disbondmentsofpipelinecoatings andtheir effects ......cathodic disbondment is of the same order of...

concern limited to buried pipelines onshore. Cases ofcorrosion and stress corrosion cracking (SCC) on oldburied pipelines coated “on the ditch” with coal tar orasphalt enamels or cold-applied tapes have been known fora long time. No case of external corrosion of pipelinesimmersed in seawater has been detected so far using in-lineinspection (ILI), despite, most likely, the existence of somecoating disbondment. Despite the assumption of some coat-ing disbondment in seawater, corrosion protection is main-tained, probably because the high conductivity and homo-geneity of seawater make it easier for the CP current toaccess the exposed steel and protect it.

Summaries of our company’s past experience withvarious kinds of pipeline coatings have been presentedin previous papers.1–9 In particular, at the 16th

International Conference on Pipeline Protectionin Paphos, the authors presented a paper on

failures recently discovered on“newer” coatings

18 www.paintsquare.comJ P C L S e p t e m b e r 2 0 0 9

uried and submerged pipelines are pro-tected from external corrosion by a coat-ing system, which is considered passive.Coatings are practically always applied topipe lengths in specialized coating plants, andcontinuity of coverage is ensured after girth

welding through field joint coatings (FJC). Cathodic pro-tection (CP) is an essential, complementary, “active” pro-tection system aimed at preventing corrosion at coatingdefects, where the pipe steel surface is exposed to thecorrosive electrolytic environment. As long as coatingsremain bonded to steel and CP is correctly applied,monitored, and maintained, no corrosion risk exists.The majority of known corrosion cases result

from disbonding of coatings, which may preventaccess of the cathodic protection current tosteel. The cause of failure, known as the“CP current shielding effect,”

appears to be a

Disbondments of Pipeline Coatings

and TheirEffects

on CorrosionRisks

By D. Melot, G. Paugam,and M. Roche, Total SA, France

B

steel surface together with poor bond-ing of HSS on the 3LPE plant-appliedcoating at the overlaps had allowedwater to penetrate at the steel surface,leading to corrosion because of the “CPshielding effect” (Fig. 1).Further excavations of the pipeline

revealed that the HSS residual adhe-sion to the steel was also practicallyzero on sections at lower operationtemperature (down to 35 C [95 F]) butwithout significant corrosion.

1166--IInncchh OOiill PPiippeelliinnee iinn SSyyrriiaaILI operations carried outon a 16-inch x 7.1 mmwall thickness oil exportpipeline operated in Syriafor about 12 years haverevealed severe externalcorrosion at many girthweld areas. These areashad been coated with HSS(hot-melt adhesive type)applied directly to a wirebrush-cleaned surface,without liquid epoxyprimer (Fig. 2).Excavations have con-firmed the indications ofILI and revealed severalcorrosion craters under-neath the surface of thefield joints with significantpresence of mill scale.Corrosion is clearly due to

disbondment of HSS. The surfacepreparation was poor and the HSSoverlap on the PE plant-applied coatingwas too small (1 cm). The soil is very aggressive (brackish

water with a chloride concentration of2 g/liter) and crystals of salt wereobserved under the disbonded HSS.

before the PE/PP. Specific examples ofsuch failures are given below.

1188--IInncchh OOiill PPiippeelliinnee iinn GGaabboonnIn this case, presented earlier,10 exter-nal corrosion was detected through ILIon the first 15 km, which is the hottestside (>55 C [131 F]) of the 18-inchRabi-Batanga oil pipeline, after 15years of operation in the ground. Thepipeline is buried in wet, compactedsand (pH of sample, 5.4). Heat-shrink-

able sleeves were the hot-melt adhesivetype and were applied on a fast-curingliquid epoxy (of nominal maximumoperating temperature 80 C [176 F]).Wire brush cleaning as per St 3 wasused for surface preparation. The appli-cation was fully surveyed by a compa-ny inspector.Massive disbonding of HSS on the

such as heat-shrinkable sleeves, three-layer polyethylene (PE) coatings, andfusion-bonded epoxy (FBE) coatings.10

The present article first updates andcompletes the information presented atthe Paphos conference on the recentcases of coating failures encountered. Italso summarizes the results obtainedfrom some laboratory test programsaimed at trying to explain the prob-lems for improving the future choicesand the specifications of the company.

