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Insert-type Hearing Protector Measurement System

The FitCheck hardware / software system has been designed to allow the hearing conservationist to measure the attenuation provided by insert-type hearing protectors on the individual wearer. This capability eliminates the need for inaccurate safety factors and laboratory test methods that are designed to predict field attenuation. The noise attenuation provided to wearers of insert-type protectors varies widely across the general population. Current laboratory performance ratings represent a best-fit situation under closely supervised conditions. The attenuation provided to poorly-trained plug wearers or to individuals with narrow, sharply bending or slit-shaped ear canals may be only a fraction of the labeled laboratory values. In its’ recommendations to the Environmental Protection Agency (EPA), FitCheck has been identified by the National Hearing Conservation Association (NHCA) Taskforce as a superior alternative to relying on the labeled NRR of a hearing protector. The FitCheck measurement system performs several functions for the hearing conservation program administrator, including: 1) Training of wearers in correct fitting procedures, 2) Random field sampling of protector effectiveness, 3) documentation that training was provided and that proper protection was provided to the employee, and 4) identification of failing or deteriorating protectors and changes in ear physiology. The hardware used in the FitCheck consists of a commercial 16-bit IBM PC sound card, custom designed headphones and a custom-designed black box. The PC parallel printer port is used to provide data communication from the PC to the FitCheck hardware. A patient switch and a 12 volt DC power source are also included.

FitCheck software includes database functions to store all attenuation measurements. The database is recorded in Microsoft ACCESS format, and includes reporting functions in Microsoft Excel. As an additional feature, all of the hearing protectors listed in the NIOSH compendium of hearing protective devices are included in a separate database. The FitCheck attenuation measurements may be graphed against the laboratory data to provide a visual indication of individual protector fit. The graph serves as an instructional tool when training the hearing protector user.

Download the software for the FitCheck for insert-type system here

Download the software for the FitCheck USB system here