Washington Administrative Code
Title 296 - Labor and Industries, Department of
Chapter 296-817 - Hearing loss prevention (noise)
Section 296-817-30015 - Use these equations when estimating full-day noise exposure from sound level measurements
You must compute em-ployee's full-day noise exposure by using the appropriate equations from Table 2 "Noise Dose Computation" when using a sound level meter to estimate noise dose.
Table 2 Noise
Dose Computation
|
Description |
Equation |
|
Compute the noise dose based on several time periods of constant noise during the shift. |
The total noise dose over the work day, as a percentage, is given by the following equation where Cindicates the total time of exposure at a specific noise level, and Tindicates the reference duration for that level. D = 100*((C1/T1) + (C2/T2) + (C3/T3) + ... + (Cn/Tn)) |
|
The reference duration is equal to the amount of time of exposure to continuous noise at a specific sound level that will result in a one hundred percent dose. |
The reference duration, T, for sound level, L, is given in hours by the equation: T = 8/(2^((L - 90)/5)) |
|
Given a noise dose as a percentage, compute the equivalent eight hour time weighted average noise level. |
The equivalent eight-hour time weighted average, TWA, is computed from the dose, D, by the equation: TWA8 = 16.61* Log10(D/100) + 90 |
Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, and 49.17.060. 03-11-060, § 296-817-30015, filed 5/19/03, effective 8/1/03.
