Window ejected flame height and heat flux along facade with air entrainment constraint by a sloping facing wall

Abstract

External building facade fires from window of under-ventilated enclosure fire poses a serious fire hazard to upper floors. This paper investigates specially the constraint effects of a sloping facing wall (similar to hillside building with a hillside slope nearby) on the external facade flame behavior, which is quite different from that with no such constraint boundaries. Experiments are carried out in a 0.4m cubic scale enclosure fire model with various window geometries and a sloping facing wall at different sloping angles from horizontal level. It is found that, the gas temperature inside the enclosure is nearly uniform both with and without sloping facing wall. The facade flame height increases with the increase in sloping wall angle, especially as it is over 60°. Non-dimensional models are proposed to correlate the flame heights with the sloping facing wall angles. The change of heat flux upon the facade with sloping facing wall angle shows similar behavior as flame height. The variation of heat flux is then found to be well accounted for by change of flame height accordingly for different sloping facing wall angles with a proposed correlation.