This document specifies principles for the structural integrity management (SIM) of offshore structures subjected to known or foreseeable types of actions. This document specifies requirements and provides recommendations applicable to the following types of fixed steel offshore structures for the petroleum and natural gas industries: — caissons, free-standing and braced; — jackets; — monotowers; — towers. This document is applicable to topsides, including but not limited to the main decks, deck legs, topsides modules, crane pedestals, helideck, drilling derrick, skid beams, flare booms, exhaust towers, radio tower, conductor support frames, and lifeboat davits. In addition, it is applicable to compliant bottom founded structures, steel gravity structures, jack-ups, other bottom founded structures and other structures related to offshore structures (e.g. underwater oil storage tanks, bridges and connecting structures), to the extent to which its requirements are relevant. This document contains requirements for planning and engineering of the following tasks: a) integrity management data requirements; b) in-service inspection and integrity management of both new and existing structures; c) assessment of existing structures; d) evaluation of structures for reuse at different locations; e) evaluation of structures for their future removal.