Owner/operators of chemical processing and petroleum refining sites often ask whether unconfined hydrogen vapor cloud explosions (VCEs) can actually occur. This question normally arises during the course of a consequence-based facility siting study (FSS) or a quantitative risk assessment (QRA). While it is generally recognized that a hydrogen release within a process enclosure could lead to an explosion, the potential for an external hydrogen release to cause a VCE is not as widely recognized and is often questioned.

VIII.8  Hydrogen Safety Panel and Hydrogen Safety Knowledge Tools

AS THE WORLD SEEKS TO IDENTIFY alternative energy sources, hydrogen-powered fuel cells offer a broad range of benefits for the environment, the economy, and energy security. Hydrogen fuel cells have the potential to replace the internal combustion engine and to provide power in a wide range of stationary and portable applications.

VIII.10  Hydrogen Safety Panel

The Hydrogen Safety Panel was tasked with conducting work under the project “Hydrogen Safety Panel Review of Department of Energy’s Fuel Cell Projects,” through memorandum purchase order DCO-0-40618-01 with the National Renewable Energy Laboratory using American Recovery and Reinvestment Act (ARRA) funding.  Panel members reviewed project safety plans, conducted safety review site visits for selected projects, and prepared safety evaluation reports for the sites visited that included safety recommendations for the project teams.

It has been suggested that separation or safety distances for pressurised hydrogen storage can be reduced by the inclusion of walls or barriers between the hydrogen storage and vulnerable plant or other items. Various NFPA codes [1] suggest the use of 60
inclined fire barriers for protection against jet flames in preference to vertical ones. Work by Sandia National Laboratories [2] included experiments and modeling aimed at characterisation of the effectiveness of barrier walls at reducing hazards.