Recent Feedback on Disbonding of Pipeline Coatings

Various practical case studies follow.Cases related to heat-shrinkablesleeves (HSS) used for field joints andwhich overlap the factory-applied 3-layer PE/polypropylene (PP) are themost important as far as corrosion isconcerned. Even if the problems relat-ed to loss of adhesion of 3LPE/PPcoatings do not lead to significant cor-rosion, the phenomenon must be betterunderstood to prevent the risk for thefuture.

Heat-shrinkable Sleeves Used for Field Joint Coating

Recent in-line inspections (ILI) carriedout on a series of buried pipelines haveshown massive disbonding of HSS withsignificant corrosion underneath after10 to 15 years of operation in theground. These coating failures andsubsequent corrosion have been noticedprincipally at moderately elevatedtemperatures (about 50–60 C[122–140 F]) and on coating systemsthat had been applied to a wire brush-cleaned surface specified at St 3cleanliness level (~SSPC-SP 3, PowerTool Cleaning), with or withoutapplication of a liquid epoxy primer

19www.paintsquare.com J P C L S e p t e m b e r 2 0 0 9

Fig. 1: Lack of adherence of HSS on PE (top) and steel(below) on 18-inchGabon.All photos courtesyof the authors.

nificant corrosion has been foundunderneath the disbondment of the3LPE.

18-Inch Oil Pipeline in GabonAlso presented earlier,10 disbonding ofa 3LPE coating occurred on the same18-inch Rabi-Batanga pipeline in Gabon.The coating was a low-density PE. Itwas applied partly by the side extrusionprocess (with PE adhesive applied byextrusion) and partly by the longitudi-nal extrusion process (with PE adhesiveapplied by powder). The application wasin compliance with the company specifi-cation requiring a minimum of 70micrometers FBE beneath the PE.The 3LPE plant-applied coating gener-

ally appeared to be correct externallybut was found fully disbonded betweenthe FBE and steel when cut for inspec-tion with a tool at the excavation loca-

tions in the hottest part of the pipeline.Except for the presence of a layer ofmagnetite on the steel surface, no signifi-cant corrosion of the steel was noticed.Excavations showed that in a few cases,where some minor corrosion wasreported by ILI on a few pipe lengths,the PE coating was found longitudinally

and on a 6-inch oil pipeline inFrance (Paris basin). Again,the operating temperaturewas about 50 C [122 F] inboth cases.

Disbonding of 3LPE/PP Used in Plant-Applied Coatings

Massive losses of adhesion of3LPE coatings between theepoxy layer and the steelafter 10 to 15 years’ opera-tions have been observedsince 2004 through excava-tions carried out after thedetection of corrosion at fieldjoints under disbonded HSS.The disbondments of 3LPEhave been noticed most often

when the operating temperature of thepipeline is about 50–60 C (122–140F) in wet environments. So far, no sig-

The soil is especially aggressive nearthe Al Furat river, where the majordefects were found. The area near theriver is very saline and has been inten-sively irrigated for a few years. Inaddition, the temperature is high (> 55C [131 F]) on the first 20 km of thepipeline, the most affected part. Thecorrosion appears to have been veryhigh. The value of 0.7 mm/yr estimat-ed as the maximum corrosion rateunder the disbonded coating at 50 C[122 F] in the laboratory studydetailed below roughly corresponds tothe maximum corrosion rate thatcould have been occurring here over10 years of operation.

