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Installation Procedures for Composite Repairs

June 2005



Installation Procedures for Composite Repairs

June 2005



AEA Technology ii

Title Installation Procedures for Composite Repairs

Customer

Customer reference

Confidentiality,

copyright and

reproduction

Warranty

File reference 57756001

Report number AEAT – 57756

Report status June 2005

AEA Technology plcBuilding 551.11Harwell International Business CentreHarwellOxfordshire OX11 0QJEngland

Tel: 00-44-870-190-2227Fax: 00-44-870-190-2225

Name Signature Date

Author SR Frost

Reviewed by

Approved by



AEA Technology iii

Contents

1. INTRODUCTION ...........................................................................................................1

2. SCOPE............................................................................................................................1

3. RISK ASSESSMENT...................................................................................................3

4. DEFINITION OF REPAIR CLASS..............................................................................3

5. MATERIALS OF CONSTRUCTION ..........................................................................4

5.1 Types of repair .........................................................................................................5

5.2 Reinforcement Systems ........................................................................................5

5.3 Resin Systems .........................................................................................................6

5.4 Adhesives..................................................................................................................7

5.5 In-fill Compounds....................................................................................................8

5.6 Surface Preparation Agents .................................................................................8

6. STORAGE CONDITIONS............................................................................................8

7. METHOD STATEMENTS............................................................................................9

8. INSTALLER QUALIFICATIONS ..............................................................................10

9. INSTALLATION GUIDANCE ....................................................................................11

9.1 Surface Preparation..............................................................................................11

9.2 Laminate Lay-up ....................................................................................................13

9.3 Cure...........................................................................................................................15

9.4 Key Hold Points .....................................................................................................16

9.5 Documentation.......................................................................................................17



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10. LIVE REPAIRS........................................................................................................18

11. REPAIR OF CLAMPS, PIPING COMPONENTS, TANKS OR VESSELS....19

12. SYSTEM TESTING.................................................................................................19

13. FIRE SERVICE........................................................................................................20

14. ELECTRICAL CONDUCTIVITY...........................................................................21

15. INSPECTION ...........................................................................................................21

16. HEALTH AND SAFETY.........................................................................................21

17. ENVIRONMENTAL CONSIDERATIONS ...........................................................22

18. FUTURE MODIFICATIONS ..................................................................................22

19. DECOMMISSIONING.............................................................................................23

20. BIBLIOGRAPHY.....................................................................................................23

APPENDICES .....................................................................................................................25

Appendix 1: Glossary of Terms .....................................................................................26

Appendix 2: Installer Qualification................................................................................28



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1. INTRODUCTION

Codes and standards for pressurised equipment provide rules for the design, fabrication,inspection and testing of new piping systems. These codes do not address the fact that

equipment degrades in service or may require to be up-rated due to a change in duty, nor dothey consider options for remedial action should such events occur. This document providesguidance for the installation of one repair option: the external reinforcement and the repair of damage such as holes in pipe or pipe components using composite materials. Theprocedures described in this guidance note can be used to assist in the application of composite reinforcements to allow damaged pressurised equipment to continue to operatesafely.

The application of a composite repair involves the completion of a bonded connectionbetween it and the underlying pipe and the quality of this bond is a key factor in the success of the repair. The most important element within the bonding process is surface preparation,and failure to execute this task correctly will lead to a reduced level of performanceirrespective of other issues such as the quality of the mechanical design of the repair laminate itself. As such it is important that installation instructions for the bonding operationare followed rigorously.

A further key point that must be considered in the design and application of a bonded repair isthat the combination of pipe material/surface preparation technique/composite laminate is thebasic design unit. Suppliers of repair options will have qualified their materials, design andapplication procedures on this basis. It is not valid therefore to substitute the specifiedsurface preparation method for another unless it has been explicitly demonstrated to be fit for purpose as part of a total bonded arrangement.

The development of this document was carried out in collaboration with a number of organisations representing material suppliers, users and regulatory agencies. Thoseinvolved included Shell, BP, Saudi Aramco, Amerada Hess, Petrobras, Statoil, BG-Hydrocarbon Resources Ltd, DML, WTR, Clock Spring and IMG.

2. SCOPE

The installation procedures given in this document cover situations involving damagecommonly encountered in utility oil and gas pipework systems. The procedures are alsoapplicable to the repair of pipelines. They are not intended to provide a definitive guideline for

every possible situation that may be encountered. However, they are intended to be usedflexibly and can, in principle, be used as a basis for repairs to uncommon situations that arenot explicitly covered.

Procedures in this document cover the repair of carbon steel pipework and pipeworkcomponents, and pipelines originally designed in accordance with a variety of pipe standardsincluding ISO 15649/13623, ASME B31.1/B31.3/B31.4/B31.8 and BS 8010. The followingcircumstances are addressed:

• external corrosion, which may or may not cause leaking, and structural integrity needs tobe restored. In this case it is probable that with suitable surface preparation theapplication of a composite repair will arrest further deterioration;



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• external damage such as dents, gouges, fretting (at supports) where structural integrityneeds to be restored;

• internal corrosion, which may or may not be leaking, and there is a need to restorestructural integrity. In this case it is probable that corrosion will continue and theassessment must take this into account;

• structural strengthening to account for an increase in pressure rating or other loads inlocal areas.

Pipe services that are considered are:

• utility fluids, diesel, seawater, air;

• chemicals;

• produced fluids, including gas and gas condensate.

The upper pressure/temperature limits are dependent on the type of damage being repairedand the type of repair being used. These limits are determined by the qualification testingrequirements presented in the following sections. A lower temperature limit of -500C can be

assumed but further considerations in the design are required. Also, the internal fluids and, or external environment can reduce these pressure/temperature limits.

Use of this document outside these service ranges is possible subject to the comments givenbelow.

The composite materials considered within the document are those with glass (GRP) or carbon (CFRP) reinforcement in a polyester, vinyl ester or epoxy matrix.

Examples where the details of the application are outside the above scope, but where theintent of the design guidelines may be used coupled with a more complete analysis are:

• other pipe specifications;

• other tubular products, e.g. caissons;

• other pressurised parts, e.g. storage tanks and pressure vessels;

• other pipe materials, e.g. alloyed steel;

• other degradation mechanisms, e.g. wall loss due to erosion;

• other service conditions, e.g. process fluids or operating envelope;

• other composite material systems.

Elements of the procedures are also applicable to those repair systems with different designfeatures, e.g. those that use elastomeric seals or other means of containing the fluid.

The operational envelope described in this scope is intended to cover the majority of applications and experience at the time the document was prepared. The allowable pressurefor repairs in leaking pipes is lower due to the fact that in these circumstances the repair material is in direct contact with the process fluid and subject to loadings that are moresevere than in the non-leaking case. For the non-leaking case there is considerablesuccessful experience at high pressures especially for pipeline applications. There are someexamples where the composite repair option is in use or being considered for more arduousconditions and for more complex repairs. This flexibility in materials and design options isone of the key advantages with composites.



