DIN EN ISO 12944 "Coating materials - Corrosion protection of steel structures by coating systems" standardizes corrosion protection by organic wet coating systems on "black" and also on hot-dip galvanized steel (duplex systems). The standard, which dates mainly from 1998, has been completely updated and supplemented by the new Part 9, which regulates coating systems for offshore structures. This part replaces the withdrawn standard ISO 20340: 2009 and defines performance requirements for coating systems as well as test methods and evaluation criteria for coating systems for offshore and related structures. For the first time, the coating standard DIN EN ISO 12944 takes into account the durability of hot-dip galvanized steel to some extent and enables coatings on hot-dip galvanized steel to be thinned by a third, allowing this to be done even in highly corrosive offshore applications. Table 3 of Part 9 defines the minimum requirements for coating systems and their initial performance. Comparing the requirements for corrosion category CX (Corrosivity: extreme), which includes offshore areas with high salt exposure such as oil platforms and wind farms, but also industrial areas with extreme humidity and aggressive atmosphere, it is evident that coatings on hot-dip galvanised steel can be thinner and can be applied with fewer layers. The minimum number of layers is indicated here as 2 and the minimum nominal layer thickness on the metallic coatings as ≥ 200 µm.
Autor(en): Ke
