GP 06-40 - Pipeline Coating Selection

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Guidance on Practice forPipeline Coating Selection

GP 06-40

BP GROUPENGINEERING TECHNICAL PRACTICES

Document No. GP 06-40

Applicability Group

Date 15 February 2007


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15 February 2007 GP 06-40Guidance on Practice for Pipeline Coating Selection

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Foreword

This is the first issue of Engineering Technical Practice (ETP) BP GP 06-40. This Guidance onPractice (GP) is based on parts of heritage documents from the merged BP companies as follows:

Amoco

A CP-COAT-00-E Corrosion ProtectionCoatingsGeneralSelection Specification.

A CP-COAT-00-G Corrosion ProtectionCoatingsGeneralGuide.

ARCO

ES 503 Coatings for Buried Steel Piping.

Copyright2007, BP Group. All rights reserved. The information contained in thisdocument is subject to the terms and conditions of the agreement or contract under whichthe document was supplied to the recipients organization. None of the informationcontained in this document shall be disclosed outside the recipients own organization

without the prior written permission of BP Group, unless the terms of such agreement orcontract expressly allow.


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Table of Contents

Page

Foreword ........................................................................................................................................ 2

Introduction..................................................................................................................................... 4

1. Scope .................................................................................................................................... 5

2. Normative references............................................................................................................. 5

3. Symbols and abbreviations.................................................................................................... 5

4. Surface cleanliness and surface preparation ......................................................................... 5

5. Pipeline coating systems selection......................................................................................... 6

6. Line pipe coatings.................................................................................................................. 6

6.1. General....................................................................................................................... 6

6.2. Health and safety considerations ................................................................................ 6

6.3. Resistance to mechanical damage ............................................................................. 6

6.4. Resistance to the operating environment .................................................................... 8

6.5. Compatibility with cathodic protection ......................................................................... 8

6.6. Coating selection ........................................................................................................ 9

7. Field joint coatings ................................................................................................................. 9

7.1. General considerations ............................................................................................... 9

7.2. Coal tar and asphalt enamels ..................................................................................... 9

7.3. Cold applied tape coatings........................................................................................ 10

7.4. Fusion bonded epoxy powder ................................................................................... 107.5. Liquid applied coatings ............................................................................................. 10

7.6. Heat shrink sleeves................................................................................................... 11

7.7. Polyolefin coated line pipe ........................................................................................ 11

Bibliography.................................................................................................................................. 17

List of Tables

Table 1 - Comparison of line pipe coating properties .................................................................... 13

Table 2 - Field joint coating options............................................................................................... 14

Table 3 - Comparison of field joint coating properties.................................................................... 15


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Introduction

This Guidance for Practice covers the selection of external line pipe and compatible field jointcoatings for new pipelines both onshore and offshore. Coating options for the refurbishment of

coatings on onshore pipelines are more limited and are covered by GIS 06-405. For the purposes of

this document the term line pipe refers to sections of manufactured pipe normally 12 metres

(40 feet) in length and usually prepared and externally coated under factory conditions, except for the

cutback at either end. The coating is stopped short of the pipe ends to facilitate butt welding of

adjacent sections of line pipe together without causing coating damage to the line pipe coating. The

field joint encompasses the butt weld, the cutback area and an area of overlap onto the line pipecoating.

The guidance provided is based upon the experience of BP and other major pipeline operators plus

information gathered from a number of documented sources. These documents include; independent

test reports, national and international standards, published papers, coating manufacturers published

data, and private communications.

A significant amount of the guidance provided in this document is based upon the results from

laboratory tests, either directly in accordance with, industry, national, and international standards or

slight modifications to them to more accurately represent the conditions experienced in practice. It

should be borne in mind that the range of external pipeline coatings that are commercially available

covers a number of diverse generic types. As many of the test methods are not universally applicableto every available pipeline coating system, the comparative assessments based on the results of these

tests alone are subjective. The most reliable testament to satisfactory performance can only be

provided by investigation under the specific conditions to be encountered in practice. Such testing

and/or the accumulation of reliable on site performance data is expensive and time consuming and has

been very limited to date.

