MSD-PROJ-AK-12-00507 - Specification for Temporary Repair
Transcript of MSD-PROJ-AK-12-00507 - Specification for Temporary Repair
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Table of Contents
1. Objective, target group and provision ..................................................................... 6
1.1 Objective ........................................................................................................................... 6
1.2 Definitions and Abbreviations ............................................................................................ 7
1.3 References ........................................................................................................................ 8
2. Requirements for piping repair methods ................................................................ 9
2.1 General ............................................................................................................................. 9
2.1.1 Personnel qualifications ...................................................................................................................... 9
2.1.2 Documentation .................................................................................................................................. 10
2.1.3 Inspection .......................................................................................................................................... 10
2.2 Philosophy ...................................................................................................................... 10
2.3 Defect Assessment ......................................................................................................... 10
2.3.1 Corrosion Assessment ...................................................................................................................... 11
2.4 Operating Condition Assessment .................................................................................... 14
2.5 Repair Options ................................................................................................................ 14
2.6 Testing of Temporary Repairs. ........................................................................................ 14
3. Products for Weldless Couplings And Clamps .................................................... 15
3.1 General ........................................................................................................................... 15
3.2 Off-the-shelf Designs ....................................................................................................... 15
3.3 Engineered Designs ........................................................................................................ 16
3.4 Suppliers ......................................................................................................................... 16
4. Products for Composite Wrap Systems ................................................................ 17
4.1 General ........................................................................................................................... 17
4.2 Off-the shelf systems ....................................................................................................... 18
4.3 Engineered Composite systems ...................................................................................... 18
4.4 Application to External Corrosion .................................................................................... 19
4.5 Application to Internal Corrosion ...................................................................................... 19
5. Acceptance Criteria for Damage to Flanges ......................................................... 20
5.1 Repair Methods for Flanges ............................................................................................ 20
5.2 RTJ - Flanges .................................................................................................................. 20
5.2.1 Acceptable damage/repairs to RTJ flanges ...................................................................................... 20
5.3 Raised Face Flanges ...................................................................................................... 23
5.3.1 Acceptable damage/repairs to RF flanges ........................................................................................ 23
5.4 Machining ........................................................................................................................ 24
5.5 Epoxy type flange repair .................................................................................................. 26
5.5.1 Requirements for application ............................................................................................................ 26
5.5.2 Raised Face Flanges ........................................................................................................................ 27
5.5.3 Ring Type Joints ................................................................................................................................ 28
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5.6 Repair methods for piping ............................................................................................... 28
5.6.1 General .............................................................................................................................................. 28
5.6.2 Clamps for temporary repair ............................................................................................................. 28
5.6.2.1 Standard Clamp and Coupling for temporary repair .................................................................... 28
5.6.2.1.1 Straub-Open-Flex 1L .................................................................................................................... 29
5.6.2.2 Special Clamp for temporary repair ............................................................................................. 30
5.6.3 Engineered Composite Repairs ........................................................................................................ 31
5.6.3.1 General ......................................................................................................................................... 31
5.6.3.2 Design requirements .................................................................................................................... 32
5.6.3.3 Applicability of repair system ........................................................................................................ 32
5.6.3.4 Internal Corrosion ......................................................................................................................... 32
5.6.3.5 External Corrosion ....................................................................................................................... 33
5.6.3.6 Documentation ............................................................................................................................. 33
5.6.3.7 Deviations ..................................................................................................................................... 33
5.6.3.8 Inspection ..................................................................................................................................... 34
5.6.3.9 Training and qualification ............................................................................................................. 34
5.6.3.10 Curing of composite repairs ......................................................................................................... 34
5.6.4 Tape activated with water for temporary repair ................................................................................. 35
6. Accepted cold installation methods ...................................................................... 36
6.1 General instructions ........................................................................................................ 36
6.2 Selection of cold installation methods .............................................................................. 36
6.3 Materials ......................................................................................................................... 37
6.4 Manufacturers machines and rotating tools ..................................................................... 37
6.5 Qualification of methods .................................................................................................. 37
6.6 Qualification of personnel ................................................................................................ 37
6.7 Documentation ................................................................................................................ 37
6.8 Use of installation flanges in HC systems ........................................................................ 38
6.9 Requirements for mechanical couplings .......................................................................... 38
6.10 Metal to metal press fitted components ........................................................................... 38
6.10.1 Quickflange ....................................................................................................................................... 38
6.10.1.1 Seal .............................................................................................................................................. 39
6.10.1.2 Materials ....................................................................................................................................... 39
6.10.1.3 Special installation considerations ............................................................................................... 39
6.10.1.4 Training ........................................................................................................................................ 39
6.10.1.5 Qualified range for All systems .................................................................................................... 40
6.10.2 Lokring, LTCS-A333 and SS40 ......................................................................................................... 40
6.10.2.1 Description ................................................................................................................................... 40
6.10.2.2 Sealing ......................................................................................................................................... 41
6.10.2.3 Special installation considerations ............................................................................................... 41
6.10.2.4 Materials ....................................................................................................................................... 41
6.10.2.5 Training ........................................................................................................................................ 41
6.11 Special couplings ............................................................................................................ 42
6.11.1 Morgrip .............................................................................................................................................. 42
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6.11.1.1 Description ................................................................................................................................... 42
6.11.1.2 Sealing ......................................................................................................................................... 43
6.11.1.3 Special installation considerations ............................................................................................... 44
6.11.1.4 Materials ....................................................................................................................................... 44
6.11.1.5 Training ........................................................................................................................................ 44
6.11.1.6 Qualified range ............................................................................................................................. 44
7. Appendices .............................................................................................................. 45
7.1 Appendix A: Design Data Sheet for an Engineered Repair (Ref basis ISO/TS 24817) .... 45
7.2 Appendix B: Suggested Technical Solutions ................................................................... 48
Table of Tables and Figures
Table 1 - Approved Products ........................................................................................................................... 16
Table 2 - Approved Products ........................................................................................................................... 19
Table 3 - Guideline for use of water-activated tape ......................................................................................... 35
Table 4 - Repair Classes ................................................................................................................................. 48
Table 5 - Technical solutions for piping repair and cold installation methods ................................................. 51
Figure 1 - Galvanic Table ................................................................................................................................ 13
Figure 2 - API BX ring Gasket when energised ............................................................................................... 20
Figure 3 - Type 'R' Gasket when energised .................................................................................................... 21
Figure 4 - Location of typical RTJ ring (type R) sealing surface...................................................................... 21
Figure 5 - Acceptable damage to RTJ flanges ................................................................................................ 21
Figure 6 - Damage to ring sealing surface ...................................................................................................... 22
Figure 7 - Damage to ring sealing surface ...................................................................................................... 22
Figure 8 - Damage on sealing surface ............................................................................................................ 23
Figure 9 - Inside edge damage ........................................................................................................................ 23
Figure 10 - Class 150# and 300# .................................................................................................................... 24
Figure 11 - Class 600# and higher (used on some older installations) ........................................................... 24
Figure 12 - Dimensioning of Ring-Joint Facing (all pressure rating classes) .................................................. 25
Figure 13 - Definition E modified and tf modified ............................................................................................. 25
Figure 14 - Straub-Open-Flex 1L type clamp .................................................................................................. 29
Figure 15 - Quickflange system ....................................................................................................................... 39
Figure 16 - Lokring system .............................................................................................................................. 40
Figure 17 - Example of Lokring component..................................................................................................... 40
Figure 18 - Morgrip System ............................................................................................................................. 42
Figure 19 - Morgrip Flange System ................................................................................................................. 43
Figure 20 - Morgrip Sealing System ................................................................................................................ 43
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1. OBJECTIVE, TARGET GROUP AND PROVISION
1.1 Objective
The objective of this document is to outline the basic requirements for repair methods and cold installation
methods. The requirements in this document shall form the basis for repairs and cold installation methods
for plants in operation. This document is intended to provide guidelines for evaluation and assessment of
temporary repairs to pipework on the Neptune Netherlands platforms.
For the organisational aspects, refer to the document "raising a Temporary repaired TR Work Order
(doc ref 1319827).
When the need to apply a repair to a piping system arises, a rapid response is normally required. It is
normally preferred to perform repairs without "hot work", and there are a variety of weld less products to
enable this. This document appraises the products and places limitations on their use for hydrocarbon and
utility services. It is also intended that these guidelines will provide information on the application of such
repairs in order to control and prevent inappropriate application and serve as an aide and be used in
conjunction with the temporary repair procedure.
In the context of this work, a repair is taken to mean an existing pipe with a leak or identified defect which
is modified in-situ or a section replaced so that the system is fit for continued operation.
