The investigation of explosions involving fuel gases and air can be quite simple at times, where an origin may be obvious and the cause may be as simple as an open fitting on a gas pipe being close to a pilot light on an appliance. In may other cases the investigation may be complex in that evidence may have been destroyed or scattered over an extremely large area. Fuels and oxidizers involved may or may not be easily identified. The fuel gases involved are often dissipated before any investigators are on the scene. The explosion origin may be difficult to isolate due to a lack of explosion seating. Propagation patterns may be lacking or conflicting due to the complexities of blast wave reflections. Ignition sources may be extremely difficult to identify, due to problems in establishing the origin, or perhaps in sorting out the source from a plethora of viable sources. Thus, analytical tools are sorely needed to assist the engineering investigator in the conduct of such a complex investigation.

A recent paper by Mniszewski and Campbell tabulated a number of analytical tools to assist in the investigation of fuel releases resulting in explosion ^[1]. This current paper adds to those tools a promising new technique derived from available fire models, which allows one to determine the way leaking gas mixes with air and how that mixture distributes itself throughout a building or open area. While the thrust of this paper is related to investigation, the technique also...