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3. RISK ASSESSMENT

For each repair situation a risk assessment shall be carried out. In most cases the riskassessment will be carried out by the owner/user. The objective of the assessment shall be

to establish the Class of the repair and this determines the detail of the design method to becarried out together with the requirements for supporting documentation. The riskassessment shall include consideration of the hazards associated with system service, theavailability of the personnel with the necessary skills, the ease with which it is practicable toexecute surface preparation operations, availability of design data, leak before break,inspectability, and performance under upset and major incident situations including fire,collision and environmental loading.

The risk assessment shall also provide information and data describing any hazards for inclusion in the repair method statement to be used on site.

Leak before break is a general characteristic of composite materials under internal pressureloading. Generally, failure is through weeping of the process media through the wall thicknessof the laminate. For repairs, there will be an additional failure mechanism due to possibledelamination of the repair from the parent steel. This type of failure will also be characterised by leak before break. Suppliers of repair materials will have experience relating to their specific products and confirmatory test information from any qualification testing that hasbeen carried out.

4. DEFINITION OF REPAIR CLASS

Specific repairs shall be allocated to a particular class following completion of the riskassessment. Repair Classes are defined in Table 1.

Class 1 repairs cover pressure ratings up to 10 bar g and therefore are appropriate to themajority of the utility service systems on an offshore facility. This Class is intended for thosesystems that do not relate directly to personnel safety or safety critical systems.

Class 2 repairs cover pressure ratings up to 20 bar g and therefore are appropriate to thosesystems that have specific safety related functions.

Class 3 repairs cover pressures up to the qualified upper pressure limit. This Class isappropriate for many of the systems transporting produced fluids on an offshore facility.

Hazards for these systems derive primarily from the nature of the fluids they convey.

For applications not included in the above, they shall be designated as Class 3.



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Repair Class Typical Service Pressure Temperature

Class 1

Low specification duties,

e.g. static head, drainsCooling medium, sea(service) water, utilityhydrocarbons

< 10 bar g -200 to 400 C

Class 2 Fire water/deluge systems < 20 bar g -200 to 1000 C

Class 3

Produced water andhydrocarbons, flammablefluids, gas systems.Class 3 also coversoperating conditions moreonerous than described.

Qualified upper limit

-500 toqualified upper

limit

Table 1: Repair classification

The ASME PCC-2 (high risk metal pipe) standard refers only to Class 3 systems. This isbecause the scope of the ASME standard in terms of potential applications is significantly wider than this guideline for off-shore use and attempting to define a generic Class systemwould be too complicated.

The ASME PCC-2 (low risk metal pipe) standard is equivalent to Class 1 systems.

The definitions for Class 1 to 3 given in Table 1 cover the majority of composite repairscarried out at the present time. It is not intended that the data presented in Table 1 should

preclude the use of composites for other duties. For more onerous applications detailedconsideration between the owner/user and supplier is required.

The derivation of the definitions for the repair classes involved the consideration of typical repair situations and the repair options currently available. The intention is to ensure that these procedures allowed the use of simple repair procedures and techniques for straightforward scenarios (Class 1), whilst establishing a means of increasing the level of conservatism for the higher risk duties (Classes 2 to 3). The selection of Class is governed by the output of the risk assessment.

5. MATERIALS OF CONSTRUCTION

A discussion of the details relating to material of construction is given in the followingsections.

The production of a composite laminate requires the combination of a network of fibrousreinforcement and a thermosetting polymer matrix that is subsequently subject to a chemical curing process. This often involves the use of a liquid resin and layers of reinforcing material at the point of application, which means that the load carrying material is formed as the repair is carried out. The final properties of the material are significantly influenced by the method of application, the details of the lay-up and the form of reinforcement used. This is due to

possible variations in the fibre fraction in the composite, fibre orientation with the respect tothe applied loading, and the achieved state of cure. There are alternatives ('prepregs')



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whereby the constituent materials are brought to the repair site already combined in a partially cured state and these materials reduce the number of variables that may be present during material application, but further processing (curing) is still required. In both circumstancesthe properties that deliver the required mechanical and environmental performance are not developed until the point of installation. This issue is similar, in principle, to that for thebonded connection where the load carrying capacity of the joint is not achieved until the repair is complete. These points emphasise the need for installation practices to be fully controlled to ensure that the materials present in a repair are the same from a technical point of view asthose that have been qualified by the supplier.

5.1 Types of repair

Repairs that are currently supplied fall into two generic types: ‘bandage’ and ‘engineered’. Inthe first, material often in a pre-packed form can be held as a stock repair and the intent is for them to be applied by maintenance personnel on the facility. In the second case the repair isspecified and designed on a bespoke basis and, in many cases, installed by specialist

contractors.

Broadly, the principles governing installation are the same in both cases, although it should benoted that the use of the pre-packaged option does not reduce the need for ensuringpersonnel are suitably trained.

The lifetime of the repair is defined during design. Generally lifetimes can be split into short-term and long-term. These term designations can have an effect on design, materials of construction (including surface preparation) and documentation requirements. Short-term isintended to denote those situations where the repair is required to survive for a limited period,after which it shall be replaced. Each case should be the subject of an individualassessment, but in any event short-term implies a period of less than 2 years. Typical of

these applications will be those where immediate repair action is necessary and the pipe willbe assessed further at the next scheduled inspection interval or shut down. Long-term isintended to denote those situations where the repair is required to reinstate the pipe to itsoriginal design lifetime or to extend its design life for a specified period.

The effect of the short-term/long-term designation manifests itself primarily in the design of the repair through more onerous qualification procedures and design factors. In the context of installation it is important that the repair method as qualified is applied with the same degreeof attention regardless of its design lifetime.

5.2 Reinforcement Systems

Most of the repair systems covered by this document employ either glass or carbonreinforcements. Both of these materials are stable and do not require particular considerationin terms of storage conditions (see Section 6), handling or shelf life.

In principle all types of reinforcement can be used, e.g. woven and random fabrics or unidirectional. In some cases the repair laminate will be anisotropic, i.e. the strength andstiffness in the direction of the fibres will be greater than in other directions, and the designprocedures used in the assessment of the repair will have taken this into account. It isimportant that the installation method statement gives explicit information on the dispositionand orientation of individual layers.



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The effect of fibre orientation can cause variations in stiffness and strength values that aretypically in the range between 2 (glass) and 10 (carbon). The correct application is essential

particularly for carbon fibre materials. This requirement also applies to woven materialswhere the properties in the warp and weft directions are nominally the same. Where thesurface onto which the repair is applied is of complex geometry it may be a requirement of the design for these layers to be rotated with respect to one another to achieve a quasi-isotropic lay-up (so that the properties are nominally the same in all directions).