Repair methods described in this document is recommended for repair of the unacceptable damage to
flanges, pipes and fittings. The purpose of the repairs is to keep the system running until a replacement
can be made or as a permanent repair. This document is developed to achieve a uniform practice for the
repair of piping systems in operation. This document describes when and how to use patches, clamps, or
wrapping with composite materials, as a temporary or permanent repair method for piping systems, so
that normal operations can be maintained without unnecessary replacement. Choice of repair- and cold
installation method shall be based on a documented technical / economic evaluation.
There are five types of repair:
Replace like for like
Temporary repair, time limited solution
Permanent repair, not like for like but without time limit
Temporary repair requiring engineering approval, time limited solution
Permanent repair requiring engineering approval, not like for like but without time limit.
The cold installation methods described in this document are selected components that are found
qualified and acceptable for use on our platforms.
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1.2 Definitions and Abbreviations
ESV Emergency Shutdown Valve
FKM Elastomer (Viton)
GRP Glass-Reinforced Plastic
HNBR Elastomer
IACS International Association of Classification Societies Ltd
NBR Elastomer (Nitrile)
NDT Non Destructive Testing
PCC Post Construction Code
PM Preventive Maintenance
PSV Pressure Safety Valve
PWHT Post Weld Heat Treatment
RF Raised Face
RTJ Ring Type Joint
SAP Systems, Applications, and Products in Data Processing
SCC Stress Corrosion Cracking
SJA Safe job analysis
TA Technical Assessment
WPQ Welding Procedure Qualification
WPQR Welding Procedure Qualification Record
WPS Welding Procedure Specification
can Statement with option for Vendor to implement.
competent person A person with predefined training and certificate
Criticality Verbal form used in to describe the evaluation of HSE / regularity consequences
due to a possible leakage
may Verbal form used to indicate a course of action permissible within the limits of this
specification
non critical
systems
Product or product code where all the following apply: The fluid handled is non-
flammable, nontoxic, and not damaging to human tissues.
Permanent repair Repair where improvement is considered sufficient to restore the integrity of the
pipe for remaining lifetime.
Pipe class design
pressure
The pressure at the system temperature according to piping class sheet
Plant(s) Verbal form used to define validity area of this document. Plant(s) includes topside
offshore installations and above ground on onshore plants / installations.
shall Verbal form used to indicate requirements strictly to be followed in order to
conform to the standard and from which no deviation is permitted, unless
accepted by all involved parties
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should Verbal form used to indicate that among several possibilities one is recommended
as particularly suitable, without mentioning or excluding others, or that a certain
course of action is preferred but not necessarily required
System design
pressure
The maximum design pressure for a specific line given on the P&ID and line list or
PSV set pressure in ESV segment
temporary repair Repair where replacement or new repair is planned later and normally at the next
planned shutdown.
1.3 References
API 570 In-service Inspection, Repair and Alteration of Piping Systems
API 2201 Safe Hot Tapping Practices in the Petroleum & Petrochemical
Industries
ASME B16.5 Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24
Metric/Inch Standard
ASME B16.9 Butt Weld shapes
ASME B31.3 Process Piping
ASME PCC-2 Repair of Pressure Equipment and Piping
ISO/TS 24817 Composite repairs for pipework -- Qualification and design,
installation, testing and inspection
ISO 6162-1 Hydraulic fluid power -- Flange connections with split or one-piece
flange clamps and metric or inch screws -- Part 1: Flange connectors,
ports and mounting surfaces for use at pressures of 3,5 MPa (35 bar)
to 35 MPa (350 bar), DN 13 to DN 127
ISO 6162-2 Hydraulic fluid power -- Flange connections with split or one-piece
flange clamps and metric or inch screws -- Part 2: Flange connectors,
ports and mounting surfaces for use at a pressure of 42 MPa (420
bar), DN 13 to DN 76
General Specification 525
(MSD-PROJ-AK-12-000525)
Specification for Painting and Coating
General Specification 503
(MSD-PROJ-AK-12-000503)
Specification for Pipe Fittings and Valves
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2. REQUIREMENTS FOR PIPING REPAIR METHODS
2.1 General
During inspections and execution of maintenance for plant in operation it is occasionally found damage
has occurred to pipe, flanges, valves or other equipment that requires some form of repairs. Acceptance
criteria's and repair methods are described in this paragraph. Choice of repair method, Evaluation of repair
method should be based on the following criteria:
Safety and risk consideration
Time until the next scheduled shutdown
System criticality, pressure-class/operational pressure and temperature
Extent of damage and the possibility for further development of damage (media and corrosion)
External or internal damage
The need for inspection
Complexity of repair
Accessibility for inspection
Geometric design, static and dynamic load of the component or system
Repair time and the consequences of shut down
Expected remaining lifetime
2.1.1 Personnel qualifications
Machining:
Machining shall only be performed by a qualified operator with knowledge / experience in the use of
necessary tools.
Application of composite materials (repair composites. GRP lamination, etc.):
Personnel that shall apply the coating shall have the necessary product knowledge and practical exercises
conducted under the supervision of the supplier or paint contractor. The operator shall have knowledge of
the required purity / roughness on the steel surface, the curing time / mix of product, application
techniques, safety, etc.
For composite repairs for pipe work the requirements in ISO/TS 24817 (Petroleum, petrochemical and
natural gas industries -- Composite repairs for pipework -- Qualification and design, installation, testing
and inspection) for "Installer qualifications" shall be fulfilled. On request written documentation /
certification for personnel qualifications shall be provided.
Use of compression type and clamp type fittings
Only personnel trained in the application of these systems shall be allowed to install them.
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2.1.2 Documentation
A temporary repair that requires follow up or may have consequences for possible future repair shall be
documented within company guidelines, refer to "raising a Temporary repaired TR Work Order (doc ref
1319827).
2.1.3 Inspection
Repair of damages on piping systems should be categorised as a temporary or permanent repair (see
definitions) prior to performing the repair. Based on damage, damage mechanism and consequence of a
leakage a temporary repair shall be evaluated for the need for future inspections to ensure that the applied
materials / coating remains intact, thus preventing a further development of the damage.
2.2 Philosophy
For Piping Systems, the repair philosophy in descending order of preference shall be:
Replace like for like
Temporary repair, time limited solution
Temporary repair requiring engineering approval, time limited solution
Permanent repair requiring engineering approval, not like for like but without time limit.
Temporary repairs shall be shall time limited to the next scheduled maintenance stop of the system of
which the repair is a part with a maximum duration of 1 year. This time may only be deviated from after
approval by an authorised person.
2.3 Defect Assessment
The defect assessment shall be in line with 'Praktijkregels voor Drukapparatuur’:
3.1 Opstellen herbeoordelingsplan
3.2 Beschrijving en aanvaarding van inspectiemethoden en technieken.
3.3 Beoordeling van lnspectie en onderzoeksresultaten
4.1 Fitness for service
5.2 Stappenplan voor reparatie en niet ingrijpende wijzigingen
Consideration shall be given to:
Has the piping been replaced or repaired before?
Has the piping failed in the same manner as before?
Do redundant connections need to be replaced?
Is there an advantage in reducing the line size if practical?
Is the condition of tie-in flange faces acceptable?
Have operating conditions changed over the life of the problem area?
Has material selection been a factor?
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2.3.1 Corrosion Assessment
To properly understand corrosion mechanisms a general description of the major corrosion mechanisms
is given in this paragraph.
The internal or external defects encountered are likely to be attributed to:
Uniform corrosion, general or localised attack.
Crevice Corrosion
Galvanic activity
Pitting
Erosion corrosion
Stress corrosion
Fatigue
In general, the following conditions increase the chance and severity of corrosion:
High temperature
High chloride concentrations (i.e. at lot of salt)
High CO2 concentrations
The presence of water
The presence of oxygen
Carbon Steel
In most cases corrosion of carbon steel is general corrosion, i.e. wall thickness, will reduce over a large area
at a uniform rate. If specific process conditions are right (or wrong) localised corrosion can happen such as
Top of Line corrosion, due to CO2 and condensing water. Carbon steel can also corrode locally due to a
corrosive liquid dripping on to steel. Also, external corrosion, due to damage of the coating, is generally
localised.
Carbon steel / CRA connections
The combination of carbon steel and CRA (Corrosion Resistant Alloy 316, duplex etc.) can also lead to
corrosion, specifically galvanic corrosion when the materials used are electrically connected and there is
an electrolyte (water) present. The CS acts as an Anode and the CRA is the Cathode. The CS will go into
solution (i.e. dissolve, disappear) while the CRA remains unaffected. The smaller the anode the faster it
goes into solution. If the anode is very large compared to the cathode, the rate of corrosion is slow.
