An Integrated EPC-Operational Process Safety Lifecycle Model: Coupling HIRA, FMEA, and Quantitative Risk Assessment for Explosion and Fire Disaster Prevention in Hydrocarbon Facilities

Abstract

The Oil and Gas (O&G) and downstream petrochemical industries handle massive volumes of volatile hydrocarbons under extreme thermodynamic conditions, making them exceptionally vulnerable to catastrophic loss-of-containment events. Historically, safety management strategies have operated in silos: occupational safety dominates the Engineering, Procurement, and Construction (EPC) phase, while Process Safety Management (PSM) and Quantitative Risk Assessment (QRA) govern the operational phase. This fragmented paradigm overlooks a critical reality: procedural and mechanical deficiencies during EPC (e.g., inadequate weld fusion, improper flange torqueing, incorrect valve selection, and deficient pre-commissioning testing) represent the latent pathogens that directly trigger major operational disasters. This research presents an integrated, closed-loop process safety lifecycle model that bridges this divide by systematically coupling Hazard Identification and Risk Assessment (HIRA) and Failure Mode and Effects Analysis (FMEA) during EPC execution with QRA thermodynamic and blast consequence modeling. Utilizing rigorous forensic case studies of landmark disasters—including the IOCL Jaipur terminal fire (2009), the ONGC Hazira gas terminal leak (2020), and the IOCL Mathura refinery incident (2020)—we establish direct causal links between construction QA/QC failures and operational vapour cloud explosions (VCE) and boiling liquid expanding vapour explosions (BLEVE). Mathematical consequence modeling utilizing the Roberts fireball formulation for a 3,602,137 kg gasoline inventory yields a maximum fireball diameter (D_max) of 889.09 m, a duration (T_max) of 68.98 s, and an active surface emitting power (SEP_max) of 333.98 kW/m2, producing lethal thermal radiation (>63 kW/m2) even at 500 m standoff distances. TNT-equivalency modeling of a 450,000 kg vapor cloud generates a blast yield of 169,188 kg TNT, establishing peak overpressure contours via Hopkinson-scaled distance (R_bar). Furthermore, a quantitative FMEA framework establishes a strict threshold (RPN > 100) mandating automated safety instrumented systems—specifically Remote Operated Shut Off Valves (ROSOVs) and emergency depressurization interlocks—prior to mechanical completion. The proposed framework provides an empirical, standards-compliant methodology for EPC contractors and plant operators to eliminate latent hazards at the build stage, ensuring inherent process safety across the entire asset lifecycle