The ever-increasing use of hydrogen in the transport sector requires very high safety standards. However, due to the lack of information regarding the safety level of hydrogen systems, risk assessments tend to be over cautious in determining the consequences of accidental releases and could impose restrictive technical regulations.

This drove the National Institute of Industrial Environment and Risks (INERIS) along with the French Atomic Energy Commission (CEA), the French automotive manufacturer PSA PEUGEOT CITROËN and the Research Institute on Unstable Phenomena (IRPHE) to submit with success a project called DRIVE (Experimental Data for the Evaluation of Hydrogen Risks, for the validation of numerical tools and for the Edition of guidelines) to the National Research Agency in June 2005. This project aims at providing quantitative experimental data for automotive applications to strengthen the risk assessments. The work program of DRIVE covers all aspects of the accidental chain: hydrogen releases, formation of an explosive atmosphere (ATEX), ignition of the ATEX, flame propagation and its consequences. State-of-the-art risk assessment and mitigation techniques are also considered.

After a brief description of the DRIVE project, this paper will present the available results dealing more particularly with the leak quantification of hydrogen components, the hydrogen dispersion in free and confined spaces and the characterisation of hydrogen jet fires issuing from high-pressure sources (up to 900 bars).