bs sponge private limited - India Environment Portal

B.S. SPONGE PRIVATE LIMITED
Village: Taraimal, Tehsil: Gharghoda, District: Raigarh, (C.G.)
REIA Report for the Proposed Mini Integrated Steel Plant
Chapter – 3
3.2.1.1 Background noise
Baseline noise data has been measured at different locations using A-weighted sound
pressure level meter. The equivalent day-night noise levels in the study zone are ranging
from 44.10 dBA to 51.65 dBA.
3.2.1.2 Sources of noise
Typical considerations in environmental noise assessment can be divided into two
categories, one is related to noise sources and the other related to potential receiver.
Two quantities are needed to describe completely the strength of the source. They are
sound Power level and directivity. Sound Power levels measures the total sound Power
radiated by the source in all directions where as directivity is a measure of difference in
radiation with direction. This concept of sound Power level and directivity index makes it
possible to calculate the sound pressure level created by the source.
3.2.2 Community noise
The ambient noise level is characterized by significant variations above a base or a
residual noise level. The residual noise level is that level below which the ambient noise
does not seem to drop during a given time interval and is generally caused by the
unidentified distant sources. It differs in rural and urban areas. At night, its level is low
due to lesser elements of noise. The annoyance that people experience depends upon the
number of noise elements that produce noise concurrently at a given time that occur
during a time interval.
The noise rating developed by EPA for specification of community noise from all
sources is the day night sound level, Ldn. It is similar to a 24 hour equivalent sound level
except that during the night period, which extends from 09.00 p.m. to 6.00 a.m. A 10
PIONEER ENVIRO 3 - 11 Environmental Impact Assessment Report
Laboratories & Consultants Pvt. Ltd.