A comparison of three models for the simulation of accidental fires

Assumptions made and results obtained when applying three fire modeling approaches to study three accidental fires that occurred in single-family dwellings are presented in this article. The modeling approaches used are: a simplified analytical model of fire growth, a zone model (CFAST), and a field model (FDS). The fires predicted are: a house fire of suspected initial location but of unknown ignition source, a small-apartment fire initiated by the ignition of a sofa, which extinguished due to oxygen depletion, and a one-story house fire started by a malfunctioning gas heater. The input to each model has been kept as independent as possible from the other models while consistent with the forensic evidence. The predictions from the models of the fires' characteristics are analyzed in the context of the forensic evidence for each accidental fire to compare the models' predictive capabilities. It is found that in spite of the differences in the sophistication of these three modeling approaches, the results are in relatively good agreement, particularly in the early stages of the fire. Simpler models can be used as a first step towards less approximate modeling or to confirm the order of magnitude of the results from more complex models. The results of this study can be used to reach conclusions about the complexity of the model required to describe a particular fire scenario.