A risk-based approach to identify safety-critical equipment in process industries

Abstract

Establishing safety-critical equipment (SCE) in process industries is essential to reduce the risk of catastrophic accidents due to equipment failure. Despite the significant role of risk in the definition of SCE, there are still challenges to identifying and prioritizing risk-based SCE that require further investigation. To address the current gap, a quantitative risk-based approach is presented to identify and prioritize SCE. To do this, Hazard and operability study (HAZOP) is employed for hazard identification; the Bow-tie model and Bayesian network are used for probabilistic cause-consequence analysis, and consequence modelling is used to complete the risk-based approach. The approach here not only aids in making the system more reliable by recognizing the equipment and barriers that reduce the risk of major accidents, but it also aids in the development of maintenance management by reducing the associated costs. The proposed framework then is employed to identify and rank SCE in a high-toxicity petrochemical processing unit. The results show that there are 9 major accident scenarios in the studied unit. As well, rapture in the Phosgene absorber tower 36611 is the worst scenario with a fatality number of 247 and a probability of 0.01/yr. Also, the results indicate that 22 pieces of equipment have the highest safety criticality rating and need more attention in the maintenance plan.