5
NOISE REDUCTION RATING (NRR)
The NRR for the AESEM1S Situational Awareness Bluetooth Earmuffs is 21dB. It is tested
and in accordance with ANSI S3.19-1974. To ensure adequate hearing protection, the
earmuffs must be properly fitted according to the FITTING EARMUFFS section.
ANSI S3.19-1974 TESTING
Frequency (Hz) 125 250 500 1000 2000 3150 4000 6300 8000 NRR
Mean Attenuation 34.3 31.7 36.1 35.3 37.7 40.4 41.0 46.3 45.8
21
Standard Deviation
3.9 3.0 3.3 3.6 3.9 4.3 3.6 4.1 2.8
NOTE: The above table is based on a headband force of 12N.
The level of noise entering a person’s ear when the hearing protector is worn
as directed, is closely approximated by the difference between the A-Weighted
environmental noise level and the Noise Reduction Rating (NRR).
EXAMPLE:
• The environmental noise level as measured at the ear is 89dB(A).
• The NRR is 21dB.
• The level of noise entering the ear is approximately equal to 68dB(A).
CAUTION: For noisy environments dominated by frequencies below 500 Hz, the
C-weighted environmental noise level should be used.
NOTE: Although hearing protectors can be recommended for protection against the harmful
effects 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 gunfire. The Environmental Protection Agency uses the Noise
Reduction Rating (NRR) as a rating of a hearing protector’s noise-reducing performance.
Klein Tools cannot guarantee the suitability of the NRR as a method of rating protection as
protection relies on the level and exposure of sound and how well a product fits.
AUDIO INPUT LEVEL
The audio level in the hearing protector is dependent on the audio input level.
To prevent harmful noise levels, the AESEM1S Situational Awareness Bluetooth
Earmuffs automatically default to 85dB(A) when wirelessly connected to a music
device. If the hearing protector is either wirelessly connected or wired to a music
device with a high audio output level, it is the user’s responsibility to set the audio
input level to safe level.
See table in FEATURE DETAILS section for noise exposure levels.
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