Other CasesSimilar cases were discovered recent-ly, again using ILI, on the 12-inchCoucal-Rabi pipeline, again in Gabon,


Tests Temperature Longitudinal Side extrusionof test extrusion

Average peel strength 23 C (73.4 F) 94 ± 9 226 ± 34

(N/10 mm) 60 C (140 F) 38 ± 3 142 ± 13

Cathodic disbonding @ - 1.5 V, 23 C (73.4 F) 6.3 ± 0.7 6.6 ± 0.4

28 days (radial length in mm) 60 C (140 F) 32.2 ± 1.6 28.6 ± 4.1

Table 1: Test on 3LPE Coated Pipe Samples Stored During 15 Years

Fig. 2: Heavy corrosion under disbonded HSS (16-inch Syria)

Fig. 3: Disbonding of 3LPE at 35 C ([95 F] 18-inch Gabon)

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cracked and open at the 3 o’clock and 9o’clock positions. Measurements on PEsamples taken at these locationsrevealed a significant thermal agingeffect (as shown by loss of elongation atbreak, increase of viscosity, Shore Dhardness and IR spectrum).In addition to the details previously

given,10 it has been further noticed thatloss of adhesion existed at tempera-tures as low as 35 C (95 F), as shown inFig. 3. In this case, as compared withwhat was discovered at higher temper-atures, the epoxy primer was more visi-ble and no magnetite had been formed.

Also, it has been demonstrated that thisloss of bonding occurred with the twosupplies of coated pipes, with two dif-ferent coating processes and with twodifferent epoxy powders. Peel strengthand cathodic disbondment measure-ments carried out on spare pipes thathad been stored directly exposed to UVand atmospheric equatorial conditionsgave the results summarized in Table 1,which demonstrates again that the lossof adhesion in the ground is related toexposure to soil conditions (especially

water diffusion). It is also notable thatpeel strength is much higher with later-al extrusion as compared with longitu-dinal extrusion (the difference is relat-ed to the type of adhesive) but thatcathodic disbondment is of the sameorder of magnitude (no significant dif-ference between the two epoxy pow-ders), with the value measured at 60 C(140 F) being very high.

Other CasesLocal disbondment has been observedon the 16-inch Syrian oil pipeline onwhich severe corrosion was found

under HSS (Fig. 4). In France, a shortlength of pipeline with a 3LPP coatingoperating at ambient temperature hassuffered complete loss of adhesionwithout any corrosion. In this case,because all other inspected parts inclose vicinity did not show disbond-ment, this observation tends to demon-strate that this loss of adhesion couldbe due to a specific application prob-lem.In Indonesia, a section of a 3LPP

coated offshore pipeline (with concrete


weight coating) operating at about 80 C(176 F) has been cut out for inspectionrelated to internal corrosion.Disbondment of 3LPP from the steelwas observed, showing that disbond-ment seems to be possible offshore also.

Laboratory Studies and an Engineering Approach

A Parametric Study of the “CP Shielding Effect” under Disbonded Coatings

Gaz de France (Direction de laRecherche) and Total have carried outstudies in the Gaz de France laborato-ries to assess the influence of the mainparameters governing the corrosionrate underneath a simulated coatingdisbondment. In particular, the studyassesses corrosion as a function of thedistance from the point where a directcontact exists with the external elec-trolyte. Parameters studied were theheight of the gap between the steel andthe simulated disbonded coating,whether the water was stagnant orchanged, the resistivity of water, theapplication of various levels of cathodicprotection, and the absence of cathodicprotection. All tests were carried out atambient temperature. The main resultsare discussed below. More details maybe obtained in published papers.11,12,13

The test plan is summarized in Table2. The detrimental effect of renewal ofwater was clearly demonstrated. In thecase of stagnant water, the corrosionrate becomes practically zero, with orwithout cathodic protection within afew centimeters of the artificial coatingdefect. Of course, this testing does nottake into account any possible develop-ment of microbiologically induced cor-rosion (MIC) that could occur in theactual situation. This result is easilyexplained by consumption of dissolvedoxygen through the corrosion process.Any renewal of water increases thecorrosion rate when the distance fromthe artificial defect increases, even whencathodic protection is applied. Some posi-

Fig. 4: Disponding of 3LPE (16-inch Syria)

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maximum about 0.7 mm/yr at 50 C(122 F).

