Rules for building and classing offshore installations issued by ABS

The American Bureau of Shipping has published a revised version of the rules for building and classing offshore installations.

The document was published on 1 January 2023.

The requirements for conditions of classification are contained in the separate, generic ABS Rules for Conditions of Classification – Offshore Units and Structures (Part 1). Additional requirements specific to offshore installations are contained in part 1 of this document.

Part 2 of the document covers the specifications for materials used for the construction of offshore steel structures and materials for concrete used in the construction of offshore platforms.

The requirements for welding and fabrication are contained in Chapter 4 of the separate, generic ABS Rules for Materials and Welding (Part 2) and additional welding requirements specific to offshore installations are contained in part 2, chapter 2 of this document.

Part 3 of the Rules sets out the definitions and design documentation, environmental conditions to be taken into account, and application categories based on material selection and presents the design requirements.

Part 4 details the requirements for the extension of use and reuse.

Part 5 pertains to surveys during and after the construction and installation of an offshore structure.

New text is added after the table in part 3, chapter 1, section 3 Steel Selection Criteria:

When tensile stresses through the thickness (Z direction) exceed approximately 50% of the minimum specified yield stress (as defined in the applicable ABS Rules), consideration is to be given to applying Z grade steel (refer to 2-1-1/17 of the ABS Rules for Materials and Welding (Part 2)). Alternatives to applying Z grade may be proposed provided it is demonstrated by ultrasonic testing before and after welding that no through thickness tearing has occurred, and/or the welding preparation, weld size and bead sequence is such that damaging through thickness loads induced by weld shrinkage are avoided.

If you need more information, please visit the ABS Rules and Guides page, where the document is available FOR FREE.