Study on temperature distribution and smoke diffusion characteristics of cable shafts in high-rise buildings

The smoke and poisonous gas produced during combustion is one of the direct hazards of cable fire. For power cables laid vertically in the cable shaft of high-rise buildings, the chimney effect will speed up the spread and expand the harm of cable fire. The paper proposes a simulation method based on fire dynamics theory to analyze the diffusion and spread characteristics of cable fire. First, a three-dimensional model of the double-floor cable shaft with multiple cables laid vertically inside was built in the paper. Second, with the abnormal heating caused by overload or insulation breakdown as the excitation condition, the development process of cable fire is simulated. The diffusion of smoke and gas during the whole combustion process is studied and discussed. Then, the paper compares the simulation results of the model with different fire blocking materials. The simulation results show that the application of blocking materials will cause differences between the spread of fire and flue gases, and the difference can be used to evaluate the quality and performance of the fire blocking material. Finally, A test platform is constructed to verify the validity of the simulation analysis.