Abstract

In 2001 the International Standards Organisation (1) made a resolution at it’s TC67/SC2 Plenary meeting on Pipeline Transportation Systems in Bratislava(2), to start developing external pipeline coating standards for adoption and utilization by the global market. A Work Group under the direction of the ISO TC67/SC2 (3) committee was charged with this responsibility. It’s objective being to identifying both the specific needs of the market place and to clarify which coatings standards were needed to best serve the requirements of the pipeline community. While there were already a number of existing national and company standards available for the more commonly utilised pipeline coatings, it was quickly establish that their approaches were inconsistent. These standards varied considerably in the critical aspects of establishing and confirming pipe coating quality. It was therefore establish by ISO that harmonized pipeline coating standards were needed as the pipeline markets became more global in nature. The ISO Technical Committee ISO/TC67 therefore formed a Work Group WG14 (Petroleum and natural gas industries, Subcommittee SC2, Pipeline transportation systems) to identifying which coatings standards were needed to best serve the requirements of the pipeline community. This work is now coming to fruition and in the last few years ISO has issued three external pipeline-coating standards.

This paper describes the various types of pipeline coatings that were identified by the International Standards Organisation (ISO) as candidates for a global standard and highlights the various stages of development of each document. It also references and discusses in some manner all the coatings for which ISO pipecoating standards are being prepared and published. It does however; deal more specifically with the published standards for fusion bonded epoxy (FBE) coatings (4) and Field Joint (Girth Weld) Coating, (5) while giving an over view of the Two Layer PE Standard (6) that has recently been added to the ISO Coating Standards family.

Introduction

In 2001 the ISO Technical Committee TC67/SC2 met in Bratislava and laid out a programme to identify which pipeline coatings required an international standard. Representatives from the following countries conducted the review:

Canada, France, Germany, Italy, United Kingdom, USA

While the full gambit of various coatings was discussed, it was recognised that a priority rating had to be applied to the development of ISO External Pipeline Coating standards. Firstly, there was little point in committing a large amount of time and finances in developing and publishing standards for which there were no apparent need. Secondly, the publication of these standards needed to be expedited if they were to meet both the Industries needs and the ISO publication schedules. Focusing on a few relevant coatings would help satisfy both these criteria. It was finally agreed that while all pipeline coatings serve some important part in the battle against pipeline corrosion, there existed a need for standards on:

Two and Three Layer Polyethylene and Polypropylene Coatings;
Fusion Bond Epoxy (FBE);
Girth Weld Coatings (GWC);
and Concrete Coatings

TC67/SC2 formed Work Group Fourteen (WG14) and Matt Dabiri of Williams (USA) was appointed the convenor of this entire programme. Each of the above four coating systems were allocated a project number starting with the ‘Three Layer Polyethylene and polypropylene Coatings’ which was WG14-1. The FBE coatings work group was designed WG14-2 with the rest of the coatings being allocated corresponding numbers.

It also became quickly apparent that to meet the stringent and significant time constraints specified for the publication of ISO standards, a single standard for both the two and three layer coatings was impractical. As a result of this the proposed single standard on ‘Two and Three Layer PE/PP’, was split into separate standards. Also, as the WG14 programme rapidly expanded, the need for additional project management was required. To this end in 2006 Tom Weber (also of the USA) was approached to take on some of the workload and to work with Matt Dabiri as the co-convenor of WG14.

To this end by 2008 the structures for this development of ISO coating standards and the nominated team leader of each group was as follows:

WG14-1:ISO/DIS 21809-1 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 1: Polyolefin Coatings (3- layer PE and 3-layer PP); Denis Grimshaw (UK) (7)

WG14-2: ISO 21809-2 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 2: Fusion Bonded Epoxy Coatings, Keith Coulson (Canada). Published December 15, 2007 (4)

WG14-3: ISO/FDIS 21809-3 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 3: Field Joint Coatings, Marcel Roche (France). Published December 15, 2008 (5)

WG14-4: ISO/DIS 21809-4 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 4: Polyethylene Coatings (2- layer PE), Dennis Wong (Canada), Published November 5, 2009 (6)

Wg14-5: ISO/DIS 21809-5 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 5: External Concrete Coatings, Betty Friedman (USA) (8)

A full list of the Work Group leaders, WG14  Co-ordinators and the ISO Editorial Committee is given in Table 1.

