Discussion on new ideas for smoke exhaust in platform public areas andtrack areas of underground stations of urban rail transit

It is proposed to adopt a new smoke exhaust scheme based on “three cancellations” and “one strengthening” in the platform public area and the track area of underground stations of urban rail transit, that is, cancelling the track heat exhaust fan, cancelling the rail top air duct, and cancelling the platform smoke exhaust air duct, and strengthening the output of the tunnel ventilation system by adding electric air valves. The smoke exhaust effect of the new smoke exhaust scheme is simulated under two working conditions of platform public area fire and train fire and stopping at platform. Smoke flow, CO concentration, temperature distribution, visibility distribution and wind speed at the escalator entrance are analysed. Through field tests, the smoke exhaust effects of the new smoke exhaust scheme, the comparative scheme and the traditional scheme are compared.The results show that the smoke exhaust effect of the new smoke exhaust scheme meets the requirements of relevant specifications under two fire conditions. Because the smoke flow direction of the new smoke exhaust scheme is single and there is no “pulling” effect between different systems, its smoke exhaust effect is significantly better than that of the comparative scheme and the traditional scheme.