Noise Testing to Prevent Hearing Loss and Achieve OSHA Compliance
It has been clearly established that exposure to noise in the workplace over an extended period of time can lead to hearing loss. Noise exposure above 90 dB at a job can definitely lead to hearing loss. In fact, exposure at or above 85 dB is likely to lead to permanent hearing loss in some individuals.
OSHA requires a noise dosimetry survey to determine if workers are exposed to noise that could damage their hearing.
To satisfy OSHA’s requirement for Noise Surveys (29CFR1910.94 for General Industry, 29CFR1926.52 for Construction) involves attaching a noise dosimeter to a worker for a work shift when there is a possibility that person and persons performing similar tasks may be exposed to noise at or above the 85 dB (decibels) Action Level or the regulatory level of 90 dB.
The noise dosimeter is a small meter either worn on the belt with a line to a microphone clipped to the collar OR the newer dosimeters are only the size of a candy bar and worn on the collar.
Please note that the dosimeter is not a recorder—it takes a noise reading at ½ or 1 second intervals and accumulates the readings over a shift.
The read-out is then compared to the OSHA Hearing Conservation limit of 85 dB-A for an 8-hour work shift and the 90 dB-A compliance level for an 8-hour day.
Another important aspect of a noise survey is to perform a “Noise Map” of the work area particularly those areas that are between 85 and 90 dB requiring implementation of a Hearing Conservation Program. A Hearing Conservation Program would require individuals exposed at or above 85 dB to be given an annual audiogram and have hearing protection (plugs or muffs) available if the employee chooses to wear them. Hearing Protection is mandatory for all workers potentially exposed to 90 dB-A or above and steps must be taken to reduce the noise levers. NOTE: An employer can make hearing protection mandatory—even at 85 dB—if they so choose. Also noted on the Noise Map should be areas where the noise levels are at or above the 90 dB-A—the Permissible Noise Exposure limit for an 8-hour shift.
These noise map measurements can be useful in determining what areas are the contributors to the workers’ noise exposures and also useful in establishing locations where noise reduction may be necessary to achieve OSHA compliance.
We also have the ability to conduct an octave band analysis—and even 1/3 octave band analysis—which can be very useful in developing noise controls by engineering methods, since there are different means of noise control depending on the frequency of the noise.
Since many organizations have work shifts other than 8-hours (often 10-hour or 12-hour shifts) there are formulas for calculating the allowable noise exposure levels for such shifts.
There are specific regulatory requirements in the OSHA Noise Standards related to 1) Program Requirements, 2) Hearing Protection, 3) Audiometric Testing, 4) Training, and 5) Administrative or Engineering Controls required if the exposures are at or above the “Hearing Conservation” level of 85 dB-A or at or above the 90 dB-A PEL.