On defining a safety criterion for flammable clouds
The question is investigated of whether Lower Flammable Limit or a half of that concentration should be used as the criterion in safety analyses. Relevant experimental data, model concepts, and theoretical ideas are reviewed, and the imprecision of the question is highlighted. The opinion formed in this paper is that requiring the instantaneous centre-line concentration to be less than half the lower flammable limit is reasonable, and that relaxing this criterion would involve some risk.
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 author(s) alone and do not necessarily reflect HSE policy