2159 TY UNNOS MODULE - ELEMENTS · 2159 TY UNNOS MODULE - ELEMENTS . Document title: TY UNNOS...

Purpose of issue:

INFORMATION

Document title:

TY UNNOS LADDER BEAM TIMBER SPECIFICATION

Document revision: B

Issue date: 15 Aug 12

QUALITY • INTEGRITY • EXPERIENCE

2159 TY UNNOS MODULE - ELEMENTS

Document title:

TY UNNOS LADDER BEAM TIMBER SPECIFICATION

Purpose of issue:

INFORMATION

QUALITY • INTEGRITY • EXPERIENCE

Document tracking: Revision: Description: Issued by: Date: Checked:

Report Ref: Created 04/06/10

Author: TJM Checked: IRHJ

Signed: Signed

Document revision: B

Issue date: 15 Aug 12

Versi

on 2

.0

The quality management system of Burroughs has been approved against ISO 9001.

© Burroughs 2009 This printing work may not be reproduced by any means without prior written permission of Burroughs and it may not be used without such permission for any work other than the one for which it was intended.

2159 TY UNNOS MODULE - ELEMENTS

2159 - TY UNNOS MODULE - ELEMENTS - LADDER BEAM TIMBER SPECIFICATION

August 12 QUALITY • INTEGRITY • EXPERIENCE

© Burroughs 2010 Version 2.0

1 of 4 f:\2187 ty unnos tsb funded research\06 specifications\02 structures\2187-ladder beam timber specification.doc

1.0 Introduction

1.1 Scope of Specification

This specification identifies and defines the structural requirements of the timber to be used for the manufacture of Ty Unnos ladder beams. This specification shall be used in place of timber grading to BS EN 14081, which is not applicable to small section sizes. This specification does not confer any official strength grade and is only to be used for Ty Unnos ladder beams which have been verified by structural testing.

This document should be read in conjunction with the general timber specification which gives details of fixings and all timber gradable in accordance with BS 4978.

1.2 Codes and Standards

The structural design of all timber elements shall conform to the requirements of the relevant European Standards and Codes of Practice current at the time of tender and any others that are applicable. These include:

BS EN 14081 Visual Strength Grading of Softwood - Specification BS EN 338:2003 Structural Timber – Strength Classes BS EN 1995-1-1:2004 Eurocode 5: Design of Timber Structures – Part 1-1: General – BS EN 1990:2002 Eurocode: Basis of Structural Design BS EN 12369-1:2001 Wood-based Panels – Characteristic Values for Structural Design

– Part 1: OSB, Particleboards and Fibreboards





2.0 Materials

2.1 Precluded Materials

The following materials are specifically precluded from all specifications pertaining to works carried out under this contract.

(a) High alumina cement or concrete

(b) Woodwool slabs as permanent shuttering

(c) Calcium chloride in admixtures for use in reinforced concrete

(d) Asbestos in any form

(e) Sea dredged aggregates for use in reinforced concrete unless otherwise instructed by the client

(f) Calcium silicate bricks

2.2 Timber Size

This specification is only applicable to timber which can not be strength graded in accordance with BS EN 14081. Only sections With a cross sectional area less than 2000mm2 or a thickness less than 25mm should be selected in accordance with this specification.





2.3 Un-graded Softwood for Ladder Beams

For all timber sections which comply with the size limitations set out in 2.2 the following conditions must be satisfied:

Timber with wane will be accepted provided that at no point the cross section dimensions of the timber is less than the nominal size less 3mm tolerance.

Full depth fissures are only permitted at the ends of sections and shall be limited in length to the section thickness.

Partial depth fissures shall be limited in length to 1.0m or ¼ the length of the section.

All timber shall be free from knots exceeding 50% of the face width. No distinction shall be made between knot holes, dead knots or live knots.

All timber is to be free from abnormal defects such as compression wood, insect damage (e.g. work holes, pin holes) or fungal decay (but not sapstain). These defects are permitted if the strength reduction caused by the abnormal defect is obviously less than caused by a permissible knot and does not progress after conversion and/or drying

All timber is to be free from active insect infestation. Wood wasp holes are not permitted.

Sections longer than 2.0m shall be free from excessive bow, spring or twist which would detrimentally effect fabrication.

Any parts of a timber section which does not conform to the above should be cut out of the section and discarded. Any good sections less than 100mm long after this process should also be discarded.

3.0 Workmanship Generally

3.2 Moisture Content

At the time of fabrication moisture content of timber to be not more than 18% but also not more than 7% different from that expected during service. Unless stated otherwise the equilibrium moisture content under normal service conditions is to be taken as Table 1 of BS 5268 : 1996.





3.3 Site Storage

For the storage of all timber on site or in the workshop:

Keep timber dry and do not overstress, distort or disfigure sections or components during transit, storage, lifting, erection or fixing.

Store timber and components under cover, clear of the ground and with good ventilation. Support on regularly spaced, level bearers on a dry, firm base. Open pile to ensure free movement of air through the stack.

Individual member markings to be visible when members are stacked.

Arrange sequence of construction and cover timber as necessary during and after erection to ensure that specified moisture content is not exceeded.

4.0 Jointing Timber

4.1 Jointing and Fixing Generally

Where not specified otherwise, fastenings, fixing and jointing methods and types, sizes and spacing of fastenings to comply with relevant European Standards.

All metal fasteners shall comply with BS EN 14592 and metal connectors shall comply with BS EN 14545

4.2 Glued Joints

Glued joints are not permitted in the ladder beams.

www.burroughs.co.uk The quality management system of Burroughs has been approved against ISO 9001.

© Burroughs 2009 This printing work may not be reproduced by any means without prior written permission of Burroughs and it may not be used without such permission for any work other than the one for which it was intended.

Registered Office: 4 Radnor Court 256 Cowbridge Road East Cardiff CF5 1GZ

T: 029 2064 7484 F: 029 2064 7499 E: [email protected]

Registration No: 2256733 VAT Registration No: 484 3312 48

Group branches: Isle of Man and Ireland. Burroughs is the trading name of Alistair Burroughs Design Partnership Ltd.

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