Field Joint CoatingsIt is believed that disbonding of HSS maybe due to surface preparation by brushcleaning and the effect of higher temper-ature. Corrosion under disbonded HSSmay be due to • the penetration of water through dis-bonded overlaps on plant-coating;• the shielding effect preventing CP,together with a too weak “true” level ofCP; or• an increase in the corrosion rate


tive effect can be seen when CP level isenhanced. The detrimental effect ofincreasing the height of the gap betweenthe steel and coating in the studied rangeexplains why disbondments seem tohave generally no detrimental conse-quence on corrosion with three-layerpolyolefin (3LPO) systems: the gap in the3LPO systems remains very low, com-pared to the case of other coatings suchas coal tar or asphalt enamels, tapes orheat-shrinkable sleeves (HSS).Analysis of the results shows a

Gaussian shape distribution of around0.15 mm/yr with the maximum corro-sion rate reaching 0.35 mm/yr. Thisdistribution of corrosion rates may beinterpreted as the same as seen on aburied pipeline, at ambient tempera-ture, that may be subjected to coatingdisbonding without knowing the specif-ic combination of influencing parame-ters. This distribution also correspondsto values commonly found in practice.For instance, NACE RP0502-200214

states that a corrosion rate of 0.4mm/yr under disbonded coating mayoccur in the absence of any specificdata. Taking into account a general rulethat the corrosion rate is roughly mul-tiplied by 2 when the temperature isincreased above 30 C (86 F), we mayassume that the average corrosion ratecould be about 0.3 mm/yr and the

because of the temperature.For the time being, it has been decided

(at our company) to require, as a mini-mum before HSS application, Sa 2 1⁄2abrasive blast cleaning of girth welds anda liquid epoxy primer applied foronshore buried pipelines or when thetemperature is higher than 50 C (122 F).However, the general trend is to apply,instead of HSS, liquid polyurethane(PUR) or epoxy-modified polyurethaneas a field joint coating onshore, which iscurrently being done on a major gaspipeline in construction in Yemen (Fig. 5).The system used a PUR-type productdesigned for 80 C (176 F) maximumoperating temperature. The applicationparameters, equipment, and personnelhad been accepted after a full qualifica-tion process comprising a ProcedureQualification Trial (PQT) at the coatingapplication contractor premises and veri-fication in the field at the start-upthrough a Pre-Production Trial (PPT). Tests carried out on samples taken

from the qualification trials were carriedout by a third party laboratory, mainlybased on measurement of adhesion bypull-off test as per ISO 4624 and cross-cut tests before and after immersion intap water at various temperatures (up to80 C [176 F]) and after various durations

Test n° Water Cathodic Gap Electrolyte Bubblingrenewal protection height

1 + – – – –

2 – – – + +

3 + + – + –

4 – + – – +

5 – – + + –

6 + – + – +

7 – + + – –

8 + + + + +

Upper Level (+) 0 - 850 mV 0.5 mm water aerated

Lower Level(-) 1.5 cm/min -1200 mV 4 mm saline deaerated

Table 2: Parameters of Corrosion Tests under Artificial Coating Disbondment*

Fig. 5: FJC with epoxy-modified PV applied on3LPE-coated pipes

*Key: The + symbol refers to the upper level of the parameter, and the – symbol refers to the lower level.

proprietary treatments. Tests will con-sist of: cathodic disbonding (28 days at23 C and 80 C [73 F and 176 F], and 48hrs at 65 C [149 F]); peel tests on steeland plant coating at 23, 60, and 80 Cand 100 C (for PP only); impact testsper ASTM G14; immersion tests for 28days in deionized water at 40 (104 F),60, and 80 C; and, after immersion,peeling tests on steel and overlap. Totalwill be happy to share this programwith any interested party.

Efforts to Explain DisbondmentProblems of 3LPE/PP Coatings

Possible explanations for disbonding of3LPE are • water and oxygen diffusion throughPE;

www.paintsquare.comJ P C L S e p t e m b e r 2 0 0 926

(up to 28 days). Figure 6 illustrates sucha series of pull-off tests. As shown inTable 3, values obtained on the PE plantcoating as well as directly on the steelsurface were found to be fully acceptablewhen the parameters of application wereoptimized (especially the substrate tem-perature). Surface preparation was abra-sive blast cleaning to Sa 2 1⁄2 on steel andabrasion without any complementarytreatment on the PE.In addition, Total is launching a com-

parative program for an in-depth studyof various field joint coatings (PE/PP-based HSS, liquid PUR or epoxy, flamesprayed PE/PP, etc.), especially throughhot water resistance testing and evalua-tion of the compatibility of the HSS withplant coatings in wet environments. Forthe HSS, two surface preparation levelswill be tested: Sa 2 1⁄2 (blasting to nearwhite metal, SSPC-SP 10) and St 3 (verythorough power tool cleaning, SSPC-SP 3level of cleaning). For liquid products,various surface treatments for the plant-applied coating will be tested: with andwithout oxidative flame and/or other