It is the responsibility of the reader to ensure that the information used is relevant to his or her specific

requirements.


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1. Scope

a. This GP provides guidance for the selection of shop applied and field applied externalflowline and pipeline coatings for new construction, hereafter referred to as pipeline

coatings. The primary purpose is to prevent external corrosion. Coatings which provide

thermal insulation are outside the scope of this document.

b. This document considers the following line pipe coating systems as they are the ones mostwidely used throughout BPs pipeline operations:

1. Coal tar enamel.

2. Asphalt enamel.

3. Cold applied tape wraps.

4. Single layer fusion bonded epoxy.

5. Dual layer fusion bonded epoxy.

6. Two layer polyethylene.

7. Three layer polyethylene.

8. Three layer polypropylene.

2. Normative references

The following normative documents contain requirements that, through reference in this text,

constitute requirements of this technical practice. For dated references, subsequent amendments to, or

revisions of, any of these publications do not apply. However, parties to agreements based on this

technical practice are encouraged to investigate the possibility of applying the most recent editions of

the normative documents indicated below. For undated references, the latest edition of the normative

document referred to applies.

Deutsches Institut Fur Normung E.V. (DIN)DIN 30670 Polyethylene coatings of steel pipes and fittings; requirements and

testing.

DIN 30678 Polypropylene coatings for steel pipes.

3. Symbols and abbreviations

For the purpose of this GP, the following symbols and abbreviations apply:

C.D. Cathodic disbondment

FBE Fusion bonded epoxy

SCE Standard Calomel Reference Electrode

4. Surface cleanliness and surface preparation

The importance of surface cleanliness and preparation standard to the long termperformance of a pipeline coating cannot be stressed too highly.

Poor surface preparation quality resulting from either one, or a combination ofthe following: inadequate removal of dirt and grease, inadequate removal of

mill scale and rust, dust contamination, lack of surface profile angularity, etc. is


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the major cause of premature coating failure. This is true regardless of the

generic coating type selected and the specific conditions under which the

coating is applied.

5. Pipeline coating systems selection

Each pipeline shall be considered on its own individual merits in respect of coating systems selection.

Under normal circumstances, the selection of an external line pipe coating system is

influenced by five principle factors:

Health and safety.

Resistance to mechanical damage.

Resistance to the operating environment and corrosion protection capability,with specific reference to temperature.

Compatibility between the line pipe coating, the field joint coating, and thecoating used on the bends and fittings.

Compatibility of the coating with cathodic protection.

With the exception of health and safety, which is of paramount importance, thesefactors are not given in order of priority.

6. Line pipe coatings

6.1. General

The selection of the most appropriate line pipe coating is a first priority to ensure the long term

integrity of the pipeline.

Typically the coating applied to the line pipe protects 98% of the external surface of

the pipeline; the field joint coating protects 2%.

6.2. Health and safety considerations

Coal tar enamel and asphalt coatings should not be used unless exceptional circumstances exist

which mitigate otherwise.

At one time, coal tar and asphalt enamels were the mainstay of the pipelinecoatings industry. The development of pipeline coatings which are moreenvironmentally friendly and less hazardous during application has seen a

dramatic reduction in the use of hot applied enamels over the last 10 to

20 years.

Fumes given off during the heating of coal tar contain polycyclic aromaticswhich are known carcinogens. These are also present during the heating of

asphalt enamels, but to a smaller extent.

Health and safety concerns have led to some countries prohibiting the use ofcoating products containing coal tar, while a number of leading paint

manufacturers have eliminated coal tar from their liquid coating formulations.

6.3. Resistance to mechanical damage

a. Many cases of premature coating failure can be ascribed to mechanical damage to theapplied coating system and the coating system either going unrepaired or the repair being

of substandard quality. The figures for relative resistance to mechanical damage aregiven in Table 1.


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b. For onshore pipelines, specific consideration shall be given to road, rail, river, and othertypes of pipeline crossings where thrust boring and/or directional drilling operations

require the coating to have superior resistance to abrasion and gouging.