Woven reinforcements are available in a number of forms and it is for the supplier of therepair system to specify the appropriate material. In addition to mechanical performanceother criteria that need to be considered are compatibility with the resin system and ease of application. In the latter case, for example, the details of the weave will be a determining factor in the drape characteristics of the fabric and this may be an important factor in repairsfor complex geometries. The reinforcement systems employed should be the same asthose used during qualification testing.

Handling of both glass and carbon is straightforward. Care may need to be taken with short

carbon fibres (or carbon dust arising as a result of sawing/grinding operations) in theproximity of electrical equipment.

In principle, the guidance given in this document will apply for all potential reinforcementsystems, although there may be specific issues with some of the alternatives, e.g. aramidfibres can be prone to water absorption. Specific guidance should be sought from thesupplier.

5.3 Resin Systems

A variety of matrix materials are used for composite repair. Most systems employ styrenated

(polyester or vinyl ester) or epoxy resins, but polyurethanes, phenolics and furanes have alsobeen used.

The correct mixing of resin components is essential and due regard should be taken of theeffect of the ambient conditions prevailing at the time of the repair, and any effect these mayhave on required mixing ratios and the curing reactions.

Styrene based resins are normally ambient temperature cure and require the addition of small quantities of catalyst and accelerator for curing to start. Proper measuring equipment must be used as small changes in the amount of accelerator or catalyst have a significant influence on the rate of the curing reaction. It is by changing the relative amount thesematerials that pot life and time to cure can be controlled to suit site conditions. However, it is

important that supplier's limits are observed in order to prevent under cure (styreneevaporation can be a significant factor if the reaction is too slow) or excessive heat generation(the reaction is strongly exothermic) which could cause laminate damage through cracking,especially in thick laminates, or reduce the performance of an adhesive bond. To simplify repair operations it is recommended that resins should be obtained in pre-accelerated form(PA) so that only catalyst need be added at site. Should ambient conditions dictate that normal mixing ratios are not suitable advice should be obtained from the material supplier who may be able to supply special formulations. In some industries it is the norm to usestyrenated resins specially formulated to limit the emission of styrene into the atmosphere(LSE resins). This is accomplished by adding a wax component that comes to the surfaceduring cure. It is recommended that these systems are not used for repair applications as



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the presence of the wax can adversely affect mechanical properties, especially bonding.Further comment on the release of styrene into the atmosphere is given in Section 16.

Epoxy systems are generally two part systems consisting of a resin and a hardener. Theseare mixed in similar proportions, but the individual components still need to be metered accurately for the achievement of the desired material performance. The curing of certainepoxy formulations can be adversely affected by the presence of water so appropriatematerial storage conditions of material prior to use are important (see section 6).

In many cases resins will contain fillers to impart specific characteristics. Wherever possiblethe addition of these further additives should be carried out by the material supplier. It isrecommended that fillers of any type are only added where there is a specific technicalrequirement for their use. This is especially important for glass reinforced materials wherethe translucent nature of unfilled laminates can greatly assist subsequent inspection.

Examples are thixotropic agents to aid lamination on vertical surfaces, flame retardants, UV inhibitors and pigments. Generally, these should be limited to <3% by weight. Bulking fillers

such as talc should not be used as they impair laminate properties and can hinder application.

Many systems, including some of the epoxy range, can require the application of heat to effectcure and the achievement of the correct temperature regime for a given set of ambientconditions should be an important aspect of the repair method statement. The extent of cureachieved during installation should be the same as that assumed in the design. This mayinvolve the measurement of glass transition temperature (Tg) or heat distortion temperature(HDT).

Where 'prepregs' are used these will often incorporate epoxy resins which are partially cured.Final cure is effected after application usually with the application of heat.

Prepreg materials can simplify the installation process, as there is no need for further additionof chemicals. There is, however, some loss of flexibility and shelf life.

The use of other resin systems also require attention with respect to matters such asstorage, mixing and curing. Particular attention needs to be given to the curing of phenolicsand furane where the control of cure is particularly important.

In the cure of phenolic and furane resins water is formed as a bi-product of the reaction and this must be removed by heat if the cure is to be complete. If this is not done correctly delaminations or porosity may result. Another issue with these particular systems is that acid catalysts are often used. This could preclude them from the repair of carbon steel pipe asthe acid can cause corrosion of the steel surface.

5.4 Adhesives

For many repair options the resin comprising the matrix in the composite also acts as theadhesive between the repair material and the underling pipe. In other circumstances aseparate adhesive material may be used to effect load transfer at this interface.

The materials issues affecting adhesives are broadly similar to those for the resins cited inSection 5.3.



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5.5 In-fill Compounds

For certain repair situations an in-fill compound will be required between the pipe surface andthe composite lamination. This may be a feature of the specific repair option or it may berequired in individual circumstances to repair local damage to restore a cylindrical profile to

the external surface of the pipe. Normally, in-fill compounds will consist of proprietaryresin/filler systems. In-fill compounds must have sufficient toughness, and compressivestiffness and strength to ensure adequate load transfer from the pipe to the repair.

In-fill compounds will pose the same materials issues as adhesives and resins. The in-fillcompound should be compatible with the resin system used.

5.6 Surface Preparation Agents

Surface preparation agents are used for some repair options. For repairs to carbon steel pipea durable bonded connection can be obtained by cleaning/degreasing to remove

contamination followed by grit blasting. For other metallic substrates chemical pre-treatments are often a precursor to the achievement of an acceptable bond and these mayinvolve the use of aggressive etching or other surface modification agents.

The preparation of surface pre-treatments should be carried out by the suppliers. Mixing of chemicals should not be carried out on site.

A key point that has been cited in Section 2 is that surface preparation methods are notinterchangeable. The procedure used for surface treatment is an integral part of a givenrepair method and an alternative cannot be used in lieu of that which has been qualified by thesupplier.

It is often helpful if a small amount of pigment is included in the surface preparation solution.This provides a visible means to check that it has been correctly applied over the surface

prior to bonding.

6. STORAGE CONDITIONS

Storage of material should comply with the supplier’s instructions. Manufacturer's MaterialsSafety Data Sheets should be retained for reference. It should be noted that the materials

used will need to be stored and controlled according to COSHH (or similar) regulations. Attention also needs to be given as to how combinations of chemicals are to be stored.These issues will need to be addressed in the risk assessment for the chemical store.

An example of the importance of storage conditions related to accelerators and catalysts for styrenated resins. These must not be kept adjacent to one another as if inadvertently spilled and mixed they may cause an explosive hazard

All materials should be clearly labelled with relevant Health and Safety data, batch number,expiry date and any other relevant technical information.



