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750 Introduction to Industrial Hygiene Skip to main content

Controlling Noise

Work Practice Controls

Work practice controls, also called administrative controls, are changes in the workplace that reduce or eliminate the worker exposure to noise. Examples include:

  • Operating noisy machines during shifts when fewer people are exposed.
  • Limiting the amount of time a person spends at a noise source.
  • Providing quiet areas where workers can gain relief from hazardous noise sources (e.g., construct a sound proof room where workers' hearing can recover - depending upon their individual noise level and duration of exposure, and time spent in the quiet area).
  • Restricting worker presence to a suitable distance away from noisy equipment.

Controlling Through Distance

Controlling noise exposure through distance is often an effective, yet simple and inexpensive administrative control.

As the distance from the sound source increases, decibel levels decrease.

This control may be applicable when workers are present but are not actually working with a noise source or equipment. Increasing the distance between the noise source and the worker, reduces their exposure. In open space, for every doubling of the distance between the source of noise and the worker, the sound level of the noise is decreased by 6.02 dB. No matter what the scale of measurement, you will get about a 6 dB sound level drop for every doubling of distance. You can see how this works by entering values in the table below.

There is a risk of exposure to:

Initial distance from sound source  meters or feet
Sound level at the initial distance  dB
Increased distance from sound source  meters or feet
Sound Level at increased distance  dB
Sound level decreased by  dB

Hearing Conservation Program

An effective hearing conservation program must be implemented by employers in general industry whenever worker noise exposure is equal to or greater than 85 dBA for an 8-hour exposure or in the construction industry when exposures exceed 90 dBA for an 8 hour exposure. This program strives to prevent initial occupational hearing loss, preserve and protect remaining hearing, and equip workers with the knowledge and hearing protection devices necessary to protect them. For more information on hearing conservation programs, review OSHAcademy Course 751, Hearing Conservation Program Management.

Personal Protective Equipment

Hearing protection devices (HPDs), such as earmuffs and plugs, are considered an acceptable but less desirable option to control exposures to noise and are generally used during the time necessary to implement engineering or administrative controls, when such controls are not feasible, or when worker's hearing tests indicate significant hearing damage.

Knowledge Check Choose the best answer for the question.

5-6. An effective hearing conservation program must be implemented by employers in general industry whenever worker noise exposure is equal to or greater than _____.