Interpreting the Sound Ratings of a Unit

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 (8 hrs.) begins (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.