The mechanical damage sustained by the coating on a pipeline can take manyforms. During pipe handling, transportation, and pipeline construction, the pipe

coating can suffer impact damage from momentary heavy contact with foreign

objects and abrasion damage from more prolonged contact and relativemovement against the same.

If the coated pipe has a tortuous route between the coating plant and theconstruction site involving many stages of handling, resistance to impact and

abrasion is a key parameter to consider when selecting the external pipe

coating.

Experience has shown that coating repairs carried out in the field remain areasof weakness due to the constraints on coating application quality achievable in

the field compared to the optimum coating application conditions in the factory.

On buried pipelines in particular, these locations are invariably those wherecoating breakdown occurs first. In general terms, the extent to which the coating

suffers mechanical damage in service is likely to be much less for subsea

pipelines than for those buried on land. The environment surrounding a subseapipeline is likely to change very little with time, and mechanical damage in

service is not normally a significant issue in the absence of unwitting third-party

intervention. By contrast, the coating on an onshore pipeline, buried beneath a

minimum of 1 to 2 metres (3 to 7 ft) of backfill of often dubious quality, can

suffer varying degrees of impact, shear, abrasion, indentation, and penetration

during backfilling. Pipe settlement, cyclic fluid temperatures, and seasonal

changes in the water content of the surrounding soil all conspire to place

additional forces on the coating in service. It is regularly found that areas of

significant external metal loss on existing buried pipelines are associated withthe steel having become exposed to the environment as a direct consequence of

the coating suffering mechanical damage due to contact with the ground.

The figures for relative resistance to mechanical damage given in Table 1 inthe impact, indentation, and abrasion columns, are based upon a

comparative assessment. The value 1 is ascribed to the coating with the lowest

resistance to that form of damage in each case. The figures given for all of theothers reflect the relative amount by which they are more resistant to the specific

damage type. The coating with the highest figure in each column has the

greatest resistance to that form of damage. Both the value 1 (least resistance)

and the highest figure (greatest resistance) in each column are highlighted.

The impact resistance values are based upon the energy required (Joules permm (ft-lb/in) of coating thickness) to impart a holiday in the coating. The test

method used to derive the majority of this data is in accordance with the method

described in ASTM G14 and/or a modified version of this test using angular tups

in addition to the standard hemispherical tup. The coating with the lowestresistance to impact is single layer FBE (at both 20 and 50C (68 and 122F))

with three layer FBE-polypropylene having the highest resistance.

The values for indentation/ penetration reflect the relative resistance of eachcoating to point loading in accordance with DIN 30670, DIN 30678, ASTM G17,

and/or a modified version of ASTM G17 which uses angular indentors. The

values are based upon the physical measurement of the actual depth of the

indentation. Cold applied tapes and coal tar and asphalt enamels are

particularly prone to penetration damage as reflected in the much higher values

ascribed to the alternative coating systems at the same temperatures.


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The figures for abrasion resistance are based upon a series of full size tests inwhich the effect of reciprocal pipe movement relative to the soil was simulated

[1]. The maximum depth of penetration was assessed by physical measurement.

The greater resistance of fusion bonded epoxies, particularly ruggedised dual-

layer formulations, to this type of damage compared to polyolefins is evident

from a comparison of the figures for the different coating systems.

6.4. Resistance to the operating environment

Since most of the materials used as protective coatings for pipeline externals arechemically inert, a major consideration regarding the performance of the

coating system is likely to be the operating temperature and its influence upon

the mechanical properties of the coating. The data in Table 1 clearly shows howtemperature can have a significant effect upon the mechanical properties

(including adhesion) of the external coating, its resistance to the stresses acting

upon it in service, and the likelihood that the coating will be breached within the

required design life.

While the majority of the line pipe coatings show a gradual decrease inmechanical integrity with temperature, fusion bonded epoxies also undergo a

step change in physical properties at the glass transition temperature. Thisusually involves a significant fall in the adhesion quality and a change in the

coating itself from a rigid to a rubbery material with a much higher tendency for

water uptake. The standard range of fusion-bonded epoxies which have been

available for 20 to 30 years have glass transition temperatures between 95 and

110C (203 and 230F). In general terms, the maximum operating temperatureof a pipeline which has an external stand alone standard FBE coating should

not be higher then 5C (9F) below the established glass transition temperature.

