NORSOK M-501

NORSOK M-501 is the Norwegian offshore industry standard for surface preparation and protective coating, setting requirements for coating-material selection, surface preparation, application, and inspection on offshore installations. Edition 6 was issued in 2012. It defines numbered coating systems for different exposures, for example system 1 for carbon steel up to 120 C, plus thermally sprayed metallic and passive-fire-protection coatings, and it requires qualification testing of several systems before use. The standard specifies a high blast grade, typically Sa 2.5 to Sa 3 with a defined surface profile, and tight inspection of film thickness and curing. It does not cover pipelines or pipeline risers. NORSOK M-501 is widely cited beyond the Norwegian sector as an offshore coating benchmark.