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Control of the temperature during storage is particularly important. Shelf lives could bereduced significantly if temperatures are allowed to exceed those specified. Freezingtemperatures should also be avoided.

Many of materials that are used are formulations involving a number of separate chemicalsand additives. These mixtures are often supplied in the form of suspensions or emulsionsand freezing can affect their stability.

Reinforcements should also be carefully stored to ensure that condensation either due tostorage of material below the dew point or on movement between areas at differenttemperatures cannot occur.

Shelf lives quotes by the supplier’s should be observed.

Resin systems can deteriorate over time, especially in high ambient temperatures, and catalysts can lose their activity. Material should be disposed of at any time where there isany evidence of changes in, for example, colour, smell, viscosity or tack.

Disposal of time expired material should be carried out the required manner and according tosupplier’s instructions.

Generally, chemicals should not be mixed prior to disposal, although resin may be converted it to solid form though the addition of curing agents. This operation must be done with care ascuring reactions are exothermic and the heat generated from hardening resin in bulk cancause high temperatures.

7. METHOD STATEMENTS

Each repair should be covered by a method statement that addresses each of the mainprocedures to be carried out.

Input to the method statement would come from the following:

• Risk assessment (supplied by owner/operator);

• Working conditions (supplied by owner/operator);

• Installer training/qualification (supplied by vendor);

• Design information;

− plant operating conditions, layout, etc (supplied by owner/operator)

− design of repair (supplied by repair vendor)• Materials information (supplied by repair vendor).

Typically a method statement should include the following information:

Health and Safety

List of materials to be handled including copies of Manufacturer's Safety Data Sheets.COSHH assessment for process.Details of protective measures to be adopted.List of hazards associated with equipment to be repaired and equipment in the vicinity of therepair site with protective measures.



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Installer Training

Details of training requirements for installers.

Repair Design

Details of laminate lay-up including disposition and orientation of individual layers of reinforcement (this may be presented as a written description or a drawing incorporatingstandard details such as overlap and taper information).

Repair Application

Details of surface preparation procedure, including method of application, equipment to beused and inspection method.Details of in-fill required to achieve a smooth outer profile prior to the application of thelaminate.Details of time limitations between stages of the repair, e.g. between surface preparation and

lamination.Details of lay-up procedure including if the laminate is to be applied in stages.Details of curing procedure including post curing if necessary.

Quality Assurance

Details of hold/inspection points in the repair (see Table 2).Details of any materials tests to be carried out (see Section 9).Details of any systems tests to be carried out (see Section 11).

Environmental

Information on disposal of unused material.

8. INSTALLER QUALIFICATIONS

Suppliers of repair methods will have qualified their system for use in specific applications incomplying with the requirements of the design method (see AEAT - 57711). Personnelinvolved in the installation of composite repairs should have had appropriate training and bequalified in the repair method to be undertaken. This should include the handling of compositematerials, surface preparation, lay-up techniques, quality control procedures, and health and

safety issues. It is important that the training given provides sufficient technical background toallow personnel to obtain a good understanding as to why key operations such as surfacepreparation, material handling and lay-up technique are so important.

It should be noted that training is an essential element of a successful repair. This alsoapplies to the use of material in the pre-packaged form (see Section 5.1). Selection of thesematerials does not reduce the need for ensuring personnel are suitably trained.

Ideally training should include practical demonstration through the pressure testing of demonstration samples. Guidance on installer qualification is given in Appendix 2.

It should be noted that training in one repair option does not necessarily qualify personnel for

alternative methods.



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Installation personnel should be the subject of a continuing review of competency with a logkept of experience in the application of repairs. This is important as the levels of competenceand experience achieved by an individual installer should also considered in the context of repair activities. For example, working in confined spaces or applying material aroundcomplicated geometries can pose additional difficulties that should be taken in to account.

Supervisory personnel should also be trained in the relevant technique and ideally shouldhave had a period during which they were engaged in the application of repairs. Supervisorsshould also be the subject of a continuing review of competency.

Guidance on the content of a suitable training programme may be obtained from ISO 14692 where the training requirements for the installation of composite (GRP) pipe are given. Full details of pipe jointing approval schemes are also given in related NTS (Norway) and CSWIP (UK) documents.

9. INSTALLATION GUIDANCE

Suppliers of repair material should provide full installation instructions for their repair systems.

The guidance given in the following sections is intended to complement that given bysuppliers and to emphasise the key operations necessary for a successful repair. In theevent of conflict the supplier should be contacted for clarification.

For certain repair methods it is intended that the remedial work is carried out by specialistcontractors and it would be expected that these personnel would be well versed in repair techniques. In these circumstances the guidance proved below would be of value to theowner/operator of a facility as background information and to appraise them of the facilities

they need to provide.

Full instructions for each repair situation should be given in the method statement prepared ineach instance.

9.1 Surface Preparation

Surface preparation is single most important operation in the achievement of a successfulrepair.

The surface preparation should extend over the whole surface onto which the composite

laminate is to be applied.

There are a number of surface pre-treatments, but they normally entail cleaning/degreasingand surface abrasion. This may (or may not) be accompanied a subsequent chemicaltreatment stage. For repairs to carbon steel pipe a durable bonded connection can beachieved with cleaning to remove debris and corrosion products followed by mechanicalabrasion as the sole surface preparation activity. In these circumstances it is important thatthe nature of the abrasion technique is fully specified. This should include the grade andduration of shot blasting, the grade of any abrasive paper or other equipment that is used.Surface roughness gauges or other measurement technique should be used to check thatthe prepared surface is as required by the specification. All paint, tape, corrosion, dust or other loosely attached debris should be removed.



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The surface preparation issues that govern the performance of a repair material areanalogous to those that are considered to be important in the application of painting systemsand other protective coatings. These are generally listed as: the presence of rust and mill scale, the presence of surface contaminants and the profile of the surface following

preparation. ISO 8501, 8502 and 8503 provide methods of assessing these factors and ISO8504 provides guidance on the preparation methods that are available for cleaning steel substrates. ISO 8501 incorporates the well established Sa series for blast cleaning. Thesestandards (and this document) do not contain recommendations for surface quality requirements for specific circumstances.

Irrespective of the procedures used to prepare the steel substrate, the surface will consist of a series of random features that are not easily characterised. There are no methods for uniquely defining the essential quality of a surface on a quantitative basis. The norm is toemploy visual (photographic standards) or tactile (surface profile comparators) to makecomparative assessments. Due to the complexity of the situation it is important that whenspecifying a surface preparation method both the method of preparation (type of abrasive,hand/power tool, etc) and the description of the prepared surface (Sa, St, etc) are defined.

It is not the purpose of this document to imply that levels of surface preparation must be the‘best’ that can be technically achieved. In many cases simple methods are preferred due tothe limitations of what is achievable on site. The key point is that the quality of the surface that is achieved should be the same as that used in the qualification of the repair method in thefirst instance.

