Performance of smoke elimination and confinement with modified hybrid ventilation for subway station

Abstract Smoke is the element of a fire that causes the greatest loss of life. The importance of eliminating smoke is underscored in the fire safety engineering of underground subway stations. In this study, an experiment and a numerical simulation were performed to determine the efficacy of different ventilation modes. The experiment was conducted on a 1:50 scale model of a subway station and a complementary Fire Dynamics Simulator (FDS) simulation was performed on a full scale station. The influences of natural ventilation, mechanical ventilation and hybrid ventilation were examined. The results indicated that natural ventilation was good for smoke elimination when the fire source was under the dome, and the gas temperature measured in the middle of the basement 1 decreased significantly as the size of the vent increased. Smoke was exhausted from the basement 1 and fresh air supplied into the basements 2 and 3, which had the best efficacy when managing the smoke diffusion. No matter that the fire source was under the dome or out of the atrium, the carbon monoxide (CO) concentration was the smallest when the modified hybrid ventilation system was in operation. At the same time, changes in the natural ventilation vent had an influence on smoke elimination and the efficacy of smoke elimination became better with the increasing of the dimension of the vent when the fire location was under the dome.