Environmental, Health and Safety Services

Hearing Conservation Noise Surveys

Noise Measurements

Noise Surveys

Noise monitoring or measuring should be conducted when exposures may be at or above 85 dB. Factors which suggest that noise exposures in the workplace may be at this level include employee complaints about the loudness of noise, indications that employees are losing their hearing, or noisy conditions which make normal conversation difficult. Another indicator is if, after being exposed to high noise levels on the job, employees notice that speech and other sounds are muffled for several hours or they develop ringing in their ears.

EHS will correspond with the appropriate supervisors to schedule and conduct noise surveys. A noise survey should be conducted at work areas where it is difficult to communicate in normal tones. A common rule of thumb is that if employees have to shout to communicate with each other at a distance of three feet, noise levels may be excessive. A noise survey should also be performed if, after being exposed to high noise levels during the workshift, employees notice that speech and other sounds are muffled for several hours or they develop ringing in the ears.

Preliminary

A preliminary noise survey determines whether a potential noise problem exists and, if so, indicates how serious it is.

If the measured noise levels provide an estimate 85 dBA eight-hour time weighted average (TWA) or greater, the employees will be retained in the HLP.

Detailed

The preliminary noise survey helps determine specific locations, work practices, or equipment that require more detailed study and attention. The purposes of a detailed noise survey are:

  • To obtain specific information about the noise levels for each employee's job,
  • To develop guidelines for establishing engineering and administrative controls,
  • To identify jobs where HLP enrollment of employees is required, and
  • To define areas or processes where hearing protection will be required.

Prioritizing

The initial prioritization for scheduling noise surveys was based on the anticipated or reported factors. After actual measurements of the intensity, duration, and type (impact or steady state) and determination of the number of employees exposed to the noise hazards, the EHS develops a revised prioritization list for engineering and administrative controls by department.