Thermal Protection and Fire Resistance of High-Pressure Hydrogen Storage

The paper focuses on the main unresolved safety issue for hydrogen-powered vehicles, i.e. the fireresistance of onboard hydrogen storage. The experimental study supported by numerical analysis hasbeen undertaken in order to achieve fire resistance rating of high-pressure hydrogen tank beyondpotential car fire duration, i.e. of the order of 2 hours. The experimental programme comprised ofbonfire tests of carbon-fibre reinforced plastic tanks with polymer liner both bare and thermallyprotected, in line with Global Technical Regulation on Hydrogen and Fuel Cell Vehicles #13. Testedparameters included different levels of thermal protection, different bonfire heat release rates, tankswith and without prehistory of pressure cycling. It was experimentally demonstrated that the thermalprotection solution in form of epoxy-based intumescent paint is capable to increase fire resistancerating of carbon-fibre plastic tank from current 6-12 minutes to beyond 2 hours. This breakthroughachievement in fire resistance rating of on-board hydrogen storage has a potential to impact on safety design of tanks and to reduce range of hazards in case of accident scenario like a car fire, e.g. complete elimination of catastrophic tank rapture in a fire or longer release from a pressure relief device resulting in a shorter hydrogen jet fire. Smaller bonfire heat release rate was shown to increase fire resistance rating of the tested tank though still complying with the Global Technical Regulation #13. Tank pressure cycling did not have impact on the tank fire resistance rating.