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To investigate the events that could arise when fighting fires in vehicles with carbon fiber reinforced plastic (CFRP) hydrogen storage cylinders, we conducted experiments to examine whether a hydrogen jet diffusion flame caused by activation of the pressure relief device (PRD) can be extinguished and how spraying water influences the cylinder and PRD. The experiments clarified that the hydrogen jet flame cannot be extinguished easily with water or dry powder extinguishers and that spraying water during activation of the PRD may result in closure of the PRD, but is useful for maintaining the strength of CFRP composite cylinders for vehicles.

Fuel cell vehicles represent a new system, and their safety has not yet been fully proved comparing with present automobile. Thorough safety evaluation is especially needed for the fuel system, which uses hydrogen as fuel, and the electric system, which uses a lot of electricity. The fuel cell stacks that are to be loaded on fuel cell vehicles generate electricity by reacting hydrogen and oxygen through electrolytic polymer membranes which is very thin. The safety of the fuel and electric systems should also be assessed for any abnormality that may be caused by electrolytic polymer membranes for any reasons. The purpose of our tests is to collect basic data to ultimately establish safety standards for fuel cell stacks. Methanol pool flame exposure tests were conducted on stationary use fuel cell stacks of two 200W to evaluate safety in the event of a fire.

To investigate methods of conducting flame exposure tests (bonfire tests) on high-pressure hydrogen gas cylinders that are safe and have high accuracy across repeated tests, we used numerical simulation and experiments to analyze the feasibility of using substitutive gases for filling as well as the effects of the burners used as the fire source. Through a series of virtual experiments using substitutive gases, flame scales, and filling pressure as parameters, we examined the maximum internal pressure, the rate of pressure rise, and the starting time of Pressure Relief Device (PRD) activation. Because substitutive gas properties differ from those of hydrogen gas, we concluded that using substitutive gases would be inappropriate. In addition, we observed that when the flame scale was small, the cylinder's internal pressure before the thermal-activated PRD activation, the rate of pressure rise, and the starting time of PRD activation all increased rapidly.