ISO 12944-9: Defining Laboratory Test Methods for Offshore and Related Structures

ISO 12944-9: Defining Laboratory Test Methods for Offshore and Related Structures

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Improving the Quality of Protective Coating Systems in the CX Environment

In this article, we conclude our series examining ISO 12944 by describing ISO 12944-9, which was introduced to the standard in the 2017/18 revision to improve the quality of protective coating systems in extremely corrosive environments.

ISO 12944-9: A brief history

In the previous version of the standard, the corrosive category C5 (very high corrosivity) had been sub-divided into C5-I (industrial environment) and C5-M (marine environment).

In some cases, the descriptive ‘marine’ was taken to include offshore structures such as oil and gas rigs. However, the coating specifications for such offshore structures are specifically addressed in ISO 20340 (Performance requirements for protective paint systems for offshore and related structures). The differences between the two standards were marked, and created confusion and potential risk.

Specifically, there was an anomaly between the laboratory testing standards for coatings systems for offshore structures. While both ISO 12944 and ISO 20340 included a series of laboratory accelerated tests to verify the performance of candidate systems, the tests required under each standard were incompatible:

  • For ISO 12944 C5-M the test regime was relatively benign (1,440 hour hot salt spray and condensation test).
  • For ISO 20340, there was a much more onerous test. This included a week-long cyclic test of three days hot salt spray, one day in a deep freeze (-20 degrees Celsius), and three days in a QUVA accelerated weathering machine. This one-week cycle was repeated 25 times.

The repeated changes of hot/cold and wet/dry conditions place much more stress on a coating system compared to the static conditions of continuous salt spray. Consequently, only the very best performing paint systems would pass the cyclic test regime, whereas it would be relatively easy to get a ‘standard’ coating system to pass the ISO 12944 C5-M test.

The result?

Coatings were potentially being specified for severe offshore marine environments that weren’t fit for such purpose, and several product failures ensued under these conditions.

The ISO working group TC35/SC14 agreed that the C5-M corrosivity category should be abolished, with the C5 category that covers very high corrosivity limited to onshore structures. In addition, ISO 12944 would incorporate ISO 12340 as the new Part 9 category of CX (extreme corrosivity), covering offshore steelwork.

Coatings recommendations categories in the CX environment

And so to the coatings recommendations within ISO 12944-9, which are divided into the following three categories:

1.     Atmospheric Exposure Areas

For general atmospheric exposure, it is expected that most coating systems will be based on zinc-rich primers. The very stringent pre-qualification accelerated cyclic test referred to above, with extremely low allowance for coating disbondment and corrosion from the scribe, means that non-zinc primers are unlikely (but not impossible) to pass.

The only exception to the very strict test parameters is for coatings that will be used on areas that may be subject to a high probability of mechanical impact and damage such as decks and lay-down areas. Here, zinc-rich coatings may fracture and disbond with the impact. Therefore, coating systems for such areas may utilize more traditional high-build coatings which have an allowance for slightly higher disbondment on the test schedule.

2.     Immersed Areas (with cathodic protection)

These areas (classified as Im4 in ISO 12944-2) are tested for cathodic disbondment to ISO 15711 – Method A, plus a seawater immersion test to ISO 2812-2. They are not tested using the cyclic ageing test.

3.     Splash/Tidal Zone Areas (with cathodic protection)

The splash zone is the portion of an offshore structure that suffers the highest level of corrosion stress. These areas will be subject to constant wet/dry cycling due to tidal movement and wave splashing with highly oxygenated sea water, and coupled with intense UV reflection off the water’s surface and the possibility of mechanical impact from flotsam or boat contact.

Splash zone areas have a significantly thicker coating specification and must pass the combined suite of laboratory tests of cyclic ageing plus immersion and cathodic disbondment tests.

‘Fingerprinting’ of coatings

It is mandatory that all coatings tested to the requirements of ISO 12944-9 are ‘fingerprinted’ by laboratory analysis.

This is done by taking paint samples from test batches and combusting them to ash. This is then analysed using Fourier Transform Infrared (FTIR) spectroscopy. This gives a detailed chemical profile of the coatings that can be used to compare against production batches to ensure that formulations are not changed post-test by the manufacturer. Routine batch checks are required to be undertaken during a project.

Thickness – a key difference in ISO 12944-9

ISO 12944-9 is extremely detailed with regards to surface preparation and quality control requirements that are commensurate with the need for the best possible coating practice to withstand the most corrosive environments. Hence, there are some differences between this part of the standard that covers CX environments and the rest of ISO 12944.

A key difference is that in Part 9, all specified coating thicknesses are minimum requirements. No dry film thickness readings are permitted below the specified level.

