The field of consequence modelling is highly developed and there are several softwares that are commercially available to model the discharge, dispersion, fire and explosion of gases and liquids.
The techniques fall under three categories:
Empirical models: There are based on the correlation of experimental data, and their accuracy and applicability relate to the experimental database. These models are accurate within their range of validation but should not be applied to scenarios outside the range of the underlying experimental data. Examples of empirical models for predicting gas explosion loads include Baker-Strehlow, Congestion Assessment Method and the Multi-Energy method.
Phenomenological (Integral) models: These models are more fundamentally based than the empirical models. They attempt to model, although in an approximate way, the underlying important physical processes. Their predictive accuracy will be better than that provided by the empirical models. They provide the ability to interpolate more accurately between data and to extrapolate with more certainty to situations not addressed by experimental work.
Numerical Models: These models are the most fundamentally based, in that they solve the underlying equations describing gas flow, turbulence and combustion processes. They have the potential for providing a higher predictive accuracy and a greater potential for addressing any scenario. IN practice, the accuracy is limited due to the required computing power, the accuracy of the numerical methods and the underlying physical sub-models. These models generally require a high level of user expertise.
Detailed guidance on consequence modelling can be found in the following selected references:
1) A Guide to Quantitative Risk Assessment for Offshore Installations, Spouge, J., CMPT, 1999
2) Lees’ Loss Prevention in the Process Industries, Mannan, S. (ed), 3rd edition, Elsevier Butterworth-Heinemann