Numerical model of upward flame spread on practical wall materials

The focus of this paper is the development of a thermal, finite difference numerical model to describe one-dimensional upward flame spread on practica l wall materials. Practical materials include composite materials and those that char, in addition to clean burning, homogeneous materials. A set of e quations used in the model is developed and the methods for obtaining neces sary "fire properties" are discussed. Some of the particular features of th e model include the use of a correlation for flame heat feedback and the us e of an experimentally measured mass loss rate to incorporate the burning c haracteristics of practical materials. A comparison of the numerical predic tions with the experimental results for flame heights and temperatures are shown for Douglas fir particle board. The model correctly predicts trends b ut underpredicts the name heights and pyrolysis height in the cases tested. Two additional cases are shown for materials for which experimentally meas ured heat release rate data are used in place of the mass loss rate data. T he flame and pyrolysis height predictions are in much better agreement for these cases. Further efforts to obtain material property data that is appro priate for flame spread modeling is indicated by this work. (C) 2001 Elsevi er Science Ltd. All rights reserved.