Newer developments have included fusion bonded epoxy coatings withsignificantly higher glass transition temperatures (125 to 150C (257 to 302F))and lower application temperatures than the standard range. At this time, there

is insufficient data available on which to base any firm guidance with regard to

the selection of these coatings. Notwithstanding the above, three layer fusion bonded epoxy-polypropylene

coatings incorporating certain standard fusion bonded epoxies as the first layer

have shown satisfactory performance at operating temperatures up to 125C(257F)4.

6.5. Compatibility with cathodic protection

a. Most, if not all, pipelines should be protected from external corrosion by a combination ofa protective coating and cathodic protection.

Therefore, an important property of any pipeline coating is its ability to withstand

C.D.

b. The coating adhesion shall be resistant to the elevated pH in the immediate vicinity of anyholiday in the coating and the diffusion of water through the coating film due to the

applied voltage across it.

The elevation in pH is due to the electrochemical reactions taking place at the

cathodically-protected steel surface.

The majority of data that exists concerning the compatibility of line pipe coatings

with cathodic protection has been derived from small scale, short-term laboratorytests of the type used to verify the quality of factory applied line pipe coatings. There

is a wealth of such data for fusion bonded epoxy and fusion bonded epoxy polyolefin

coatings, which demonstrates that in coating systems with fusion bonded epoxy as


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the first layer, the coatings are extremely resistant to C.D. at ambient temperatures

if applied in accordance with the manufacturers recommendations to correctly

prepared substrates. The resistance to C.D. of the alternative coating systems at any

temperature and fusion bonded epoxy based coatings at elevated temperatures isless well documented.

6.6. Coating selection Table 1 compares the adhesion strength and the resistance to mechanical

damage and C.D. for the line pipe coating systems listed above. In some cases,

this data extends over a range of temperatures. The final column provides

guidance on the maximum operating temperatures for these generic coating

types.

The values for adhesion strength are minimum values measured during theproduction coating of line pipe and/or required by international standards.

Apart from the three layer FBE-polyolefin coatings, there is little documented

quantified information on the effect of substrate temperature upon adhesionstrength that can be used to determine appropriate upper temperature limits.

7. Field joint coatings

7.1. General considerations

a. Table 2 summarizes the field joint coating options available for each generic line pipecoating system discussed in clause 6 above.

Two major factors influence the selection of the field joint coating; compatibility

with the line pipe coating and the service conditions. Adequate performance of both

the line pipe and field joint coating is needed the projected life of the pipeline(usually 30 years minimum).

b. The method of application shall be conducive to the environmental conditions and the rateat which the pipeline is laid.

While historically the simplicity of the field joint coating application procedure has

been paramount, in recent years tremendous strides have been made in the

development of on-site, automated coating application equipment by field joint

coating contractors. When operated and maintained correctly, this equipment

ensures consistency of field joint coating quality while optimizing the production

rate.

c. Table 3 gives a comparison of the properties of the field joint coatings reviewed in thisclause.

The same comments made in clause 6.6 in respect of Table 2 are also applicable

with respect to Table 3, with one exception. In Table 3, the comparative rankings for

Indentation and Penetration are given in 2 separate columns. The Indentation

column rankings are based upon standard test methods described in DIN 30670,DIN 30678, or ASTM G17. The Penetration column rankings are based on a

modified version of ASTM G17, in which angular indentors were used and which

more closely represent the conditions experienced in practice on a buried pipeline.