The repair of other metallic pipe such as alloyed steel is likely to require a chemical treatmentfor a satisfactory repair.

The surface preparation of GRP pipe requires mechanical abrasion only. The bonding of material onto phenolic GRP pipe can be problematical and the pipe vendor should be

contacted in each instance.

Any chemicals used for surface preparation should be within the recommended shelf life,freshly mixed (where appropriate) and applied strictly in accordance with the supplier'sinstructions.

The time period between the completion of surface preparation stage and the application of the composite laminate is an important factor in the achievement of a good adhesiveconnection. The time period between surface preparation and laminate application should notbe more that 4 hours.

Generally, it is good practice to apply repair material as soon as possible after the surfacehas been treated. Water absorption onto a freshly prepared surface can be rapid as can thereaction of the surface with air and both of these factors can impair the achievement of agood joint. The surface preparation of a number of repair sites before any laminate material has been applied would not be recommended practice. The minimum and maximumallowable time between surface preparation and bonding should be specified in the method statement.

In all cases it is important that prepared surfaces are protected from contamination prior tothe application of the repair laminate. Any sign of deterioration of the prepared surfacethrough handling, the presence of water or other influence should be cause for rejection andthe surface preparation procedure repeated.



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infusion process. Other proprietary systems also are available involving, for example, thebonding of fully cured composite material onto a repair site.

For all options it is recommended that the necessary materials and tools are prepared andbrought together at the repair location prior to the work commencing. Where material needsto be pre-heated to achieve an elevated temperature this should be done in a controlledmanner. Any material that has been pre-heated and then subsequently not used should bediscarded even if it has not been mixed with other material.

Reinforcement should be pre-cut ideally away from the immediate vicinity of the repair in anarea where dimensions can be properly measured and material bagged ready for use after

preparation. The requisite amounts of resin, catalyst or hardener and any other ingredient or permitted filler should be accurately measured and thoroughly mixed. Dual volume syringescan be a useful means of achieving this for two part systems.

For certain repair methods it is necessary to use proprietary in-fill compounds to make goodlocal surface imperfections, e.g. external corrosion damage. The final geometry of the

surface should be measured and should comply with the specified tolerances. The externalsurface of the filler should be prepared according to instructions.

Where a separate adhesive material is required to achieve a bond between individuallaminate layers attention needs to be given to ensure that the adhesive is applied uniformlyand that the bond line thickness is in accordance with the design.

Individual layers should be applied to the repair site in a sequential manner in the order specified in the method statement. Particular care should be taken with directionalreinforcement where the fibre alignment needs to be controlled according to the requirementsof the design. The overlaps between individual layers will be dependent on the nature of thereinforcement and these should be defined as part of the laminating procedure. Overlaps

should be staggered around the geometry of the repair area. Consolidation of the layers of reinforcement and resin can be accomplished through the use of simple hand tools such asrollers. This needs to be carried out thoroughly to ensure adhesion between individual layersand to remove air inclusions, but excessive pressure should be avoided to prevent damage or undesired reorientation of fibres.

The geometry and orientation of the pipe being repaired can have an influence on the quality of the repair. Small diameters and regions of rapidly changing curvature, e.g. a teeintersection, can be difficult to laminate due to the resistance in the reinforcement to drape.The use of lighter weight fabrics or directional reinforcement to 'tie' the laminate into difficult areas can be useful. On vertical surfaces drainage of resin prior to cure may causedifficulties and the addition of thixotropic additives may be required.

The minimum thickness for the repair laminate shall be 5 mm. The extent of the laminateover the surface should be specified within the design. This should normally be the larger of 100 mm or 2(D.t)0.5 in all directions beyond the damaged region, where D and t are theexternal diameter and thickness of the pipe respectively. Care should be taken to ensure thatthere are no significant discontinuities in laminate thickness at the edge of the repair.Typically thickness should be tapered to give a minimum slope of 6:1.

In the event of excessive heat generation in resin containers, evidence of premature gelation,or a significant increase in viscosity, the material should be discarded and a further batch of material prepared.



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Where the external finish of a repair laminate is important as it is intended to carry a bearingload, e.g. within a support, the surface can be moulded flat by applying a former prior to finalcure.

Any spillage, drips or runs, which may later flake off, should be removed. The outer surfaceshould have a smooth contour.

For major repairs there may be a need for material to be applied in stages with cure occurringbetween them. In these circumstances it may be necessary to lightly abrade the curedsurface to ensure good secondary bonding.

Ideally, repairs should be carried out above the dew point. However, it is possible to proceedin conditions of low ambient temperatures with suitable local protection to the repair area.This may involve the use of temporary covers or housings. The material supplier should becontacted for confirmation that resin curing will continue to be satisfactory. Similar considerations should be taken in regions of high ambient humidity. Where condensation ispossible, e.g. repair onto a cold pipe, this should be considered at the outset of material

selection and design.

Ideally, repairs should not be applied when the temperature of the surface is less than 3 °C above the dew point of the surrounding air or when the relative humidity of the air is greater than 85% unless local conditions dictate otherwise. Guidance on the estimation of the

probability of condensation can be found in ISO 8502-4. Also, the pipe surface temperature,ideally, should always be more than 5 °C.

It is not possible to determine the properties of the actual repair laminate. However, it wouldbe possible to prepare a sample laminate along side the repair using the same materials.This could be used to measure parameters such as fibre content and mechanicalcharacteristics. Generally, this option would only be considered for Class 3 repairs.

The minimum thickness of 5mm was considered to be the norm at the time this document was prepared. In most cases the cost of the material is not a significant element in that for the total repair operation. There may be circumstances where this requirement could berelaxed, e.g. the use of a GRP repair to provide external corrosion resistance to significant lengths of pipe and there is little or no load carrying requirement for the composite.

Approximate calculations using analysis for a beam on an elastic foundation indicates that the specified extent of repair laminate is satisfactory for leaking pipes.

9.3 Cure

The cure of a repair laminate is strongly influenced by temperature and the correct mixing of resin constituents prior to lamination. It is important that the prevailing temperature conditionsare considered when, for example, resin catalyst levels are being assessed. On no account,however, should the limits set by suppliers be exceeded without recourse to further information. It should be noted that for curing in extreme ambient conditions there may bespecial resin formulations that may be more suitable.

Cure can be assisted by keeping the repair laminate covered with, for example, a plastic filmduring installation. This protects the laminate from mechanical abuse and water, retains heat and excludes air that can inhibit the cure in certain resin systems. This is especially important for thin repair laminates where there may be insufficient material to retain heat

generated due to cure.



