Three Tier Tunnel Ventilation System

摘要

Delhi Metro is the world's 8th longest metro system and India's first modern public transportation system built on state of the art technologies. The present network is of 347.6 kilometers (216 miles) with 253 stations including 66 underground stations. The typical length of an underground stations box is approximately 265 meter (869 feet) for 6 car train in different phases of MRTS construction in Delhi. This paper presents an optimization initiative that was taken at Ashram underground station of Line-7 of Phase-Ⅲ, where the station box was originally planned with 266 meter (873 feet) length with a depth of 20.7 meter (68 feet). The land of entire station box could not be acquired because of legal issues and thereafter, it was planned to accommodate the station box within 151 meter (495 feet) length only with same depth of 20.7 meter (68 feet). The same was achieved by segregating the Environmental Control System (ECS) rooms, Tunnel Ventilation System (TVS) rooms and Auxiliary Sub Station (ASS) rooms, which occupy the maximum area in the station, as a non-typical arrangement in concourse and mezzanine levels of the station. This paper presents the details of an unique Tunnel Ventilation System installed perpendicular to the longitudinal axis of the station. The Tunnel Ventilation Fans are provided at Concourse and Mezzanine levels and the nozzles are provided at the Platform Level. The overall TVS was provided in three tier arrangement with vertical plenums on each side of the station which leads to the reduction in length of the overall station box. The layout of the 3-tier TVS along with different mode of operation has been explained in detail. The simulation studies conducted and the actual field testing and commissioning data after implementation are also presented in the paper.