This International Standard specifies requirements and provides recommendations applicable to fixed concrete offshore structures for the petroleum and natural gas industries, and specifically addresses a) the design, construction, transportation and installation of new structures, including requirements for in-service inspection and possible removal of structures, b) the assessment of structures in service, and c) the assessment of structures for reuse at other locations. This International Standard is intended to cover the engineering processes needed for the major engineering disciplines to establish a facility for offshore operation. It can also be used for the design of floating concrete structures as specified in ISO 19904-1 [11] (and the future ISO 19904-2 [12] when published) and for arctic structures (as specified in the future ISO 19906 [7] when published). In order to provide a standard that will be useful to the industry, a comprehensive treatment of some topics is provided where there is currently no relevant reference. For such well-known topics as the design formulas for concrete structural members, this International Standard is intended to be used in conjunction with a suitable reference standard for basic concrete design (see 8.2.1). The designer can use suitable national or regional design standards that provide the required level of safety. Only other ISO documents will be referenced directly in the text.