Verifying the attenuation of earplugs in an auto parts factory in China

This study compared methods used to predict the attenuation of earplugs with the results from objective attenuation measurements. Personal noise measurement and earplug fit-tests were performed on 385 workers from an Auto parts factory. All participants used one type of pre-molded earplugs. 78.2% of workers had LAeq8h above 85 dB(A). The mean Personal Attenuation Ratings (PAR) was 7 dB (median 5 dB, SD 7.2 dB), well below the earplug's single number rating (SNR) of 25 dB and de-rated SNR (15 dB). No PAR increment was detected with increasing LAeq8h (F = 0.657, p = 0. 709). Neither the noise attenuation rating (indicated in the product's label) nor the de-rated value predicted the level of hearing protection device attenuation obtained by the workers who were wearing earplugs. Objective measurements of earplug attenuation could improve the effectiveness of hearing conservation programs. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.