• water saturation and diffusion inFBE layer, depending on the type ofepoxy;• superficial corrosion of steel surfaceforming magnetite;• all these steps being accelerated bytemperature; and• the possible effect of internal stress-es in PE/PP due to the thermal historyduring application, which could helpexplain why such massive disbond-ment does not occur with FBE coatings.(FBE is not subject to thermal agingduring application.)Significant corrosion under disbond-

ed 3LPE only occurs when it is alsocracked due to thermal ageing, whichleads to a significant gap between thedisbonded coating and steel. The gapallows renewal of aggressive speciesand the CP current shielding effect.Since 2006, the efforts contributing

to the explanation of this phenomenonhave concentrated on the following.• Launching of a fundamental study asPh.D. work on adhesion mechanisms ofepoxy, as illustrated in another paperpresented at the 17th InternationalConference on Pipeline Protection15

• Participation in a study on the devel-opment of a new accelerated testensuring a better qualification thatcould predict long term behavior (car-ried out for EPRG, European PipelineResearch Group). Conventional peelingtests and cathodic disbonding testsused up to now failed for such a predic-tion. This study is still running and theresults are confidential for the timebeing• A study of water sensitivity of sixepoxy powders, carried out by IFP(French Institute of Petroleum). The

Polyguard has been ISO 9000 certified since 1996.Current certifications are:- American Natl. Standards Institute- Dutch Council for Certification- Deutscher Akkreditierungs RatPhone: (1) 214.515.5000 www.polyguardproducts.com

Why you needPolyguard RD-6

CATHODIC SHIELDING BYDISBONDED COATINGS

Extracted from NACE document “Coating Failure Definitions in Relation to CP”Definition of “Shielding With No Holiday”

“A substantial diversion of cathodic current away from its intended target (i.e.steel substrate) due to a disbonded coating with ahigh dielectric characteristic and no holidays on the disbonded coating. Steel substrate is deprived of protective current and

corrosion can continue undetected and unchecked, including MIC activity, until failure occurs. Traditional diagnostic techniquessuch as CIS and DCVG cannot identify the existence of such anomalies.”

Graphic Illustration of Shielding

Two corrosion coatings are proven to be non-shielding, that is to allow passage of protective CP current into disbonded areas. Oneof these is FBE. The other is the Polyguard RD-6 coating system. After 21 years, and thousands of installations, there has neverbeen serious corrosion found under the Polyguard RD-6 coating system.

DISBONDMENTEven the best coatings candisbond in areas over time. Disbondment risk is greatestwith girth weld coatings whichare application sensitive andsubject to soil stress.

HIGH DIELECTRICCorrosion coatings with solidfilm backing have this highdielectric characteristic.

INSIDIOUS #1We at Polyguard believe that theproblem of shielding disbondedcoatings is one of the mostserious in the pipeline industry.Our belief is reinforced as largeoperators who discover theshielding problem convert toour RD-6 coating system.

INSIDIOUS #2Shielding hides corrosion not only from CP, but fromcommon diagnostic techniques.Shielding is truly an insidiousphenomenon.

Visit www.polyguardproducts.com to review the dozens of technical papers published on the subject of shielding since the mid 1980’s, and to see an animated graphical explanation of CP shielding.


