Identification of Hazards and Risk Assessment among Various Units of Ilam Gas Refinery using the Integrated Approach of Bow-tie and FMEA Methods

Introduction: Risk assessment is a systematic and essential procedure to determine the effects, events, and consequences of human activities on perilous systems. This study aimed to identify the hazards and determine the total risk of various units of Ilam Gas Refinery.   Materials & Methods: This descriptive-inferential study assessed the risks on 18 various units of Ilam Gas Refinery through a combination of Bow-tie and FMEA methods. Initially, the top event, threats, consequences, as well as preventive and recovery measures were identified using the Bow-tie method. Afterward, Risk Priority Number (multiplying severity, occurrence, and detection) was obtained by FMEA. Finally, the risk level was divided into three groups of low, moderate, and high crisis. Findings: Based on Bow-Tie, the release activity of H2S gas was introduced as the top event. Furthermore, tank leakage and burst, corrosion and wear of pipes and fittings, human error, poor operating conditions, and natural factors in the threat role, as well as damages to human and environmental resources and financial losses were identified as consequences. Based on FMEA, the hazard of tank leakage and burst with two effects of human and environmental damages was in the level of high (major) crisis and was recognized as the most important hazard.   Discussions & Conclusions: Gas refineries are faced with many hazards due to the nature of the work process. The integrated approach of Bow-tie and FMEA is a suitable method for risk assessment in such industries.