This document provides requirements and guidance for the structural design and/or assessment of floating offshore platforms used by the petroleum and natural gas industries to support the following functions:

• —

  production;

• —

  storage and/or offloading;

• —

  drilling and production;

• —

  production, storage and offloading;

• —

  drilling, production, storage and offloading.

This document is not applicable to the structural systems of mobile offshore units (MOUs). These include, among others, the following:

• —

  floating structures intended primarily to perform drilling and/or well intervention operations (often referred to as MODUs), even when used for extended well test operations;

• —

  floating structures used for offshore construction operations (e.g. crane barges or pipelay barges), for temporary or permanent offshore living quarters (floatels), or for transport of equipment or products (e.g. transportation barges, cargo barges), for which structures reference is made to relevant recognized classification society (RCS) rules.

This document is applicable to all possible life-cycle stages of the structures defined above, such as:

• —

  design, construction and installation of new structures, including requirements for inspection, integrity management and future removal,

• —

  structural integrity management covering inspection and assessment of structures in-service, and

• —

  conversion of structures for different use (e.g. a tanker converted to a production platform) or re?use at different locations.

The following types of floating structure are explicitly considered within the context of this document:

1. a)

   ship-shaped structures and barges;

2. b)

   semi-submersibles;

3. c)

   spars;

4. d)

   shallow-draught cylindrical structures.

In addition to the structural types listed above, this document covers other floating platforms intended to perform the above functions, consisting of partially submerged buoyant hulls made up of any combination of plated and space frame components. These other structures can have a great range of variability in geometry and structural forms (e.g. tension leg platforms) and, therefore, can be only partly covered by the requirements of this document. In other cases, specific requirements stated in this document can be found not to apply to all or part of a structure under consideration.

In the above cases, conformity with this document requires the design to be based upon its underpinning principles and to achieve a level of safety equivalent, or superior, to the level implicit in it.

This document is applicable to steel floating structures. The principles documented herein are, however, considered to be generally applicable to structures fabricated in materials other than steel.