Polyguard in Quark:Layout 1 8/26/09 11:43 AM Page 1

Water temperature Adhesion on steel (MPa) Adhesion on abraded PE (MPa)

23 C (73.4 F) 15 to 20 5 to 15

60 C (140 F) 15 to 20 5 to 11

80 C (176 F) 15 to 20 5 to 10

Table 3: Adhesion Tests After Immersion for 28 Days of PE Coated with Liquid Applied PU-type at FJC

Fig. 6: Pull-off and cross-cut tests at ambient temperature on PU-type product on steel(below) and PE (above) surfaces after immersion in tap water for 28 days and 80 C ([176

F] below) and at 23 C ([73 F] above)

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Why you needPolyguard RD-6

CATHODIC SHIELDING BYDISBONDED COATINGS

Extracted from NACE document “Coating Failure Definitions in Relation to CP”Definition of “Shielding With No Holiday”

“A substantial diversion of cathodic current away from its intended target (i.e.steel substrate) due to a disbonded coating with ahigh dielectric characteristic and no holidays on the disbonded coating. Steel substrate is deprived of protective current and

corrosion can continue undetected and unchecked, including MIC activity, until failure occurs. Traditional diagnostic techniquessuch as CIS and DCVG cannot identify the existence of such anomalies.”

Graphic Illustration of Shielding

Two corrosion coatings are proven to be non-shielding, that is to allow passage of protective CP current into disbonded areas. Oneof these is FBE. The other is the Polyguard RD-6 coating system. After 21 years, and thousands of installations, there has neverbeen serious corrosion found under the Polyguard RD-6 coating system.

DISBONDMENTEven the best coatings candisbond in areas over time. Disbondment risk is greatestwith girth weld coatings whichare application sensitive andsubject to soil stress.

HIGH DIELECTRICCorrosion coatings with solidfilm backing have this highdielectric characteristic.

INSIDIOUS #1We at Polyguard believe that theproblem of shielding disbondedcoatings is one of the mostserious in the pipeline industry.Our belief is reinforced as largeoperators who discover theshielding problem convert toour RD-6 coating system.

INSIDIOUS #2Shielding hides corrosion not only from CP, but fromcommon diagnostic techniques.Shielding is truly an insidiousphenomenon.

Visit www.polyguardproducts.com to review the dozens of technical papers published on the subject of shielding since the mid 1980’s, and to see an animated graphical explanation of CP shielding.


Polyguard in Quark:Layout 1 8/26/09 11:43 AM Page 1

http://www.polyguardproducts.com


results of these tests are summarized ina paper also presented at the 17th

International Conference on PipelineProtection.16

Hydrothermal Aging of LDPEThermal aging of various PE materials(low density stabilized by ethylenevinyl acetate (EVA)) or not, 2 types ofmedium density) from various suppli-ers has been studied in wet conditions,whereas the present methods used forqualification are restricted to dry condi-tions. The question was: Does physico-chemical thermal aging happen to PEup to 100 C (212 F) in water?The tests were carried out by

Korrosionstechnik Heim. The followingtest conditions were used: dry air at 100C (212 F); demineralized water at 60 (140F), 80 (176 F), and 100 C; and air saturat-ed with water vapor at 60 and 80 C. The effect of aging was assessed using

elongation and tensile strength at breakand Melt Mass Flow Rate (MFR). Nosignificant change was noticed after5,000 hours of testing for all productsand all test conditions. Consequently,no explanation has been given so far forwhat was noted on the Rabi pipelinewhere cracking of PE topcoat in somelocations led to corrosion. Loss of theEVA additives is still the proposedanswer, but not a proven explanation.A bad batch of PE could be involved inthis issue.

Conclusion: Present Situationand Future Work

The major corrosion problems arerelated to disbondment of heat-shrink-able sleeves applied on field joints ofburied pipelines. For Total, abrasiveblast cleaning is now mandatory beforeapplication of HSS and not only “rec-ommended” for new onshore pipelines.

