Engineering Critical Assessment for MAOP Reconfirmation: Insights From a Project Instituted by a Consortium of Pipeline Operators

Abstract Part 1 of the Gas Mega Rule (RIN-1) became effective July 1st, 2020. A key component of RIN-1 is the requirement for the reconfirmation of maximum allowable operating pressure (MAOP) for certain segments of gas transmission pipelines. Pursuant to 49 CFR §192.624, MAOP can be reconfirmed using one of six methods: hydrostatic test, pressure reduction, Engineering Critical Assessment (ECA) (as prescribed in 49 CFR §192.632), pipe replacement or pressure reduction for segments with small potential impact radius or an alternative technical assessment subject to notification in advance to the Pipeline Hazardous Materials Safety Administration (PHMSA) in accordance with 49 CFR §192.18. The regulations in 49 CFR §192.632 specify the necessary elements for an ECA for MAOP reconfirmation, however they do not provide detailed instructions for executing an ECA. A Consortium of pipeline operators initiated a pilot project to develop ECAs for pipelines requiring MAOP reconfirmation, using the guidelines in 49 CFR §192.632. This initiative offered key insights into how pipeline operators can leverage established integrity management (IM) activities and principles to support ECA objectives. While certain consensus standards, such as American Society of Mechanical Engineers (ASME) standard B31.8S and American Petroleum Institute (API) recommended practice 1160 have long provided guidance on pipeline integrity management, it’s crucial to recognize the distinctly different objectives of integrity management and ECA, despite their significant technical overlap. Pipeline operators have employed data integration and integrity assessment principles in these standards for integrity management for decades, and many of the activities supporting IM objectives are relevant to ECA objectives. Integrity management is an ongoing process, whereas ECA for MAOP reconfirmation is typically a one-time analysis confirming that the pipeline’s design and construction are suitable for operating at the established MAOP. This paper will explore the similarities and differences between ECA and IM objectives, the assessment of relevant threats and conditions pursuant to 49 CFR §192.632 and examine data requirements that are relevant to each.