Influence of open and closed windows on the vertical spread characteristics of fire

In order to systematically explain the spreading mechanism of vertical fire, Pyrosim software with fire dynamic modules is used to simulate the fire spreading characteristics in a five-storey residential apartment building. The vertical spread characteristics of fire, high-temperature smoke, and leap-frog behavior are analyzed by evaluating the distribution of pressure, temperature, and gas flow velocity in the studied numerical fire field. In addition, considering the possible cases of high-rise building fire in reality, the fire spreading characteristics of three different opening sequences of glass windows are given: (i) only the windows on the first floor are open; (ii) the windows are randomly opened by the high temperature of the glass; (iii) all glass windows from the first to the fifth floors are open. The simulation results show that an appropriate increase of turbulent flow in the low-level area can greatly reduce the fire temperature in the high-level area, which can provide a certain reference for the safety and design of building fire protection in the future.