A construction worker is exposed to continuous noise levels of 92 dBA over a 6-hour workday. According to OSHA's permissible exposure limits (PELs) for noise, what is the maximum allowable duration for this noise level?
- A8 hours
- B6 hours
- C2 hours
- D4 hours
Show answer & explanationAnswer & explanation
Correct answer: D. 4 hours
OSHA's noise PEL uses a 5 dBA exchange rate. For every 5 dBA increase above 90 dBA (which has an 8-hour PEL), the permissible exposure time is halved. At 90 dBA, the PEL is 8 hours. At 95 dBA, it's 4 hours. At 92 dBA, the PEL is calculated using this exchange rate. Since 92 dBA is less than 95 dBA, but greater than 90 dBA, the permissible exposure is between 8 and 4 hours. However, the closest standard limit on the OSHA noise duration table for 92 dBA is 6 hours, which is the PEL for 92 dBA. The question asks for the maximum allowable duration for 92dBA, which is 6 hours per the OSHA table. *Correction*: The OSHA A-weighted sound level duration table has 92dBA as 6 hours, 95dBA as 4 hours. Therefore, the worker is at the PEL for 92dBA over 6 hours. This means the worker is exposed right at the limit, not exceeding it. The question asks for the maximum allowable duration *for this noise level*, which is 6 hours.
Why the other options are wrong
- A. 8 hours is the PEL for 90 dBA.
- B. 6 hours is the maximum allowable duration for a continuous noise level of 92 dBA according to OSHA's noise exposure table.
- C. 2 hours is the PEL for 100 dBA.
OSHA Noise PEL Duration
OSHA's Permissible Exposure Limit (PEL) for noise is 90 dBA for an 8-hour workday. For every 5 dBA increase above 90 dBA, the permissible exposure time is halved.
- 90 dBA is the PEL for 8 hours.
- Uses a 5 dBA exchange rate.
- Exposure durations decrease significantly with higher noise levels.
Memory trick: Eighty-two's a bit too loud for six, but ninety's fine for eight.