CCPS Presentation Session: Integration of Human Factor into Risk Assessment

Abstract

Hazard and operability studies (HAZOPs) are common process hazard analysis (PHA) tools which have been shown to be an effective method of identifying risks within chemical processing facilities. However, one of the biggest challenges in HAZOPs is assigning the risk ranking of a scenario based on the severity of the consequence and the likelihood of the initiating event. Biases introduced at this stage of the process, including motivational biases and cognitive biases, can lead to inconsistencies in results and inaccurate assessment of the risk. One method of establishing consensus is voting on the severity and likelihood. Voting is first performed prior to detailed discussion of the scenario. Next, the scenario and voting results are discussed to elevate the collective knowledge of the HAZOP participants, and then a second, final vote is performed. In this study, a series of PHAs were performed on a variety of different petrochemical processes (upstream, midstream, and downstream) for multiple different companies (149 HAZOP participants). Participant polling data across different consequence categories (health and safety, environment, financial) was evaluated to determine if there were any trends in voting patterns based on the participant role (engineer vs. operator vs. project manager vs. facilitator) or the number of years of experience of the participants. The two primary factors which were evaluated were risk acceptance (how severe an individual deemed the consequence to be compared to the group consensus) and persuadability (how likely an individual was to change their mind during the second vote after group discussion). This information is useful for determining biases that arise while assessing the severity and likelihood for HAZOP scenarios and determining which key people should participate in a HAZOP. The information from this study can be used to help develop strategies that can be used to reduce these biases, with the ultimate goal of improving facilitator techniques and HAZOP results.