Determination of the Equivalent Continuous Sound Level (Leq) in Industrial Indoor Space Using GIS-based Noise Mapping

Background: The present study aimed to replace the integrated sound level meter by the noise map of a work environment in order to estimate the equivalent continuous sound level (Leq) as an important quantity in the noise monitoring of continuous noise sources. Methods: In this theoretical-experimental study, the grid method was initially used. Sound pressure level (SPL) was measured at the selected stations in three noisy industrial halls. Data analysis was performed in ArcGIS 10.2 software, and the noise map was plotted for each hall separately. Afterwards, the different zones with various SPL intervals were calculated on each noise map, and Leq was determined. For the comparisons, Leq was also calculated using logarithmic equations, based on which the integrated sound level meters were programmed. Results: The proposed method was highly accurate with the relative error of less than 2%. Furthermore, it decreased the number of mathematical operations 7-15 times compared to the conventional logarithmic method. Conclusion: According to the results, the available GIS-based software could be accurately replaced by the routine Leq measurement hardware to estimate the Leq spatial noise in noisy industrial environments.