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Where elevated temperatures are required for cure it is recommended that these areachieved through the use of heating blankets that fully cover the repair laminate. Heatingblankets should extend beyond the repaired region by at least 50 mm. A protective filmshould be positioned between the blanket and the laminate to prevent material being bondedto the blanket. The temperature should be monitored throughout the curing process.

Pre-heating the pipe surface prior to the application may also be useful, but it should beensured that this would not adversely affect the surface preparation that has been carried out.The use of heated air guns directed to the surface of a curing laminate is not recommended due to the likely evaporation of reactants from the surface.

The time for full cure is dependent on the type of resin used in the repair and ambientconditions. The extent of cure may be measured using Barcol or Shore hardness or DSC(Differential Scanning Calorimetry). Acceptance values should be obtained from the supplier for each repair method. Details of the test methods are given in BS2782: Part10: Method1001, ISO 868 and ISO 11357 respectively. Typical Barcol hardness values for styrenated

resins are in the region 35 to 40 (Shore hardness approximately 60), but in any case shouldbe at least 80% of the value obtained from cast resin specimens.

The extent of cure achieved during installation should be the same as that in the design.

The repaired pipe may be returned to service after full cure has been achieved, assuming thepipe service has been reduced prior to repair application. Guidance for the repairs of livepipes are given in Section 10.

A Barcol or Shore hardness impresser is a simple hand held tool that can give an immediateindication of the degree of cure. DSC is a laboratory base technique requiring a small sampleof resin. It gives an accurate measure of the degree of cure. Other methods are available to

assess cure such a residual styrene content (BS 2782: Part4: Method432A) and the acetonetest (assessment of surface tact after exposure to acetone).

9.4 Key Hold Points

The key hold points to be observed during a repair are dependent on the repair class and aresummarised in Table 2.



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Hold Point Class Checked by

Method Statement All Classes Installer

Materials Preparation

− reinforcement

− resin

All Classes

All Classes

Installer

Surface Preparation

− inspection

− mechanical test

All ClassesClass 3

Installer (Class 1)Supervisor (Class 2 and3)

Filler Profile All Classes (whereappropriate)

Installer

Stage Check onReinforcement

Class 3 Installer

Tests on Repair Laminate

− cure

− thickness

− dimensions− external

inspection

All classes All classes

All classes All classes

Installer (Class 1)Supervisor (Class 2 and3)

Pressure Test Inspection Authority

Table 2: Hold Points During Manufacture

The stipple test can be included as an extra key hold point during surface preparation if requested by the end user.

9.5 Documentation On completion the repair should be permanently marked with its reference number. Alogbook opened for each repair and retained for its service life. The records that should beprovided with each repair should include:

Material Records

Record of resin type and quantity.Record of reinforcement type and quantity.Record of personnel on the fabrication.Record of layers and orientation of reinforcement.

Record of surface preparation procedure.Record of cure system.Record of post cure.

Quality Control Records

Repair reference number.Visual inspection report.Thickness measurement.Repair dimensions.Barcol or Shore hardness measurement (if carried out - dependent on resin system).DSC measurement (if carried out - dependent on resin system).

Bond strength measurement (if carried out - usually Class 3 repair only).



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Laminate strength measurement (if carried out - usually Class 3 repair).NDT results (if carried out)

Independent Inspection

Report (if carried out).

Service Inspection

Details of service inspection intervals.

A summary of documentation requirements is given in Table 3.

Documentation

requirementClass 1 Class 2 Class 3

Material records− resin

− reinforcement

− personnel

− lay-up

− surface preparation

− cure

ü ü ü ü ü ü

ü ü ü ü ü ü

ü ü ü ü ü ü

QC records

− repair reference

− visual inspection

− thickness

− dimensions.− Barcol, Shorehardness/ DSC

− bond strength

− laminate strength

− NDT*

ü ü ü ü

ü

ü ü ü ü

ü

ü

ü ü ü ü

ü

ü ü ü

Independent inspection ü ü

Service Inspection ü ü ü

* subject to availability of appropriate technique (see AEAT - 75394)

Table 3: Documentation Requirements

10. LIVE REPAIRS

Repairs to live pipe systems are possible provided that the associated hazards are fullyconsidered in the risk assessment for the operation. This should include any hazards tosurrounding live equipment in addition to that being repaired. Live repairs would normally becarried out with some reduction in line pressure.



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Where the pipe to repair is leaking the effect of this on the likely success of the repair shouldbe considered. Reference should be made to the material supplier. Whilst there are resinsystems for which it is possible to achieve an acceptable bonded connection when surfacesare wet, a dry situation is preferred where possible. A distinction should be made betweensurfaces that are wet and those where there is flowing water. In case of the latter, the leakshould be plugged prior to the repair being applied. The plugging method should beconsidered as integral part of the repair and the total arrangement should have beendemonstrated to be satisfactory by the supplier through qualification.

In the event of the repair being carried out under reduced pressure conditions the repairedpipe may be returned to full service after full cure has been achieved.

Repairs that are plugged to stem flowing water will have been treated as leaking pipes for the purposes of design qualification and will be been subject to the appropriate tests (see AEAT -57711).

11. REPAIR OF CLAMPS, PIPING COMPONENTS,TANKS OR VESSELS

The design of composite repairs of clamps, piping components, tanks or vessels, may becarried out using the procedures given in AEAT - 57711.

It is likely that prior to applying the composite repair in-fill materials will be used to provide asmooth external contour.

Guidance for the surface preparation of clamps is the same as for repairs on pipe (Section

9.1).

The details of repairs to clamps, piping components, tanks or vessels including the finalgeometrical form prior to the application of the composite repair shall be provided by thesupplier. The arrangements at the edges of the repair are particularly important. The supplier should demonstrate the suitability of these details through prototype pressure testing.

Prototype testing is recommended for these types of repairs. The effects of local variations ingeometry are not easily amenable to calculation (see AEAT – 75484) and testing will confirmthat these features do not adversely affect the performance of the repair..

12. SYSTEM TESTING

If required system pressure tests should be specified by the end user.

For most repairs process control as described in Section 9 is a satisfactory means of assuring fitness for purpose. For Class 3 this will require the performance of a bond test asdescribed in Section 9.1.

All repairs should be cured in accordance with the Repair System Supplier instructions beforepressure testing.



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Where required, hydrotesting shall take the form of a service test at 1.1 times the operatingpressure for a period of at least 60 minutes over which any changes in pressure andtemperature should be recorded. Any signs of leakage from the repair should be cause for rejection of the repair. The repaired system should be flushed with an appropriate mediumprior to testing.

All supports and anchors should be in place prior to pressure testing. Temporary supports or restraints can be added if necessary.

If the test pressure exceeds the pressure for which the repair has been designed then thishigher pressure should be considered as a separate design case. For the purposes of thecalculation the test condition may be treated as an occasional load.