In addition, the general trend is toapply, instead of HSS, liquidpolyurethane (PUR) or epoxy for fieldjoint coating onshore.It is of utmost importance to demon-

strate whether an improvement of theadhesion safety margin of 3LPO coat-ings is possible or not. If not, modifica-tion of Total’s basic choice could bechanged in favor of FBE, in spite of thebetter mechanical resistance of 3LPOcoatings (generally considered as a plusby pipe laying contractors). Parametersrelated to the composition of epoxypowders have been studied. Methodssuch as measurement of “Wet Tg” andthe use of two-layer FBE/adhesivecoatings are very promising approachesfrom lab studies. However, the differ-ences noted in water intake do not cor-relate with the severe loss of adhesionof the coating when immersed in water,especially when water temperature is

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above ambient. For the time being, thefollowing criteria have been introducedin Total’s general specifications forselection of epoxy primer: waterabsorption lower than 10% after 28days at 80 C and “Wet Tg” greater thanmaximum operating temperature +10C above the operating temperature.The future work necessary for a bet-

ter knowledge of the problem of 3LPOdisbondment will be researchedthrough a continuation of the studiesat IFP, especially on test samples takenfrom actual pipes recently coated forvarious projects, and also on otherepoxy powders and surface prepara-tion systems. The Ph.D. work launchedto better understand the mechanism ofbonding of epoxy to steel will addressfactors such as mechanical vs. chemi-cal anchor, surface preparation andtreatment, and internal stresses withinthe coating. In addition, the study car-

ried out in the U.S. on the internalstresses will be highly profitable forthe development of knowledge.17

Continuation of field experiencefeedback will be organized in order tobetter know the influence of parame-ters such as temperature or soilhumidity. All possible efforts will bemade to push operating subsidiaries toperform excavations and field mea-surements in order to contribute toand assess correlations between dis-bondment and soil and operating para-meters.A more relevant accelerated aging

test allowing a better prediction oflong term behavior remains to beestablished (especially through EPRGcollaboration) and implemented in thefuture revision of ISO 21809 stan-dards currently on the way of comple-tion based on a conventionalapproach.

AcknowledgementsThe authors wish to thank their compa-ny and affiliates for permitting the publi-cation of this paper. Many thanks also toGaz de France, Direction de laRecherche, for the permission to publishinformation given in the section on para-metric studies.

Editor’s Note : This article is based on apresentation at the 17th PipelineProtection Conference, Oct. 17–19, 2007,and is published here with the permissionof BHR Group, the organizers.

References1. M. Roche, J.P. Samaran, “Pipeline coatings performance: Field experience of an operating petroleum company,” Corrosion/87 paper no. 28, NACE International, 1987, Materials Performance, Nov. 1987, p. 28.

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a SPYfor

For more details on SPY® products and our complete line of SPY® Holiday Detection Equipment visit our website @ www.picltd.com.

PIPELINE INSPECTION COMPANY, LTD. PH: (713) 681-5837 • FAX: (713) 681-4838

SPY® Model 780, 785 and 790Portable Holiday Detectors• New ergonomic design• Pipe coating inspections up to 60”• Extremely durable• Infinite voltage setting on the fly

Compact,lightweightwet sponge

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every missionInspect Any Metal Surface Coating

For pipes, tanks or any coated contoured surface in the field or inside your manufacturingfacility, we simplify coating integrity testing

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SPY® Wet Sponge PortableHoliday Detectors• No belts, lightweight, fast set up

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SPY® In-Plant HolidayDetector Systems

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Volume discounts on detectors available through our

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(excludes Model 670)

2. M. Roche, P. Auclair, P. Couget, “Progress in pipeline protection andinspection—The experience of Elf Gabon,” 8th International Conference on Internal and External Protection of Pipes, BHRA, 1990, Florence, Italy, p. 65.

3. M. Roche, “Corrosion hazards related to pipes: How to control

them,” Conference Paper, Offshore Hazards and their Prevention, London, April 30–May 1, 1990.

4. M. Roche, “Coating disbondment leads causes of external pipeline corrosion,” Oil & Gas Journal, p. 49, April 1, 1991.

5. M. Roche, “TotalFinaElf experience in corrosion management of

pipelines,” 2nd Conference of Corrosion in Oil Industry, Tehran, Iran, Feb. 18–19, 2003.

6. M. Roche, “How Total manage pipeline integrity,” 15th InternationalConference on Pipeline Protection, BHR Group, Oct. 29–31, 2003, Aachen, Germany.

