Prevention of risks in hydrogen transport

This paper addresses key safety aspects related to hydrogen transport including: • lethal risk, maximum allowable operating pressure, and design factors; • the reliability index under seismic loading conditions; • safety distances in the event of an explosion or jet fire following a hydrogen leak. Hydrogen is a hazardous gas that can pose fatal risks through thermal effects (burns) or overpressure. The nature and severity of these risks depend primarily on the gas release rate following pipeline rupture. Estimating this rate requires determining the size of the breach, which can be evaluated using finite element analysis combined with a Crack Tip Opening Angle (CTOA) criterion. These risks are further amplified by hydrogen-induced embrittlement of pipeline steel, which reduces material toughness and increases susceptibility to fracture. Risk assessment is therefore conducted using a probabilistic approach, based on an admissible failure probability of 10⁻⁵. This approach enables the determination of either a design (sizing) factor or a reliability index. Risk mitigation also involves defining appropriate safety distances. In this study, these distances are evaluated using the ALOHA software, accounting for explosion and jet fire scenarios resulting from hydrogen leaks.