Making the grade in the wind power and offshore sector
1 min read
Since the end of 2013, a particular grade of coating has been used by Siemens Wind Power (SWP) on of wind turbine blade fasteners. SWP required that the coating must be able to exist in a C5-H environment (according to ISO-12944) without corrosion of the substrate material even after a 1440 hours salt spray test. The material chosen was Geomet 321 and this is now being applied with a thickness of 15 microns.
At the same time, GE Power & Water (General Electric's division responsible for the construction of wind power plants) has approved the zinc flake systems Geomet and Geoblack in its latest standard P14A-AL-0218. Specific requirements such as 1000 hours salt spray resistance could be met and mechanical damage tests were convincing.
In addition to these new standards, the systems Geomet 321 + Plus VLh and Geomet 500 + Plus XL have been certified by the institute Germanischer Lloyd for the corrosion protection of fasteners in oceanic and offshore atmosphere with high salinity levels (C5-M high according to ISO-12944). This means a salt spray resistance of 1440 up to 2016 hours without appearance of red rust.
NOF Metal Coatings Group was also first to be certified by two different institutes which both confirmed the potential of low thickness corrosion protection for offshore installations. As well as recent certificates from Germanischer Lloyd, the French Corrosion Institute had already certified Geomet and Dacromet technologies in 2010 and proved their ability to pass the ISO Norm 20340 standard (performance requirements regarding coating systems for the protection of offshore plants and associated facilities), which corresponds to level C5-M (according to ISO-12944).
The tests according to the ISO-20340 standard include 25 cycles of one week each, with three days of UV exposure with condensation, three days of salt spray tests and one day of low temperature exposure at -20°C.