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Key concepts
More stringent noise level rules and exposure criteria are likely.
Dosimeters provide an 8-hr TWA and/or the dose.
Integrating sound level meters are useful for detailed noise studies and "what-if analyses.
Reducing noise in plants has been, and will continue to be, a goal of industries worldwide. Not only are workers concerned about noise, but so are the neighborhoods and communities that border industrial areas.
And, there is no indication that regulations will be relaxed. On the contrary, some organizations favor more stringent rules and noise exposure criteria. Therefore, plant personnel will be increasingly studying their noise levels.
The question is: Should they use a sound level meter or dosimeter to do the job? A good answer is: It depends!
Perspective is important
The desired end result or the person performing the test often determines the type of equipment chosen. An industrial hygienist is usually interested in the workers' total noise exposure, either in time weighted average (TWA) or Daily Dose. These single numbers indicate whether the worker is in compliance with the applicable regulations.
The hygienist is probably more familiar with dosimeters, so this type of instrument is probably his first choice. Also, the hygienist is usually less concerned with how to reduce the noise, because in many organizations that is not his responsibility.
The plant engineering staff, however, must fix the problem and is more concerned with sound levels and how much they can be lowered. There is a good chance that a mechanical engineer dealing with noise problems has not had a basic course in acoustics. However, he would easily understand, and feel comfortable with, noise levels expressed in decibels. Therefore, he would prefer a sound level meter.
The plant manager is interested in both knowing if workers are in compliance and how the noise will be reduced.
Dosimeters
A dosimeter is essentially a special-purpose sound level meter. It is small enough to be worn by the worker and goes where he goes to measure the noise level exposure. The microphone is usually on a short cable clipped to the shirt or helmet, while the body of the unit clips to a belt or is put in a pocket.
Output of the dosimeter is usually the...