Percent of PEL to which worker exposed. C nT n where C n indicates the total time of exposure at a specific noise level and T n indicates the reference duration for that level as given by Table G-16a. Multiply each value by its time weighting.
A time-weighted average is equal to the sum of the portion of each time period as a decimal such as 025 hour multiplied by the levels of the substance or agent during the time period divided by the hours in the workday usually 8 hours.
Multiply the weight by each value. Dose 100 x C1T1 C2T2 C3T3. The daily dose can be converted to an 8-hr Time-Weighted Average -TWA by the formula. The PELs listed in Table Z-1 are eight-hour Time Weighted Average TWA or Ceiling Limits C.