Structure for the Development of ISO  Coating Standards

The development, review and voting for all ISO Coatings standards encompassed four distinct and separate stages. These were basically:

CD; Committee Draft
DIS; Draft International Standard
FDIS: Final Draft International Standard
IS: International Standard

Table 1

Committee Draft CD

Each work group was formed and populated with nominated members of both the participating (P members) and observer (O members) countries of ISO. Typical industry committees normally consist of volunteers who offer their services in developing standards. However, within ISO only nominated persons are recognised. These persons have to be nominated by their respective national standards writing organisations e.g., British Standards Institute (UK), Deutsches Institut fur Normung (DIN of Germany), Standards Council of Canada (Canada), in order to participate on these work groups.

In the case of FBE coatings (Work Group WG14-2), there was extremely wide interest in participating on the preparation of this standard. Representatives of the following countries, were nominated to partake and support the work groups activities:

Brazil, Canada, France, Germany, Italy, Norway, United Kingdom, UAE, USA.

See Table 2 for a complete list of the contributors to the development of 21809-2

Each country is charged with nominating parts or portion of their national standard (if one was available) for inclusion in the draft ISO standard. A number of items were felt by each of the Work Groups to be of critical importance, e.g., compliance reporting; yet generally none of the current international standards appeared to address these issues. This being the case the Work Groups developed the requirements by accepting commonly utilised industry practices. In total a consensus is reached on the contents of the draft standard and the document prepared. This draft document being then forwarded to ISO for comments and a subsequent vote on its acceptance by the ISO countries.

All of the proposed WG14 coating standards indicated in the Introduction of this paper, were approved at the committee draft (CD). This allowed them to then progress to the next stage of preparation, namely the Draft International Standard (DIS).

Table 2

† Work Group Leader of TC67/SC2 WG14-2
* Not an official member of WG14-2, but made a major contribution to Clause 14:  ‘Test Reports and Certificate of Compliance’
# Coordinator of Work Group WG14 of  TC67/SC2

Draft International Standard (DIS)

The initial portion of the development of this stage of the standard is a review by the work group of all the comments that accompanied the vote at the CD stage. Subsequently the work group will then build a DIS that addressed all the comments, typos and suggestions for change. Before the DIS is however re-issued for vote and review as a Final Draft International Standard (FDIS), the ISO editorial committee (EDC) subjects the DIS to an editorial review. This is to ensure that all the suggested revisions and technical concerns have been correctly addressed. The comments submitted with the vote are either incorporated in the new draft of the standard or accompanied by an explanation from the Work Group as to why they felt the comments were not valid and therefore not included in the revision.

After a successful editorial review, the document is than prepared for issue and vote as an FDIS.

Final Draft International Standard (FDIS)

As with the DIS, the initial portion of the development of this stage of the standard is a review by the work group of all the comments that were submitted along with the vote at the DIS stage. Again the Work Group would classify the submissions as being perceived as non-persuasive and are ignored or as persuasive in which case the DIS would be revised to accommodate the persuasive comments. Another review by the ISO editorial committee (EDC) would be conducted to ensure that all the comments, typos and technical concerns have again been adequately and correctly addressed.   This being the case, the draft is then issued to ISO for voting as an FDIS.

International Standard (IS)

At the FDIS vote the member countries can no longer provide comments but have to vote either to accept or reject the standard. For example the 21809-2 standard for external FBE coatings was successfully accepted by a vote of 19 to accept, 3 abstentions and one negative vote from France. The process utilised by ISO for these voting stages is that the document must attain 66.66% or more positive votes (abstentions are not counted in the vote) and no more than 25% of negative votes. These criteria being satisfied, the document is then deemed acceptable  for publication.

