Final answer:
The OSHA's PEL requires hearing protection for noise levels exceeding 85 decibels (dBA) over an 8-hour period to prevent hearing loss.
Step-by-step explanation:
The minimum noise level that necessitates the use of hearing protection equipment according to OSHA's Permissible Exposure Limit (PEL) is 85 decibels (dBA) as a Time-Weighted Average (TWA) over an 8-hour period.
This recommendation is supported by several government agencies and health-related professional associations. Exposure to sound levels at or above 85 dB over this time frame without adequate hearing protection can lead to hearing loss. The decibel scale, which measures sound intensity, is logarithmic and hence more aligned with human auditory perception, making it easier for people to relate to decibel levels such as 85 dBA than sound intensities in watts per square meter.