Therefore, a 316L ½" plug in a carbon steel piping system will not cause a lot of corrosion, but a CS plug in
a duplex system will have a high corrosion rate.
The solution is to choose materials that are closer to each other on the galvanic chart or isolate the
materials from each other.
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Galvanic Corrosion
Alloys are listed in the order of the potential they exhibit in flowing sea water. Certain alloys indicated by
the symbol (symbol) in low velocity or poorly aerated water, and at shielded areas, may become active and
exhibit a potential near -0,5 volts.
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Figure 1 - Galvanic Table
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CRA (Corrosion Resistant Alloys, 316L, duplex, etc.)
CRA's are corrosion resistant due to the passive layer that forms under the influence of oxygen during the
fabrication process. Damage to the passive layer will result in a galvanic cell much like galvanic corrosion
described above, only now within one material. The damaged area becomes the Anode, while the rest of
the pipe is the Cathode. Corrosion of CRA's is therefore localised corrosion manifesting itself as pits,
wormholes or cracks. These are difficult to detect and can propagate quite fast.
2.4 Operating Condition Assessment
A full assessment of the operating conditions to which the repair will be subjected shall be completed
including.
Fluid
Design pressure
Min/Max Operating Temperature
Location
Inspection Access
Hazardous Area
2.5 Repair Options
For repair options see Appendix B.
2.6 Testing of Temporary Repairs.
When a repair is necessary due to loss of wall thickness or a loss of containment (i.e. a hole) and the pipe is
repaired either for a defined period of time or as a permanent repair, the integrity of the repair shall be
proven. Testing shall be performed after completion of the repair and prior to bringing the line back into
service, compliance with En-13480 / Warenwet (0.9 x original test Pressure for 30 minutes duration).
Atmospheric open drain lines are the only exception and may be flushed or filled with water and leak tested
instead of doing a pressure test as described above.
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3. PRODUCTS FOR WELDLESS COUPLINGS AND CLAMPS
3.1 General
There are numerous devices available that cover pipe clamps and pipe connectors. As their names imply,
the former usually clamp over the pipe while the latter replaces pipe connections, such as flanges, by being
designed to accept the bare ends of pipe.
Any repair performed using these devices shall be designated as either temporary or permanent as well as
"off-the-shelf' or "Engineered".
With either type (clamp or connector) the performance requires attention to the preparation of the pipe
surface receiving the clamp or the connector. As with over-wrap systems all loose paint and corrosion
deposits shall be removed, and the corrosion effects will be "stopped".
Leakage prevention is usually achieved through the use of elastomeric seals or linings (metal to metal)
incorporated in the devices casing, being forced against the pipe wall.
If used as a repair device on gas conveying lines they shall be classified as temporary, unless the clamp has
been engineered specifically for that situation.
Where used on any other service, "off-the-shelf' designs will only be applied following discussions with the
manufacturer on the suitability of the sealing material for the liquid being handled and on the pressure
rating of the clamp or connector body. Any device must be considered before application for its suitability
to the system design pressure (MAWP) and temperature range.
These devices may counter the effects of internal or external corrosion, but where there is a need for the
repair to contribute to the structural strength of the corroded pipe then only engineered designs shall be
considered as suitable.
A clamp is unlikely to be able to impart sufficient grip to resist axial movement. Depending on the
connector selected some do have a mechanical arrangement that can impart and resist axial movement.
3.2 Off-the-shelf Designs
The most common type of clamp in this design is the elastomer lined clamp, which is deployed by placing
it over the defective area and then tensioning it up circumferentially hence compressing the lining to make
a leak proof connection. A similar application description applies to those clamps using local split
circumferential seals instead of a lining; pressure energised seals are preferred.
These standard clamps are only considered suitable for straight pipes, where they are not required to
impart or resist a mechanical force in an axial direction. In addition, this style of clamp is restricted to class
150# rated piping systems. For class 300# and above, the more robust types of clamp with rigid body are
required.
For bends and where axial restraint is required, only engineered clamps should be utilised or standard off
the shelf clamps can be considered when additional support is added, the repair must engineered for the
application.
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3.3 Engineered Designs
These may be considered for application in any medium as a permanent fix. By implication, these are
clamps have been specifically selected, designed and manufactured for a specific application and specific
service conditions.
Engineered clamps can be applied to hydrocarbon liquid and non-hydrocarbon liquid conveying piping as
either temporary or permanent repairs provided the supporting mitigation is prepared and deemed
acceptable.
Engineered clamps are usually a two-piece construction with the mechanical joint in one plane and
injection energised seals along the joint line and around the penetrations. With respect to the casing
pressure retention ability they are likely to be designed to a pressure vessel standard; usually either ASME
VIII or PD5500.
To improve rigidity of the clamp the internal void spaces between the pressure retaining casing and the
enclosed pipe is filled with a solidifying resin; that resin should not be relied on to act as an additional seal.
Due to a possible increase in weight/load using this type of clamp, a support review shall be performed. As
a result, additional support(s) may be required to mitigate undue pipe stress.
It is necessary to ensure that such clamps have incorporated in their design a provision for restraining any
axial movement that may arise due to the application.
Clamps with energised seals will require periodic inspection to ensure the seals remain energised.
Some Manufactures limit the number of times a clamp seal can be re-energised.
TYPE OF PRODUCT VENDOR PRODUCT
Clamp Furmanite Box clamp
Coupling Technom tools Lokring
Hydratight Morgrip
Verwater Quick Flange
Straub METAL-GRIP
Table 1 - Approved Products
3.4 Suppliers
For list of suggested technical solutions specific limitations, see “Appendix B: Suggested Technical
Solutions” to this document. This appendix is for internal use only. Other solutions may be accepted by
Company based on a technology assessment.
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4. PRODUCTS FOR COMPOSITE WRAP SYSTEMS
4.1 General
Composite over-wraps are repair systems that encase the pipe in the vicinity of the defect by wrapping
around it several layers of an epoxy impregnated tape (wraps).
Depending on the pressure rating it is an alternative to weld repairs, fitting of metal sleeves or other
mechanical type repairs.
Over-wraps can be used to repair pin holes and compensate for lost wall thickness.
The flexibility of over-wrap materials and the application options are a key advantage with this type of
repair. It is possible to use over-wraps on steel piping Class 150# and 300#. Engineered over-wraps are
available for pressures above Class 300# but need rigorous testing and engineering qualification prior to
installation. All repairs using composite wrap shall comply with the requirements of ISO/TS 24817
(Petroleum, petrochemical and natural gas industries -- Composite repairs for pipework – Qualification
and design, installation, testing and inspection).
Over-wraps can be made compatible with most fluids conveyed on a production platform or gas
processing plant. However, these systems should not unless engineered specifically, be used on gas
systems where there will eventually be a through wall leak within the lifetime of the piping; the
permeability of the over-wrap generally makes it unsuitable for this application. In certain low-pressure
gas; systems there may be circumstances where there use may be technically justifiable considered
acceptable.
The application of over-wraps shall preferably be done with the system shutdown, but it only requires to
be drained where the repair is to a leak.
Over-wrap repair durability is only as good as the bond adhesion between the parent metal and the applied
over-wrap. Therefore, surface condition is the key to a successful repair. Surface abrasion by shot blasting
or other means, followed by chemical cleaning and finally a rinse with potable water is a satisfactory
approach. It is also preferable and good practice to ensure that the prepared surface is dry immediately
prior to applying the over-wrap.
Seawater shall not be used as a final rinse of any surface of the repair area; residual salt crystals can
adversely affect the bond. Once an over-wrap is applied it is necessary to leave it to harden (cure). Even
though it may be dry to the touch this does not indicate that it is fully cured or has reached its full strength.
Always follow the supplier's instructions on cure times and the environmental temperature associated
with these times is met. It may be necessary to build a habitat around the repair and employ warm air
blowers to achieve an adequate air temperature. Application temperatures usually have to be above 10ºC;
data accompanying the supplier's material should advise on this.
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Where practicable the corrosion area or pitting should be arrested and filled with an "epoxy putty" prior to
applying an over-wrap; Over-wrap suppliers will advise on a suitable "putty" to use.
When applying an over-wrap, the suppliers' instructions on safety matters shall always be followed.
Rubber gloves, eye protection and long-sleeved coveralls shall be the least protective clothing worn by all,
including standby or inspection personnel involved in the repair. It is recommended that only technicians
trained in the application technique shall make these repairs.
4.2 Off-the shelf systems
These are composite over-wrap systems that can be purchased from a supplier as a "do-it-yourself” kit.
