scope:

General

The ABS Rules for Building and Classing Floating Production Installations (FPI Rules) require strength and fatigue assessment of the topside module/hull interface on the ship-type installations. The hull interface structure specified in the ABS FPI Rules is the interface structure between the main hull and topside structures, including associated stools and elastomeric bearings, as fitted. Topside modules are the discrete structural units that support production facilities and supporting systems, and fatigue analysis of these structures is not required by the FPI Rules.

For ship-type floating production installations such as FPSOs, topside modules installed on deck of an installation may include but are not limited to oil/gas processing modules, gas compression modules, power generation modules, flare tower, vent stack, helideck, pipe rack, and laydown areas. Newer generations of topside structures are large in size and heavy in weight. They are important parts of the installation structures that are critical to the operation and structural integrity of ship-type installations. Thus there may be a need to perform the fatigue assessment in addition to strength evaluation of the topside structures.

As a supplement to the fatigue assessment of the topside interfaces on ship-type installations, these Guidance Notes provide the recommended procedures for performing fatigue assessment of the topside structures on ship-type installations. In general, Guidance Notes are not mandatory requirements.

Note that Installation, Ship-type installation or Unit, as used in these Guidance Notes, refers to ship-type floating production installation.