Principles adopted for the design of tunnel ventilation and environmental control system in Delhi Metro

摘要

Delhi is planning to commission its first underground Mass Rail Transit System (MRTS) by March 2005. The city experiences extreme variations in its climate. The temperature varies from around 0 degree C in winter up to 47 degree C in summer along with wide changes in humidity levels. The conceptual design of Environmental Control System has to consider such varied weather conditions so as to ensure acceptable environment conditions for the travelling passengers during all the seasons. The fire and life safety of the patrons also needs to be given adequate importance by designing efficient smoke extraction system within station areas and also for the tunnels. This paper describes the basic objectives and the principles adopted for the design of Tunnel Ventilation (TVS) and Environment Control System (ECS) for the Delhi Metro Rail Transit project. For this project different concepts of tunnel ventilation system and ECS were examined in detail. After considering the techno-economic viability of different systems; the users and their culture, the need for safe evacuation in case of fire emergencies and guidelines of the National Fire Protection Association, USA (NFPA) (4) in general, it has been concluded to adopt the 'Closed System' for tunnel ventilation along with air-conditioning of the station areas and the coaches. The system shall also have provisions for modification on to Platform Screen Door (PSD) system in future. The influence of various parameters in the proposed system are also discussed.