7.2. Coal tar and asphalt enamels

The early over the ditch methods of applying asphalt and coal tar enamel

coatings meant that field joints were not in themselves a specific concern, as the

coating could be applied in a continuous manner along the pipeline way leave. It

was only when these materials began to be applied to individual lengths of pipe

under factory conditions that field joints became a subject of specific attention. At


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first, the field joints were coated in an analogous manner to the line pipe; that is,

using hot enamel and fabric reinforcement applied as a full circumferential wrap or

granny ragging, as it was commonly known. This procedure, which has

significant health, safety, and environmental risks, has been largely superseded overthe last 30 years by the application of cold applied tapes, two component liquid

applied coal tar epoxy, or coal tar urethane, or radiation cross linked polyethylene

(HSS PE) shrink sleeves.

7.3. Cold applied tape coatings

By the very nature of their composition and temperature limitations, the onlyviable field joint coating option on line pipe coated with cold applied tape wrap

is to use an identical material to the line pipe coating at the field joints.

Due to the thermoplastic nature of cold applied tape wraps, the terminationsadjacent to the field joint are easily damaged by pre-heating and post-heating

operations.

Cold applied tapes are regarded as the simplest coatings to apply at field joints,as less skill is required compared to the alternatives available. Nevertheless,there are a minimum number of application parameters that need to be satisfied

during their application, if they are to provide external corrosion protectionover a reasonable time frame. Due to their comparatively poor resistance to soil

stressing particularly at elevated temperatures (> 40C (> 104F)), their use

should be limited to smaller diameter pipelines (< 18 in), pipelines conveying

non-hazardous products, and ambient operating temperatures.

7.4. Fusion bonded epoxy powder

One of the major advantages of fusion bonded epoxy powder coatings is thatthey can be applied to line pipe, bends and fittings, and field joints, alike. This

enables just one coating system to be specified for the entire pipeline,

eliminating problems with the selection of the external coating at field joints in

situations in which two generically different coatings may have otherwise been

applied to the parent pipe on either side of the field joint. However, as stand-alone field joint coatings, they are not compatible with any line pipe coatingother than fusion bonded epoxy.

Unlike coal tar and asphalt enamel coatings and cold applied tapes, theapplication of FBE coatings in the field requires sophisticated equipment in the

form of induction heating coils, fluidized beds, and flock spraying equipment. A

satisfactory long-term coating performance is reliant upon a high quality of

surface preparation and a rigid adherence to established coating applicationprocedures in the field.

7.5. Liquid applied coatings

To combat extreme weather conditions, liquid polyurethane and epoxy field joint

coatings normally comprise 100% solids materials applied at elevated temperatures

by mix at the gun hot twin airless spray equipment, often with pipe pre-heat and

sometimes post-heat to accelerate the curing rate even further. Induction heating is

the preferred method for both pre- and post-heating for optimum control and

reproducibility of the heat profile. As with fusion bonded epoxy coatings, the

performance of liquid applied coating systems at field joints is reliant upon a high

quality of surface preparation and adherence to established coating applicationprocedures.


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7.6. Heat shrink sleeves

Radiation cross linked heat shrink sleeves require pre-heating of the field jointfollowed by post-heating after fit up of the sleeve to shrink the sleeve down to fit

snugly on the pipe. The traditional method of heat application is by manually

operated open flame torch. Apart from inherent health and safety risks, this

method results in a non-uniform heat input across the field joint. This non-

uniform heating pattern produces differential shrinkage rates across the fieldjoint, leading to wrinkling and blistering of the sleeve and widely differing

qualities of adhesion. In cases of extreme heat input, the sleeve may char and/orthe adjacent line pipe coating may be damaged due to overheating. A significant

improvement in the heating pattern and consistency of adhesion can be achieved

by using induction heating in place of open flame torches to apply the preheat.

Polypropylene shrink sleeves provide a step change in the quality of theadhesion that can be achieved to both steel and polypropylene line pipe coatings

and resistance to mechanical damage compared to their polyethylene based

counterparts. In order to fully realize the capabilities of polypropylene heat

shrink sleeves, induction heating is required to provide uniform pre-heat to the

pipe. As these field joint coatings are a comparatively recent development, track

records are limited to date.