This is not the case for C1 to C5 specifications for dry film thickness, for which thickness values are nominal as defined by ISO 19840. This standard allows a small percentage (usually 10% or 20%) of dry film thickness readings to dip down below the nominal value, though no individual reading can be below 80% of the nominal value, and the overall average reading must be above the nominal value.

Piece-meal introduction of ISO 20340 into ISO 12944

The intention is to blend the CX specification requirements and testing schedules into ISO 12944 so that they are more aligned with other corrosivity categories as detailed in ISO 12944-5 and ISO 12944-6. However, in the 2018 iteration, this was not possible.

Therefore, as a first step, ISO 20340 was ‘bolted onto’ ISO 12944 as Part 9 of the standard. This bolt-on was added largely unchanged from the original, though with some tightening of the accelerated testing requirements that forced the use of zinc-based primers for general atmospheric exposure. Thus, there is some repetition from other parts of ISO 12944.

Further discussion of ISO 12944 is due to commence this summer, with a deadline of 2025 for the next issue of the standard – so watch this space!

The Institute of Corrosion Coating and Inspection Training Courses will help ensure your painters and inspectors work to the latest industry standards and benefit from new technology and innovative approaches. For more information, contact us today.

Other articles in our ISO 12944 series:

ISO 12944-8: Technical Writing of Coating Specifications

ISO 12944-8: Technical Writing of Coating Specifications

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A Powerful Tool in the Development of Specifications for New Work and Maintenance

ISO 12944-8 is often overlooked, though it contains a huge amount of information that enables competent technical writing with regards to coating specification for new build projects or maintenance of existing structures and items.

If you are writing such coating specifications, it’s crucial that you observe all other parts of ISO 12944 – and the templates contained within ISO 12944-8 help ensure you do this.

Why ISO 12944-8?

ISO 12944 is the globally recognised standard used by the protective coatings industry to develop and verify coating specifications for corrosion protection of steel structures. The most referred to parts of ISO 12944 are:

As well as referencing these and other parts of the standard, Part 8 of the standard explains the value of creating reference areas to set a benchmark for the standards of workmanship of surface preparation and coatings application. Thus, it also enables the finished appearance of the system and relevant inspection and quality control requirements to be established at this primary stage before the project commences.

A set of powerful specification templates

The templates contained within this part of the standard are powerful tools. They ensure that you include all that is needed when documenting the technical requirements of a coating specification, whatever the new build or maintenance project.

There are four basic types of specification templates within ISO 12944-8. You’ll see that there is a certain amount of overlap and repetition between them, but it is important to recognise that each is tailored to a different stage of the project.

1.     Contents of a project specification (Pre-commencement)

The project specification sets out a broad overview of the project with all the factors to be considered before the project bids are in place. This includes:

  • Name and location of the project
  • Key contact details
  • Definition of required durability and corrosivity
  • Descriptions of the constituent elements of the construction
  • Any special considerations and constraints
  • Overview of the required coating systems and surface preparation
  • Overview of the quality control and inspection requirements
  • Reference area requirements

It also includes the provision of a pre-work meeting in which all parties can discuss the project.

2.     Contents of a protective coating system specification (Detailed coating specification)

This specification template drills down further into substrate dressing and preparation requirements, describing the protective coating system with details that include:

  • Wet/dry film thickness
  • Edge protection
  • Technical and safety data sheets
  • Pre-qualification test results

It also includes an overview of inspection requirements and documentation of results.

3.     Contents of a paintwork specification (Application and inspection methodologies)

The paintwork specification focuses on the qualification requirements for paint inspectors and applicators. This document forms the framework for a working method statement that will enable the job to be undertaken to the required standard.

4.     Contents of an inspection and assessment specification (Detailed quality plan)

This template provides a detailed description of the inspection stages to be undertaken by the contractor and independent inspectors. It includes a full QA and inspection plan, as well as the requirements for document control and distribution of records.

Annexes and flow charts

In addition to the specification templates, ISO 12944-8 presents a series of informative annexes. These outline basic headings to be included in a specification, plus the key aspects that need to be considered in the preparation, inspection, and reporting of a reference area.

You will also find a series of flow charts. These help you to map out the steps needed to prepare for new work or maintenance work, and provide templates for both types of projects.

ISO 12944-8: A powerful tool

In conclusion, ISO 12944-8 is an exceptionally powerful tool.

The templates, annexes, and flow charts ensure that even a relatively inexperienced person can create a technically correct specification document that will enable a coating project to be executed in full accordance with best industry practice.

Our final article in this series covering ISO 12944 discusses Part 9 of the standard: protective paint systems and laboratory test methods for offshore and related structures.

The Institute of Corrosion Coating and Inspection Training Courses will help ensure your painters and inspectors work to the latest industry standards and benefit from new technology and innovative approaches. For more information, contact us today.