Status of International Pipeline Coating Standards

Work on the three coating standards for Three Layer Polyolefin (PO), FBE and Field Girth weld coatings were all initiated during 2002. The Two-layer PE coating standard (which was a spin off from the original Three and Two layer PO Standard) was initiated in 2004, while the concrete standard was started in 2005. At present their status being:

WG14-1: Still at Draft International Standard Stage. Publication is now anticipated later in 2010 or early 2011

WG14-2: Published December 15, 2007

WG14-3: Published December 15, 2008

WG14-4: Published November 5, 2009

WG14-5: Final Draft International Standard is now out for vote with publication anticipated by the summer of 2010

With the exception of WG14-1 all the standards are presently within the ISO publication schedules. WG14-1 has been plaqued with a change of scope (removal of the two layer PE coating) and concerns about differences between European and North American protocol for the application and testing of the final product.

Figure One: Plant Application of Fusion Bond Epoxy Coatings to High Pressure Line Pipe

ISO Standard 21809-2 Fusion Bond Epoxy

As with all the proposed ISO pipeline coating standards, this document specifies the qualification, application (see Figure 1), testing (See Figure 2) and handling (see Figure 3) of the plant application of single layer FBE coatings applied to the external surface of the pipe for the corrosion protection of bare steel pipe. As the pipe is intended for use in pipeline transportation systems for the petroleum and natural gas industry, this coating is tested/evaluated to ensure its suitability to act as the primary corrosion protection system when combined with cathodic protection systems (9)(10).

Figure Two: Laboratory Testing of Pipeline Coatings for Assessment of Compatibility with Cathodic Protection

This 21809-2 standard provides in one single document a consistent and unified approach to the international requirements for coating line pipe with FBE. While there are in fact a number of other industry standards relating to the application of FBE coatings, it quickly becomes apparent that they are all different. One of the Work Group members recently recorded that some engineers have stated that the ‘wonderful thing about standards is that there are so many to choose from’. (11). While this statement is true, the fact is that not all these standards are created equal or are at the same level of quality and technical competence. This has ultimately led to some inconsistency with the worldwide use of FBE coatings. This probably accounts for why the level of corrosion protection afforded by FBE and other pipeline coatings has varied over the years. This can be a real challenge when working in the global markets as the requirement for suppliers, manufacturers, applicators and end users vary from one standard to another. The objective of this 21809-2 FBE standard was to provide a consistent worldwide approach for all the pipeline stakeholders during the purchasing, manufacturing and application of FBE.

Figure Three: Rail Transportation of Line Pipe that has been Coated with Plant Applied Fusion Bond Epoxy Coating

The first task for the FBE work group to overcome was the preparation of a Committee Draft (CD) that identified the critical and requisite components leading up to and during the process of applying FBE to line pipe. The work group immediately identified some shortcomings within the existing standards, e.g., the test method and interpretation of the DSC cure evaluation, inconsistent cathodic disbondment testing methods. This resulted in the inclusion of some alternative testing activities and the addition of a more balanced programme for testing, quality assurance and the document control of these activities. Some of the more critical shortcomings revolved around the lack of plant qualifications, harmonization of test methods and their criteria, along with a more concise document and test report procedure.

The progress of the document from a CD to a FDIS resulted in the evolution of a balanced document that was convenient for designers, department managers, production controllers and end users. The criteria and stipulated requirements of the 21809-2 standard was not fundamentally different in approach to any of the available standards. However, while not jeopardizing any fundamental requirements, for the first time in the pipeline industry the 21809-2 standard offered a balanced document that satisfied the needs of all the stakeholders and not just the customer or end users (which is common with numerous other documents).

The contributors of 21809-2 now feel confident that this standard has the ability to predict and identify defective materials or coatings. It also can direct the user to make the appropriate adjustments or corrections at the raw material manufacture, plant approval and project application stages to ensure that only the highest integrity coatings are presented for utilised by the pipeline industry.

