Applications of Hearing Protector Fit Testing – Outcomes of the International Hearing Protector Fit-Testing Symposium

Shortly after the U.S. Environmental Protection Agency (EPA) promulgated the regulation that required labeling of all hearing protection devices (HPDs) with the Noise Reduction Rating (NRR), studies were undertaken to examine methods that could be used to estimate workers’ noise exposures. The NRR was shown to overestimate the attenuation that workers were likely to achieve in everyday environments. While various approaches to derate the attenuation rating have been recommended and required by institutions and national bodies, the derating fails to accurately estimate exposures for most persons. With untrained workers, attenuations can frequently be less than the derated value. Conversely, trained workers have been shown to achieve attenuation that is more than derating would predict. Individualized experiential fit training in the proper donning of earplugs, has been demonstrated as an important method to develop the “muscle memory” necessary to consistently fit earplugs. An evidence-based intervention demonstrated a 20% improvement in a study within a military occupational health clinic providing services to both civilian and defense workers. Challenges associated with the NRR and derating, and the benefits of hearing protector fit testing (HPFT) will be reviewed.