What is the decibel measure beyond which is sound is considered unwanted noise?

Question

I want the measure like 120 decibels.

It would also be helpful is a website link is included.

Answer 1

NIHL (Noise Induced Hearing Loss)  can be caused by a one-time exposure to an intense “impulse” sound, such as an explosion, or by continuous exposure to loud sounds over an extended period of time, such as noise generated in a woodworking shop.

The loudness of sound is measured in units called decibels. For example, the humming of a refrigerator is 40 decibels, normal conversation is approximately 60 decibels, and city traffic noise can be 85 decibels. Sources of noise that can cause NIHL include motorcycles, firecrackers, and small firearms, all emitting sounds from 120 to 150 decibels. Long or repeated exposure to sounds at or above 85 decibels can cause hearing loss. The louder the sound, the shorter the time period before NIHL can occur. Sounds of less than 75 decibels, even after long exposure, are unlikely to cause hearing loss.

Although being aware of decibel levels is an important factor in protecting one’s hearing, distance from the source of the sound and duration of exposure to the sound are equally important. A good rule of thumb is to avoid noises that are “too loud” and “too close” or that last “too long

Please try the following links:

http://www.nidcd.nih.gov/health/hearing/...

http://www.infoplease.com/ce6/sci/A08358...

http://www.businesslink.gov.uk/bdotg/act...

http://www.answers.com/topic/noise-pollu...

Alvin