Harbor Freight Tools Ear Muffs Product manual

HEARING PROTECTOR ITEM 97849

The EPA has selected the NRR as the measure of a hearing protector’s noise reducing capabilities. Harbor Freight Tools makes no warranties as to the suitability of the NRR as a measure of actual workplace protection since such protection is highly dependent on user training, motivation, and utilization. A better estimate of workplace protection can be obtained by derating the labeled NRR by 50%.

The NRR calculated from this attenuation data is 34. Improper fit of this device will reduce its effectiveness in attenuating noise. Consult instructions for proper fit.

The level of noise entering a person’s ear, when a hearing protector is worn as directed, is closely approximated by the difference between the A-weighted environmental noise and the NRR.

ATTENUATION DATA ANSI S3.19-1974

Test Frequencies (Hz)

Mean Attenuation (dB)

Standard Deviation (dB)

Example:

1.) The environmental noise level as measured at the ear is 92 dBA.

2.) The NRR is 34 decibels (dB).

3.) The level of noise entering the ear is approximately equal to 58 dBA.

CAUTION! For noise environments dominated by frequencies below 500 Hz, the C- weighted environmental noise level should be used.

125 250 500 1000 2000 3150 4000 6300 8000

9.6 28.1 38.9 52.7 55.2 49.6 43.1 33.8 41.2

5.8 1.6 3.3 3.2 3.3 5.5 4.2 3.4 3.6

The NRR used in the above example was achieved under laboratory conditions.

Although hearing protectors can be recommended for protection against 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.

NRR (without

40CFR211 correction)

NRR

Wear Instructions

1. Adjust the band to the proper position.

2. Pull hair out of the way and out from beneath the muffs.

3. Adjust the height of the cups so they fully enclose the ears and the cushions press equally around the ear.

4. It is important that cushions seal completely around the ear.

5. Always wear ANSI-approved safety glasses when working with tools and equipment. When using these ear muffs with safety glasses, the safety glasses must have thin temples that fit closely around the head or thin straps, this will help ensure a good fit and better protection.

SAVE THESE INSTRUCTIONS.