Only systems that come complete with "How-to-use", Safety instructions shall be purchased. As they have
not been "Engineered" for a specific repair the information on the number of layers to be supplied or the
extent of the overlap are unlikely to be included. For that reason, off-the-shelf systems shall only be used
on ANSI 150# piping, also, any repair shall be classified as temporary. Neither shall they be used in any
hydrocarbon liquid service where the repair is expected to contribute to the strength of the pipe or survive
a future leak.
As guidance on the number of layers and overlap to be applied, unless previous experience suggests
differently, the following rules of thumb shall be used.
(i) The minimum over-wrap built up thickness shall be greater than 5 mm or the thickness equivalent
to 5 layers of wrap, whichever gives the greater value.
(ii) The extent of the lay-up in way of the repair zone shall be the larger of 100 mm or (2 x sq root of
the (pipe o.d. (mm) x wall thickness (mm)) either side of the periphery of the area under repair.
Note: the 100 mm size will cover ASME Class 150# and 300# pipes up to 10" Nominal Diameter and wall
schedule 30 and 40. Above this range the extent of the lay-up shall be calculated.
4.3 Engineered Composite systems
These are composite over-wrap systems that shall be engineered, and purpose designed for each
application and pipe work configuration. They shall usually be applied either by specialist supplier or by
specially trained third party contractors under his supervision.
The design validation will be made by the specialist supplier or his appointed contractor and as a minimum
shall meet the requirements the AEA technology guidelines (March 2002). Published by H.S.E. (UK).
All designs shall be validated by qualification testing to demonstrate dependability and durability as well
as application technique and step plan. The latter two shall mirror the procedures that will be used for the
on-site repair, including surface preparation.
All designed over-wrap repairs shall be performed, as a matter of choice, by the supplier who has
engineered the repair and conducted the qualification tests. Similarly, the personnel involved in applying
the over-wrap shall also carry out the on-site repair.
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4.4 Application to External Corrosion
For external corrosion, without perforation of the pipe wall, such a repair shall maintain the mechanical
properties of the pipe in the event of a complete perforation. The arrangement of such repairs shall permit
regular and meaningful inspection to be carried out. It shall also be a requisite that all surface pits etc. are
filled with epoxy putty prior to the application of the over-wrap.
For external corrosion, where there has been a perforation of the pipe wall, such a repair shall be classified
as temporary where the pipe is conveying hydrocarbon liquids. If the pipe were conveying non-
hydrocarbon liquids, then the repair can be permanent. The arrangement of such repairs shall permit
regular and meaningful inspection to be carried out.
4.5 Application to Internal Corrosion
It is likely that countering this form of corrosion can only be tackled by applying an Engineered Overlay to
the outside of the pipe. Therefore, applying the same approach as for external corrosion will be the only
course of action available. Should however suitable access be available then an internal repair may be
engineered. These latter repairs will also follow the terms noted for the external corrosion.
TYPE OF PRODUCT VENDOR PRODUCT
Composite Wrap
Synthoglass type SG
Table 2 - Approved Products
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5. ACCEPTANCE CRITERIA FOR DAMAGE TO FLANGES
5.1 Repair Methods for Flanges
General requirements:
Before considering a repair with the use of repair compound (epoxy) or welding investigate
whether the damage can be repaired by machining.
Flanges must be checked with respect to critical dimensions and any measurements above
tolerance will be a deciding factor in whether welding is required or if machining is sufficient.
For welding repairs of gasket surface (ring grooves, flat face, raised face, etc.) machining tools
must always be used to prepare a new gasket surface. Other repaired areas can be smoothed by
grinding.
Repairs using epoxy shall only be performed to prevent further development of a damaged
component. This will have no compensatory effect to the strength of the component.
If the damage is greater than the acceptance criteria given, then one of the following actions must be
taken prior to operation:
Permanent repair: Damage removed by machining, welding or replacement.
Temporary repairs: Machining to a minimum thickness, the damage is not removed but reduced to
within the acceptance criteria and the damage is accepted for further operation.
Temporary repairs with compensating measures: Applicable when the damage is outside the
acceptance criteria. This option should only be used after a comprehensive risk assessment.
(Compensatory measures may be gas measurement on hydrocarbon lines and splash cover for
water injection etc.)
5.2 RTJ - Flanges
5.2.1 Acceptable damage/repairs to RTJ flanges
It is not acceptable to use epoxy for the repair of the ring sealing surface.
Damage that may cause the ring to be in contact with the bottom of the groove is not acceptable due to
possible metal to metal contact between the raised faces. There shall always be a gap between the RF of
the flanges; blade thickness gauge must be used to verify that there is sufficient gap, with the exception
of API flanges where the final gap is much smaller.
Figure 2 - API BX ring Gasket when energised
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Figure 3 - Type 'R' Gasket when energised
A limited uniform circumferential mark from previous installed rings is acceptable if depth is less than
approximately 1 mm.
Figure 4 - Location of typical RTJ ring (type R) sealing surface
Damage outside the ring sealing surface:
Damage outside "ring sealing surface" can normally be
accepted. The ring sealing surface is normally visible when
opening flanges in operation. The ring sealing surface is
defined as the area between: maximum 15% of the groove
depth from top or bottom of ring groove, see Error!
Reference source not found..
Restricted damage outside the ring groove is acceptable
on the "raised portions.
Repair with epoxy can be performed for damage outside
the ring groove.
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Figure 5 - Acceptable damage to RTJ flanges
Damage of the ring sealing surface
Damage is accepted if they do not cover more than
25% of the width of the ring sealing surface.
When there are multiple independent damages
across the ring sealing surface, the distance
between the damages shall be at least 4 times the
width of the damage.
Small patchy damage (pitting) may be acceptable
provided:
D ≤ 1mm
The distance between the pits: >2 x D
Damage area shall be less than 50% of the
ring sealing surface width.
D = diameter of each pit
Figure 6 - Damage to ring sealing surface
Figure 7 - Damage to ring sealing surface
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5.3 Raised Face Flanges
5.3.1 Acceptable damage/repairs to RF flanges
Raised Face Flanges the damage can be repaired with epoxy as detailed below.
Where spiral wound gaskets are used, epoxy shall not be used on the active sealing surface.
Damage in the sealing surface
Localized damages as shown in the figure and
damages from the outside into the raised face
surface can normally be accepted.
When there are multiple pits within large parts of
the sealing surface, the clearance between the
individual pits shall be at least 4 times the extent
of each pit.
Damages in the seal faces, measured as a radial
projection, can be accepted if they do not cover
more than 30% of the width of the gasket surface.
Damages should not be deeper than 5mm, except
the edge damage as shown in Figure 8. A radial
projection is defined as the difference between an
inner and outer radius surrounding the damage
which is the radius from the centre line of the pipe.
Damages less than 0,5mm do not need to be
repaired.
Figure 8 - Damage on sealing surface
Damages of internal edge
Damages of internal edge around the bore, may be
acceptable if it does not cover more than 30% of
the width of the gasket surface:
BMax = 0.20 x A
A=OUTSIDE DIAMETER RAISED FACE-INSIDE DIAMETER PIPE
2
Figure 9 - Inside edge damage
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5.4 Machining
Machining as a repair method for flanges (without welding) may be used provided that the thickness and
tolerances are according to ASME B16.5 and requirements given below.
A repair done by means of machining can result in that component thickness reaches its minimum value.
In such cases it is important to follow up with inspections to ensure that a further reduction of the material
thickness does not result in an unacceptable condition. For flanges that has been previously machined this
must be taken into consideration.
Prior to machining flange faces, the pipe flexibility shall be evaluated to ensure that the reduced length of
the flange not will impose additional stress to the piping system.
The pipe assembly after repair shall be according to C097-AKE-L-SP-0002 "Piping Fabrication,
Installation and Testing Specification" without springing or forcing pipe work to avoid undue stressing.
Raised face flanges
Machining of Raised Face flanges can be carried out according to the following guideline:
1) Machining of the flange raced face is acceptable if damage ≤ 1.2 mm for class 150# and 300#. If
the flanges touch the outer diameter this indicates too high bolt tensioning.
2) Machining of the flange raced face is acceptable if damage ≤ 6.2 mm for class 600#. If the flanges
have contact on the outer diameter this indicates too high bolt tensioning.
Figure 10 - Class 150# and 300# Figure 11 - Class 600# and higher (used
on some older installations)
3) Machining of the flange raced face with damage deeper than 1,2mm for class 150#, 300# and
600#.
a. Check the extent of damage (depth/height)
b. Height E shall be no less than 0,8 mm
c. Check the required machining of the flange ring (tf) to establish the re-establish the raised
face E of minimum 0,8 mm.
d. The flange thicknesses between all bolts holes shall be measured by callipers, minimum
measurements are noted.
e. Check that tf is thicker than minimum thickness according to ASME B16.5 after the
required machining
f. tf is thinner than minimum thickness according to ASME B16.5 flange calculation shall be
performed to verify the flange capacity.