In circumstances where it is considered necessary to carry out a hydrotest to 1.5 timesdesign pressure (e.g. piping systems) to the maximum allowable operating pressure (MAOP)of the pipeline special consideration should be given to ensure that the test pressure does notcause additional damage to other parts of the system. Where a 1.5 or MAOP hydrotest is

specified the test pressure should be regarded as separate design case (see AEAT 57711).For the purposes of the calculation the test condition may be treated as an occasional loadand the design strains/design factors specified for Class 1 repair, design lifetime 1 year, maybe used.

The repaired system should be flushed with an appropriate medium prior to testing.

Hydrotesting will usually only be carried out where the repair has been to a leaking pipe.Where a repair is undertaken on damaged pipe where the residual wall thickness is still abovethe design code minimum there is little value in conducting a hydrotest.

The use of a service test to confirm fitness for purpose is as a result of concerns that re-

testing to 1.5 times design pressure or to the MAOP of the pipeline may cause additional damage to a pipe system that has been the subject of deterioration. For Class 1 repairs

pressure testing may not be practical as this Class covers open drains.

The use of process control will only be satisfactory if the procedures described in thisdocument are observed.

When considering test requirements it should be noted that the failure modes of compositecomponents under sustained pressure are benign. This will also likely to be the case wherethe repair is for a leaking pipe where any failure will be through delamination at the steel/repair interface.

13. FIRE SERVICE

The requirements for fire performance should be identified in the risk assessment. Flamespread and smoke generation should also be considered in the assessment. Due accountshall be taken of the response of the complete system (original pipe and the repair). In manycases additional fire protection will not be necessary, as the damaged steel pipe may still beable to perform satisfactorily during the short duration of a fire event.

Strategies for achieving fire performance include the following:



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• application of additional composite material such that enough basic composite will remainintact for the duration of the fire event;

• application of intumescent external coatings;

• application of intumescent and other energy absorbent materials within the laminate;

• use of resin formulations with specific fire retardant properties.

Further guidance on the design and testing of composites for fire performance may beobtained from ISO14692.

14. ELECTRICAL CONDUCTIVITY

For repairs to steel or other metallic pipework it is likely that the properties underlying pipe willsatisfy electrical conductivity requirements.

Where the pipe to be repaired is insulating, e.g. GRP, and electrical conductivity requirements

are specified the properties of the repaired arrangement should be measured to ensure thatthe original characteristics of the system are restored. Guidance on how thesemeasurements can be taken is given in ISO 14692.

15. INSPECTION

Composite repairs if unpigmented are amenable to visual inspection and the ingress of fluidwithin the laminate or at the interface between it and the parent steel can be seen, particularlyif unnecessary fillers or pigments are excluded from the repair material.

Any sign of delamination between the composite laminate and steel pipe would also be a signthat the repair should be rejected.

Further information on inspection methods can be obtained from AEAT - 75394.

16. HEALTH AND SAFETY

Health and safety issues should be fully addressed in the risk assessment and repair methodstatements. In the majority of cases the hazards associated with composite repair methodscan be catered for using simple protective equipment. Reference should be made to

supplier’s instructions, local regulations and any permit to work procedures. Manufacturer'sMaterials Safety Data Sheets should be read and understood before a repair is started. Thismay entail a COSHH assessment for the process.

Resins and associated chemicals, surface preparation agents and adhesives will havequoted TLV limits for short and long term exposures. It is unlikely that these will be exceeded given the relatively small quantity of material used in repairs, especially those executed inopen situations. However, in addition to TLV limits the ALARP (as low as reasonably

possible) principle is applicable. This can be accommodated by adopting simple safety procedures that will limit operator exposure. For example, directing personnel to stand suchthat prevailing airflows draw fumes away from the breathing area and the use of covers oncontainers can be very effective.



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Where repairs are carried out in enclosed spaces or if overhead working is necessary further consideration may be required.

If forced ventilation is deemed to be necessary experience has shown that relatively slow, but constant air velocities are the most effective. Strong and local extraction in the immediatevicinity of a composite surface can have an adverse effect by removing material throughevaporation. It should be noted that when considering ventilation strategies many of thechemical species of concern are heavier than air. Styrene (a component of polyester and vinylester resins) is an example where a downwards extraction away from the operator is themost effective.

The quantity of many chemical species in the atmosphere may be estimated using Draeger tubes and measured values compared with allowable limits.

Where repair material is to be machined, for example, drilling for boltholes, grinding for surface preparation, secondary bonding or material removal, precautions need to be taken tocontain the dust hazard.

Where possible such operations should be carried out in the open air with operators wearing the recommended protective clothing. If the amount of material to be removed is largeextraction local to the repair site should be provided. Carbon dust could pose a specific hazard to any electrical equipment in the vicinity of the repair.

The ALARP principle is a feature of UK legislation for Health and Safety. For many chemicals defined short and long-term limits are given which are regarded as pragmatic and achievable with prevailing manufacturing practice. However, they should be considered asmaxima and the onus is on the organisations concerned with a given activity to use'appropriate' measures to limit operator exposure. This approach is different to that adopted in other countries where it is the norm to stipulate lower limits even though these may not be

achievable in practice.

17. ENVIRONMENTAL CONSIDERATIONS

All repair materials shall be designed to allow for satisfactory disposal according to prevailingenvironmental regulations. Given the relatively small amount of material employed it isunlikely that repair operations will pose an environmental risk. However, in addition to anyspecific requirements the BATNEEC (Best Available Technique Not Entailing Excessive Cost)principle is applicable which requires the environmental impact of any activity to beminimised.

Special attention should be given to the disposal of unused chemicals and resins that may beleft after a repair operation. In some circumstances it is possible to recycle materials for reuse, e.g. acetone and other solvents. Incineration in the open air should not be carried out.

The BATNEEC principle should be regarded in the same way as ALARP.

18. FUTURE MODIFICATIONS

Existing repairs may be modified, but this would only be after a design assessment andspecific design approval of the new repair. For example, the upgrade of the pressure rating of



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a repair may be achieved by the application of further material. However, for some materialoptions it is difficult to achieve a successful bond onto an existing fully cured compositelaminate. Reference should be made to the supplier.

In the event of the failure of a repair the preferred course of action would be to remove theoriginal material first. The repair of a leaking laminate through the simple application of additional thickness, particularly if the leak is caused by a delamination at the laminate/pipeinterface, is unlikely to be successful.

A repair with a short lifetime cannot have its lifetime extended through the later addition of further material (see Section 5.1) unless it can be demonstrated that the design does not relyon the original repair to contribute to repair integrity.

Different repair systems should not be mixed at the same repair site without reference to thesuppliers concerned.

19. DECOMMISSIONING

Reference should be made to the risk assessment prior to decommissioning. If necessary aseparate risk assessment should be carried out to cover this activity.

