Study on emergency ventilation strategies for various fire scenarios in a double-island subway station

The double-island subway station with complex structure and dense crowds brings about serious fire safety issues. Aiming to control fire-induced smoke, numerical simulations were conducted to investigate the emergency ventilation strategies. The numerical model was validated by the reduced-scale model experiments and full-scale experiments. Various ventilation modes were compared under different fire scenarios and platform screen door (PSD) types. The results demonstrated that a reasonable co-work mode of ventilation system was vitally important in preventing smoke dispersion and reducing pollutant concentration. Opening the screen doors was found to be conducive to the joint ventilation in the platform and tunnel under the type of full-height PSD, whereas whether opening the half-height PSD had little influence on ventilation effect. On this basis, the optimal ventilation modes were developed respectively for platform fire, fire inside the carriage and carriage fire, among which the best control measurement for carriage fire was related with the location of the train. Additionally, a reasonable optimization of the ventilation system could further improve the safe environment. This work could provide guidance for emergency response under sudden fire accident, and provide reference for engineer design of ventilation system in the metro stations.