“The analysis of the dispersion and spreading of potential accidental gas phase releases is useful when developing emergency response plans and as a part of process hazard analysis. It is also a useful tool when assessing the need to prevent these releases and in evaluating proposed mitigation strategies. Estimating and understanding the process requires some knowledge of source behavior, the mechanics of atmospheric transport and dispersion, the congestion of the area into which the release occurs and the geography of the surrounding area.
In a given analysis, parameters governing the release scenario and the environment need to be defined; these include a source definition, definition of ambient conditions, release types, and possible release scenarios.
Adapted from reference: Center for Chemical Process Safety. (1995). Understanding Atmospheric Dispersion of Accidental Releases – 1.2 Release/Dispersion Scenario Overview. Center for Chemical Process Safety/AIChE
“A leak of gas can be very hazardous. If the gas is flammable, a major fire or explosion can ensue; if the gas is toxic, workers may be overcome.
The study of dispersed gas behavior has two major components. The first is to determine concentrations of gas downwind of the release point. These concentrations will depend on a plethora of factors such as the density of the gas, the amount released, weather conditions, and the roughness of the ground surface. The second part of the gas modeling has to do with the effect of the gas on the human body.”
Adapted from reference: Sutton, Ian. (2012). Offshore Safety Management – Implementing a SEMS Program – 7.12 Gas Dispersion Analysis