Fire Spread Scenarios Involving Hydrogen Vehicles

Fire spread between vehicles provides a potential risk in parking areas with many vehicles. Several reported very large fires caused the loss of a great number of vehicles. These fires seem to be in contradiction to the European design rules for car parks assuming only a very limited number of vehicles may be on fire at the same time. The fire spread in a car park environment is dependent on many factors of both the vehicles and the structure, e.g. the latter has an impact on the rate of fire spread due to reradiation of the vehicles heat release. Therefore, a CFD model is established to develop a tool to assess vehicles and better understand fire scenarios in different structures. Further, the model enables testing of building design to prevent and mitigate such fires scenarios involving hydrogen vehicles. In this study, a real layout of a car park is modelled to investigate the effects of hydrogen emergency releases that have used different TPRD diameters. The results provide insight into the behaviour of hydrogen cars and the release pattern of the TPRD's as well as the temperature development of the concrete ceiling and concrete beams above the cars. It shows that the TPRD diameter has a little effect on the TPRD activation time of the no.1 vehicle when the amount of H2 in the tank is the same. For the surface temperature of the ceiling and beam, the peak temperature for a 1mm diameter TPRD release is found highest.