Understanding and managing the risk during transient operations

Abstract

This paper presents the results from more than 50 incidents attributed in part to the process safety risks associated with abnormal, transient operations during start-ups and shutdowns. A transient operation is defined in this paper as the time when the process is in transition between one operating state and another. In particular, the transient operations-related focus is on the time when equipment is taken from its safe, idle state to its safe operating conditions (a start-up) and vice versa, when the equipment is then taken back to its safe, idle state (a shutdown). There are 10 different start-up and shutdown operating modes during normal operations, abnormal operations, and emergency operations. The incidents in this review were attributed to weaknesses in administrative controls that did not work as planned and engineering controls that did not perform as expected. Due to these weaknesses, unexpected events occurred, resulting in quick decisions made without adequately understanding the hazards, evaluating the risks, or managing the changes. In many cases, had the asset integrity and reliability program been in place or effective operational readiness review performed before attempting the process restarts, the risks associated with the transient operating mode could have been reduced.

Analysis of the impact of a pandemic on the control of the process safety risk in major hazards industries using a Fault Tree Analysis approach

“…The restriction of the scope of analysis was based on the assumption that the two above-mentioned pillars have an immediate impact on the capability of an organization to identify and evaluate their risk exposure as well as their practical ability to manage these risks from an operational standpoint during a pandemic. Additionally, a recent study which reviewed over 50 incidents in the literature that were caused due to abnormal or transient operations during startups and shutdowns attributed nearly 74% of the incidents to the two pillars that were selected for this study ( Vaughen, 2020 ). However, it needs to be noted that the decision to restrict our analysis to only two pillars is not meant to underplay the importance of the other two pillars.…”