Earmuffs continued
- Effectiveness of muff based on headband tension and fit of dome over
the ears
- Hair, glasses, hats may interfere with proper fit of cuff and affect
sound reduction
- Do not store hardhat mounted muffs with cuff pressing against the
hardhat - this will flatten cuff and reduce its effectiveness
6. Selecting Hearing Protection Devices
CSA Standard Z94.2 - 94 - Hearing Protectors
| Noise Level |
Recommended Hearing Protection |
| < 85 dBA |
no protection required |
| up to 89 dBA |
Class C |
| up to 95 dBA |
Class B |
| up to 105 dBA |
Class A |
| up to 110 dBA |
Class A plug + Class A or B muff |
| > 110 dBA |
Class A plug + Class A or B muff + limited exposure |
7. Noise Reduction Rating
The number gives the amount of noise reduction the hearing
protection device provides
| Class A |
24+ |
| Class B |
17 - 24 |
| Class C |
less than 17 |