Individual Fit Testing of Hearing-Protection Devices Based on Microphones in Real Ears among Workers in Industries with High-Noise-Level Manufacturing

Abstract

Hearing-protection devices (HPDs) are particularly important in protecting the hearing of workers. The aim of this study was to prevent hearing damage in workplaces in Taiwan. It was conducted to determine the actual sound attenuation of the personal attenuation rating (PAR) values when wearing HPDs via measurements from field microphones in workers’ real ears (F-MIRE). Across 105 measurement trials for the Classic™ roll-down foam earplug HPDs worn by the workers, there were 23 cases of ineffective protection (including caution and fail); the proportion was 20% (including the first measurement and re-wear of HPDs after education and training). In addition, re-education and training in how to wear the HPDs was provided, improving wearing skills. A total of 29 testees wearing the Classic™ roll-down foam earplug HPDs failed to meet the pass standard for the first PAR test, and 6 of them improved and subsequently passed the PAR test. The improvement rate was 20%. These 23 testees switched to another HPD, namely Kneading-Free Push-Ins™ earplugs. From this group, 16 effective sound attenuation values were obtained, with an improvement rate of 70%. However, seven testees failed to pass the PAR test, and after education, training, and replacement of HPDs with different types, they still could not pass the PAR test. At that time, even if the UltraFit™ pre-molded earplugs were adopted again for wear and replacement, they were still unable to pass the PAR test. This HPD was eventually replaced with the PELTOR X4A Earmuff HPD and then tested again, with these HPDs finally passing the PAR test. In Taiwan, the use of fit testing has been increasing but it is not a common practice, and few studies on hearing-protection fit testing have been conducted in this country. The goal of this study was to gain more insight into the current hearing protection situation, including field attenuation of HPDs obtained by workers, the effects of training on improving the attenuation of HPDs after F-MIRE measurements, and the awareness of hearing health and motivation on the use of HPDs in a high-noise-level environment.

Evaluating the Effectiveness of Earplugs in Preventing Noise-Induced Hearing Loss in an Auto Parts Factory in China

“…Both the generalized linear model and logistic regression model showed that earplug attenuation had no significant effect on the hearing of participants. These findings are in agreement with the evidence from previous studies that the use of HPDs in the workplace is often inconsistent and not fully effective [ 7 , 9 , 18 , 19 , 20 , 21 , 22 ]. Specifically, these findings are consistent with Groenewold’s [ 5 ] report which showed self-reported use of hearing protection devices at work was not significantly associated with the odds of high-frequency threshold shifts among 19,911 noise-exposed U.S. workers.…”

“…However, multiple studies of the training methods have shown that they failed to teach how to properly fit their earplugs [ 9 , 19 , 20 , 21 ]. Individual training along with HPD fit testing has been shown to teach poorly performing subjects to insert earplugs properly and achieve sufficient attenuation [ 7 , 9 , 21 , 22 ]. To improve earplug fitting skill and to train workers to wear them correctly, individual fit-testing was recommended to the surveyed auto parts factory.…”

Verifying earplug attenuation and evaluating the effectiveness of one‐on‐one training along with earplug fit testing at nine facilities in China

“…In this study, workers from the training group were shown how to wear plugs correctly. This training strategy has been adopted in numerous studies 10,21,23,24 and PARs improved significantly across these studies. Federman and Duhon 32 evaluated three different training paradigms with 79 US Marine Corps training recruits.…”

“…A number of fit‐test systems are commercially available, including 3M™ E‐A‐Rfit™ Dual‐Ear Validation System, VeriPRO fit‐test system, and the FitCheck Solo™ fit test system 15,20,21 . The 3M™ E‐A‐Rfit™ Dual‐Ear Validation System was introduced to Chinese HPD users several years ago and demonstrated value for verifying sufficiency of attenuation 22–24 .…”

Factors influencing the use of hearing protection devices in Irish mine workers

“…Workplaces with a strong safety culture and that provide practical health and safety management are associated with greater adherence to wearing HPDs. There is a positive association between HPD use, training, years of service, education levels, gender, and type of HPD (Thepaksorn et al, 2018;Chien-Chen and Terng-Jou, 2020).…”