discovered during the course of the survey. Where a new node is located during the survey, the Contractor shall request the Employer’s Representative [Specialist responsible for the design of the Works] to assign the node a new number which the Contractor should use in the report.

3 Length of drain: shall be measured between

the exit faces of the manhole or access chamber at the point of entry to the next manhole or access chamber. These are referred to as the Node Points.

4 Method of inspection: Should always be

CCTV. 5 Pre-cleansing: is to be specified by the

Employer’s designer [Specialist responsible for the design of the Works]. The minimum pre-cleansing should be sufficient to ensure that the camera can pass through the drainage system. Warning, pre-cleansing the drain may remove evidence of Service Defects within the system.

6 Location: should grade each drain in terms

of its location. Graded A/B/C should determine how important the drain is in terms of consequence of failure.

Table NG 2908/1: Strategic grade Grade Position of drainA Transverse drain

Central reserve Carrier drain in motorway/trunk road

B Verge Shoulder C Remote from carriageway

and verge

7 Year of construction: where this is known the information should be included, but is more applicable to new onstruction.

8 Name of the Surveyor: should be the name

of the Surveyor undertaking the survey and not the name of the Contractor. This should be the person for whom certification has been submitted.

NG 2909 Drain Condition Inspection General

1 The Employer [Specialist responsible for the design of the Works] should supply the Contractor with 2 sets of plans showing the drains to be surveyed. The Survey Contractor should return one copy of the plans accurately referencing the extent of the completed survey.

2 Where the covers will be removed by the

Employer this should be stated in Appendix 29/1.

3 The CCTV camera lens should be positioned

to a tolerance of ± 10% of the vertical drain dimension. The Employer’s Representative should check that the Contractor has procedures in place to ensure compliance with the tolerance in the positioning of the camera. Should the alignment be outside the tolerance, the survey for that section of drain should not be accepted.

4 The length of drain from the zero chainage to

the cable calibration point should be recorded and reported. The Employer’s Representative should ensure that the Contractor supplies the records for scrutiny on a daily basis.


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NG SAMPLE APPENDIX 29/1: CCTV SURVEY OF ROAD DRAINAGE SYSTEMS [Note to the compiler: This should include] 1 Identification of the plans and details of the survey [2904.1] 2 The location of the surveys is to be detailed in accordance with sub-Clause NG2908.8 [2904.2] 3 Requirement for Pre-cleansing [2904.4] 4 Where traffic management is to be provided by the Contractor details of the Employer’s requirements in

respect of the traffic management should be inserted. [2904.6] 5 Restricted working hours or work periods outside normal hours to be scheduled. [2904.12] 6 Responsibility for clearing blockages to be stated. [2904.13] 7 The content of the survey report, including number of copies and types should be specified [2905.1] 8 Requirement for items of the survey report to be provided to the Employer’s Representative [Specialist

responsible for the design of the Works] during the survey. [2905.2] 9 Recording format should be specified [2905.5] 10 Changes to the coding used for the survey should be specified [2905.8] 11 Photograph size should be stated if different from specification [2905.13] 12 Requirement for colour film or digital imager should be stated [2905.13] 13 Photographs intervals should be defined [2905.14] 14 The format for the presentation of survey photographs is to be specified. [2905.18] 15 The format for the presentation of photograph negatives where different to the specification [2905.19] 16 Requirement to photograph defects, features and condition to be stated [2908.10] 17 Where the removal and replacement of all manhole or access chamber covers will be undertaken by the

Empolyer, this should be stated [2909.1]

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