-Hearing conservation听力保护.ppt

In this course we will cover the following topics…;Company should implement a Hearing Conservation program to protect employees from over-exposure to noise in the workplace.;Master Content Page | Chapter 2 – Background information of noise | Page 1 of 3;What exposure to loud noise will do?;If two people 3 feet apart must shout to be heard, the background noise is too loud (above 85 dB).;Conductive – outer ear to footplate of the stapes;Sociocusis = hearing loss due to insult noise i.e. walkman, radios and rock music, etc.;Tinnitus can interfere with work, sleep, and normal communication with others.;The cochlea, is a spiral structure in the inner ear that looks like a snail shell. It contains about 40,000 hair cells that move in response to sound waves.?These movements stimulate nerve cells to send messages to the brain, which the brain interprets as sound;When exposed to excessive levels of noise without proper hearing protection, the hair cells are damaged and destroyed, resulting in hearing loss.;The process of hearing loss looks like the sward which we pace back and forth on.;Response to different intensity of sound;Any area at or above 85 dB (A) when 8 – hour average noise exposure requires use of hearing protection.;High frequency sounds are the first to be lost.;Master Content Page | Chapter 5 – Hearing protection methods | Page 1 of 9;Whenever feasible, engineering controls should be employed first. However engineering controls are not always practical or do not effectively reduce noise to acceptable levels. In this case personal hearing protection is needed.;There are two basic of types of hearing protectors, ear plugs and ear muffs. Disposable ear plugs are made of a soft foam, and similar materials.;Purpose: to reduce your potential for hearing loss due to occupational noise.;NRR is the noise reduction rating of the protector, in dB, indicated by manufacturer. Noise reduction ratings of 15 – 33 dB are typical for most personal hearing protection. The high