Individual fit testing of hearing protection devices

While hearing protection devices (HPD) have been the last and often only line of defense against noise-induced hearing loss in the workplace, their performance has been suspect. Laboratory evaluations have not proven to predict the actual performance of HPD in the field. Individual fit testing of HPD will allow the determination of HPD performance on individual workers, and this will improve the ability to select HPD appropriate for given noise exposures and intervene with workers to ensure sufficiency in HPD performance. A modified microphone-in-real-ear (F-MIRE) has been adapted to test a variety of HPD quickly and reliably in situ. A dual-element microphone and software combination permits reliable noise reduction measurements. Statistically developed compensation factors permit direct comparison of F-MIRE predicted personal attenuation ratings to traditional laboratory measures of HPD performance using real-ear-attenuation-at-threshold assessments.