Specifies performance requirements for anti-corrosion coatings systems used on offshore platforms and related structures. The standard aims to ensure the durability and effectiveness of the Coating system in the marine environment to cope with severe corrosion stresses. The standard requires that the Coating system must have adequate protective performance in laboratory tests and emphasizes the use of correct Coating construction methods to ensure performance in practical applications. ISO 20340 is a supplement to the ISO 12944 standard, covering requirements for atmospheric corrosion environment, structural design, surface preparation and Coating construction. The second edition replaces the first edition with technical revisions.