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g. Machining to be performed according to the geometry requirements of ASME B16.5.
RTJ flanges
Damaged RTJ flanges can machined according to the following guideline:
Figure 12 - Dimensioning of Ring-Joint Facing (all pressure rating classes)
a) Check the flange history to ensure that the flange is not previously machined
b) Check the extent of damage in the groove (depth/height)
c) Check the machining depth required to the flange face and groove to re-establish undamaged
groove dimensions
d) Based on c) establish the new E modified (height of raised face)
e) The flange thicknesses over all bolt holes tt are measured by calliper, minimum measurements are
noted.
f) tt modified in the groove is tt +E modified - E according to table 5 in ASME B16.5
g) Check that tt modified is thicker than minimum thickness according to ASME B16.5 (tt minimum)
after the required machining.
h) If tt modified is thinner than minimum thickness according to ASME B16.5 (tt minimum) flange
calculation shall be performed to verify the flange capacity. Calculation is not required if tt
minimum - tt modified according to table 2.2.
i) Machining to be performed according to the geometry requirements of ASME B16.5.
j) Check if piping system is flexible enough to compensate reduction of the length of the flange.
k) Check roughness of groove.
Figure 13 - Definition E modified and tf modified
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5.5 Epoxy type flange repair
Epoxy type filler materials shall be applied according to the supplier's application procedure. The
Application Procedure shall be accepted by Company and be in accordance with the requirements of this
paragraph. Damages shall not exceed the acceptance criteria given above. in paragraphs 5.2.1 / 5.3.1
A Material Safety Data Sheet shall be available for all products.
The filler material datasheet shall state limitations to upper and lower temperature limits for dry
conditions and in contact with fluid. Materials in contact with the fluid shall be checked for chemical
resistance. The filler material limits shall be compatible with design criteria's for the piping system that it
shall be used on.
A repair with epoxy shall be categorised as a temporary or a permanent repair based on the criticality of
the system.
A temporary repair shall be subject to inspection to ensure that the applied coating remains intact, thus
preventing a further development of the damage.
5.5.1 Requirements for application
Preparation of damaged area:
For damages with deep pits, the transition between adjacent surfaces and damage surface need to be
ground to achieve a smooth transition with no sharp edges.
Epoxy must not be applied to "needle pitting" as these should always be opened up with grinding tools
before epoxy is applied.
Clean and dry surface:
If there is oil residue on the steel surfaces, for example in the pores, this must be removed before
application of epoxy. Salt residues must be removed and the cleanliness must be verified by using the
salinity tester. Dirt, grease, oil, etc. shall be removed with suitable detergent (Belzona NF, Chesterton 277
or equivalent). The environmental condition for applying the product shall be according to
recommendations from the manufacturer.
Blast Cleaning:
The surfaces shall be repaired must be blasted to SA 2.5 and a surface profile of min 75µm. Epoxy should
be applied immediately after blast cleaning to prevent the steel to oxidize.
If it is not possible to blast clean the surface should be sanded or scratched mechanically to achieve the
specified cleanliness and surface profile.
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Application Technique:
Epoxy shall be applied according to recommendations from the manufacturer, using a stiff bristles brush
or plastic applicator. It is important to avoid air pockets between the applied mass and the surface.
Trapping of air must be avoided by wetting the surface profile with a stiff bristles brush and work the mass
into the surface profile to assure good adhesion to the surface. The coating is formed to the desired pattern
with a trowel/spatula.
Maximum thickness for application of epoxy is normally 6 mm, ref manufacturer's recommendation. If the
depth of the damage exceeds 6 mm additional layers is required to avoid air bubbles in the epoxy materials.
Due to amine diffusion on the surface during the first part of the curing process, additional layers must be
applied within 2 hours (at a temperature 20 - 25°C). If the time exceeds 2 hours the epoxy must be rubbed
or cold jet /dry ice blasting before the next layer is applied.
5.5.2 Raised Face Flanges
Minor damage:
By repairing minor damage to the gasket surface, where flange mould is not used, the epoxy is applied on
the flange surface as evenly as possible over the damaged area.
Apply epoxy according to the application technique described above.
Avoid filling the grooves with epoxy in the intact part of the gasket sealing surface.
After curing, the gasket surface shall be smoothed by machining or by using grinding paste, etc.
Larger damages repaired with flange mould:
Use of flange mould shall be according to recommendations from the manufacturer. Flange mould and
bolts shall be applied with minimum 2 layers with a suitable release agent.
Apply epoxy according to the application technique described above. By using the plastic applicator
additional material shall be applied as a V shaped to ensure that trapped air is squeezed out during
assembly of the mould.
The profile in the flange mould shall be wetted using stiff bristles brush and extra material shall be applied
so that the obstruction of air is avoided. The flange mould shall be pressed directly against the flange
surface and the bolts tightened using the cross tightening technique while the excess epoxy is removed.
The flange mould is fabricated with machined grooves (gramophone grooves) which creates a replica in
the epoxy flange facing.
The curing shall be according to the manufacturer's recommendation. After curing the bolts shall be
loosened and release the mould by using flange mould jack bolts. The form should not be hammered loose.
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5.5.3 Ring Type Joints
Epoxy can be used to completely fill the ring groove and cover the complete face of the flange, effectively
changing the flange to a flat face. Only a flat face gasket can now be installed. This type of repair requires
TA approval. (HOLD)
5.6 Repair methods for piping
5.6.1 General
Below the following terminology are used:
Pipe class design pressure: The pressure at the system temperature according to piping class
sheet.
System design pressure: The maximum design pressure for a specific line given on the P&ID and
line list or PSV set pressure in ESV segment.
The repair of piping shall be performed to meet the pipe class design pressure and temperature.
When there are no other alternatives than repairing the line according to the system design pressure, the
repair shall be approved by the system technical responsible and discipline technical responsible.
The repair shall be documented in Maximo or other relevant systems.
Repair of a pipe according to operational pressure is not acceptable.
The below described methods shall not be used when cracks are present.
For list of qualified technical solutions specific limitations, see appendix to this document. The appendix is
for internal use only. Other solutions may be accepted by Company based on a technology assessment.
5.6.2 Clamps for temporary repair
Clamps may be used as a temporary repair to stop a leakage or to reinforce and secure the integrity when
the wall thickness is reduced.
5.6.2.1 Standard Clamp and Coupling for temporary repair
This section includes clamps and couplings that can be installed without cutting the pipe.
Clamp/coupling may be used as a temporary repair to stop a leakage or secure the integrity of the piping
system when the wall thickness is reduced.
Lifetime is limited to the first opportunity to perform a permanent repair. A permanent repair shall be
performed maximum 3 years after the temporary repair.
Standard clamp/coupling shall be used according the requirements herein and to manufacturer’s
installation procedure.
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The clamp/coupling materials shall be selected and evaluated based on the pipe materials and location
due to exposure to saliferous atmosphere.
The soft sealing material shall be compatible with the medium and temperature.
Requirements for fire insulation shall be evaluated based on the system criticality and area fire
classification. If clamp/coupling with soft sealing material is used on firewater systems, the
clamp/coupling shall be fire insulated.
The damage shall be completely covered by the clamp/coupling and the pipe shall be free from damages
in the clamp/coupling seal area.
Establish work order for permanent repair when temporary clamp/coupling is used.
For fully rated piping (Typical: 20 barg / class 150#) shall the piping system be de-rated to maximum
system design pressure. The maximum system design pressure shall be below or equal to the
clamp/coupling maximum pressure as specified in the tables below.
5.6.2.1.1 Straub-Open-Flex 1L
Straub-Open-Flex 1L rubber seal clamp can be used as temporary repair method on systems with
maximum system design pressure 16 barg.
Description
Straub-Open-Flex 1L shall be installed without
cutting the pipe and is therefore suitable for
temporary repairs on pipes with typical minor
corrosion damages.
Figure 14 - Straub-Open-Flex 1L type clamp
Sealing materials
Soft sealing material shall be NBR.
Clamp Materials
The materials shall be SS316 (manufacturer's materials specification W5)
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5.6.2.2 Special Clamp for temporary repair
Split sleeve repair special clamps may be used as a temporary bolted type repair method to stop leakages
or to secure the integrity when the wall thickness is reduced. These types of clamps are typically tailor-
made and may be used based on economical and safety evaluation compared with a system shutdown.
