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Hearing protection

What are Personal Attenuation Ratings and can they be used in lieu of annual audiograms?

Responding is Jeffrey Birkner, vice president, technical services and quality assurance, Moldex-Metric Inc., Culver City, CA.

The Personal Attenuation Rating system is a new technology being used by many companies with hearing protection programs. Several systems that measure the PAR are available from different manufacturers. One of the systems was developed by NIOSH, which is one of the most highly respected government health and safety agencies in the world. Generally speaking, PAR systems are used to determine the level of attenuation an individual is receiving from a particular hearing protection device that is inserted into the ear canal. It cannot be used for banded HPDs. It utilizes a computer with a sound card that accurately generates sound at very specific levels and frequencies, specially made headphones, and a handheld signaling device. The test is similar to taking a hearing test at a doctor’s office, except that it is done twice: once without a hearing protector in place and once with one in place. Simply stated, the difference in hearing ability between the two tests tells you how well a given HPD is working.

PARs can be used to test and train individuals in the proper use of hearing protectors and also to determine what an individual’s actual attenuation might be. It also allows the employer to assist the employee in choosing hearing protection that best fits the worker and provides the appropriate level of protection for their specific environment.

It is important to note that these systems cannot be used in lieu of a comprehensive hearing protection program as required by 29 CFR 1910.95 when noise levels exceed 85 dBA. Although 90 dBA is the permissible exposure limit, 85 dBA is the action level where a program must be implemented. The PAR can be used as part of the program to assist in training, selection and determining efficacy, as stated above. It cannot be used as a replacement for the required annual audiograms. PARs are a very useful tool to aid in compliance with hearing conservation programs; however, it is not the entire answer in implementing a program. Rather, PARs are one element that adds to the arsenal in protecting people’s hearing, which is one of the most common health hazards.

Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.

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