ABSTRACT
Noise pollution is a major issue in many industries, as the sound pressure levels (SPLs) much higher than the permissible levels cause many physiological and psychological problems to the workers. Stone-crushing units generate noise levels in the range of 90–100 dB. The SPLs in the stone-crushing industry in Kannur district, Kerala, India are measured and analyzed. To see the effects of loading, the measurements are taken at three different load conditions; no load, partial load, and full load. As a mitigation effort, a noise enclosure for the operator working nearby the crushing machine is designed and fabricated. The enclosure is fabricated using a plywood that has a coating of mass-loaded vinyl (MLV). The acoustic performance of the enclosure is evaluated by simulating SPLs of the same amplitude and frequency artificially inside the laboratory. The proposed enclosure is found to reduce the noise levels at all frequencies in the range of 200–1250 Hz. A significant reduction of 20 dB is found in the frequency of 630 Hz.
