A quantitative risk assessment method for hydrogen fuel cell vehicles in residential garages

Abstract

Since hydrogen fuel cell vehicle (HFCV) has zero emission and no pollution, it is one of main development directions of new energy vehicles in the future. Parking time of the vehicle in the garage far exceeds the driving time. The ventilation in residential garage is insufficient and therefore the leaked hydrogen is more likely to be accumulated. Jet fire and explosion bring serious casualties and property losses. It may also cause oxygen concentration reduction leading to hypoxia asphyxiation in the residential garage scenario. A quantitative risk assessment method based on Hydrogen Plus Other Alternative Fuels Risk Assessment Models (HyRAM+) assessment framework and Latin Hypercube sampling (LHS) method is proposed. The uncertainty of hydrogen leak frequency, leak detected and isolated probability, ignition probability and asphyxiation probability are fully quantified. The randomness of occupant locations is considered by LHS method. Risk metrics are calculated to measure the severity of accidents, and whether the risk is within the acceptable risk range is judged. The assessment results show that the risk contribution rate of jet fire is significantly higher than that of explosion and asphyxiation. Average individual risk at each pressure and HFCV is far below 10⁻⁵ in current case, which is within the acceptable risk level of the staff. The most effective factors for reducing system unreliability and the main sources of risk are identified.