How To Use the Calculator
An 8-hour time-weighted average is computed from a set of noise exposures. For each exposure, enter a Location with the noise level in the Noise Exposure box and the hours and minutes the subject is exposed to that noise level.
As an example: Say an employee works for 2.5 hours in 90 dBA and 5.5 hours in 85 dBA.
(1) In Location 1 enter 90 dBA and 2 hours and 30 minutes.
(2) In Location 2 enter 85 dBA and 5 hour and 30 minutes.
This results in a TWA (8-hour time-weighted average) of 87 dBA and a dose of 65.7%.
OSHA Requirements for this TWA
- No OSHA requirements per 29 CFR 1910.95
- Notify worker that his/her noise exposure meets or exceeds 85 dBA 8-hour TWA
- Allow worker to observe noise measurements
- Implement engineering and administrative controls to reduce exposure if possible
- Provide hearing protectors to worker at no cost
- Ensure worker wears hearing protectors
- Ensure worker wears hearing protectors if he does not have a baseline or experiences an STS
- Conduct baseline audiogram within 6 months of worker's first exposure at or above 85 dBA
- Conduct annual audiograms thereafter
- Train worker in effects of noise, purpose and use of hearing protectors, and purpose of audiometric testing
- Repeat noise monitoring if change to production, process, equipment or controls
