Decibel Limits

Decibel limits refer to the maximum levels of sound intensity considered safe for human hearing over specific periods of exposure. The decibel (dB) scale measures the loudness of sound, where higher decibel levels indicate louder sounds.

Key points about decibel limits and safe exposure:

• 85 dB is generally recognized as the threshold where prolonged exposure can start to cause hearing damage. For example, an 8-hour exposure to 85 dB noise is considered the maximum safe limit without hearing protection.

• The Occupational Safety and Health Administration (OSHA) sets specific limits for workplace noise exposure, requiring hearing protection when noise exceeds these levels for the corresponding durations:

  Decibel Level	Maximum Exposure Time
  90 dB	8 hours
  95 dB	4 hours
  100 dB	2 hours
  105 dB	1 hour
  110 dB	30 minutes
  115 dB	15 minutes

• Importantly, for every 3 dB increase above 85 dB, the safe exposure time is cut in half. This means that noise at 88 dB is twice as loud and safe exposure time is halved compared to 85 dB.

• Sounds above 130 dB can cause immediate pain and potential hearing damage even after very brief exposure, such as a jet engine or gunshot.

• Continuous exposure to noise levels above 70 dB over time can also contribute to hearing loss, so limiting exposure and using hearing protection is advised when noise is loud or prolonged.

In summary, decibel limits are guidelines to prevent hearing damage by controlling the loudness of sound and the duration of exposure. Hearing protection is recommended when noise levels reach or exceed 85 dB for extended periods, with stricter limits as noise levels increase.