prEN ISO 19901-3

This part of ISO 19901 provides requirements, guidance, and information for the design and, fabrication of topsides structure for offshore structures. It complements ISO 19902, ISO 19903, ISO 19904-1, ISO 19905-1 and ISO 19906, which provide requirements for various forms of substructure. The actions on topsides structure, and the action effects in the structural components are derived from this part of ISO 19901, where necessary in combination with other International Standards in the ISO 19901 series. The resistances of non-cylindrical structural components of the topsides structure can be determined by the use of national building standards, as specified in this part of ISO 19901. The resistance of cylindrical structural components are to be in accordance with ISO 19902 but may be according to national building standards, as specified in this part of ISO 19901. This part of ISO 19901 is applicable to the following: — topsides of fixed offshore structures; — discrete structural units placed on the hull structures of floating offshore structures and mobile offshore units; — topsides of arctic offshore structures, excluding winterization ( ISO 19906). If any part of the topsides structure forms part of the primary structure of the overall structural system which resists global platform actions, the requirements of this part of ISO 19901 are supplemented with applicable requirements in ISO 19902, ISO 19903, ISO 19904-1, ISO 19905-1 and ISO 19906. This part of ISO 19901 does not apply to those aspects of topsides structure that form part of the overall structural system of floating offshore structures and mobile offshore units that are governed by the rules of a recognized certifying authority and which are within class rules. The fire and explosion provisions of this part of ISO 19901 can however be applied to those parts of the hulls of floating offshore structures and mobile offshore units that contain hydrocarbon processing, piping or storage. This part of ISO 19901 addresses the following aspects of topsides structure: — design, fabrication, installation and modification; — prevention, control and assessment of fire, explosions and other accidental events. NOTE Requirements for structural integrity management are presented in ISO 19901-9. This part of ISO 19901 applies to structural components including the following: — primary and secondary structure in decks, module support frames and modules; — flare structures; — crane pedestal and other crane support arrangements; — helicopter landing decks (helidecks); — permanent bridges between separate offshore structures; — masts, towers and booms on offshore structures.