Assessment of structural integrity for existing offshore load-bearing structures (Edition 1, March 2009)
The principlal standard for offshore structures is NORSOK N-001, Integritry of offshore structures which especially refers to ISO 19900, Petroleum and natural gas industries- General requirements for offshore structures. This NORSOK standard, N-006 gives additional requirements for assessment of the structural integrity of offshore structures in-service and for life extension.
This NORSOK standard specifies general principles and guidelines for assessment of the structural integrity of existing offshore structures as a supplement to NORSOK standard N-001 and should be used in conjunction with NORSOK standards N-003, N-004 and N-005. The present standard serves as an alternative to NORSOK N-001 for cases where structures are to be operated beyond original design requirements and structural resistance is not easily verified through ordinary design calculations, and where use of additional information gained through the life of the structure can be used to demonstrate structural adequacy.
The standard is applicable to all types of offshore structures used in the petroleum activities, including bottom founded structures as well as floating structures. As the majority of ageing facilities are fixed structures of the jacket type, the detailed recommendations given are most relevant for this type of structure.
The standard is applicable to different types of materials used including steel, concrete, aluminium, etc.
This NORSOK standard is applicable to the assessment of complete structures including substructures, topside structures, vessel hulls, foundations, mooring systems and subsea facilities.