General conclusions
A number of general conclusions of the affects of noise on performance have emerged. Steady noises without special meaning do not seem to interfere with human performance until the level exceeds about 90dB. Intermittent and impulse noises are more disruptive than steady-state noises. even when the sound levels of irregular bursts are below 90db . Noise is more likely to reduce the accuracy of work than to reduce the total quantity of work.
What can be done?
One of the simplest things that can be done is to insure that employees have good hearing protection.
Form 1910.95 from the U.S. Department of Labor covers regulations for occupational noise exposure. It lists the limits required by law for exposure to harmful noise, and establishes when hearing protection is necessary.
Links
Hearing Protection - How hearing protection works.
How the Hocks Noise Braker® Helps Industry - The specific benefits of the Noise Braker® for industry.