Noise Control in Granite Stone Slicing Factory

Abstract

Generally, the noise levels in Granite stone slicing factory are relatively higher than theaccepted limits for occupational noise exposure. This study aimed to determine suitable andpractical methods for controlling noise pollution in the factory. Three controlled areas were studied;(1) control at the noise source by reducing a vibration and friction of stone slicing machine; (2)control at the sound conduction pathway by installing a wall between the machine and worker; and(3) control at the receiver by using a personal ear plug or ear muff. All methods were evaluated bymeasuring the noise level before and after the implementation. Additionally, the satisfactionquestionnaire was also used for the evaluation. It was found that the average and maximum noiselevels of the Granite stone slicing factory at 5 working positions were ranging from 86.7-102 dB-Aand 88.5-103.5 dB-A, respectively. Most of the noise levels were higher than 90 dB-A which is thestandard occupational noise exposure for 8 hours per day from Ministry of Interior. The implementationsindicated that in order to conserve a hearing of workers by keeping the exposure below 90 dB-A, acooperative method between control noise at the source and the receiver was required to implement.Moreover, both methods were suitable and practical for the factory to perform with the level ofsatisfaction ranging from high to very high (3.24). Although the second method could reduce thenoise levels about 6.7-7.8 dB-A, but there were some limitation for using this method thus the level ofsatisfaction was ranging from moderate to high (2.88). The hearing test demonstrated that 40% ofthe workers were susceptibility to noise induced hearing loss at the noise frequency between 3,000-8,000 Hz. In addition to controlling the noise at the source and at the receiver is strictly undertaken,the administrative noise control by assigning the workers to work in a quieter area is also recommended.

Keywords : Noise Pollution / Granite Stone Slicing Factory / Hearing Conservation