Numerical study of effects of wind on the vertical fire spread with vertical/horizontal spandrel

Abstract

Due to the importance of preventing the vertical fire spreading along with buildings, two fire inhibition methods were raised by the National Construction Code clause [1] C2.6(a) including vertical spandrel of at least 900 mm high or horizontal spandrel of at least 1100 mm deep. This project aims to answer the research question of whether vertical spandrel of 900 mm and horizontal construction of 1100 mm are equivalent in performance in inhibiting the vertical fire spreading under the effects of wind using fire dynamics simulator (FDS) simulations. The geometry of the simulations is modified from experimental works conducted by Oleszkiewicz [2] by adding an air opening on the back wall. The preliminary results show that by slightly increasing the front wind (the wind direction is normal to the front opening of the building) from 0 m/s to 0.5 m/s, the radiation heat transfer from the flame to the above floor is increased slightly, however, further increasing the front wind speed will reduce the radiative heat flux on the above floor, due to the blocking effect of the front wind. When the front wind speed increases to above 4 m/s, the flame is blocked within the room. When the side wind (the wind direction is parallel to the front opening of the building) is introduced, there is a slight increase in heat flux for the wind speed of 1~4 m/s. Based on the preliminary simulation results, it is found that for the wind conditions, fire load and building structure investigated in the paper, the performance of the 900 mm vertical spandrel is lower than the horizontal spandrels even for the horizontal spandrel of 500 mm.