Hydrogen Related Risks Within a Private Garage - Concentration Measurements in a Realistic Full Scale Experimental Facility-Paper

Next generation of hydrogen energy based vehicles is expected to come into widespread use in the
near future. Various topics related to hydrogen including, production, storage, and application of
hydrogen as an energy carrier, have become subjects of discussion in the framework of various
European and International projects. Safety information is vital to support the successful introduction
into mainstream and public acceptance of hydrogen as an energy carrier. One of such issues, which is
seeking major attention is related to hydrogen powered vehicles parked inside a confined area (such as
in a private garage). It is of utmost importance to predict, if uncontrolled release of hydrogen from a
vehicle parked inside a confined area can create an explosive atmosphere. Subsequently, how the
preventive measures can be implied to control these explosive atmospheres, if present inside a
confined area? There is a little guidance currently developed for confined areas accommodating
hydrogen fuelled vehicles. It is essential that mitigation measures for such conditions become
established.
Characterization of different scenarios those may arise in a real situation from hydrogen fuelled
vehicle parked inside a garage and furthermore, the investigation of an optimal ventilation rate for
hydrogen risk mitigation are some of the main objectives described in the framework of the present
study. This work is an effort to provide detail experimental information?s in view of establishing
guidelines for hydrogen powered vehicles parked inside a private garage. The present work is
developed in the framework of a European Network of Excellence HySafe and French project DRIVE.
Present paper describes a purpose built realistic Garage test facility at CEA to study the dispersion of
hydrogen leakage. The studied test cases evaluate the influence of injected volumes of hydrogen and
the initial conditions at the leakage source on the dispersion and mixing characteristics inside the free
volume of the unventilated garage. The mixing process and build-up of hydrogen concentration is
measured for the duration of 24 hours. Due to safety reasons, helium gas is used to simulate the
hydrogen dispersion characteristics.
Key words : Garage, Hydrogen safety, Concentration measurements, flow regimes.