ISO Standard 21809-3 Field Joint Coating

This part of ISO 21809 specifies requirements for field joint coating of seamless or welded steel pipes for pipeline transportation systems in the petroleum and natural gas industries as defined in ISO 13623. (12). It details the requirements for the qualification, application and testing of the corrosion protection coatings applied to steel surfaces left bare after the pipes and fittings (components) are joined by welding (see Figure 4). It does not however address additional mechanical protection, thermal insulation or joint in-fills for concrete weight-coated pipes.

The work on the field joint coating precipitated a wide interest from the international pipeline community and the following countries nominated representatives to partake and support the work groups’ activities:

Brazil, Canada, France, Germany, Holland, Italy, Mexico, Norway, United Kingdom, USA.

The primary priority was to identify the various types of field joint coatings available in the market and to determine their level of acceptance within the pipeline industry. From that review, the following comprehensive list of coatings were deemed of significance importance to include in the 21809-3 standard:

Hot-applied bituminous tapes
Petrolatum tapes
Wax tapes
Cold-applied polymeric tapes
Heat-shrinkable materials, polyethylene-based
Heat-shrinkable materials, polyethylene-based, applied over a liquid or fusion-bonded epoxy layer
Heat-shrinkable materials, polypropylene-based, applied over a liquid or fusion-bonded epoxy layer
Single-layer fusion-bonded epoxy powder
Two-layer fusion-bonded epoxy powder
Liquid epoxy or derivatives
Liquid polyurethane or derivatives
Fibre-reinforced epoxy
Fibre-reinforced vinylester
Cast polyurethane
Flame-sprayed polypropylene powder applied over an epoxy layer
Polypropylene tapes/sheets hot-applied over an epoxy layer
Injection-moulded polypropylene over an epoxy layer
Flame-sprayed polyethylene powder applied over an epoxy layer
Polyethylene tapes/sheets hot-applied over an epoxy layer
Thermal spray aluminium (TSA)
Hot-applied microcrystalline wax coatings
Elastomeric coatings, polychloroprene-based
Elastomeric coatings, EPDM-based

Figure Four: The Joining of High Pressure Line Pipe in the Field by Girth Welding

As with the FBE (21809-2) standard the first item the work group had to overcome was the preparation of a Committee Draft (CD). These identified the critical and requisite components leading up to and during the process of applying field girth weld joint coatings to line pipe. (see Figure 5). The work group immediately identified some shortcomings within the existing standards in relation to critical deficiencies revolving around the lack of application and procedure qualifications, pre-production qualifications and pre-production trials. Also the harmonization of test methods, test criteria, along with a more concise document, inspection and test report procedure were identify as critical parameters to the successful application of a field coating. To ensure that all those aspects were covered in the standard, the following clauses were developed:

Application procedures and qualification
Application procedure specification (APS)
Coating materials
Procedure qualification trial (PQT)
Pre-production trial (PPT)
Qualification of coating and inspection personnel
Production testing and inspection
Certificates of compliance and traceability

As with all the proposed ISO pipeline coating standards, this document specifies that coatings applied to this standard are tested/evaluated to ensure its suitability to act as the primary corrosion protection system when combined with cathodic protection systems (ISO 15589-1/2) P Petroleum and natural gas industries — Cathodic protection for pipeline transportation systems — Part 1 On land Pipelines and Part 2 Offshore Pipelines). (9)(10).

