A model for the fire-fighting activity of local residents in urban fires

A physics-based urban fire spread model formerly developed by the authors was refined, with the additional consideration of the effect of the fire-fighting activity of local residents. The major refinements to the existing model are as follows: (1) the effect of water discharge against individual fire-involved compartments is evaluated by incorporating suppression factors into the governing equations of the one-layer zone fire behavior model, and (2) the behavior model of the local residents involved in fire-fighting activity is developed and combined with the existing urban fire spread model. The proposed model was applied to simulate fire spread behavior in a hypothetical urban area where 121 buildings of identical configuration were aligned in a regular pattern. The effects of parameters such as the fire detection time and the number of water supplies on the fire spread behavior were tested. In addition, the proposed model was applied to investigate the fire spread behavior of the 1976 Sakata Fire. The results showed that the fire-fighting activity was effective, especially for the suppression of fire spread in the direction orthogonal to the wind. Although there were discrepancies between the simulated burnt area and the actual burnt area identified by the post-event survey, a qualitative agreement on several features of the fire spread was obtained.

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► Urban fire spread model formerly developed by the authors was refined.
► The new model considers effect of fire-fighting activity by local residents.
► The model was applied to investigate fire spread behavior of the 1976 Sakata Fire.
► Fire spread was effectively suppressed in the direction orthogonal to the wind.