Table : TABLE 3.2
Decibel Levels of Some Common Sounds
DecibelsExamplesExposure Danger
180Rocket launching padHearing loss inevitable
140Shotgun blast, jet planeAny exposure is dangerous
120Speakers at rock concert, sandblasting, thunderclapImmediate danger
100Chain saw, pneumatic drill2 hours
90Truck traffic, noisy home appliances, lawn mowerLess than 8 hours
80Subway, heavy city traffic, alarm clock at 2 feetMore than 8 hours
70Busy traffic, noisy restaurantCritical level begins with constant exposure
60Air conditioner at 20 feet, conversation, sewing machine 
50Light traffic at a distance, refrigerator 
40Quiet office, living room 
30Quiet library, soft whisper 
0Lowest sound audible to human ear