Simulation Study Of Inhibition Effect Of Fire Overhangs On Typical Building Facade Material Flame Spread

With the rapid development of urbanization, the number of urban high-rise buildings showed rapid growth trend. High-rise building can not only greatly improve the utilization of land, but also can make the population relatively concentrated so as to improve work efficiency, but it also brings a lot of other issues, for example, as building height increases, fire hazard increases, the difficulty of fire safety design also increases, and the current organic external insulation materials and decorative materials widely used in high-rise buildings also increase their fire risk greatly. Thus it will cause serious damage to property and casualties once the fire. Fire overhangs is one of the most commonly used control facility for a barrier facade vertical fire spread on high-rise buildings, therefore, to explore fire suppression mechanism of the fire overhangs on typical vertical wall building materials play an important role in the development of the method of the fire overhangs suppressing building facade fire spread.To understand the phenomenon of typical building facade material flame spread, this work did some research on the influence of fire overhangs on typical building exterior materials of fire spread upward by computer numerical simulation, revealing fire spread upward barrier mechanism of fire overhangs on the building exterior materials for building facades, developping the method of fire overhangs suppressing building facade fire spread, providing a theoretical basis and technical support for the external walls of high-rise building fire protection design. The specific research work focuses are as follow:Reserch on the influence of size and location of overhangs on typical building exterior materials fire spread upward. The numerical simulation model of the fire overhangs suppressing building facade fire spread was established. Under the same conditions of combustible materials, a series of numerical simulation experiment was studies by changing the length, width and position of the overhangs, the results showed that when the overhangs length was greater than the critical length, with the increase of the length of the overhangs, the overhangs width of the critical point decreased rapidly at first, then come to a critical point and kept constantly; With the increasing of the distance from the bottom edge of the fire to th overhangs, the effective flame arrester of fire overhangs gradually increased, that is to say the overhangs height lower, the fire resistance better; Obtained non-dimensional model of overhangs length and width with the heat release rate by numerical simulation results.Reserch on the relationship between the size of critical overhangs with the size of typical building facade materials. By changing the size of materials on fire, through numerical simulation experiment results, the length and width of critical overhangs under different conditions was obtained. Fitting determined the relationship between the critical overhangs length with materials on fire was a linear, the relationship between the critical overhangs width with materials on fire was quadratic polynomial; and the calculated empirical formula was obtained, the numerical relationship between critical overhangs size with materials on fire was established and validated.