Department of Occupational Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran , nilo.mrs@gmail.com
Abstract: (631 Views)
INTRODUCTION: Noise is one of the harmful factors in workplaces. The most important effect of long-term exposure to it is hearing loss and its impact on the human auditory system. This effect is understandable despite its irreversible and permanent nature. One of the easiest ways to use this adverse effect is earmuffs. Nowadays, earmuffs are used with different sound insulation. Moreover, aerogels are acoustic and thermal insulators and can be a suitable alternative to the currently used compounds.
METHODS AND MATERIALS: Three models of Iranian, Taiwanese, and American earmuffs were assembled with two models of aerogel (thickness of 5 mm and density of 120 kg/m3 as four layers and thickness of 10 mm and density of 140 kg/m3 as two layers). The noise reduction of the assembled earmuffs was investigated using an acoustic head mannequin.
RESULTS: The obtained results showed that the acoustic properties of the earmuffs assembled with aerogel pads have been improved compared to before, and this difference is significant in Iranian earmuffs. The highest reduction was observed at the frequency of 8000 Hz, which was 34.5, 42, and 47.9 dB for the two-layer assembly and 33.5, 43.1, and 46.7 for the four-layer assembly in Iranian, Taiwanese, and American earmuffs. It was also found that double-layer aerogel pads performed better than four-layer pads.
CONCLUSION: Assembling earmuffs with aerogel pads can significantly improve acoustic performance and increase the amount of noise reduction in earmuffs. Of course, using the maximum amount of sound reduction requires sufficient monitoring of their correct use and the necessary training for their regular use.
Type of Study:
Research |
Subject:
Noise Received: 2022/01/29 | Accepted: 2023/09/10 | Published: 2023/12/31