Flame Extension Length Beneath an Inclined Eave Induced By Facade Fire Plume

The inclined eave above a window is a common building structure in real life, and the building facade fire plume extension below an inclined eave is an important danger source, which might ignite the adjacent rooms through thermal impact. While, few researches focus on the physical mechanism of this extension behavior. This paper experimentally studied fire plume extension under an inclined eave ejected from compartment fires. The small-scale compartment with a facade wall and an eave wall were applied in the experiment, in which the eave height and inclination angle could be adjusted. Results show that: (1) The upstream flame extension length increases as the eave inclination angle increases due to the enhancement of momentum by buoyancy. The downstream flame extension length decreases as the eave inclination angle increases due to the weakening of momentum caused by buoyancy, and is lower than the upstream flame extension length. (2) Through momentum and energy analysis, the heat release rate of upstream flame is greater than that of the downstream flame, and this difference increases with the increase of the eave inclination angle. (3) The flame extension behavior was revealed, and the prediction models were developed which characterizes the effect of eave inclination angle (0–20°) and the extension flame heat release rate, and through which the two flame extension lengths were well represented.