Post-crash fuel leakage and fire safety experiments for hydrogen vehicles

  • Published: U.S. National Highway Traffic Safety Administration (NHTSA), Paper Number 11-0439, 2011
  • Authors: Hennessey, B., Reuther, J.J., John, J.S., Shawcross, P.E., & Kimmel, G.
  • Date Added: 06 Feb 2014
  • Last Update: 06 Feb 2014
  • Format: pdf


To access the safety of the proposed allowable leak rate for hydrogen, through leak ignition experiments in and around vehicles and vehicle compartment simulators.


Experiments: Leak rate vs. concentration build-up in and around an intact automobile; Ignition and combustion tests in an automobile compartment simulator containing known concentrations of hydrogen; full-scale leak, ignition and fire tests on intact and crashed automobiles.

Key Findings:

  • Data indicated that leak rate was not the most important metric when identifying minimum allowable post-crash leak rate.

  • Instead, the volume of hydrogen leaked into the automobile compartments to accumulate locally to 5%, or to a level exceeding the lower flammability limit of 4% is important.

  • All accumulation of hydrogen within passenger compartments should be avoided.

  • More than one sensor in vehicle compartments may be required for alarm purposes.

  • Vehicles that vent passenger compartments upon impact are warranted.Flammability tests on fabrics exposed to hydrogen or hydrogen flames may have merit.


Post-crash, fire, hydrogen vehicles.


Hydrogen vehicle experiments.