Acoustic Associates, Ltd.

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

Specialists in Hearing and Acoustics

 

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The Noise Exposure Survey

 

A Noise Exposure Survey is conducted for several reasons to:

1) identify employees with noise exposures over a time-weighted average (TWA) of 85 dBA who must be included in a hearing conservation program,

2) establish a representative noise dose for each job category,

3) classify the risk of noise induced hearing impairment for each job category,

4) select adequate hearing protection,

5) identify areas which should be considered for administrative or engineering controls, and

6) determine the work relatedness of significant shifts in hearing thresholds.

 

The equipment used in this type of survey must meet OSHA and ANSI specifications and hold current calibration. Most of our instruments hold the superior Type I precision rating. They also contain special integration circuitry to compute the energy average noise level. This type of averaging capability is critical in obtaining accurate readings, especially when noise is not steady.

 

The survey should be conducted by a professional with training and work experience in assessing noise exposure. Our professionals hold either current certification in the Institute of Noise Control Engineering (INCE) or a Professional Engineering (PE) license.

 

PERSONAL MONITORING - There are two ways to conduct a exposure survey. The first method is called the personal monitoring method. In this method, dosimeters are worn by employees to continuously sample and integrate the noise level. Although dosimetry is useful, it must be performed with caution because measurements can be sabotaged by disgruntled employees.

In addition, if sample durations are not long enough or the noise exposure profile during the sample is atypical, then readings can project inaccurate long-term exposures. Dosimetry is most useful when employees are very mobile or the plant is very large (e.g., refinery, petrochemical or power plants). In general, this approach yields exposure levels 1-3 dBA higher than area monitoring method.

 

AREA MONITORING - The second method is called the area monitoring method. Here, integrating sound level meters are used to take sound energy samples at representative employee locations in the plant. Based on these levels and information on employee movement into different areas or jobs, the long-term noise dose for each job category is determined.

When conducted by a noise specialist, the area method is preferred because:

1) calibration is more accurate,

2) infrequently operated plant equipment can be activated for a short time so that its effect can be included in the analysis, and

3) the resultant noise exposure profile provides diagnostic value and permits "what if" analyses to assess the affect of administrative or engineering controls.

 

Our unique noise exposure profile shows the sound levels measured in different areas of the plant, the partial noise dose of various job activities, the total daily noise exposure for each job category, a hearing loss risk assessment, and a recommended minimum noise reduction rating for hearing protectors.

 
   
 

1278 West Northwest Highway, Palatine, IL  60067

phone: 847-359-1068     fax: 847-359-1207

email: info@AcousticAssociates.com