Two devices are commonly used to measure sound levels in commercial and industrial workplaces.
A sound level meter is used to measure sound pressure levels in decibels (dB). The device is often tripod-mounted and used in a fixed location.
A noise dosimeter is a specialized, portable sound meter used to measure a worker’s noise exposure over time and small enough to be worn for an entire shift.
Measuring sound levels for the purpose of determining occupational noise exposure must take into account a “time-weighted average noise level of 85 dBA or higher over an 8-hour work shift.”
Consult your safety manager or an environmental safety and health professional for assistance with compliance and noise exposure mitigation. Resources are available from OSHA and industry groups.
Three factors combine to determine whether you’re at risk for hearing damage from noise exposure: sound level, time and distance. Sounds above 85 decibels are risky and sounds above 125 decibels will cause immediate hearing damage.
The risks increase with the amount of time you’re exposed to loud noise, and how close you are to the source of that noise. The louder it is, the longer you’re exposed and the closer you are to it, the more you’re at risk for hearing damage.
The Occupational Safety and Health Administration (OSHA) requires employers to take steps to reduce occupational noise exposure when an employee is exposed to a “time-weighted average noise level of 85 dBA or higher over an 8-hour work shift.”
Included in every Apex 3-Series Wireless Headset, the Sonetics Personal Sound Dosimeter (PSD), is the first line of defense for your hearing protection plan, alerting you to potentially hazardous noise levels. The PSD measures sound pressure levels using microphones inside the headset’s ear domes. The PSD records sound exposure data for up to 24 hours, or until the PSD is reset.
The PSD uses the data it collects about your noise exposure to begin lowering the maximum sound level of your headset’s speakers until you reach the 85dB threshold specified by OSHA standard 1901.95(c)(1). To put that in context, normal conversation is about 60dB.
When the PSD reaches 60% of total allowable noise exposure, it begins to lower the maximum decibel level of the headset’s ear dome speakers in steps, from 95dB down to 85dB after the PSD has recorded 90% of your maximum allowable noise exposure.
The PSD reports total noise exposure when you power down the headset. A voice prompt announces “Dosimeter” and a number from 0 to 100. The number is a percentage of your total time-weighted noise exposure over an eight-hour period.
The Environmental Protection Agency requires any hearing protector sold in the U.S. to have a noise reduction rating (NRR). NRR is a measure of a hearing protection device’s ability to reduce the wearer’s sound exposure. The higher the number, the greater the potential for noise reduction.
Sonetics headsets have a Noise Reduction Rating of 24 decibels (24dB NRR).