Final answer:
A single hearing protection is required when the noise levels exceed 85 dB. Exposure to noise levels higher than 85 dB can cause damage to hearing over time. To prevent this, it is important to wear earplugs or earmuffs, limit exposure time, and increase distance from the noise source.
Step-by-step explanation:
The noise levels at which a single hearing protection is required are those that exceed 85 dB.
Several government agencies and health-related professional associations recommend that 85 dB not be exceeded for 8-hour daily exposures in the absence of hearing protection.
Exposure to noise levels higher than 85 dB can cause damage to hearing over time. To prevent this, it is important to wear earplugs or earmuffs, limit exposure time, and increase distance from the noise source.