Which noise level corresponds to a daily exposure time of 1.5 hours?

• A. 102 dB
• B. 90 dB
• C. 105 dB
• D. 115 dB

Answer: (A)

The concept here is how long you can be exposed to a given noise level before reaching a standard daily limit. With the OSHA PEL approach, a common rule is that increasing the level by 5 dB cuts the allowable time in half. Starting from 90 dB for 8 hours:

• 95 dB → 4 hours

• 100 dB → 2 hours

• 105 dB → 1 hour

• 110 dB → 30 minutes

• 115 dB → 15 minutes

Your target is 1.5 hours, which falls between 2 hours (at 100 dB) and 1 hour (at 105 dB). Interpolating between these two points puts the corresponding level roughly in the low 100s, about 102 dB. So a noise level around 102 dB matches a daily exposure of about 1.5 hours.

The other levels don’t fit: 90 dB corresponds to 8 hours, 105 dB to 1 hour, and 115 dB to about 15 minutes.