To ensure correct design of the clamp the following information shall be provided to the
manufacturer/supplier:
Pipe size and reference to actual piping class sheet and the exact measured diameter/ovality of
the pipe.
Available length and volume around the pipe and restrictions if any
Piping isometric (geometry)
Working condition (access, scaffolding requirements)
System design pressure and temperature range
Required lifetime the repair shall be designed for
Material handling equipment available and the need for lifting lugs
Bolt lubricant used on the plant
Environmental condition (saline atmosphere, water spray, mechanical ventilated area, etc).
Medium and chemical content (e.g. methanol, oil, hydrocarbon gas, etc.)
Supplier shall advise:
Required pipe surface finish where clamp shall be installed
Clamp weight and specific material handling requirements
Required assistance for installation of clamp
Supplier shall provide:
Special clamp with design documentation including calculations and drawings
Installation procedure including bolt torque required for bolted connections based on specified
lubricant
Installation if requested
Specific requirements:
The damage shall be completely covered by the clamp
The clamp should be accessible for visual inspection. (Need for inspection shall be evaluated based
on the media in the pipe).
Establish work order for permanent repair
The repair shall be documented in relevant systems.
Requirements for fire insulation shall be evaluated based on the system criticality and area fire
classification. If clamps with soft sealing material on firewater systems, the couplings shall be fire
insulated.
The use of clamp shall be in accordance with ASME PCC-2 "Mechanical Clamp Repair"
Clamp shall as a minimum be approved for system design pressure
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Additional weight caused by the clamp shall be evaluated by a stress/pipe support engineer.
Evaluate if the clamp shall be able to take additional axial loads (structural clamp)
Ensure that the chemical resistance of gasket materials is compatible with the medium
Default clamp materials should be CS. However the clamp materials should be evaluated based on
pipe material, the corrosion effect of the medium and expected lifetime
5.6.3 Engineered Composite Repairs
5.6.3.1 General
The purpose of piping repair by Composite Repair is to reinforce the piping with unacceptable wall
thickness in order to re-establish the pipe's pressure capacity for systems 600# and above.
The quality of the composite repair system comprises, but is not limited to:
Initial pipe
Surface treatment of initial pipe
Composite Repair Systems including reinforcement (e.g. fiberglass) and resin (e.g. epoxy)
Qualification, design, installation, testing and inspection of Composite Repair shall be according to ISO/TS
24817 ("Petroleum, petrochemical and natural industries - Composite repairs for pipe work - Qualification
and design, installation, testing and inspection"), except as modified herein.
Other general requirements:
For enquiry to repair system Supplier, appendix A shall be filled in by Neptune and issued to
supplier (if applicable), to ensure relevant information is available to design the composite repair.
The personnel used to perform the composite repair shall meet the requirements in section 5.6.3.9
The qualified Suppliers and limitations to the products are listed in appendix B. The appendix is for
internal use only. Other Suppliers may be accepted by Company based on a technology
assessment/Qualification.
The repair shall be done according to Suppliers installation procedure.
Surface finish shall be minimum SA 2.5 in bonding area. (A coupon may be located above the thin
area or the hole in the pipe. The area under the coupon or a reduced surface finish locally on the
damaged area may be acceptable if there is a risk for further damage/leak. The area covered by
the coupon or the local damage area not blasted shall be taken as the actual defect.)
Post curing shall be specified by Supplier (if required).
Requirements for fire protection shall be evaluated
Fire protection shall be applied if required. Alternative methods of fire protection may be used
upon Company acceptance.
For pipes with both internal and external corrosion, the table for internal corrosion shall be used.
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5.6.3.2 Design requirements
In addition to ISO/TS 24817, the following design requirements apply for the repair system:
The resin shall be self-extinguishing.
The pipe without laminate shall be able to sustain all loads except for the circumferential load from
internal pressure (hoop stress). Additional pipe supports may be added to fulfil this requirement.
5.6.3.3 Applicability of repair system
Composite Repair Systems shall not be used to repair:
Circumferential and longitudinal cracks
Damage surrounding the entire circumference of the pipe, unless detailed pipe stress calculations
can document that remaining piping has sufficient structural strength (without Composite Repair)
Repair lifetime
The required lifetime of the repair system shall be defined in the repair data sheet, Appendix A.
For the purpose of standardization the minimum lifetime of the repair shall be designed for 10 years unless
specified otherwise in the tables below.
Short lifetimes are intended to apply to those situations where the repair is required to sustain until the
next shutdown. It may be limited by the defect type and service conditions, e.g. internal corrosion.
Long lifetimes are intended to apply to those situations where the repair is required to re- instate the
substrate to its original design lifetime or to extend its design life for a specified period.
Once the lifetime of the repair has expired, the owner shall either remove or revalidate the repair system.
5.6.3.4 Internal Corrosion
General requirements for internal corrosion:
Prior to lamination, carry out corrosion mapping of the damaged area.
Establish corrosion rate based on historical data.
For substrates with active internal corrosion, the repair laminate shall be designed on the
assumption that a through-wall defect will occur if the remaining wall thickness at the end of
service life is expected to be less than 1 mm.
If it can be documented by NDT that there has been no further wall thinning then the repair lifetime
may be extended. Repeat inspection at determined intervals to evaluate development of damage.
Damages that are not covered by below acceptable limits shall be subject to local evaluation and
deviation request (See Appendix A).
Max extent of damage 25% of circumference.
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5.6.3.5 External Corrosion
General requirements for external corrosion:
Prior to lamination carry out corrosion mapping of the damaged area.
Repair lifetime shall be defined and included in the design data sheet in appendix A and shall be
within the lifetime guaranteed by the composite suppliers.
Damages that are not covered by below acceptable limits shall be subject to local evaluation and
deviation request (See section 5.6.3.7)
Max extent of damage 25% of circumference
5.6.3.6 Documentation
In addition to documentation requirements detailed in ISO/TS 24817, the following additional
requirements apply:
The repair system supplier shall provide application procedure developed by the supplier and
accepted by the Company.
HSE datasheets for products used shall be according to "Technical environment for offshore
platforms and facilities".
Applicable isometric drawings shall be updated and inspection number shall be included on the
drawing.
The following As Built documentation shall be provided: Design report, material data, surface
treatment report, hardness/curing log of primer and laminate build up.
For documentation update requirements refer to EPN Management system
5.6.3.7 Deviations
Deviations should be avoided. However if a deviation is required the following information shall be
provided in the application through the MOC procedure
Design data sheet in Appendix A (including important information like expected future corrosion
rate for internal corrosion/erosion). One data sheet to be completed for each repair.
Pictures of piping to be repaired
Applicable isometric drawing(s) and P&ID(s)
The content in the dispensation application shall be based on local knowledge of the piping system, pipe
supporting and medium in the pipe and shall be technical recommended by the local piping responsible.
Dispensation shall contain documented information about corrosion rate, details of damage, area, layout
(geometry) etc. This information shall be added into the Data sheet in Appendix A.
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5.6.3.8 Inspection
Laminate
The repair system supplier shall provide guidance on techniques and methods for inspecting the repair
system (ref. ISO/TS 24817). This guidance shall as a minimum include defect types and allowable limits for
the composite repair systems. These techniques shall be applied immediately after the repair system
application and during the lifetime of the repair system.
The lamented area shall be inspected according to extent of the damage and consequence of a leakage.
The maximum inspection interval shall be 4 years, in order to determine condition of the repaired system.
5.6.3.9 Training and qualification
This section outlines the minimum qualification of installer and supervisor on NEPTUNE ENERGY BV
installations or plants:
The basic skills/experience and training level of Installer and supervisor shall be according to the
requirements given in ISO/TS 24817.
The personnel that shall undertake repairs shall be approved to class 3 repairs and defect type B
qualification test (ref. ISO/TS 24817) and shall hold a certificate providing details of the repair
method qualified for. The certificate shall follow the holder and shall be documented when
requested. The validity of the certificate shall follow ISO/TS 24817.
The employer of the repair system installer shall keep a record of the completed training and a
logbook of all repair applications performed.
5.6.3.10 Curing of composite repairs
The time for full cure is dependent on the type of resin used in the repair and on the ambient conditions.
The repaired substrate may be returned to service only after full cure has been achieved.
Supplier shall describe required temperature and time for curing in their design report and calculations.
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5.6.4 Tape activated with water for temporary repair
Defect type Maximum system design pressure (bar)
for 150# piping class
Maximum
temperature
(°C)
Service
conditions
Maximum
lifetime
(years)Surface
preparation
Sa2.5
Surface
preparation
ST3
Surface
preparation
ST2
Internal
corrosion
(wall loss
and/or
through
wall defect)
15 (1) 10 (1) 2.5 (1) 70 Non critical
systems.
