This report is part of a project funded by HSE to investigate the phenomena of spontaneous ignition of accidental hydrogen releases. Over the years there have been reports of hydrogen leaks igniting for no apparent reason, and a number of potential ignition mechanisms have been proposed. Investigations of these ignitions have often been superficial, with a mechanism postulated which, whilst appearing to satisfy the conditions prevailing at the time of the release, in general does not stand up to rigorous scientific analysis. Some of these proposed mechanisms have been simulated in the laboratory under superficially identical conditions and appear to be rigorous and scientific, but the simulated conditions often do not have the same large release rates or quantities, mainly because of physical constraints of a laboratory. With the advent wide spread use of high pressure hydrogen storage for vehicles and other applications, there is a clear need to try to understand the probability of this phenomena to occur and also the physical causes of these ignitions so that design guidance can be developed. The report reviews available literature that may be of use in the experimental phase of the above project. It includes a summary of the literature previously identified on this phenomena and identifies new literature/information that could have a bearing on this project.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
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