Instruction Manual
Page 11
NRR Information
Although hearing protectors can be recommended for protection against the
harmful eects of impulsive noise, the Noise Reduction Rating (NRR) is based
on the attenuation of continuous noise and may not be an accurate indicator of
the protection attainable against impulsive noise such as gunre.
The level of noise entering a person’s ear, when hearing protector is worn as
directed, is closely approximated by the dierence between the A-weighted
environmental noise level and the NRR.
Example:
1. The environmental noise level as measured at the ear is 92 dBA.
2. The NRR is 22 decibels (dB)
3. The level of noise entering the ear is approximately equal to [92dB-22dB]
Caution: For noise environments dominated by frequencies below 500 Hz the
C-weighted environmental
noise level should be used.