7.7. Polyolefin coated line pipe

7.7.1. General

The generic coatings listed above have limited adhesion to polyethylene andabrasive blast cleaning or mechanical roughening of the surface of the

polyethylene is a minimal requirement in order to attain a measure of adhesion

in the case of liquid applied coatings, cold applied tapes, and heat shrinksleeves. With cold applied tapes and radiation cross linked polyethylene heat

shrink sleeves; this is offset to a small extent at ambient temperatures by the

rigidity of the plastic backing. There is some evidence that the adhesion level

between the field joint coating and the polyethylene can be optimized byjudicious selection of the type and particle size distribution of the abrasive, but

this has not been reliably documented.

Attempts to enhance the adhesion of coatings to polyethylene by flame treatmentof the polyethylene substrate have given variable results in general and

moderate improvements in adhesion at best.

7.7.2. Fusion bonded epoxy-polypropylene

Three layer fusion bonded epoxy-polypropylene coatings are the only pipelinecoatings with an established operating temperature limit in excess of 90C

(194F), and their use is confined mainly to preventing external corrosion ofpipelines operating between 90 and 125C (194 and 257F).

To date, five different field joint coating systems have been used on line pipecoated in the factory with three layer fusion bonded epoxy-polypropylene. All of

these systems incorporate the application of FBE as the first coating layer in anidentical manner to that described in clause 7.4, followed by a flock sprayed

layer of polypropylene copolymer adhesive within the gel time of the FBE to

ensure adequate cross linking.

Good interlayer adhesion is dependant upon a chemical reaction between thefusion bonded epoxy and the polypropylene co-polymer adhesive. This can only

take place when the fusion bonded epoxy is in a liquid state but has not had timeto cure. This period is normally of the order of 20 to 40 seconds following

application of the FBE.


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The principle difference between each of the field joint coating types is themanner in which the outer layer(s) of polypropylene/ polypropylene copolymer

is(are) applied. There are six different types as follows:

- Sintered polypropylene copolymer.

- Co-extruded polypropylene sheet plus polypropylene welding.

- Flame sprayed polypropylene copolymer.

- Injection moulded polypropylene.

- Co-extruded polypropylene tape.

- Polypropylene heat shrink sleeve.

The sintered polypropylene copolymer field joint coating application methodinvolves the build up of the copolymer coating by flock spraying as a dry

powder, the residual heat in the pipe from the fusion bonded epoxy application

process being used to melt and coalesce the copolymer particles. As polyolefins

have a low thermal conductivity, the thickness that can be achieved is limited to

less than 1 mm (0,04 in) with the added risk that the final copolymer layer may

be porous, unless supplementary heating is applied externally. Without thesupplementary external heating, this type of coating is likely to be extremelypoor quality by comparison with the alternatives available and described below.

The co-extruded polypropylene sheet method gives a sound field joint coatingwith properties equivalent to that of the line pipe coating, but requires precise

cutting of the sheet to fit the field joint area, preheating of the sheet, and then

preparation and sealing of the longitudinal and circumferential edges of the

sheet to the line pipe coating by extrusion welding using a polypropyleneconsumable. This field joint coating system is, therefore, time consuming to

apply correctly.

Of the five systems described, flame spraying is perhaps the most versatile as itcan also be used to coat fittings and pre-formed bends at a wide range of

coating thicknesses. The polypropylene co-polymer powder is propelled undergas pressure through a flame. The individual particles and the coated surface

are heated by the flame enabling a fully fused coating to be produced. Theapplication technique requires a high degree of skill in order to apply the

coating to a uniform thickness without slumping.

Injection moulding of polypropylene at field joints has been used only rarely andexclusively on offshore pipelines. It requires bulky and sophisticated equipment

and has a reputation for being more costly compared to the alternative systems

available. Nevertheless, it gives an extremely robust field joint coating almostequal in properties to the line pipe coating.

Polypropylene tape wrapping is the most recent development and may beregarded as an extension of the co-extruded sheet method. Being of a single

material and more flexible than the sheet, it is applied to the field joint as aspiral wrap in an analogous way to cold applied tape, rather than as a single

sheet. Good adhesion both between successive spirals, to the pipe, and the line

pipe coating requires preheating of the tape and the substrate as the tape is

applied, followed by post heating.


