| Popis: |
An important question to ask in regard to hearing protection devices (HPDs) is how much hearing protection they can provide. With respect to the law, at least, this question was answered in 1979 when the U. S. Environmental Protection Agency (EPA) promulgated a labeling regulation specifying a Noise Reduction Rating (NRR) measured in decibels (dB). In the intervening 25 years many concerns have arisen over this regulation. Currently the EPA is considering proposing a revised rule. This report examines the relevant issues in order to provide recommendations for new ratings and a new method of obtaining the test data. The conclusion is that a Noise Reduction Statistic for use with A weighting (NRSA), an A–A’ rating computed in a manner that considers both intersubject and interspectrum variation in protection, yields sufficient precision. Two such statistics ought to be specified on the primary package label—the smaller one to indicate the protection that is possible for most users to exceed, and a larger o... |
