Effect of smoke screen height on smoke flow temperature profile beneath platform ceiling of subway station: An experimental investigation and scaling correlation

• Reduced-scale experiments on platform fire at subway station.
• Temperature profile along platform ceiling measured and collapsed.
• Effect of smoke screen height on temperature profile clarified and interpreted by a scaling analysis.
• A scaling correlation is proposed and well verified by the experiments.

This paper presents experimental study on the effect of smoke screen height on temperature distribution of fire-induced flow beneath platform ceiling of subway station. A reduced-scale (1:10) subway station experimental model including the lobby, platform and tunnel is developed. The temperature beneath the platform ceiling is measured by K-type thermocouples at different fire heat release rates (HRR) simulated by using a LPG gas burner for different smoke screen heights at the stairs connecting the platform and the lobby. Results show that the temperature profile can be well correlated by an exponential decay function. The temperature decays faster generally as indicated by a higher exponential power index (K  ), which increases with increase in smoke screen height or decreases with increase in HRR of the fire. Based on scaling analysis, a global formula is proposed (W+2H)1/5Q̇1/15(Z0-H)1/3, to correlate the value of K proportionally, as well verified by the experiments.