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Table 1 - Comparison of line pipe coating properties

Adhesion StrengthC. D.1,5(mmRelative Resistance to Mechanical Damage

(1-Lowest Resistance) [3]23C(73F

Generic Type

TotalCoating

Thickness(m (mil)) Temp

(C (F))

Peel(N/mm(lb/in))

Pull off(MPa (psi)) Temp

C (F)Impact *

Indentation/Penetration #

Abrasion 28 day

Asphalt Enamel4 000-6 000(160-240)

25 (77) 5 (29) N/A 20 (68) - 1 - 10 (0,

Coal Tar Enamel4 000-6 000(160-240)

25 (77) 5 (29)> 2,4

(> 350)20 (68) - 1 - 10 (0,

Cold Applied Tape 3 000 (120) 22 (72) 2 (11) N/A 20 (68) 3 (56) 1 - 12 (0,

20 (68) 1 (19) 220 (2) FBE Single Layer

350-600(14-24)

25 (77) N/A> 21

(> 3 000) 50 (122) 1 (19) 180 55 (0,2

20 (68) 7 (131) 250 5FBE Dual Layer(Ruggedised)

750-1 350(30-54)

25 (77) N/A> 21

(> 3 000) 50 (122) 7 (131) 180 125 (0,2

20 (68) 14 (262) 10 1 2 LayerPolyethylene

1 000-2 000(40-80)

23 (73) 4 (23) NA50 (122) 7 (131) 10 1

-

23 (73)20 (224)[4], [5]

40 (104) 15 (86)

20 (68) 14 (262) 10 1

60 (140) 8 (46)

3 Layer FBE- HDPolyethylene

2 500-3 500(100-140)

80 (176) 5 (29)

N/A

50 (122) 7 (131) 10 1

5 (0,2

23 (73) 20 (114) 20 (68) 16 (299) 20 -

70 (158) 15 (86) 50 (122) 15 (281) 13 -

90 (194) 8 (46) 110 (230) - 8 -

3 Layer FBE-Polypropylene

2 500-3 500(100-140)

125 (257) 2 (22)

N/A

125 (257) - 4 -

5 (0,2

* Impact rankings based upon the energy required to produce a holiday in J/mm (ft-lb/in) of coating thickness# Indentation rankings compares the resistance to penetration under constant load

Abrasion ranking compares depth to which the coating is penetrated for a fixed load and No. of cycles

Depends upon the specific FBE product used

Performance assumed to be the same as for three layer FBE-PE

Single layer FBE suffered through film penetration

Figures relative to 2 Layer PolyethyleneCommunicated Data

Upper temperature limit for coal tar ena

Higher temperatures (< 100C (< 212F

coat.

@ Upper temperature limit for dual layer F

independent test data.


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Table 3 - Comparison of field joint coating properties

Adhesion StrengthRelative Resistance to Mechanical Damage

(1-Lowest Resistance) [6], [7], [8], [9]

Generic Type

TotalCoating


(C (F))Peel(N/mm

(lb/in))

Pull off(MPa(psi))

Temp(C (F))

Impact Indent # Penetration Abrasion Gougin

20 (68) 8 (150) - 223 4 -FBE Mono Layer

350-600(14-24)

25 (77) N/A> 21

(> 3 000) 50 (122) 10 (187) 50 4 -

0 (32) 6 (112) - 400 - -

20 (68) 10 (187) - 250 8 -

50 (122) 12 (225) - 100 5 -

FBE Dual Layer(Ruggedised)

750-1 350(30-54)

25 (77) N/A> 21

(> 3 000)

80 (176) 10 (187) - 33 - -

0 (32) 4 (75) 177 201 - 201

20 (68) 6 (112) 233 107 7 107

50 (122) 10 (187) 35 46 3 46Liquid Applied Epoxy

750-1 000(30-40)

23 (73) N/A> 21

(> 3 000)

80 (176) 8 (150) 7 9 - 9

0 (32) 10 (187) 75 151 - 151

20 (68) 12 (225) 17 46 - 46

50 (122) 12 (225) 9 7 - 7

Liquid AppliedPolyurethane

750-1 000(30-40)