The 21809-3 standard provides a consistent approach to the application and testing of each of the numerous girth weld coatings covered by the requirements of the standard. While there are some general common requirements for the surface preparation, coating application, testing and repairs, each of the girth weld coatings have been  specific categorised into one of the following coating types:

Bituminous, petrolatum, wax and polymeric tapes (Clause 10 of ISO 21809-3)
Heat-shrinkable coatings (Clause 11)
Fusion bonded epoxy powder coatings (Clause 12)
Liquid coatings (Clause 13)
Polyolefin based coatings (Clause 14)
Thermal spray aluminium (TSA) coatings (Clause 15)
Hot applied microcrystalline wax coatings (Clause 16)
Elastomeric coatings (Clause 17)

Each of these coating types has detailed requirements relating to the Coating identification and coating descriptions. Specific surface preparation requirements are defined, as obviously each coating type will require difference types of substrate preparation. While some coatings may only require hand tool cleaning (ISO 8504-3) (13): others can only provide an optimum performance if applied over power tool or abrasive blasted surfaces. These are clearly identified and describe in this new ISO pipeline coating standard.

Finally the application parameters and quality assurance testing techniques are addressed for each particular coating category. Items such as pre and post heating and any post cure requirements are itemized along with specific testing parameters and protocols. The overall objective is not to make all the coatings equal. However, the requirements should ensure that once the designer has selected a specific coating, he obtains the specific characteristics on the final field applied coating. This ultimately will provide full confidence that the coating system is totally ‘fit for purpose’.

This 21809-3 standard provides in one single document a consistent and unified approach to the international requirements for applying field joint coatings to line pipe. The primary objective of 21809-3 was to overcome any inconsistent approach and to ensure a level platform of requirements for all the various types of coatings.

The progress of the document from a CD to a FDIS resulted in the evolution of a balanced document that was convenient for designers, production controllers, field contractors and pipeline companies to utilize. For the first time in the pipeline industry the 21809-3 standard offers a balanced document that satisfied the needs of all the stakeholders and not just the design engineer, customer or pipeline companies.

Figure Five: Field Applied Application of Coatings to the bare Steel Area After Girth Welding

ISO Standard 21809-4 Polyethylene Coatings  (2- layer PE)

This latest addition to the family of ISO Pipeline coating standards was published on November 5, 2009. It follows the format of it sister standards from 21809. It basically classifies the two layer PE by the type of adhesive utilized with an over layer of extruded PE. There are three types of classifications are as follows:

asphaltic modified rubber adhesive
non asphaltic modified rubber adhesive (e.g. butyl based)
hot melt or polymeric adhesive

The standard provides guidelines for the various requirements for each of the virgin and applied adhesive type, including those for thickness, operating temperature, stress levels, adhesion and soften points etc. Details requirements for the virgin and applied PE along with a testing programme for the plant-applied two layer systems are defined within the document.

Consideration for Future Work

Since the initialisation of work on the ISO 21809 series of pipeline coating standards in 2001 there was little if any variation to the original proposed catalogue of standards. However, in the last 18 months there have been a number of significant additions to the programmes. These are as follows:

Firstly, a new work item has been proposed to expand the scope of the FBE Standard 21809-2. It has now been proposed that  ISO 21809-2 be revised to include both dual layer FBE Coatings and systems that can operate beyond the present glass transition limit of 120°C.

Secondly, at the meeting on TC67/SC2 (Petroleum and natural gas industries, Subcommittee SC2, Pipeline transportation systems) in Denmark in 2008, a new work item was proposed for the initiation of a standard for ‘Wet thermal insulation coatings’. The Technical committee accepted this proposal on wet thermal insulation coatings. Work Group Nineteen (WG19) has been formed to undertake the preparation of an additional ISO coating standard to cover the qualification, application and testing of wet thermal insulation coatings for pipelines, flow lines equipment and sub sea structures.

Thirdly, additions to the systems included in 21809-3 are already being prepared and being considered for inclusion. This encapsulates even more types of girth weld coatings to provide the end-user with even more options to consider when designing their pipeline anti-corrosion systems.

