Hydrogen is currently regarded as an energy carrier for the future, and power generation using fuel cells is a promising technology for next generation vehicles due to their efficiency and zero emissions. Inside the project ?H2 Filiera Idrogeno? funded by ?Regione Toscana?, a hydrogen power propulsion system will be installed on a light commercial vehicle based on the Piaggio Porter van. A risk analysis is a primary element in assessing the safety of a new technology, and one of the essential stages is the evaluation of event consequences. A key component of a risk analysis of a hydrogen system is developing an understanding of the behaviour of fuel releases in realistic scenarios. Such knowledge allows the development of measure to minimize the probability of an accident, and of methods to mitigate the consequences if an accident should occur. In this work the study of different paths for hydrogen released from the system to reach the interior of the vehicle had been carried out and experimental tests had been made to investigate realistic release scenarios.