Simulation-based safety analysis of hydrogen storage tank leakage using ALOHA and PHAST

Hydrogen energy systems are vital to sustainable energy infrastructure but require thorough safety assessment due to the hazardous properties of H2 gas. This study conducts a comparative simulation-based safety analysis of hydrogen storage tank leakage using two consequence modeling tools of ALOHA and PHAST. The analysis considers a cylindrical tank under various failure scenarios, including continuous leaks, jet fires, vapor cloud explosions, and catastrophic rupture. Three meteorological conditions are evaluated to examine atmospheric stability effects on hazard dispersion. According to ALOHA modeling results, the flammable vapor cloud reaches a distance of 422.5 m under Class F stability (1.5 m/s wind speed), whereas this hazard zone decreases to roughly 83.2 m under Class D conditions at an equivalent wind speed. PHAST provides more detailed results, with jet fire thermal radiation reaching approximately 16 kW/m² at 7 m from leak source and rupture scenarios producing overpressure zones up to 210 m. The comparison shows ALOHA is suitable for rapid emergency response, while PHAST delivers comprehensive engineering-focused risk evaluation essential for facility design and regulatory compliance. Integrating both tools offer a robust framework for assessing hydrogen storage risks, aiding operational safety and emergency planning. The results underscore the value of using multiple modeling tools to support hydrogen infrastructure safety and standard development.