How to Conduct Sound Surveys for Occupational Health and Safety

Do you suspect your workers are being harmed by excessive noise? A walkaround site survey is the first step to addressing this issue. Take individual decibel level measurements at discrete locations in your facility during typical operation. This important process can help answer these questions:

• What piece of machinery contributes to excessive or dangerous noise?
• Where in the plant are workers exposed to dangerous noise?
• Who is the most at risk of excessive noise exposure?

If this simple walkaround measurement indicates potential problems (levels greater than 80 dB), a more systematic plant sound survey may be needed. As a part of the survey, potential problem areas can be plotted on a noise survey map (also known as a sound map or occupational noise survey). This can be as simple as using an existing site map and hand noting the decibel level of each location measured.

Measurement Tips

• Before measurement, calibrate your Sound Level Meter according to manufacturer’s instructions
• Use Frequency Weighting A
• Use Slow Time Weighting

Resources

Limits for noise exposure vary across the world. Please use resources appropriate for your location when seeking out specific standards. In general, OSHA regulations set the legal limit for exposure at an average of 90 dBA over an 8 hour day. However, there is ample evidence that lower doses of noise can damage hearing.

US

• OSHA technical manual - an example of how to sketch a noise survey
• Department of Defense Noise Survey – DOD guide to conducting a Sound Level Meter survey

Canada

• Noise Measurement in the Workplace from the Canadian Centre for Occupational Health and Safety

Australia

• Safe Work Australia Guide to Noise at Work

European Union

• Noise Health and Safety Directives in the EU

Further Investigation with Noise Dosimetry

If any areas of a plant are identified as having noise levels over 80 dBA, consider getting a clearer picture of the noise exposure to individual workers using Noise Dosimeters. These are small noise measurement devices worn by a worker for a typical work shift. Learn more about noise dose measurements.

Next Steps

When developing a plan for mitigating the effects of noise, consider the following

Reduce the effects of noise with

• Engineering Controls
  • Isolate loud equipment (barrier between employee and equipment)
  • Utilize sound absorption panels
  • Utilize low-noise tools
  • Maintain and lubricate machinery and equipment
• Administrative Controls
  • Rotate workers to quieter equipment
  • Reduce the hours per day at noisy stations
• Personal Protective Equipment

Continue to monitor and measure noise dose on a regular schedule

A hearing conservation program may be required and can include

• A plan for hearing protection
• Employee training
• Annual hearing exams for workers