Allowable Exposure Time - OSHA (T)

The allowable time of a noise exposure based on the allowed 90 dB averaged over 8 hours with a 5 dB exchange rate. This equation can used to administratively control exposures to below the OSHA allowed amount.

Time to Reach 100% Noise Dose (hours)	Exposure Level
Time to Reach 100% Noise Dose (hours)	OSHA PEL (dBA)*	NIOSH REL (dBA)**
8	90	85
6	92	86.2
4	95	88
3	97	89.2
2	100	91
1	105	94
0.5	110	97
0.25	115	100

*Based on 5 dB exchange rate

**Based on 3 dB exchange rate

Formula

T = \( \frac{8}{2^{\frac{LA-90}{5}}} \)

Variable	Unit
LA	A-weighted sound level at operators’ position

Allowable Exposure Time - OSHA (T)

T = \( \frac{8}{2^{\frac{LA-90}{5}}} \)

hours =

8 / 2 ^{(LA
- 90) / 5}