Muhandisī-i bihdāsht-i ḥirfah/ī (May 2023)
Experimental Study of the Sound Emission Pattern Based on Acoustic Characteristics in Typical Industrial Manufactories in Hamadan, Iran
Abstract
Background and Objective: Noise pollution inside buildings is caused by frequent sound reflection from their inner surfaces. The purpose of this study is to experimentally study the sound emission pattern based on acoustic characteristics in typical industrial manufactories. Materials and Methods: This study was conducted in rectangular cubic manufactories with a volume of less than 2000 m2, between 2000 to 3000, and 3000 to 4000. The space reverberation time was measured according to the ISO 3382-2-2008 standard, and the sound emission pattern in manufactories was performed according to the ISO 11690 standard. The space sound level was measured based on the distance from the source with pink noise. In order to simulate sound parameters, the radiation tracking method was used in Odeon. Data analysis was conducted using the SPSS software. Results: The average reverberation time in manufactories under 2000, between 2000-3000, and between 3000-4000 m2 was 1.75, 2.25, and 2.77 sec, respectively. The measured reverberation time had a significant correlation with the predicted reverberation time (r=0.95, P=0.05). The average sound reduction based on the distance from the source was 4, 3, and 3 dB in manufactories under 2000, between 2000-3000, and between 3000-4000 m2, respectively. There was also a negative significant correlation between the sound reduction level and the reverberation time (r=-0.97, P=0.05). The correlation between the measured and predicted sound levels was determined (r=0.95). Conclusion: Reverberation time calculated by Sabin and Eyring’s formula showed higher values than those of the measurement method. There was also a significant relationship between the average sound reduction pattern and the average time of vocalization. Therefore, measuring sound reduction based on the distance from the artificial source can be used to show the sound emission pattern, even on its own, due to the simplicity of the measurement method. It is recommended to be used with the reverberation time to evaluate the sound emission pattern in manufactories.
