Impact of façade type on an ejected flame propagation from a compartment opening - Experimental and numerical studies

International audienceA façade assembly including insulation materials as wood is currently utilized in an increasingly popular low-energy consumption type of buildings. The paper presents a combined experimental and numerical study on an ejected flame propagation from a compartment opening over two wooden facades (okoume and birch) and comparisons are made with an inert facade. It is ensured that when the compartment is no longer sufficiently supplied with fresh air, the heat feedback from an ejected fire is high enough for inducing an ignition of a wooden façade with a large contribution of the pyrolysis gases. Replacing an inert façade by a wooden one such as okoume or birch enhances heat release rate (HRR) by a factor of 60% with a rise of the peak in gas temperature by a factor of 50% at the upper layer due to flame spread. The fire development along a birch type façade seems more pronounced as compared to an okoume one with an increase in HRR by a factor of 15%. A series of numerical simulations is conducted to replicate and model the experimental façade fires in a full-scale. Focus is mainly given by comparing HRR and gas temperatures at different locations along a façade. The predicted gas temperatures are in good agreement with the experimental data only at the lower layer. An overprediction of the gas temperature by a factor of 50% is found during the decay phase of flame propagation along a wooden façade