Limited to
water
systems See
guideline in
Appendix C
1
Note 1: For large defects, i.e. greater than a diameter of 20 mm then this pressure limit should be
reduced by 50%.
Table 3 - Guideline for use of water-activated tape
Water-activated tape (water activated polyurethane) is a quick temporary repair method used to seal or
stop leaks by winding a glass fibre cloth with resin around the pipe.
Requirements:
Pipe dimensions 8" and smaller.
Use Supplier’s installation procedure
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6. ACCEPTED COLD INSTALLATION METHODS
6.1 General instructions
The methods for cold installations described in this section can be used as permanent installations and will
as a basis not require special inspection and follow up.
Surface preparation and protective coating of cold installation methods shall be performed according to
General Spec 525 "Surface preparation and protective coating" (MSD-PROJ-AK-12-00525).
All couplings shall be used according to manufacturer's recommendation and procedures unless described
otherwise in this section.
All permanent couplings not included in piping class shall be registered as a special item. See paragraph
6.7. Installation shall be according to Manufacturer's instructions. Additional requirements are specified
where required for each coupling type.
6.2 Selection of cold installation methods
These cold installation methods shall only be used for tie-in’s, replacement of spools (repair works) and
modifications for plants in operation after evaluation of all other alternatives.
General evaluation:
Service
Pressure Class
Temperature
Area classification
Lifetime evaluation based on coupling materials and remaining plant lifetime
Tie-ins to existing systems:
Condition of existing piping systems (wall thickness, ovality and surface condition)
Evaluation of tie-in alternatives for live systems
Hot tapping with clamp on branch
Evaluation of tie-in alternatives for systems that are shut down
Mechanical couplings
Piping system installation methods:
Evaluate if spooling with cold installation methods is acceptable
Cost of alternative acceptable methods
The degree of prefabrication of shop made spools
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6.3 Materials
All components shall have equivalent to or better corrosion resistance than the component they are
connected to, including low/high temperature compatibility. The possibility of galvanic corrosion should
be kept in mind when selecting the repair method.
All sealing material shall be suitable for the design pressure, temperature and the services specified. The
materials and gasket shall be compatible with the medium and temperature.
6.4 Manufacturers machines and rotating tools
Several of the products described in this document include use of rotating and other equipment that may
represent a risk for injury. Procedure for use of equipment shall be made available to personnel involved.
The rotating equipment shall be CE marked or have records of safe use.
6.5 Qualification of methods
The products specified in this document are those that so far have been through a technology assessment
or qualification. Other manufacturers may be accepted by Company based on a technology assessment /
qualification.
The technology assessment shall in general be based on test documentation from the manufacturer
including type approval documents and certificates.
6.6 Qualification of personnel
All products shall be installed by competent personnel. Special requirements for installation are
specified for each product.
6.7 Documentation
Piping components defined in the plant's piping classes 503 "Piping and Valve Specification" (MSD-PROJ-
AK-12-00525) shall be documented according to standard documentation requirements. For other
components Special Item numbers shall be used and marked up on the P&ID. If specific couplings are used
widely in a system, a general note can be added on the P&ID to document the use. Location of the special
item shall be marked on the Piping Isometric.
Temporary repair documentation shall be attached to the TMOC.
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6.8 Use of installation flanges in HC systems
The flanges that are described in this section are flanges that are used as alternative to field welding and
normally not split during the facilities lifetime. The intention with this paragraph is to open up for use of
flanges in areas where not accepted in new plants / Greenfield projects.
To maintain the intention of the safety case, which require that the number of flange connections should
be kept to a minimum, the following principles will apply to plants in operation.
Welded connections are preferred, but where there is a major cost / time benefit, spooling with flanged
connections may be an alternative under the following conditions:
Use of metallic ring gasket or spiral wounded gasket
Maximizing the length of spools, i.e. the number of flange connections should be minimised.
Use of installation flanges is accepted unless the explosion risk is above acceptance criteria for the area.
When evaluating the use of installation flanges, the existing risk in the area must be taken into
consideration. For example if the explosion risk is already above the normal tolerance criteria,
care/measures should be taken not to increase the risk any further.
6.9 Requirements for mechanical couplings
General requirements:
The pipe surface area shall be prepared prior to installation of the coupling
For welded pipe the weld bead shall be ground flush with pipe wall
Visual inspection shall be performed after installation.
6.10 Metal to metal press fitted components
For general technical requirements see sections 6.1 - 6.9.
6.10.1 Quickflange
The Quickflange coupling consists of a modified ASME flange installed with a hydraulic tool. This flange is
machined in such a way that it can slide onto the pipe, and the hydraulic tool expands the pipe into grooves
machined inside the flange. The result is a metal- to -metal seal between the pipe and flange.
The crevice on the inner and outer bore of the flange is sealed with a sealing compound to prevent crevice-
corrosion.
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Figure 15 - Quickflange system
6.10.1.1 Seal
The sealing system is a metal- to -metal seal between the pipe and flange. A sealing compound is used to
prevent crevice-corrosion.
6.10.1.2 Materials
The range of materials that can be used are:
Low strength carbon steel
Duplex
SS 316
Cunifer
6.10.1.3 Special installation considerations
The existing pipe where Quickflange is to be installed shall have acceptable wall thickness and shall be
within tolerances as regards ovality and damage. Visual inspection shall be performed after installation
and no cracking of base material is allowed. Pipe condition shall be checked for damages prior to
installation. Minor damages may be accepted based on acceptance from competent person / Contractor.
Sealing compound shall be used between pipe and flange to avoid corrosion. The sealing compound shall
be qualified for the service. Typical sealing compound is Belzona Type 1111. NBI Typical curing time before
testing is 4 hours.
6.10.1.4 Training
Quickflange shall be installed by competent person with "Quickflange certificate", according to
Quickflange's procedures.
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6.10.1.5 Qualified range for All systems
Quickflange is approved to 20 bar (pipe class 150#).
Quickflange may be used as permanent coupling on fully rated 150# piping class.
6.10.2 Lokring, LTCS-A333 and SS40
6.10.2.1 Description
Lokring pipe coupling consists of three parts: fitting body and two driver rings.
The coupling is installed on the outer surface of the pipe and the rings are pressed into the fitting body
using a hydraulic tool.
Figure 16 - Lokring system
Lokring is delivered as a coupling for straight pipe and couplings including reducers, caps, elbows, tees,
flanges and adapters.
Figure 17 - Example of Lokring component
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6.10.2.2 Sealing
Lokring sealing zone is defined as the area from pipe end and 1.5 x D inward.
The coupling has three metal-to-metal seals at each end. These seals are part of the coupling body and
pressed into the pipe wall when the driver ring is pressed over the fitting body. The seal are called Primary
Seal, Main Seal and the Outboard Seal as shown in the figure above.
6.10.2.3 Special installation considerations
Longitudinal scratches of any significance on the sealing area must not occur. Elevations such as
longitudinal welds, must be ground smooth with the pipe. Bumps or flat sections of the pipe must not
occur. Dimension Tolerance and ovality is controlled by an interpreter that comes with installation tool.
After installation of a lokring coupling care should be taken to restore the paint system on the pipe and
coupling as soon as possible to avoid crevice corrosion.
6.10.2.4 Materials
The coupling is delivered in material qualities CS-MAS with max corr. Allowance 1.5 mm, LTCS-A333 with
max corr. allowance 3.2 mm and 316 SS.
The coupling in carbon steel supplied in quality ASTM A675 or A513 can be used to pipe in quality ASTM
A106, A333, A53, A53E, A53S and A587.
The coupling in stainless steel is supplied in quality ASTM A276 gr. 316L SS and ASTM A479 gr. 316L SS
and can be used on pipes in quality ASTM A312 gr. 316 or 316L. The coupling of stainless steel can also be
used on pipes in the above-mentioned carbon steel grades.
6.10.2.5 Training
Lokring shall be installed by qualified personnel with "Lokring certificate", according to Lokring's
procedures.
Training required for installation is 4-hour courses qualifying for operator's certificate.
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6.11 Special couplings
For general technical requirements see sections 6.1 - 6.9.
6.11.1 Morgrip
6.11.1.1 Description
Morgrip product's may be used for critical system and high pressure repair and is available in sizes ½" - 24".
The MORGRIP design comprises of 2 key elements:
The mechanical gripping system, which comprises of balls rolling on tapers and swaging into the
outer surface of the pipe to produce the required mechanical grip
The sealing system which consists of metal-graphite-metal composite seals compressed radially
onto the pipe outer surface
Number of gripping segments varies depending on the material, wall thickness and pressure.
