You may have heard that OSHA is renewing emphasis on hearing conservation programs in your area. You may have recently learned an employee is suffering from hearing loss. Maybe you are simply an employer who wants to take good care of your employees.
Whatever your motivation for learning more about the dose of noise experienced by individuals in your facility, we’re here to help. Assessing the level of noise in your workplace is the first step. Understanding the noise level by measuring
your employees’ exposure (known as noise dose) provides the pathway toward mitigating the effects of hazardous noise.
What is Noise Dose?
Noise dose is simply a way to measure the amount of exposure to sound an individual receives in a given time period. At its simplest, it is a function of the noise level experienced and the amount of exposure time. It is expressed in the form of a percentage
of total allowable exposure. If the worker is exposed to varying noise levels throughout the day (perhaps they move around from station to station or different equipment is running at different times), it is convenient to measure noise dose with a
personal noise dosimeter. Without a noise dosimeter, computing overall noise dose for varying noise levels is complicated; due to their logarithmic nature decibel levels cannot be simply averaged.
How Do I Determine If My Employees’ Noise Exposure Level is Safe?
The first step when a noise problem in the workplace is suspected is to perform a sound survey. The simplest way to accomplish this is to measure with a handheld, calibrated sound level meter at various locations. Typically, this measurement is made with the Sound Level Meter set to frequency weighting A and time weighting Slow. The sound levels of potential problem
areas may be plotted on a noise survey map. If any area measures over 80 to 85 dB, further investigation is recommended. (If measuring with a less accurate device, for example a cell phone app, consider further measures if the noise level in an area
measures over 75 dB.)
If an individual worker is stationary all day, a sound level meter can also be used to measure noise levels and calculate dose. A Sound Level Meter designed specifically for the Occupational Health and Safety professional may
have built-in functionality to calculate and display noise dose. If the meter does not make the dose calculation, there are methods to calculate dose by hand. However, for anyone moving around to areas with varying noise levels, a personal noise dosimeter,
a small badge-type device worn by the employee during a typical work day, is the simplest and least obtrusive option for directly measuring noise dose. A noise dosimeter with built-in bump and motion detection plus sound recording option helps ensure
you’re getting data that represents the actual dose being received by the person wearing it
Which Workplace Standard Do I Need to Follow?
Allowable noise dose is not universally agreed upon.
There are unique standards in place in the EU, the US,
Canada, Australia, and elsewhere. Zero represents
no exposure and 100 or more represents “complete”
exposure, but that 0-100 means something different
depending on which standard is being used for
Each standard makes certain assumptions, including:
- The level of noise that makes a meaningful
contribution to noise dose
- The level of noise and time of exposure that is
dangerous or damaging to human hearing
What does this mean to you? When measuring with a
personal noise dosimeter, all you need to know is the
specific noise standard for your location or situation.
In the United States, most workplaces are obligated to
comply with OSHA-PEL noise exposure limit. In Europe,
workplace noise falls under EU Directive 2003/10/EC.
Larson Davis’ Spartan™ Workplace Noise Dosimeter
makes it easy to comply with a wide variety of standards