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 | |
| Discotheque/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 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.