Other articles in our ISO 12944 series:

Should Your Organisation Become a Corporate Member of the Institute of Corrosion?

Should Your Organisation Become a Corporate Member of the Institute of Corrosion?

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ICorr Corporate Membership Benefits

Corporate membership of the Institute of Corrosion is an attractive strategic business decision, and for many good reasons. When your organization becomes an ICorr corporate member, it gains access to a range of exclusive benefits. Your organization also gets to contribute to the continuing evolution of corrosion science and corrosion engineering, as well as raising its profile and impact within the industry.

ICorr: In service of our members

A few years ago, we embarked on an overhaul of the Institute. Having been founded in 1959, we felt it was time to update and upgrade, to improve and prove our global presence and strategy, and to become more approachable.

We canvassed and listened to our members and other corrosion professionals, reviewed our strategy, and rebranded. In the ongoing battle against costly and dangerous corrosion, our mission is to build better collaboration within the industry, with academia, and with governments and policymakers, and share ICorr’s corrosion expertise with the world.

We’re a values-led organization, with four core values that are the vision behind the ICorr brand:

  1. Trust and respect – we are an independent professional body, trusted and respected by the public to help reduce the impact of corrosion on infrastructure. As a not-for-profit body committed to developing the corrosion prevention industry, we are led by people with experience and expertise, with a collective credibility to help others develop the skills in corrosion science and engineering that are crucial to continually improve corrosion prevention.
  2. Experts and leaders in the field – the Institute encompasses leaders and experts in the field of corrosion prevention. This expertise enables us to advance toward our vision as we influence policy and strategy at corporate and governmental levels. Continuous improvement of knowledge and expertise is key to this – as is focus on aspects such as health and safety, equipment, and people.
  3. Innovative and forward-thinking – we are an innovative, modern, cutting-edge body that is forward-thinking and encourages the sharing of expertise. We also seek to collaborate with like-minded bodies (for example, our partnership with ABRACO) to drive the corrosion prevention industry forward.
  4. Supportive and inclusive – we provide an environment of support, networking, and education, committed to developing industry capabilities, enhancing knowledge and expertise, and enabling people to develop effective and innovative careers. To this end, we offer comprehensive training and support for all corrosion professionals, as well as networking opportunities to help our diverse membership benefit from all the Institute offers and represents.

We serve our members through many channels, including regional meetings, conferences, workshops, magazines, website, social media, training courses, mentoring, training, and an online jobs board. We host many events, such as regional and international conferences, to support the industry and debate new technology and ideas, and our network of branches meet regularly to share knowledge and promote networking opportunities.

Why become a corporate member?

As a not-for-profits body, we depend on our membership to help fund our vision. We also depend upon our membership to help us to drive progress within the corrosion prevention industry.

Of all our membership options, corporate membership provides the highest level of participation within our organization, and therefore within the global conversation around corrosion.

As a corporate member of the Institute of Corrosion, you’ll be helping to develop the corrosion prevention industry.

Specifically, corporate membership provides benefits that include:

·       The highest grade of membership offering maximum profile within the corrosion industry

There is no better way to raise your profile within the corrosion community.

·       Access to our Career Development & Progression Programmes

ICorr provides limited access to some of the best career development and progression programmes in the industry. Corrosion professionals who participate in these programmes not only enhance their own knowledge and capability, but also improve their employer’s capabilities, too – and that’s great for business.

·       Access to our online resources and libraries

Our vast (and growing) online resources and libraries are only available to our members.

·       Free-of-charge advertising in the Institute’s Corrosion Magazine

Distributed six times a year, the Corrosion Management Magazine is a leading publication within the industry and a source of knowledge and expertise for many businesses.

·       Free advertising on our website’s Member’s Directory

Advertising on our Member’s Directory will help your business to raise its profile within the corrosion prevention industry.

·       A discount of 10% on all conferences and symposia, and on selected ICorr training courses

Our conferences and symposia are leading events within the industry, and our training courses and certifications are recognised around the world – providing the qualifications and confidence that will help drive your organization toward its strategic goals.

·       A table at the annual ICorr Christmas luncheon

A never-to-be-missed occasion!

How to become a corporate member of the Institute of Corrosion

As a corporate member of the Institute of Corrosion, you’ll be demonstrating a commitment to the advance of knowledge and expertise within the industry and within your own organisation. Your profile within the industry, and with your clients, current and prospective employees, and other stakeholders, will be enhanced.

Your organization and employees will have access to a range of resources, and benefit from discounts on training, advertising, and attendance at conferences and other events. And you’ll be guaranteed a table at the ICorr Christmas luncheon.

For more information and to join the Institute of Corrosion as a Corporate Member, please email our admin team.