NIOSH Updates Science Policy on Fit Testing for Hearing Protection Devices

An update published by NIOSH in January clarifies the agency’s policy for determining the noise or sound attenuation provided by hearing protection devices for users. NIOSH now “recommends employers use individual, quantitative fit testing to evaluate the attenuation received by workers from their hearing protection devices,” the update states. The new recommendations supersede the guidance regarding hearing protector derating from chapters 1 and 6 of NIOSH’s 1998 Criteria for a Recommended Standard—Occupational Noise Exposure. Because commercially available fit-test systems were not available when the criteria document was published, NIOSH’s previous guidance “recommended derating the manufacturer’s labeled noise reduction rating to estimate a worker’s ‘as worn’ hearing protector attenuation.” The agency’s update is based in part on technological advancements and on research findings published in recent years that show that derating schemes cannot assess “proper fit” for hearing protectors.

Now that it is possible to check workers’ hearing protector attenuation at work sites, NIOSH recommends fit testing “as an essential practice to ensure that hearing protection devices are properly fit to each worker.” The agency’s science policy update does not favor a specific fit-testing method.

“Systems that compute a [personal attenuation rating] by the most current [Acoustical Society of America/American National Standards Institute] standards meet this NIOSH recommendation,” the agency’s new document explains. “In addition, any technology that directly measures and documents a worker’s protected exposure level (e.g., real-time protected exposure level monitoring) is consistent with this recommendation.”

For further details, see the full science policy update on the NIOSH website.