ToolsSound, propagation & hearing
Noise exposure time
Permissible daily exposure and noise dose for NIOSH, EU and OSHA criteria.
dB(A)
h
Recommended maximum daily exposure
1 h
Daily dose for this duration
300%
Equivalent 8-hour level (3 dB rule)
89.7dB(A)
h
Recommended maximum level for that time
91dB(A)
| Level dB(A) | Recommended maximum |
|---|---|
| 85 | 8 h |
| 88 | 4 h |
| 91 | 2 h |
| 94 | 1 h |
| 97 | 30 min |
| 100 | 15 min |
| 103 | 7.5 min |
| 106 | 3.75 min |
| 109 | 1.88 min |
For guidance only, not legal or medical advice. The EU action value triggers duties such as wearing hearing protection; the EU limit value applies at the ear, taking hearing protection into account. Rules in your country may differ; peak limits (e.g. 135–140 dB(C)) apply separately.
How it works
Hearing damage depends on level and time. With a 3 dB exchange rate, every 3 dB increase halves the permissible exposure time; OSHA uses 5 dB. The criteria differ, so check which one applies to you.
Formulas
- T = 8 h / 2^((L − L_c) / Q)
- dose = Σ t / T
- L_EX,8h = 10 · log₁₀( Σ t·10^(L/10) / 8 h )
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