Ammonia and hydrogen represent opposite ends of the spectrum with regard to the potential blast loading resulting from an accidental vapor cloud explosion (VCE), although many in industry have expressed doubts as to whether either of these fuels actually pose a VCE hazard. Ammonia is some-times discounted as a VCE hazard due to the perceived difficulty in igniting an ammonia-air mixture and/or because of its low laminar burning velocity. Hydrogen is sometimes discounted as a VCE hazard due to the ease with which a hydrogen-air mixture can be ignited and/or because of its buoy-ancy.

The purpose of this guide is to assist users of codes and standards that apply to hydrogen application and use in understanding and applying the approval, certification, listing, and labeling provisions of the codes and standards, in any application where the required certification, listing, and labeling of services, methods, or equipment has not yet been established or achieved.  

VIII.6  Hydrogen Safety Panel, Safety Knowledge Tools and First Responder Training Resources

Sodium chloride and four or five other particulate materials have been used successfully as fire suppression agents for specific combustible metal fires. The certification testing and National Fire Protection Association recommendations for using these suppression agents are summarized here. The sodium chloride based agent and ordinary sand have also been used in some sodium hydride fires, and in a sodium hydride fire test series.

Large-scale deflagration and detonation experiments of hydrogen and air mixtures provide fundamental data needed to address accident scenarios and to help in the evaluation and validation of numerical models such as the AutoReaGas code (used by Mitsubishi Heavy Industries, Ltd). Several different experiments of this type were performed. Measurements included flame-front time of arrival (TOA) using ionization probes, blast pressure, heat flux, high-speed video, standard video, and infrared video.