Significant Changes in the Twenty-Second Edition of API 1104

Abstract API Standard 1104, Welding of Pipelines and Related Facilities, (API 1104) is the most widely-used industry standard in the world for pipeline construction. For operators in the United States, the use of certain sections of API 1104 are mandated by Federal regulations for the construction of cross-country pipelines. Since the First Edition was published in 1953, API 1104 is revised regularly to adapt to changing pipeline construction, welding, and inspection practices. The current version, which was issued in July 2021, is the Twenty-second Edition, which incorporates extensive changes as compared to the Twenty-first Edition. This paper summarizes the major substantive changes between the Twenty-first and Twenty-second Editions of API 1104, and provides some insight into the rationale behind these changes. One example of a major substantive change is the introduction of “Category I” and “Category II” essential variables, which are applicable to “standard” welding procedure specifications (WPSs) and those that require hardness and/or toughness testing, respectively. The Twenty-second Edition also contains updated information on ultrasonic inspection of welds. Furthermore, requirements for the in-service repair of welds, including procedure qualification and welder qualification were added. This paper will increase the understanding of the major substantive changes in the Twenty-second Edition of API 1104 for both users and regulators. It may also be used by operating companies in transitioning their welding practices and procedures to the requirements in the Twenty-second Edition from earlier editions of the standard.