Alignment of API Offshore Structures Standards with ISO 19900 Series and Usage of The API Suite
Authors: Wisch David J. , Mangiavacchi Andrea 
Published: April 2012

Abstract
Following the beginning of the offshore industry in the late 1940s, APIstructural standards for offshore structures made their first appearance in thelate 1960s. As the offshore industry moved out of its initial cradle in theGulf of Mexico and expanded to other regions of the world, it becameincreasingly obvious that while some of the basic principles developed andadopted by the industry could be readily and effectively exported to othergeographic areas, differences in environmental conditions, working practicesand political and commercial realities provided a strong drive towardsprogressive generalization and globalization of the standards developmentactivities.
The early 1990s saw the start of an ambitious effort to develop worldwideoffshore structural standards under the aegis of ISO, with API and the USindustry providing a strong support and commitment to the initiative, alongsideother countries with an active offshore industry, such as, in no particularorder, UK, Norway, France, Italy, Brazil, etc. The ISO effort has by nowproduced the first generation of the ISO 19900 suite.
For many reasons, as described in this paper, the development of the APIstructural suite and the later ISO effort followed a different historical path, leading to a different document portfolio architecture. As part of its supportto the global initiative, over the past 6 years the API Offshore StructuresCommittee has undertaken a coordinated and very intense effort to redesign itsdocument portfolio, leading initially to a substantial alignment of the twosuites of standards, with a view to achieve a progressive merger. This paperprovides an update of the status of this effort, and some general guidelinesfor the use of the document portfolio.

Introduction
Wells in lakes, marshes and in shallow, near shore, ocean waters have beendrilled and produced since the late 1800s in several areas of the world(California, Louisiana, Venezuela, Caspian Sea, etc.). However, it was theoffshore platform installed in 1947 on a Kerr McGee lease in the Gulf ofMexico, out of the sight of land, that marked the beginning of what is todayreferred to as the offshore industry.
In the early years, fixed platforms and submersible drilling barges weremainstays of the industry. Structures were designed incorporating land-baseddesign practices modified to suit the new, unfamiliar environment. Steel andconcrete structures had been designed, built and utilized for years on land andin marine environment applications of both fresh and salt water environments, most notably port and harbor facilities as well as piers extending from land. However, moving offshore introduced a whole new set of design, construction andoperating challenges. Storm driven waves had a considerable effect on fixedplatforms, while winds became an increasingly critical factor floatingstructures, which made their appearance in the 1960s. Velman and Lagers providea comprehensive historical discussion on the development of the offshoreindustry (1).
While the design of fixed offshore structures required a significant extensionof standard practices for land structures, the practices for floatingfacilities had a historical precedent in the form of classification societyrules. In the very early days of the late 1940s and 1950s, rules for strengthand stability developed by classification societies could be applied to bargesutilized in offshore operations. Given the early reliance on class rules foroffshore barges, it became almost natural to leave it to class societies topromulgate new standards for floating facilities, rather than expecting the oiland gas industry to complete this task. As a consequence, the appearance of thefirst purpose-built drilling semi-submersible, the Ocean Driller, in 1963, ledto the first offshore industry floating standard developed by class societies, which addressed mobile offshore drilling units (MODUs).