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Physics-Based Modeling of Community Fires.


pdf icon Physics-Based Modeling of Community Fires. (1307 K)
Evans, D. D.; Rehm, R. G.; Baker, E. S.; McPherson, E. G.; Wallace, J. B.

Volume 2;

Interflam 2004. (Interflam '04). International Interflam Conference, 10th Proceedings. Volume 2. July 5-7, 2004. Organised by Interscience Communications Ltd. in association with National Institute of Standards and Technology, Building Research Establishment; National Fire Protection Association; Society of Fire Protection Engineers; and Swedish National Testing and Research Institute, Edinburgh, Scotland, Interscience Communications Ltd., London, England, 1065-1076 pp, 2004.

Keywords:

fire science; fire safety; wildland/urban interface; fire hazard; fire models; combustion; experiments; flame height; heat release rate; weight loss; ignition; structures; forestry; algorithms

Abstract:

Physics-based modeling of fires in the wildland urban interface (WUI) is used to develop practical tools for fire hazard evaluation of landscaped properties. The approach differs from that used for wildland-fire operation models in that individual fuel elements, such as trees, shrubs, and buildings are resolved, and the ignition and burning characteristics of these fuel elements are identified separately. The model is an extension of capabilities of the widely used NIST Fire Dynamics Simulator (FDS). Burns of single dry Douglas-fir trees were conducted to measure peak heat release rates, burn durations and visible flame heights. The rise and fall in the heat release rate curve for the Douglas-fir trees is represented well by a simple triangular shape. Insights from the FDS simulations of WUI fires are used to construct a user friendly fire model that can demonstrate major effects of ignition by radiant flux. This model is being implemented in EcoSmart, a web-based software tool. It provides a method to evaluate the vulnerability of structures to ignition by considering the effects of mitigation actions, such as relocating landscape plantings, and removing the lower branches of tall trees.