Some key factors that go into choosing earplugs for workers are: determining the length and intensity of noise exposure they’ll be needed for, training workers in how to use them properly and making sure they fit the individuals who will be using them.

Just in time for Better Hearing and Speech Month – May -- the National Institute for Occupational Safety and Health (NIOSH) and three partner laboratories recently evaluated three systems to measure the accuracy of the fit tests. Investigators at NIOSH, Honeywell Safety Products in San Diego, California, Michael & Associates in State College, Pennsylvania, and U.S. Army Aeromedical Research Laboratory in Fort Rucker, Alabama, each recruited 20 local volunteers to test the systems, which included the NIOSH HPD Well-Fit, Michael & Associates FitCheck and Honeywell Safety Products VeriPRO.  For comparison, the investigators used the standard laboratory-hearing protector testing protocol recommended by the American National Standards Institute (ANSI) as a control.

The findings

Study results, as reported in the Journal of Occupational and Environmental Hygiene, showed that two of the fit-test systems provided noise reduction levels that were comparable to the ANSI laboratory fit test and one system tended to underestimate the noise reduction measurements compared to the control. However, the results of the fit tests varied significantly between the four sites, with the greatest level of measured noise reduction and the smallest variation between tests noted at the Michael & Associates lab. In contrast, the fit tests at NIOSH found the lowest level of noise reduction and the largest variation between tests. These differences could stem from different levels of experience with earplug fitting among the testers and study participants. To address this issue, investigators noted that tailored training should occur before using a particular fit-test system. NIOSH plans to expand upon this research and, ultimately, develop guidelines for earplug fit testing.

NIOSH reminds safety professionals to check out resources such as the new NIOSH Sound Level Meter app. Workers can download the free app on their smartphones to measure noise levels in their own workplace and learn about noise-exposure limits and hearing-loss prevention. Knowledge of exposure levels and the noise reduction provided by properly fitting hearing protection devices can help to reduce the risk of noise-induced hearing loss.

More information is available:

• Inter-laboratory Comparison of Three Earplug Fit-test Systems
• NIOSH Noise and Hearing Loss Prevention
• NIOSH Division of Applied Research and Technology