Strategies for Noise Collection

Strategies
 
Using a cell phone app to measure noise is not considered an "official" measurement of noise exposure. It is a rough screening technique which is meant to raise awareness, and get people engaged in hazard identification and control. Depending on what question you're trying to answer, the data you collect may be sufficient, or just a "first pass" before some more in-depth investigations. There is a CSA standard devoted to how to take noise measurements "properly" (CSA Z107.56-13) which requires certain standard of equipment (at least a Type 2 Sound Level Meter). Measurements with an app on a cell phone do not meet these requirements. However, you dont' necessarily need "official" measurements to identify noise hazards and work to control them.
Determine your Question
 
  • What's my typical workplace exposure to noise?
  • What's the loudest noise I'm exposed to during my time at work?
  • Where is the noise coming from?
  • Is there a risk of losing my hearing?
  • Does my exposure to noise exceed the legal maximum?
  • Do I need to wear hearing protection?
  • Is the noise loud enough to be distracting?
  • Is it too quiet in here?
  • Is there a way to reduce noise levels?
Select a Strategy
 
  • Probably one of the most important things you can do to improve the quality of your measurement is pick a good quality app (see our suggested list).
  • Use the table below to identify your objective(s) and follow the corresponding strategy
Objective:
Sampling Strategies:
Measure my typical noise exposure:
Measure the noise within 1 meter of your ear. If the noise is constant, just measure fora period of time until the average is stable. If the noise happens in cycles, measure the average over 1 (or more) cycle(s).
Measure my peak noise exposure:
Measure the noise within 1 meter of your ear when the peak noise occurs - average only as long as the peak is happening.
Measure at the source:
Get as closer to the source of the noise as is safe. Note the distance from the source.
Measure my peak noise exposure:
Measure the noise within 1 meter of your ear when the peak noise occurs - average only as long as the peak is happening.
Evaluate the acoustics in a room:
Measure the noise under normal conditions and measure it again when people are machines are quiet. Either measure at your workstation, or measure in the center of the room (i.e., office, classroom, non-industrial space). Measure the reverberation in the room (under quiet conditions) - see suggested apps.
Evaluate the acoustics in a room:
Measure the noise under normal conditions and measure it again when people are machines are quiet. Either measure at your workstation, or measure in the center of the room (i.e., office, classroom, non-industrial space). Measure the reverberation in the room (under quiet conditions) - see suggested apps.
Compare to hearing loss exposure standards:
Comparing your measurements to official standards requires more accuracy than an app can provide – however, there are a few rules of thumb that you can use to roughly guesstimate where your measurements falls:
  • If your exposure exceeds 80 dBA for 8 hours/day, you are probably at risk for some hearing loss in the long term (40+ years).
  • If your measurement exceeds 85 dBA and lasts for 8 hours per day, you might exceed the legislated maximum allowable exposure.
Compare to acoustic standards:
Measurements taken with apps are only a very rough estimate of the acoustical properties of a room - official measuremenst are much more complicated (and expensive) - however, as a rough rule of thumb:
  • Reverberation times above 0.7 seconds indicate too much reverberation in classrooms
  • Open plan offices with noise levels below 42 dBA are too quite (outside conversations will cause distraction).
  • Open plan offices with background noise levels (i.e. without voices) above 48 dBA indicate a ventilation system which is too loud.
Identify and reduce noise source:
Measure as close to the source as is safe, and if possible (if your app provides this information), look at the octave band results. Find a good resource to investgate noise control options at this website .
Prevent hearing loss:
Identify noise sources. Apply the hierarchy of controls:
  1. Eliminate noise source
  2. Enclose/reduce noise source
  3. Prevent noise/vibrations from traveling to workers (barriers, absorbers, etc.)
  4. Protect workers (provide hearing protection and monitoring hearing ability with regular audiometric testing).