26 January 2016
By Robert Bowles, Chairman, Barrier Group
The offshore wind industry benefits from transferable supply chain skills, predominately from the marine and Oil and Gas sectors. However, in doing so, the industry mustn’t repeat the mistakes of these sectors. The challenge of corrosion control using protective coatings is one of these areas.
Barrier has developed innovative processes and expertise, built on extensive experience in the established offshore industries, which are applied to the offshore wind market.
In my experience, a coating that can be applied reliably is as important as one with ‘high performance’. It should also be tolerant of over-application, and not be specified at its minimum thickness to achieve a maximum performance.
However, as important as the coating is the contractor charged with its application. The applicator should have a proven track record and an experienced workforce.
Unfortunately, there is no independent grading of coating applicators or a database of coating failures and causes, which means the due diligence of the operators and main contractors has to be robust.
Before any coatings are applied to a major structure, a trial should be carried out with the coating system to ensure operatives are familiar with it and what equipment works best for the coatings.
The coating specification is important as it details how the system is to be inspected, when and by whom. Too many specifications assume coatings can be applied to within microns of a specified dry film thickness (DFT), when in practice it is plus or minus hundreds of microns for a high-build coating.
Specifiers often include ‘just in case’ standards, which are not relevant to the application. This leads to Confusion, Conflicts and Costs. The ideal is to focus on the areas where the coating is most likely to breakdown.
Cost savings can also be applied for inspections, essentially not repeating the ‘man marking’ process of the Oil and Gas industry, which often leads to three or more inspectors checking each other’s work. If quality is built in, only one inspector is required and another person monitoring the inspection regime.
Of course, no coating or applicator is perfect. Perfection would come at an unacceptably high price. Therefore there will be minor breakdown over the life of the coating before first major maintenance. This should be planned for.
The sooner minor repairs are made, the less costly they will be and less likely to break down again before first major maintenance. They should also be logged, and fed back to the applicators/industry so that ways can be found to reduce these on future projects.
Unfortunately, this is not the case in the Oil and Gas industry, where the same mistakes have been made for the past 40 years.
Expectations need to be realistic, the industry will not achieve an offshore 30 years to first long-term maintenance using a cheap coating and an inexperienced applicator. Neither will coatings be maintenance-free for 30 years.
However, utilising specialists that have developed innovative coatings systems and application methods, while learning from experiences in other sectors, will help deliver the construction and operational targets of the offshore wind industry.