NoiseTime-Weighted Average Calculator -OSHA TWA

Location Sound Level Exposure Time TWA Dose Level
Totals dB %
1 dBA : HH:MM
2 dBA : HH:MM
3 dBA : HH:MM
4 dBA : HH:MM
5 dBA : HH:MM

OSHA's maximum allowable daily 8-hour TWA with protection is 90 dBA or 100% noise dose.

Employer Action:

If the employee’s time-weighted average exposure is above the 90 dBA TWA8, the employer would be required to institute a full hearing loss prevention program, including: • Controlling noise as feasible, • Providing hearing protection and training for employees, AND • Instituting an audiometric testing program.

If the employee’s time-weighted average is between 85 and 90 dBA TWA8, a hearing loss prevention program must be developed and maintained for the employee including hearing protection, training and audiometric testing. Engineering and/or administrative controls are not required, but may be beneficial, since the hearing loss prevention program would no longer be required if the employee’s exposure were reduced below 85 dBA TWA8.