Muhandisī-i bihdāsht-i ḥirfah/ī (Nov 2020)
Evaluation of Environmental Noise Control at a Press Workshop of a Metal Structure Factory using the ISO 11690 Method
Abstract
Background and Objective: Noise absorber is considered the main method for noise control in propagation path. This study aimed to evaluate the effectiveness of environmental noise control using noise absorbers at a press workshop based on the recommended ISO 11690 method. Materials and Methods: This experimental study was performed at a press workshop of a metal structure company. The environmental noise control was established by the installation of a metal mesh using perforated gypsum tiles with a layer of stone wool at the ceiling. Afterward, the evaluation was conducted based on the ISO 11690 method which included the determination of the rate of noise reduction measurement from an omnidirectional source based on the distance doubling. Moreover, the noise level was measured at the defined distance from an artificial noise source along with the length of the workshop. Results: The environmental noise was reduced approximately (3 to 4 dB) after the installation of an acoustic ceiling. Furthermore, the environmental noise reduction was considerable at the frequency spectrum of 2000 Hz, 4000 Hz, and 8000 Hz. At the press workshop, the noise was reduced 4 dB based on the distance doubling from an omnidirectional source indicating a reduction in the surface noise reflections of the press workshop Conclusion: The efficiency of the environmental noise control was determined at high accuracy using noise reduction curve from an omnidirectional source, comparison of the results with the recommended optimal conditions, and sound propagation pattern in the free field of the sound.
