Hazardous Noise and Acoustical Controls

The most effective method to prevent noise-induced hearing loss in the workplace is to eliminate or reduce hazardous noise levels by implementing acoustical controls. Consideration must be given to the use of acoustical controls when intensity levels are obtained in the workplace at 90 dB(A) or greater. Generally acoustical controls consist of, but are not limited to, the following efforts:

  1. Room Treatments. Floors, walls and ceilings with high acoustical reflective characteristics add to the noise level. Treating these surfaces with absorbing materials can result in noise reduction.
  2. Barriers. A barrier or partial enclosures, which have reflective and/or absorptive characteristics, can be used to block the flow of noise energy.
  3. Enclosures. Full or partial enclosures of machines or noise sources using materials which contain the noise energy. An alternative approach would be to place the exposed worker in an appropriate acoustical enclosure.
  4. Vibration Isolation. A technique designed to separate a vibrating or noisy machine from a surface area which adds to the noise intensity (sounding board resonance). This typically is accomplished by placing special acoustical material (spring, rubber, absorption pad, etc) on or between the noise source and the surface area.
  5. Damping. A technique used to reduce the vibration of an object (machine parts, metal panel, etc) by attaching damping materials to the vibrating surface.
  6. Silencers and Mufflers. These devices are designed to attenuate or reduce the noise level resulting from rapidly escaping air.