External test ports are normally a part of the coupling. The test port may be used to verify the sealing
system prior to applying pressure in the pipe or to verify no leakage through the first sealing barrier after
pressurizing the pipe. The test port will normally not be under pressure.
Morgrip connectors may be supplied as a pipe connector, flange couplings and end cap.
Figure 18 - Morgrip System
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Figure 19 - Morgrip Flange System
6.11.1.2 Sealing
The Morgrip sealing system consists of graphite seal combined with anti-extrusion rings on both sides of
the graphite ring.
Seals are energised by connector bolting (Tensioning or Torqueing):
Twin seals with external test facility as standard
Tolerant of surface imperfections, pipeline diameter tolerances and high/low temperature
Figure 20 - Morgrip Sealing System
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6.11.1.3 Special installation considerations
Due to normally high weight of the coupling additional supporting need to be evaluated.
Installation of Morgrip does not require special tools other than cutting equipment and bolt tightening
equipment.
6.11.1.4 Materials
Coupling and anti-extrusion rings may be delivered in Carbon Steel, 316 Stainless Steel and Duplex
Stainless Steel.
6.11.1.5 Training
MORGRIP connectors shall be installed only by qualified Hydratight personnel with documented
qualification. Product specialists and installation technicians can be supplied direct from Hydratight on a
case-by-case basis.
If a significant order of topside connectors is required for a single installation, then Hydratight can offer
training packages for NEPTUNE ENERGY BV technicians to enable fast turnaround during shut down
periods.
6.11.1.6 Qualified range
Morgrip connectors may be used as permanent coupling.
Taylor-made Morgrip connectors may be supplied for sizes 1" to 42" and for pressure class up to and
including 2500#.
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7. APPENDICES
7.1 Appendix A: Design Data Sheet for an Engineered Repair (Ref basis ISO/TS 24817)
This data sheet shall form the basis of the record of the repair and scope of work provided by the owner to
the repair system supplier, and shall be used in the preparation of the design of the repair if applicable.
One data sheet shall be completed for each repair required. This shall form part of the documentation to
support Company's permanent record. (Maximo, Synergy or TMOC)
Customer Details
Contact person
Company and Plant
Address
Telephone
Pipe Details
Location (module and if
the area is classified)
Pipe identification / line
number(s)
Pipe item reference
(typical: pipe / elbow /
tee)
Pipe specification
Material
Pipe diameter
Wall thickness acc. to
pipe spec. (mm)
Medium
Design Temperature Minimum Maximum
Pipe coating
Insulation
Is there existing repair
on pipe for leak seal
Risk Assessment
Criticality
(critical / non-critical)
Repair lifetime
Other data
Loading
(See Note 1 and 2)
System Design
(temporary repair)
Pipe Class Pressure
(Permanent repair)
Comments
Pressure rating (bar)
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Axial load (kN)
Bending moment (Nm)
Shear load (kN)
Torsion (Nm)
Other loads (N)
Note 1 Any original design calculations / stress isometrics and piping isometrics should be appended to this data
sheet.
Note 2 Loads should be defined as either sustained or occasional in the comments column.
Details of Defect Area
Attach drawings of pipe system, inspection reports, digital photographs, etc. where available.
Indicate any access restrictions and proximity to other equipment.
Type of defect
(corrosion, pinhole,
crack.)
Location of defect on
elbow (see fig. x below)
Intrados Extrados
Location of defect. (12
on top of pipe and 6
bottom of pipe)
Is the defect circular
around the pipe
Defect location External (x) Internal (x)
Current wall thk (see fig.
y below)
Tmin 5 (mm) Tmin 6 (mm)
Current Area of defect
(see fig. y below)
ØD1 (mm) ØD2 (mm)
Expected wall thk (see
fig. y below)
Tmin 5 (mm) Tmin 6 (mm)
Expected Area of defect
(see Figures below)
ØD1 (mm) ØD2 (mm)
Cause Corrosion Erosion
Expected corrosion rate
(mm/year)
Fig. x: Definitions for elbow Fig. y: Definition of pipe wall thickness and areas
Anticipated Conditions during Implementation of Repair
Pipe temperature (°C)
Ambient temperature
(°C)
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Pipe pressure (MPa)
Pipe contents
Humidity (%)
External environment
Constraints
Facilities to be Provided by Client / Installation (surface prep., etc.)
Other Information
Notes: This section should include any remarks on previous repairs, fire protection requirements, etc
Prepared By: Date:
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7.2 Appendix B: Suggested Technical Solutions
The table below provides a list of process fluids and the allowable repair class for each.
Other solutions may be accepted by Company based on a technical assessment.
The responsible persons for the technical assessment shall be the Piping or Mechanical TA.
Allowable Repair Class
Produced Fluids Class A – Safety (or Environmental) Critical
Engineered Repair OnlyProduced Oil
Produced Gas
Fuel Gas
LP& HP Vent
Chemical Injection (High Pressure)
Water Injection (High Pressure)
Produced Water Class B – Safety (or Environmental) Critical
Engineered Repair Preferred. Non-Engineered
Repair may be suitable in some circumstances but
only when supported by appropriate assessment.
Closed Drains / Glycol Systems
Chemical Injection
Fire Water / AFFF
Open Drains (Hazardous)
Diesel
Domestic Services
Heating / Cooling Medium (Water Based)
Seawater Class C - Non-Safety Critical Non-Engineered
Repair Allowable Water Injection (Low Pressure)
Air Systems
Open Drains (Non-Hazardous)
Table 4 - Repair Classes
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The technical solutions for piping repair and cold installation methods outlined in Table 5 below.
Restrictions and conditions for use are stated for each repair and cold installation methods. An approved
dispensation is required for solutions not listed in table below. Additional qualified piping repair and cold
installation methods to the products listed below described herein.
Fluids Repair Rating
(Press. / Temp)
Pipe
Material
Typical Products NOTES
See Table 4 for
Class B & C Fluids
150#
All
Straub
Axial grip type coupling to
be used.
Size range 1” to 8” NB.
Larger sizes only on
approval by Tech Auth.
Use NBR seal
METAL-GRIP coupling
(20Bar g)
-20 to 80°C
Class A, B & C To 300 Bar gAll except
GRE
Pressure Containment
Clamp
Furmanite Ltd
Engineering specification
required for procurement.
Size range 4” to 24” NB
Specialist vendor
installation. Nitrile Seals
Optional grout sealant.
Class A, B & CTo 2500#
-40 to 120°C
All except
GRE
Morgrip
Hydratight LtdEngineering specification
required for procurement.
Size range 1” to 24” NB
Specialist vendor
installation.
Class A, B & C All ratings AllBox clamp
Furmanite Ltd
Engineering specification
required for procurement.
Specialist vendor
installation.
Fire protection
requirements to be
considered.
Not acceptable to over
wrap with composite repair
system as long term.
Cannot take axial loads
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Fluids Repair Rating
(Press. / Temp)
Pipe
Material
Typical Products NOTES
Class B & C
150# (20Bar g)
-10C° to 60°C
All materials Syntho-glass
For leaking pipes Uni-wrap
must also be applied.
Recommended as a
temporary DLR only.
Class A, B & C
<50 Bar g
<90 °C
All except
GRE
Belzona 1111 (Super
Metal)
Belzona International
Ltd
A two-component repair
and rebuilding material
based on ceramic steel
reinforced polymer system,
for flange facing only.
Class A, B & C
<50 Bar g
>90, <120 °C
All except
GRE
Belzona 1511 (Super HT-
Metal)
Belzona International Ltd
A two-component paste
grade system based on a
silicon steel alloy blended
with high molecular weight
reactive polymers &
oligomers. When cured,
the material id durable yet
fully machinable, for flange
facing only.
Class A, B & C
<50 Bar g
-50 to 180 °C
All except
GRE
Belzona 4301 (Magma
CR1 Hi-Build)
Belzona International Ltd
A high-performance two-
part paste that protects
against chemical attack,
for flange facing only.
See Table 4
For fluid Class
A, B & C
150#
300#
600#
900#
All except
GRE
Lokring Lokring
Technology LLC
½” up to and included 4”
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Fluids Repair Rating
(Press. / Temp)
Pipe
Material
Typical Products NOTES
Class B & C Fluids
150# (20Bar g)
-20C° to 80°C
All except
GRE
Quickflange
Quickflange AS Engineering specification
required for procurement.
Size range 1” to 12” NB.
Specialist vendor
installation. Metal to metal
& grout seals ASME B31.3
Table 5 - Technical solutions for piping repair and cold installation methods