Open AccessNoise Attenuation of Earplugs as Measured by hREAT and F‐MIRE Methods in a Japanese Metal Manufacturing Plant
Author(s) -
Kabe Isamu,
Kochi Takeshi,
Tsuruoka Hiroko,
Tonegawa Toyoko,
Denda Ikuo,
ogi Mari,
Tsuiki Hirokazu,
Mizoue Tetsuya,
Tanaka Shigeru
Publication year - 2012
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1539/joh.11-0217-fs
Subject(s) - mire , attenuation , noise (video) , absolute threshold of hearing , audiology , materials science , physics , hearing loss , medicine , optics , geography , archaeology , artificial intelligence , computer science , image (mathematics) , peat
Noise Attenuation of Earplugs as Measured by hREAT and F‐MIRE Methods in a Japanese Metal Manufacturing Plant: Isamu KABE, et al . Furukawa Electric Corporation—Objective The aim of this study was to compare the noise attenuation (NA) properties of earplugs by using the headphone‐based real‐ear‐attenuation‐at‐threshold (hREAT) and field microphone‐in‐real‐ear (F‐MIRE) techniques. Methods The subjects were 89 male workers (mean age: 44.8 ± 12.1 yr) exposed to noise above 85 dBA (mean noise exposure period: 14.3 ± 11.3 yr) in a Japanese nonferrous metal manufacturing plant. They were confirmed to have pure‐tone air‐conduction hearing threshold levels (HTLs). The hREAT and F‐MIRE NA values were measured by a Rion AG‐20A and a 3M E‐A‐Rfit, respectively. Results The NA values could not be measured by hREAT for four workers (hREAT– group). The mean NA of the earplugs for subjects for whom hREAT measurements were possible (hREAT+ group) was 26.0 ± 10.0 dB. The NA of the earplugs could be measured for all subjects using F‐MIRE, and the NAs of the hREAT– and hREAT+ groups were 9.5 ± 8.7 and 21.0 ± 7.3 dB. The mean HTL value at 500 Hz to 2 kHz was 45.8 ± 3.1 dB for the hREAT– group, which was significantly lower than the value for the hREAT+ group, 18.0 ± 8.6 dB. Conclusion Because there is a difference between the NA values obtained by hREAT and F‐MIRE, it may be necessary to compensate for this difference. In addition, workers with hearing loss and the length of the measurement time need to be taken into consideration. Finally, the F‐MIRE method may be useful for educating workers about using earplugs in noisy workplaces.