Experimental study of noise emission pattern based on acoustic characteristics in typical industrial manufactorys in Hamadan

Noise pollution inside buildings is caused by sound reflection from  internal surfaces. The purpose of the study is to experimentally study the sound emission pattern based on acoustic characteristics in industrial manufactorys.

In manufactorys, rectangular cubes with a volume of less than 2000 cubic meters, between 2000 to 3000 and 3000 to 4000 were made. The reverberation time measurement was based on ISO 2-3382:2008 and the sound emission pattern was measured according to ISO 11690 and the sound level was measured with pink noise. In order to simulate sound parameters, radiation tracking was used in Odeon. Data analysis was done with Spss.

The average reverberation time in manufactorys under 2000, between 2000-3000 and between 3000-4000 cubic meters was 1.75, 2.25 and 2.77 seconds , the measured reverberation time had a significant correlation with the predicted one (r=0.95). The average sound reduction with the distance from the source is 4, 3 and 3 dB, the correlation coefficient between the sound reduction level and the reverberation time (r=-0.97), the correlation between the measured and predicted sound level(r=0.95) was determined.

The reverberation time of the Sabin and Eyring showed higher values than the measurement method. There was a significant relationship between the average noise reduction pattern and the reverbration time. simplicity of the measurement method, the sound reduction criterion can be a good criterion to show the sound emission pattern. It should be used together with the reverberation time to evaluate the sound emission pattern in the manufactorys.