(423e) Determination of Ignition Probabilities for LNG Spills

An accidental release of liquefied natural gas (LNG) can lead to the formation of a liquid pool & vapor cloud, which can ignite in the presence of ignition sources.  The determination of ignition probability for LNG spills is an important part of quantitative risk analysis to understand the risk people may be exposed to. This paper deals with a review of the models that are currently applied in industry & provides a novel methodology to determine ignition probability. The new ignition probability model takes into account meteorological factors like wind direction, wind class & congestion level, in addition to factors affecting ignition probability which include mass flow rate of flammable materials, its reactivity & the number of ignition sources. An illustrative case study of an LNG setup present at the Brayton Fire Training Field in College Station, Texas is used for calculation of ignition probabilities. A sensitivity analysis is also performed on the new parameters that are involved in the ignition probability calculation. The estimation of ignition probability involves both qualitative identification of sources and its quantification, the results of which can be applied to risk analysis of LNG facilities.