4
LABORATORY ATTENUATION
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fit testing of hearing protectors. Research suggests that users may receive less noise reduction than
indicated by the attenuation label value(s) on the packaging due to variation in fit, fitting skill, and
motivation of the user. Refer to applicable regulations for guidance on how to adjust attenuation label
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Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR
CSA
Class
Mean Attenuation (dB)
17.9 26.0 31.3 32.4 38.9 41.3 44.7 46.2
22 dB B
Standard Deviation (dB)
4.0 2.3 2.7 3.2 3.2 3.0 3.8 4.4
Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR
CSA
Class
Mean Attenuation (dB) 17.6 24.9 33.4 39.3 41.4 46.2
21 dB B
Standard Deviation (dB) 4.2 2.7 2.3 3.8 4.1 3.0 3.4 3.0 4.7
Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR
CSA
Class
Mean Attenuation (dB)
11.4 21.7 28.9 33.1 40.8 38.8 37.3 37.3
20 dB B
Standard Deviation (dB)
2.8 2.7 2.0 2.7 1.9 3.7
Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR
CSA
Class
Mean Attenuation (dB) 20.3 26.4 32.1 33.0 39.7 34.1 39.4 40.1
22 dB A
Standard Deviation (dB) 3.9 2.7 3.0 2.8 3.7 2.9 2.3
Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR
CSA
Class
Mean Attenuation (dB) 17.6 26.1 32.9 40.9 40.0
21 dB A
Standard Deviation (dB) 3.9 3.3 2.6 2.8 2.3 3.0 2.6 2.4
* Tested with 3M™ Ceradyne™ Ballistic Helmet
** Tested with OPSCOR™ Helmet
Frequency (Hz)
125 250 500 1000 2000 3150 4000 6300 8000 NRR CSA
Class
Mean Attenuation (dB)
13.6 17.7 28.8 31.9 32.3 39.3 39.9 42.1 41.4
23 dB B
Standard Deviation (dB)
2.6 2.7 1.9 4.1 2.3 2.6
Folding headband with foam cushion*
MT20H682; AS-PATRIOT-92; AS-USCG-92
Folding headband with gel cushion**
MT20H682; AS-PATRIOT-92; AS-USCG-92 with HY80A
Backband with foam cushion*
MT20H682; AS-PATRIOT-92; AS-USCG-92
Backband with gel cushion**
MT20H682; AS-PATRIOT-92; AS-USCG-92 with HY80A
Helmet attachment with foam cushion*
MT20H682; AS-PATRIOT-92; AS-USCG-92
Helmet attachment with gel cushion**
MT20H682; AS-PATRIOT-92; AS-USCG-92 with HY80A