Enter the total sound level in decibels and the total time of exposure into the calculator to determine the total weight average (TWA) noise exposure.
The following formula is used to calculate the total weight average noise exposure.
TWA = 16.61 * log10* (D/100) + 90
D = 100 * (C / ( 2 ^ ( L-90)/5 ) )
- Where TWA is the total weight average noise exposure rating
- C is the total time of exposure
- L is the total A-weight sound level (decibels)
* Note this calculation assumes the sound level is constant for the entire duration of the day.
What is TWA?
TWA stands for total weighted average. This term is most often used in OSHA regulations to denote a total weighted average of sound exposure.
This value is used to determine the risk associated with a loud work environment.
How to calculate TWA?
- First, determine the total time of exposure.
For this example, we will use a standard 8 hour workday as the time exposure.
- Next, determine the A-weighted sound level.
For this problem, the A-weighted sound level is found to be 82 decibels.
- Finally, calculate the TWA.
Using the formula above, the TWA is calculated to be:
TWA = 16.61 * log(10) * (D/100) + 90
D = 100 * (8 / ( 2 ^ ( 82-90)/5 ) )
TWA = 113