Home NI423 Corrosion protection of steel offshore units and installation This Guidance Note provides guidelines for the prevention and control of corrosion on steel structures, appurtenances and equipment of offshore units. ReferenceTitleDateNI423 R01Corrosion protection of steel offshore units and installationMay 2006check related documents:NR445 Rules for the classification of offshore unitsNR426 Construction survey of steel structures of offshore units and installationsCheck other Bureau Veritas rules and guidelines.