noise source. path of propagation. reduce the strength. impede the acoustic energy along its transmission path. Noise Control (A System Approach). protect the individual at the receiving end from exposure to the noise. individual receiving the noise. Principle:
path of propagation
reduce the strength
impede the acoustic energy along its transmission path
Noise Control(A System Approach)
protect the individual at the receiving end from exposure to the noise
individual receiving the noise
Noise Control starts at Planning Stage
1.Noisy operations should be grouped in one area. (Why?)
2.The machines purchased should be those with low noise output.
3.Noisy areas where workers spend time should have adequate sound absorption materials on the ceiling and the walls.
4.Noisy equipment should be fastened on a rigid and heavy base with adequate isolating elements to avoid propagation of vibration.
5.Noise sources (machines) should be enclosed with structures which supply adequate sound insulation.
6.Offices and other places where mental work is carried out should be situated far from the noise source. The intervening rooms, which will act as buffers, should be used for parking, stores etc. .
Attenuation during transmission
RELATIONSHIP BETWEEN NOISE LEVELS AND EXPOSURE DURATION
Noise level (LAeq,T) dB(A) Time to reach noise exposure (LAeq,8h) of 85 dB(A)
85 8.0 hours
86 6.4 hours
87 5.1 hours
88 4.0 hours
89 3.2 hours
90 2.5 hours
91 2.0 hours
92 1.6 hours
93 1.3 hours
94 1.0 hour
95 48 min
96 38 min
97 30 min
98 24 min
99 19 min
Mild Hearing Loss
Moderate Hearing Loss
Severe Hearing Loss
Profound Hearing Loss