Interpreting the Sound Ratings of a Unit

Decibel (dB) Comparisons

Common Sounds
This decibel (dBA) table compares some common sounds and shows how they rank in potential harm to hearing. In many industries, workers are exposed to dangerous noise levels. This is particularly true in the construction, lumber, mining, steel and textile industries.

SOUND NOISE LEVEL (dBA) EFFECT
Jet Engines (Near) 140  
Shotgun Firing 130  
Jet Takeoff (100-200 Ft.) 130  
Rock Concert (Varies) 110-140 Threshold of pain (125 dB)
Oxygen Torch 121  
Disco/Boom Box 120 Threshold of sensation (120 dB)
Thunderclap (Near) 120  
Stereo (Over 100 Watts) 110-125  
Symphony Orchestra 110 Regular exposure of more than 1 minute risks permanent hearing loss (over 100 dB)
Power Saw (Chain Saw) 110
Jackhammer 110
Snowmobile 105  
Jet Fly-over (1000 Ft.) 103  
Electric Furnace Area 100 No more than 15 minutes of unprotected exposure recommended (90-100 dB)
Garbage Truck/Cement Mixer 100
Farm Tractor 98
Newspaper Press 97  
Subway, Motorcycle (25 Ft) 88
Very annoying
Lawnmower, Food Blender 85-90 Level at which hearing damage begins after 8 hours (85dB)
Recreational Vehicles, TV 70-90  
Diesel Truck (40 Mph, 50 Ft.) 84  
Average City Traffic Noise 80 Annoying; interferes with conversation; constant exposure may cause damage
Garbage Disposal 80
Washing Machine 78  
Dishwasher 75  
Vacuum Cleaner 70 Intrusive; interferes with telephone conversation
Hair Dryer 70
Normal Conversation 50-65  
Quiet Office 50-60 Comfortable (under 60 dB)
Refrigerator Humming 40  
Whisper 30 Very quiet
Broadcasting Studio 30  
Rustling Leaves 20 Just audible
Normal Breathing 10  
  0 Threshold of normal hearing (1000-4000 Hz)

Since the sensitivity of the ear to sound is not the same for all frequencies, weighting or attenuating filters are included in the sound level meter's circuits to simulate the ears' response. A noise level meter gives an instantaneous measurement of the noise present, but cannot measure the duration of the exposure. To measure the amount of noise a person is exposed to over a period of time, a "dosimeter~ or an integrated sound level meter must be used. Sources for the above include the American Medical Association and the Canadian Hearing Society of Ontario. Decibel table developed by the National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892. January 1990.