The removal of repair material may be achieved by mechanical means, although it should benoted that a well bonded repair would require a significant amount of effort for removal.Procedures should be put in place to contain any dust that may be generated.

Care should be taken to avoid damage to adjacent equipment that is to remain in service andthis should be protected if necessary.

Components should be disposed of in an appropriate manner (see Section 16)

20. BIBLIOGRAPHY

Background standards and references are given in the following sections.

Reference Standards

1 ISO 14692, Specification and recommended practice for the use of GRP piping in the

petroleum and natural gas industries.2 prEN 13121, GRP tanks and vessels for use above ground.3 ASME B31.3, Chemical plant and refinery piping.4 BS 2782: Part10: Method 1001, Measurement of hardness by means of a Barcol

impresser.5 ASTM D2583, Standard test method for indentation hardness of rigid plastics by

means of a Barcol impressor 6 ISO 868, Plastics and ebonite - Determination of indentation hardness by means of a

durometer (Shore hardness)7 ISO 11357, Plastics - Differential scanning calorimetry (DSC).8 ISO 8501, Preparation of steel substrates before application of paints and related

products9 ISO 8502, Tests for the assessment of steel cleanliness



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10 ISO 8503, Surface roughness characteristics of blast cleaned steel substrates11 ISO 8504, Surface preparation methods12 NTS-GRP-FJS/01 and NTS-GRP-INSP/01, NTS GRP guidelines for approval

schemes for fitters, joiners, supervisors and inspectors.13 CSWIP-GRP-1-96 and CSWIP-GRP-2-96, as per reference 10

Reference Publications

1 AEAT - 57711, Design of Composite Repairs for Pipework, January 20042 AEAT - 75394, NDT Techniques for the Inspection of Composite Repairs, January

2004.

3 AEAT – 75484, Composite Repairs for Piping Systems, Tanks and Pressure VesselRepair, January 2004.



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APPENDICES

CONTENTS

Appendix 1 - Glossary of Terms Appendix 2 - Installer Qualification



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Appendix 1: Glossary of Terms

Introduction

This appendix provides a glossary of terms used in this report.

Terms

Accelerator

A substance when mixed with resin and catalyst will speed up the curing reaction. Normallyused in conjunction with styrenated resins.

AnisotropicExhibiting different properties in different directions.

Barcol hardness

Measure of surface hardness using a surface impresser. Often use to assess cure instyrenated resin systems.

Cure

Setting of a thermosetting resin, e.g. polyester, epoxy, by an irreversible chemical reaction.

Cure cycle

Time/temperature/pressure cycle to achieve cure

Delamination

Separation of layers within a composite laminate or between the laminate and the steel.

Differential scanning calorimetry (DSC)

Method of determining the glass transition temperature of a thermosetting resin.

Glass transition temperature

Temperature at which a resin undergoes a marked change in physical properties.

Hardener

Component added to an epoxy resin to effect cure

Heat distortion temperature

Temperature at which a standard test bar deflects a specified amount under a given loads.

In-fill material

Material used to repair external surface imperfections prior to the application of compositerepair.

Post cure

Additional elevated temperature cure.



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Pot life

Length of time that a catalysed resin remains processable.

Shore hardness

Measure of surface hardness using a surface impresser or durometer. Often used tocharacterise elastomers and seals.

Warp/weft

Reinforcement directions in a woven cloth.



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Appendix 2: Installer Qualification

1. Introduction

The repair of pipe using composite laminates differs considerably from other repair techniques and the quality of the installation depends strongly on satisfactory craftsmanship.Training and certification of personnel is therefore a key element to the execution of asuccessful repair. This appendix outlines the minimum requirements for training, qualificationand approval of installers and supervisors.

Courses and training may be arranged by or with the assistance of the repair material

supplier.

2. Basic skills/experience

Installer

The candidate should be a minimum of 18 years of age and fulfil either of the followingexperience requirements:

• Minimum 2 years documented experience in the repair and maintenance in pipe relatedsystems.

• Minimum 2 years documented training and/or experience with fibre reinforced plastics,e.g. GRP pipe.

A log book of all repair applications should be kept and is mandatory.

To obtain the necessary 2 years experience the following should be undertaken;

• 3 month in-house training at the Repair Supplier’s office.

• 15 months supervised (by qualified Installer or Supervisor) application of repairs.

Supervisor

For entry to the supervisor course the candidate must have a minimum of 2 years experiencein repair using composite materials, must have completed at least 12 repair applicationswithin the 2 year timeframe and be in possession of a current specific approval certificate for an installer of composite repairs. Experience of the applications to complex geometries (atleast 3 applications) other than straight pipework is also required.

3. Training

The basic course should give a theoretical and practical introduction to the most importantelements in the installation of a composite repair.



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Coursework (Installer)

The course should include training in:

• Terminology, types of repair;

• Health, safety and environment;• Surface preparation;

• Material application;

• Control of repair conditions;

• Quality assurance and control.

Coursework (Supervisor)

• Supervisor's duties and responsibilities;

• Evaluation methods used in repair design;

• Methods of pipe defect assessment;

• Health and safety;• Installation checklist and hold points;

• Inspection of repairs.

Installer Specific Approval

Installers should be qualified for each specific repair method. Qualification should be carriedout on a basis of repair class (Table 1). Installers approved for a given Class can undertakerepairs at a lower level, i.e. approval to Class 3 permits repairs at Classes 1 and 2, etc.

The higher classes relate to onerous service conditions, e.g. pressure rating, and thereforerequire higher specification materials and application methods.

All specific approval tests should be carried out in accordance with a written procedure,relevant to the specific repair method and approved by the material supplier.

The test pieces shall be tested with water generally in accordance with ASTM 1599 to aminimum test pressure equal to 2 times the design pressure which shall be held for one hour with no leakage. The assembly should be inspected in stages at each incremental increasein pressure for evidence of cracks, leaks or other signs of deterioration. Before and after testing the repair should be visually inspected.

Where the repair method can be used for the repair of leaking pipes the steel pipe used in thetest specimen should incorporate a hole (see AEAT - 57711) and should be tested to failure

after the 1 hour at 2 times the design pressure. The derived value of γ derived from these

tests should be consistent with the acceptance value quoted by the supplier.

The specified acceptance value of γ should be related to the data used for repair design (see

AEAT - 57711).

4. Certificate

At the completion of an installer or supervisor course a successful candidate should beissued with a certificate providing details of the repair method of concern and the class towhich qualification has been achieved.



5. Validity

The type specific approval is valid for a period of 1 year.

All personnel who have been trained as competent applicator require to be continually workingin the application of composite repairs and will therefore not require a revalidation of their competency. Those personnel who have not applied a composite repair for more than 1 year will have to redo the training course (Appendix 2, Section 3).

grp repair

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