Sunsetting API RP 581 Risk-Based Inspection Semi-Quantitative Methodology

Introduction

Recently, I have felt a growing responsibility to share some of the industry’s history with those newer to the workforce. I also believe we need to develop the next generation of RBI and have ideas and insights on how we can effectively move forward. I hope to accomplish both in this article, focusing on three key takeaways:

1. RBI Built from Opportunity and Collaboration: Since the early 1990s, a core group of industry experts has invested heavily in upgrading the technology used to prioritize inspections and mechanical integrity. Overall, it has paid off tremendously, with the entire industry seeing increased availability, reduced leaks, optimized total spend, and lives saved.
2. Time for Evolution of RBI: With our current access to data and the computational capacity of artificial intelligence (AI) models, it’s time to transition to a next-generation RBI that will help us drive even better performance and improved safety.
3. Time to Sunset API 581: To evolve RBI effectively, I’m recommending we sunset the semi-quantitative API RP 581 technology and focus the committee’s future efforts on fully quantitative next-generation technology.

Each of these points is explored below.

RBI Built from Opportunity and Collaboration

In 1993, the industry was undergoing significant change. Due to several industry incidents that you may remember or should at least be aware of, OSHA 1910.119 was released, and Process Safety Management was emphasized throughout the entire industry. At that time, the only strategy for prioritizing inspections was the use of condition-based (a proxy for probability of failure) intervals.

Recognizing the need for more effective inspection strategies, an API-led Joint Industry Project was initiated to develop a risk-based approach for prioritizing the inspection of fixed equipment. This effort was supported by an industry-driven sponsor group composed of R&D leaders from most US refining companies, some upstream companies, and a handful of petrochemical companies. The group collaborated to review and enhance the risk-based inspection technology originally developed by DNV, USA.

The goal of this review was to gain a deeper understanding of risk and develop a methodology that would help assess potential equipment failures, ultimately aiming to reduce those caused by in-service damage. While the group believed that a fully quantitative methodology was beyond reach because of computing limitations (personal computing was in its infancy in the early 90s), there was a belief that it was possible to provide simplified methods for estimating failure rates and consequences of pressure boundary failures in terms of safety, monetary loss, and environmental impact.

After an intensive two-year development period, which included the first plant pilot study, the API sponsor group approved an initial final project report. The report, “Base Resource Document Final Report (BRD),” was published in May 1995 and revised as development continued through learnings from sponsor company implementations, leading to a publicly released API RBI Software version in May of 2000. In 2008, a second edition of the document was published and given an official API document number, API RP 581, along with the creation of its own committee to manage the continued development of the technology. Since the formation of the API 581 committee, a third (including two addenda) and a fourth edition have been released, each with updated and revised documentation.

Since its release, the API RP 581 semi-quantitative methodology has been successfully implemented around the world and continues to gain more widespread adoption today. Overall, the recommended practices outlined in API RP 580 and 581 have changed the way inspections are planned and managed, transitioning to the use of overall risk as opposed to condition-based approaches. This method of utilizing risk to prioritize and guide inspection strategy has improved reliability and greatly reduced fixed equipment leaks over the past 30 years. Although not a stated objective, using RBI has often resulted in a reduction of inspection-related costs by reducing unnecessary inspections and replacing costly internal inspections with nonintrusive inspection methods.

Overall, the impact of RBI has been undeniable. A fellow API committee member once said to me, “What we did was change the way the industry behaves and that’s a BIG (expletive) deal!” Looking back, it’s been a privilege to be a part of this movement toward changing the way the industry thinks about mechanical integrity, and yet, while technology has come a long way in 30 years, unexpected leaks continue, and cost competitive pressures are as real as they’ve ever been.