The FDS (Fire Dynamics Simulator) version 1.0 model has been exercised to show reasonable agreement between theory and experiments in the prediction of flammable concentrations in simple enclosures and open areas resulting from the release of typical fuel gases. FDS predictions for low level leaks of process chemicals behaved as anticipated, and plume centerline concentration follows the analytically predicted inverse of distance (1/r) attenuation relation, except in the near field where the effect of obstructions is expected. While the results are quite promising, additional validation is necessary for a number of other applications. Suggestions for continued validation include:

1. Comparison of a single room model results with more experimental data from different room sizes of more complex shapes and different levels of infiltration (It is clear from our attempt at model validation that experiments with sufficient detail are necessary to produce meaningful results)

2. Comparison of model results of a turbulent leak source with corresponding experiments (cases considered thus far are fairly gentle leak inflows)

3. Comparison of multi-room model results with corresponding experiments

4. Comparison of liquid fuel spill model results with corresponding experiments

5. Comparison of an outdoor model results with corresponding experiments

6. Comparison of various model results with that of an established CFD model such as FLUENT.

This type of modeling should help to make great strides in our understanding of explosion hazards by improving our knowledge of the way that a leaking fuel gas mixes with air and distributes itself across an enclosed or open space. The effects of a...