How domes improve fire safety in subway stations

Abstract

A dome is an architectural structure shaped like the hollow upper half of a sphere. Domes are widely used in subway stations to reduce the sense of oppression felt by people in underground spaces. This paper presents an analysis of the effect of domes on fire-induced smoke control in subway stations. The computational fluid dynamics method of large eddy simulation was used in the analysis. Four different grid systems were compared, and a sensitivity analysis of the model constants was performed. Different values of the Schmidt number and Prandtl number were tested, and values of 0.3 and 0.4, respectively, were adopted. The confluence, storage, and suppression effects of domes on fire-induced smoke were analyzed.The preliminary results obtained suggest that the carbon monoxide (CO) concentration in the hall of a subway station is significant lower when the fire source is located under the dome. For a subway station without a dome, there is a linear relationship between the average CO concentration and the distance from the coordinate origin. The correlation coefficient (R) for this linear relationship is 0.9957. For a subway station with a dome, there is a first-order exponential decay relationship between the average CO concentration and the distance from the coordinate origin, and the R of this relationship is 0.9988.