evacuation, hazards, subway stations
Underground subway system is the key transportation means in dense urban areas such as Hong Kong. Subway stations are crowded with passengers on the platforms and they are observed to squeeze into the train carriages during rush hours. Putting in platform screen doors made the situation even worse. As reported in the local news, subway management claims that after following the change in maximum capacity from six passengers per meter square to four passengers per meter square, the capacity is only 70% full at rush hours. However, the capacity can be over 90% of full loading under the new calculation. Subway stations become more crowded with an average weekday patronage of nearly 5.3 million passengers. Â Subway stations are mostly located in the basement or ground levels connecting the shopping mall, commercial or residential building in downtown areas. The occupancy density of passengers can be much higher than expected during festivals with fireworks show and during large-scale movements such as Occupy Central. Therefore, evacuation time in emergency situation will be prolonged. To have a better understanding of the safety issue in subway stations, evacuation time in emergency situations will be studied in this paper. Â Two subway stations, Station A and Station B are selected in this paper to study the evacuation hazard of crowded stations when a fire occurs. Station A is an interchange station between two railway lines, being one of the most crowded stations with high occupancy density. Station B is the first station in the local rail network to feature a special design - â€œLift-only Entrancesâ€. This is a deep underground station which lies under 70 m of ground level, the passengers have to be evacuated by lift. The occupancy density in Station B is relatively much lower than Station A under normal conditions at the moment, though the station can be very crowded if there are train delays due to signal failure or other reasons. Â In this paper, the evacuation effectiveness of Station A and Station B are estimated in terms of evacuation time in different scenarios by using Hydraulic Model Calculation. Moreover, the special evacuation feature of â€œLift-only Entrancesâ€ in Station B and the fire safety management strategies for emergency evacuation will be discussed.Â Â Three scenarios will be studied in each station: Â Scenario A: Assume that the passengers are evenly distributed in different exits in emergency situation. All the possible factors such as passenger behaviors and conditions are eliminated. Â Scenario B: Passengers have a higher tendency to evacuate at the larger exit, this is one of the passenger behaviors in emergency situation. Therefore, the passenger distribution which depends on the exit width will be studied. Â Scenario C: Assume that some of the exit routes are blocked. Â The most important factor for the above study is the passenger behaviors. As in scenario B, passenger behaviors would affect the evacuation time. Therefore, fire safety management is identified to be a key part in keeping efficient evacuation. For example, a good fire action plan on crowd control is needed.