23 (73) N/A> 17

(> 2 500)

80 (176) 10 (187) 7 7 - 7

0 (32) 6 (112) 61 64 - 64

20 (68) 8 (150) 18 9 - 9

50 (122) 8 (150) 15 4 - 4

Liquid Applied Coaltar Urethane

750-1 000(30-40)

23 (73) N/A> 10

(> 1 500)

80 (176) 4 (75) 13 3 - 3

20 (68) 1 (19) 11 - - -Cold Applied PE/PVCTape

2 500-3 000(100-120)

22 (72) 2 (11) N/A50 (122) - - - - -

20 (68) - - - - -Heat Shrink Sleeve-Radiation X Linked PEMastic

1 500-2 500(60-100)

23 (73) 1,5 (9) N/A50 (122) - - - - -

0 (32) 8 (150) 71 6 - 6

20 (68) 8 (150) 62 3 1 3

50 (122) 4 (75) 11 1 1 1

Heat Shrink Sleeve-Radiation X Linked PE

Adhesive/ EpoxyPrimer

1 500-2 500(60-100)

23 (73) 3 (17) N/A

80 (176) 2 (37) 1 1 - 1


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Adhesion StrengthRelative Resistance to Mechanical Damage

(1-Lowest Resistance) [6], [7], [8], [9]

Generic Type

TotalCoating


(C (F))

Peel(N/mm(lb/in))

Pull off(MPa(psi))

Temp(C (F))

Impact Indent # Penetration Abrasion Gougin

70 (158) 4 (23) 23 (73) 8 (150) 62 - - -Heat Shrink Sleeve-Radiation X LinkedPP/Epoxy Primer

2 500-3 000(100-120) 110 (230) 4 (23)

N/A110 (230) 8 (150) 10 - - -

70 (158) 15 (86) 0 (32) - - - - -

90 (194) 6 (34) 50 (122) - 18 - - -

110 (230) 2 (11) 90 (194) 3 (56) 4 - - -

3 Layer FBE-Polypropylene(Flame Spray/ Tape)

3 000-4 000(120-160)

121 (250) 4 (23)

N/A

121 (250) - - - - -

* Impact rankings based upon the minimum energy required in J/mm (ft-lb/in) of coating thickness

to produce a holiday

# Indentation rankings compare the resistance to penetration under constant blunt load inaccordance with DIN 30670 & 30678

Indentation rankings compare the resistance to penetration under constant angular load

representative of typical onshore pipeline backfill

Abrasion and gouging ranking compares depth to

fixed load and fixed No of cycles

@ Upper temperature limit for dual layer FBEs needstest data.

Depends upon the specific FBE product used


17/17

Bibliography

[1] ASTM G14 Standard Test Method for Impact Resistance of Pipeline Coatings (Falling Weight Test).

[2] ASTM G17 Standard Test Method for Penetration Resistance of Pipeline Coatings (Blunt Rod).

[3] Pipeline Research Council Coating and Backfill Optimisation Study May 2004

[4] M. Alexander. 13thInternational Conference on Pipeline Protection, Edinburgh, 1999 Three Layer

Epoxy/Polyethylene Side Extruded Coatings for Pipe for High Temperature Application

[5] D. Nozahic & L. Leiden 13th

International Conference on Pipeline Protection, Edinburgh, 1999Advanced-Three Layer HDPE System with Improved Short and Long Term Properties

[6] Advantica Report No R5777 Pipeline Coatings/Trench Backfill System Optimisation Study-Phase 2Field Joint Coatings March 2001

[7] R. Espiner, I. Thompson, J. Barnett, Optimization of Pipeline Coating and Backfill Selection Paper03046, NACE 2003

[8] Advantica Report No R4302 Pipeline Coatings/Trench Backfill System Optimisation Study-SmallScale Laboratory Test Programme January 2003

[9] Advantica Report No R5426 BP Pipeline Field Joint Coating Study: Support to Shah Deniz ExportProject July 2002

Documents

GP 06-40 - Pipeline Coating Selection