Conclusions

This series of external pipeline coating standards represents the industrial integration of pipeline standards to be published through ISO for the use on buried or submerged pipelines. Under the Vienna agreement with ISO and CEN (European Committee for Standardization) (14): these standards will be adopted as European Standards. As an international standard, this series of documents will probably supersede the present standards being published through the Standard Council of Canada, the America Petroleum Institute and the National Association of Corrosion Engineers. This will then bring a much-needed consistent and uniform approach to the qualification; application and testing of globally applied coatings. (15) This consistency of approach will help define the necessary requirements for material composition, dimensional tolerances and performance in regards to an internationally accepted set of criterion. Thus allowing objective comparisons and the elimination of the unnecessary variances in quality that the pipeline industry has encountered over the last few decades.

The ISO Work Groups responsible for the preparation of international pipeline coatings has developed a format and protocol for the construction of these coating standards. However, the introduction of new standards for thermal insulation coatings, along with the addition of dual layer and high temperature FBE coatings, demonstrate the flexibility of this protocol in readily accommodating revisions to existing coating systems. It also reflects the ability of ISO to effectively recognise the dynamic and changing nature of the needs of the pipeline industry.

The recent introduction of additional ISO pipeline coating standards, such as the Two Layer Polyolefin and External Concrete Coatings, will go even further to providing operating pipeline companies with optimum external coating systems for use on their domestic and global pipeline projects.

Acknowledgements

The author would like to thank the entire ISO TC67/SC2 Work Group 14 for their outstanding work in identifying the critical elements of these series of ISO 21809 standards. Also to Matt Dabiri and Tom Weber (both USA) as Work Group co-ordinators for the entire catalogue of ISO Pipeline Coating Standard.

Also, recognition is are due to the ISO Editorial Committee (EDC) of Rick Faircloth (USA), Richard Espiner (UK), Erling Gjertveit (Norway) and Muayyad Ajjawi (Qatar). In particular Rick Faircloth (USA) of the EDC is thanked for enlightening us during the work group meetings on the ‘secrets and mysteries’ of ISO processes and procedures.

We would also like to remember the contributions of the late Jan Verhagen (Holland) for championing this standard and to the late Gerhard Frolic (Germany) for his uncanny editorial skills during the initial drafting of these ISO standards.

References

International Standards Organization, Case postale 56, CH-1211, Geneva 20, Switzerland

20th Plenary Meeting of TC67/SC2, Pipeline Transportation Systems for the Petroleum and Natural Gas Industry, Resolution 232 and 233, Bratislava, Slovakia, June 1, 2001.

ISO Technical Committee ISO/TC67, Petroleum and natural gas industries, Subcommittee SC2, Pipeline transportation systems

ISO 21809-2:2007 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 2: Fusion Bonded Epoxy Coatings, Published December 15, 2007

ISO 21809-3:2008 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 3: Field Joint Coatings, Published December 15, 2008

ISO/DIS 21809-4:2009 Petroleum and natural gas industries – External coatings  for buried or submerged pipeline used in pipeline transportation systems – Part 4: Polyethylene Coatings (2- layer PE), Published November 5, 2009

ISO/DIS 21809-1 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 1: Polyolefin Coatings (3- layer PE and 3-layer PP)

ISO/FDIS 21809-5 Petroleum and natural gas industries – External coatings for buried or submerged pipeline used in pipeline transportation systems – Part 5: External Concrete Coatings

ISO 15589-1 P Petroleum and natural gas industries — Cathodic protection for pipeline transportation systems — Part 1 On land Pipelines

ISO 15589-2 P Petroleum and natural gas industries — Cathodic protection for pipeline transportation systems — Part 2 Offshore Pipelines  David Norman, ‘Guest Comments’, World Pipelines, November 2007, Page 3

ISO 13623:2009 Petroleum and natural gas industries — Pipeline Transportation Systems, Published June 15, 2009

ISO 8504-3:1993 Preparation of steel substrates before application of paints and related products -- Surface preparation methods -- Part 3: Hand and power-tool cleaning

CEN, European Committee for Standardization, Central Secretatiat, Rue de Stassart 36, B-1050, Brussels, Belgium

National Association of Pipe Coating Applicators Supplement 2005, Pipeline and Gas Journal, Page 71, March 2005

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