3M requests allowance of the Personal Attenuation Rating (PAR) as a viable and potentially more protective alternative to use of the NRR in order to comply with the following:
- CFR 1910.95(g)(8)(ii)(B): determine appropriate attenuation for workers who experience Standard Threshold Shift
- CFR 1910.95(i)(3): identify a variety of suitable hearing protectors with appropriate attenuation
- CFR 1910.95(i)(5): ensure proper initial fitting and supervise correct use of all hearing protectors
- CFR 1910.95(j)(1 - 4): evaluate the adequacy of attenuation for specific noise environments, verify noise exposure is adequately reduced to the targeted value, and determine when re-evaluation of hearing protection attenuation is warranted.
-CFR 1910.95 Appendix B Methods for estimating the adequacy of hearing protection attenuation
-CFR 1910.95(k)(3)(ii): train workers on the advantages, disadvantages, and attenuation of various HPD types, and instruct on selection, fitting, use, and care. - Appendix IV:C. Methods for Estimating HPD Attenuation
Hearing protector Noise Reduction Ratings (NRRs), as ascertained through standardized laboratory measurements on a small number of test subjects, are not always well correlated with field assessments of actual hearing protection attenuation for workers in the field. Yet, regulations require NRRs be used to determine the adequacy of attenuation received by individual workers. Recent technology allows individualized measurements of attenuation through hearing protection fit testing, which yields a personal attenuation ration (PAR). The PAR is measured for each hearing protector on each individual ear of each worker. The resultant PAR, together with the worker's noise exposure information, are used together to determine if a worker has appropriate protection from the noise hazard. Knowing PAR enables immediate identification of workers who are inadequately protected and allows for real-time intervention. Workers with Standard Threshold Shift can be offered hearing protectors with known attenuation values for each ear. Multiple hearing protectors can be tested per worker, to determine options of appropriate hearing protectors for each worker. Effective training can be accomplished to achieve adequate attenuation on an individual basis. New and/or inexperienced workers can be fit-checked and trained prior to working in a hazardous environment to ensure hearing protectors can be chosen and worn in a manner which affords appropriate attenuation.