What Is NRR?

NRR is the abbreviation for Noise Reduction Rating. The NRR is a number measured in decibels. It is intended to be used to compare the amount of noise being reduced by hearing protection devices.

How Do I Use NRR to Compare Hearing Protection Devices?

In general, the higher the NRR, the more noise is prevented from entering the ear. A device with an NRR of 31 will offer more protection against damaging noise than a device with an NRR of 20.

How Is The NRR Calculated?

According to EPA regulations, the ANSI Standard S3.19-1974 is the current testing standard for hearing protection devices. Ten human subjects are required for evaluation using nine test frequencies. The data is compiled and the NRR is calculated as a single number.

Is The NRR Data and Other Labeling Requirements Available?

Yes. The NRR data in addition to other labeling requirements by the EPA are as follows: