FLAME HEAT TRANSFER CORRELATIONS AND CONCURRENT FLAME SPREAD IN A CEILING FIRE

Abstract

Flame length and flame heat transfer were measured on one-dimensional horizontal ceiling confined with two water-cooled parallel soffits by using a porous line burner simulating ceiling fires. Correlations with heat release rate are derived for the flame length and the flame heat transfer. Flame spread tests were then made with the medium density fiberboard (MDF) lined along the ceiling of the same trench apparatus and exposed to upward electric heaters simulating the heating by the hot gas layer. Analysis of the test results suggests that flame spread in ceiling configuration is dominated by the preheating of the unburnt surface rather than by the augmentation of the heat release and is not sensitive to pilot flame intensity. Applicability of the linearized flame spread theory for ceiling fires is examined using the test data.