ASP question for October 21, 2026

The ASP question of the day for Wednesday, October 21, 2026, on safety math: incident rates, noise dose, slopes, lifting. Pick an answer to see the explanation and its source.

ASP Domain 1: Mathematical Calculations

A maintenance mechanic's 8-hour shift includes 4 hours at 85 dBA, 2 hours at 88 dBA, 2 hours at 102 dBA. Use D = 100 × (C1/T1 + C2/T2 + …), where C is the hours at each level and T is the reference duration for level L from OSHA Table G-16a (for example 8 h at 90 dBA, 7.0 h at 91, 6.1 h at 92, 4 h at 95, 2 h at 100). Using OSHA's noise dose method (Table G-16a reference durations), what is the mechanic's daily noise dose?

Show answer and source: 29 CFR 1910.95, Appendix A

Answer: A. 177.2%

Under the Occupational Safety and Health Administration (OSHA) noise rule, 29 CFR 1910.95 Appendix A, the daily dose adds each exposure time divided by its Table G-16a reference duration: 100 × (4/16 + 2/10.6 + 2/1.5) = 177.2%. 88.6% is exactly half of that total, so it wrongly halves the summed dose. 80.0% and 431.5% do not equal this sum of the three fractions.

On the job

An EHS manager at a printing plant totals one pressroom operator's exposure: 4 hours at 90 dBA, 2 hours at 95 dBA, and 2 hours at 85 dBA. Using Table G-16a reference durations of 8, 4 and 16 hours, the dose is 100 × (4/8 + 2/4 + 2/16), or 112.5%. Because the sum exceeds 100%, the manager flags the job for noise controls rather than judging by any single period.

Study aid, not site-specific safety advice. The official rule controls.

Answer A comes from

29 CFR 1910.95, Appendix A

“When the workshift noise exposure is composed of two or more periods of noise at different levels, the total noise dose over the work day is given by: D = 100(C1 / T1 + C2 / T2 + Cn / Tn), where Cn indicates the total time of exposure at a specific noise level, and Tn indicates the reference duration for that level as given by Table G-16a.”