7. M. Roche, “An experience in offshore pipeline coatings,” Corrosion 2004, Paper No. 04018, New Orleans, USA, March 27– April 1, 2004, NACE International.

8. M. Roche, “External corrosion of pipelines: What risk,” 14th SPE Middle East Oil & Gas Show and Conference, March 12–15, 2005, Bahrain.

9. M. Roche, “The problematic of pipeline external corrosion and its contribution to integrity management,” IIC 2005, Beijing, China, Sept. 19–23, 2005.

10.M. Roche, D. Mélot, G. Paugam, “Recent experience with pipeline coating failures,” 16th International Conference on Pipeline Protection, Nov. 2–4, 2005, Paphos, Cyprus, BHR Group. Paper published also in Protective Coatings Europe and Journal of Protective Coatings & Linings, Oct. 2006 pp. 18–28.

11.X. Campaignolle, S. Gasteau, S. Karcher, M. Meyer, “Corrosion of pipelines under cp in the presence ofcoating disbanding,” Eurocorr 2003, Budapest, Hungary, Sept. 28–Oct. 2,2003.

12.X. Campaignolle, M. Meyer, F. Bernard, S. Karcher, S. Gastaud, “Organic coatings aging consequences on under cp buried pipelines corrosion protection—simulated defects,” Corrosion NACE 2004, International Symposium, 59, New Orleans, USA, March 28–April 1, 2004.

13.X. Campaignolle, M. Roche, M. Meyer, “Corrosion externe des canalisations de transport sous protection cathodique en présence

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de décollements de revêtement,” 4ème Journées d’Aix du CEFRACOR, 20-22 juin 2006 (in french).

14.NACE RP 0502-2002, “Pipeline external corrosion direct assessment methodology,” NACE International, Houston, Texas, USA.

15. E. Legghe, E. Aragon, L. Belec, A. Margaillan, D. Mélot, M. Roche,“Loss of adhesion of three layers pipelines coatings under cathodic protection,” 17th Pipeline Protection Conference, BHRG, Edinburg, UK, Oct. 17–19, 2007.

16.V. Sauvant-Moynot, J. Kittel, D. Mélot, M. Roche, “Three layer polyolefin coatings: how the FBE primer properties govern the long term adhesion,” 17th Pipeline Protection Conference, BHRG, Edinburg, UK, Oct. 17–19, 2007.

17. B. Chang, “Residual stresses in 3 Layer Polyolefin Pipeline Coatings,” 17th Pipeline Protection Conference,BHRG, Edinburg, UK, Oct. 17–19, 2007.

Denis Mélot is responsible for non-metallicmaterials and coatings in Total UpstreamCorrosion Department. He graduated fromEcole Universitaire d’Ingénieurs de Lille(Materials Science) and has a Ph.D. inMaterials Science from Université de Lille. Hewas the Research Engineer at the University ofMassachusetts and Technical Manager for cor-rosion protective pipeline coatings in Atofinabefore joining Total in 2003.

Gildas Paugam is a Corrosion Engineer in theTotal Upstream Corrosion Department, incharge of assisting several operating compa-nies, including Gabon.

Marcel Roche graduated from INSA (InstitutNational des Sciences Appliquées) de Lyonand ENSPM (Ecole Nationale du Pétrole et desMoteurs). He specialized in corrosion from hisfirst professional occupation in 1970 withinTechnip and IFP (Institut Français du Pétrole),then for Elf Aquitaine, covering Oil Refining


JPCL

and Oil & Gas production activities. Hebecame Head of the Corrosion Department ofTotalFinaElf, now Total SA, for Upstream afterthe merger in October 2000. He participates ina number of professional organizations for thecorrosion protection industry. He is chairmanof Cathodic Protection working parties inCEFRACOR (France) and EFC (European

Federation of Corrosion), Convenor of CENTC219 WG5 on Qualification and Certificationof Personnel in Cathodic Protection and leaderof ISO TC67 SC2 WG14-3 on Field JointCoatings. He is Certified AFAQ AFNORCompétence level 3 (expert) in CathodicProtection for Land and Marine applications.


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disbondmentsofpipelinecoatings andtheir effects ......cathodic disbondment is of the same order of...

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