Noise Control

Listen up: hearing loss is preventable using noise control measures

Noise ControlAbout 30 million workers in the U.S. alone are exposed to noise at dangerous levels on the job due to inadequate noise control practices.

It's safe to say that not enough employers, or their workers, are hearing the message that noise-induced hearing loss is 100 percent preventable.

That's right, noise-induced hearing loss can be prevented, says the National Institute for Occupational Safety and Health (NIOSH), by implementing a number of noise control measures.

And it's an employer's responsibility to instate those noise control measures if workers are exposed to significant levels of damaging sounds.

OSHA identifies three approaches to noise control in the workplace and recommends using them to attack noise hazards, in the order of

  • noise source controls
  • noise path controls
  • hearing protection

Noise source controls

It's a simple concept: If you stop a noise at its source, it's no longer a hazard.

The key is to identify each source of noise and implement ways to either eliminate it or reduce it.

Ways to stop or reduce noise with source controls:

  • Keep machinery and all noise-generating equipment well-maintained and oiled.
  • Operate machines at the lowest possible speed that production allows.
  • Move machinery into stone, concrete or brick structures.
  • Equipment frames should be rigid, with machines not touching anything.
  • Isolate noisy equipment with damping suspension such as rubber footings.
  • Apply vibration-damping materials to all surfaces.

Noise path controls

If you can't eliminate or decrease a noise, the next step is to block, divert or absorb it, to somehow stop it from reaching workers' ears who will risk loss of hearing.

Noise path controls include

  • Minimizing the number of workers who are exposed to a noise hazard.
  • Isolating or moving noisy machinery whenever possible.

According to OSHA, you can reduce the noise level by up to six decibels (dB) by doubling the distance between workers and machines.

Another method of ambient noise control is placing sound panels in strategic locations as sound proofing. When a sound reaches the surface of these panels, it is absorbed by the panels instead of bouncing back into the environment.

Hearing protection

If you can't eliminate it and you can't move it, the last line of noise control defense is to use personal hearing protection equipment, including ear plugs and/or ear muffs.

OSHA requires that employers provide hearing protection devices for noise control if "any employee ... is exposed to an eight-hour, time-weighted average of 85 decibels or greater..."

The following examples will give you a sense of the decibel level of commonplace sounds:

  • a normal conversation: 40 dBA (the time-weighted average of decibels over eight hours)
  • a leaf blower: 95-105 dBA
  • most hammer drills: 102-106 dBA.

The extent of hearing loss depends upon the intensity of the noise and the length of exposure. OHSA defines acceptable levels of noise, above which hearing protectors such as ear plugs and ear muffs should be worn.

As with all personal protective equipment, the employer must provide training in the use and care of hearing protectors to ensure their proper fit and correct use.

All of these measures of noise control are components in a hearing conservation program that OSHA requires for general industry when there is significant occupational noise exposure.

Without noise control measures, noise-induced hearing loss will continue to plague the workplace and people will continue to miss the message of noise control.

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