Industrial noise monitoring using noise mapping technique: a case study on a concrete block-making factory

Noise mapping can be effective in visualizing and monitoring noise pollution levels in industrial facilities. Therefore, this study aims to measure the occupational noise at a concrete block-making factory, create hazard noise maps, assess the potential impact on employees, and to suggest appropriate Hearing-Loss Prevention Program. The noise levels at 42-mesh points distributed over all the production area are measured using a sound level meter, then Geostatistics technique is used to generate temporary noise contour maps. The daily noise dose and Time-Weighted Average noise levels are calculated. The results revealed that the Time-Weighted Average noise level at all points, based on 8-h exposure, is higher than the Recommended Exposure Limit of 85 dBA set by NIOSH. Moreover, the daily noise dose is extremely higher than 100%. Based on the results of this work, a Hearing-Loss Prevention Program is suggested, where short-term and long-term circulations of workers are advised. Additionally, it is found that, if the employees wear earplugs with Noise Reduction Ratings of 31 dB everywhere in the production area, their daily noise dose can be kept within the safe limit; however, employees working in the control room and close to the noise source are required to wear dual hearing protection device to further reduce their daily noise dose over 8-h noise exposure. The results from this case study confirmed that noise mapping can provide decision-makers with the necessary information to control and maintain safe noise exposure levels in any manufacturing plant.