Fixed Steel Standard: IS0 & API Developments
Authors: Wisch D.J. 
Published: October 2008

IS0 TC 67lSC 7lWG 3, Fixed Steel Structures, is preparing an international standard for the planning, design, construction and installation of fixed steel offshore structures. The standard is one of several under the guidance of SC 7, Subcommittee for Offshore Structures, within IS0 TC 67. WG 3 is using API RP 2A-LRFD as a basis for development of the new standard. The standard has been under development since October I993 and full drafts will be reviewed through 1997 with publication in 1998.

This paper outlines the drivers, history, and schedule. The cooperative efforts of the international community including the API Subcommittee for Offshore Structures is discussed as will the expansion and updating for RP 2A into the international standard. Special focus will be placed on the evolution of current practice into a harmonized standard to produce fit for purpose facilities meeting the challenging economical and safety drivers necessary in todays international industry.

Introduction

The offshore structures industry is young in terms of engineering, being only 50 years old. Thirty years ago, the first standard, API RP 2A1 was issued. While developed with a focus on the US Gulf of Mexico, it has become widely used internationally. Within the past twenty years, either addenda or complete standards have been developed for specific regional areas. This has resulted in a number of similar but different standards. IS0 TC 67lSC 7lWG 3 is bringing forth the best practices and developing a harmonized standard that balances fitness for purpose, economics and safety. In assessing and developing or changing any standard, it is critical to look beyond the immediate form or narrow focus and interprete the results and impact on the overall structural system for which the standard will be used. Todays offshore structures are designed with a component based design standard, yielding an end product that is a structural system. These individual aspects or components cannot be optimized in isolation without considering the overall impact on the system and the wide range of structures, from shallow single member caissons to highly redundant space frames in excess of 50,000 tons, the standard addresses.

This paper is one of four developed for the 1997 Offshore Technology Conference outlining the scope and development of IS0 standards for the offshore structures industry. The companion, OTC 84212 provides background and the interaction of the standards under development. Papers OTC 84223 and 84204 discuss the development of Fixed Concrete and Floating Systems standards currently underway.

General Background

A number of key items pertaining to the development of the Fixed Steel Structures evolved during 1991 and 1992 within SC 7 and Work Groups 1 and 2. It was the express intent of SC 7 during this period to develop and initial IS0 standard by developing a top level document outlining the scope of the standard and using the first edition of API RP 2A-LRFD5 as a reference document and developing specific regional appendices identifying specific regional documents, mostly developed by regulatory agencies, for use in the specified areas. Following completion of this initial work, a harmonized standard would then be developed.