1996 Volume 34 Issue 1 Pages 45-50
A modest assessment of noise was made in Calcutta Metro, India's first ever underground tube rail system, to examine if the range of noise levels present could endanger the hearing sensitivity of workers for the Metro. Sound measuring instruments of a sound level meter, an octave band analyzer, and a sound level calibrator were used for measuring the sound pressure levels in platforms of three stations: Esplanade, Kalighat and Tollygunge. The results indicated that the averaged A-weighted SPLs in these stations were in the range of 84-87dBA. In the coaches of the moving train the Leq values ranged 92-99dBA and LNP 105-117dBA, all exceeding the safe limit of day time noise exposure of 55dBA5) and 85dBA of ACGIH4). The SPLs at 4, 000Hz in the coaches were also in excess of safe exposure limit of 79dB6). The findings thus posed a potential threat to the workers.