Damage to the ear due to noise exposure is cumulative and irreversible. There are three things to consider about noise: How loud? How long? How close? OSHA’s permissible top limit for noise exposure over an eight-hour period is 90 decibels. Some comparative noise levels found in a public entity workplace are:
An increase of six decibels equals a doubling of noise produced (a noise level of 96 decibels is twice as harmful as a noise level of 90 decibels).
Hearing loss can be prevented by a combination of increasing the distance between the person and the noise source, decreasing the exposure time to the noise source, and using personal protective equipment. PPE options are earplugs, canal caps and earmuffs (cap mounted designs are available). Hearing protection must be comfortable to be effective. The hearing protection must be worn consistently for the entire length of the exposure. For instance, an earmuff NRR (noise-reduction rating) of 20 db for only five minutes will reduce the effective NRR to 18 db.
Don’t over protect. Select hearing protectors that provide adequate but not excessive protection for overall performance and effectiveness for employees. Workers must be able to hear talking, loudspeaker transmissions, warning signals and important machine sounds, while reducing the risk of permanent hearing damage.
Hearing Conservation, OSHA Publication 3074
Lebovics, Irene, “Turning Down the Volume: Eliminating Noise Hazards,” Public Risk, March 1997, Public Risk Management Association
U.S. Department of Labor, Occupational Safety and Health Administration. OSHA 3151-12R, 2003, page pages 30-32, Personal Protective Equipment