Noise (Hearing Protection)

How Does the Ear Work?
The ear consists of three basic parts - the outer ear, the middle ear, and the inner ear.
Each part of the ear serves a specific purpose in the task of detecting and interpreting sound.
The outer ear collect and channel sound to the middle ear.
The middle ears transform the energy of a sound wave into the internal vibrations of the bone structure of the middle ear and ultimately transform these vibrations into a compressional wave in the inner ear.
The inner ears transform the energy of a compressional wave within the inner ear fluid into nerve impulses which can be transmitted to the brain. 



How is the damage done?
•Noise damages the nerve cells that respond to sound in the inner ear, or cochlea.
•These cells work in a complex way, to give us the ability to distinguish between sounds of different tone. So when they're damaged it doesn't just mean that you can't hear quiet sounds –
•It has more subtle effects on the clearness of hearing.
•It is easy to understand that the vibration of extremely loud sounds causes direct mechanical damage.
•It breaks the sub-microscopic finger- (nerve cells) that respond to sound.
•This clearness can't be restored by an electronic support.

Can I “Strengthen Up” My Ears?
No. If you think you have grown used to a loud noise, it probably has damaged your ears. there is no treatment–no medicine, no surgery, not even a hearing aid–that completely restores your hearing once it is damaged by noise.
What is Decibels?
•Intensity of sound is measured in decibels (dB). The scale runs from the faintest sound the human ear can detect, which is labeled 0 dB, to over 180 dB 

What decibel levels are damaging to the ear?
•According to (OSHA) standards, You are risk for hearing damage if you exceed 85 dBA over 16 hours. Every increase of 5 dB in level decreases the exposure time by half. So for 90 dB, it's 8 hours; 95 db, 4 hours; 100 dB 2 hours, etc 







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What Are Hearing Protectors? How Effective Are They?
•Hearing protection devices decrease the intensity of sound that reaches the eardrum. They come in two forms: earplugs and earmuffs. 
•Earplugs are small inserts that fit into the outer ear canal. They must be snugly sealed so the entire circumference of the ear canal is blocked. An improperly fitted, dirty or worn-out plug may not seal and can irritate the ear canal.
•Earmuffs fit over the outer ear to form an air seal so the entire circumference of the ear canal is blocked, and they are held in place by an adjustable band. Earmuffs will not seal around long hair, and the adjustable headband tension must be sufficient to hold earmuffs firmly around the ear.      
                      
Who Should Wear Hearing Protectors?
If you must work in an excessively noisy environment, you should wear protectors. You should also wear them when using power tools, noisy yard equipment, a motorcycle, etc 
Habitual exposure to noise above 85 dB will cause a gradual hearing loss in a significant number of individuals, and louder noises will accelerate this damages


How High Can the Decibels Go without Affecting My Hearing?
•Many experts agree that continual exposure to more than 85 decibels is dangerous without protection. And also According to Federal (OSHA) standards 
•Does the Length of Time I Hear a Noise Have Anything to Do with the Danger to My Hearing? 
•It certainly does. The longer you are exposed to a loud noise, the more damaging it may be. Also, the closer you are to the source of intense noise, the more damaging it is.

Can Noise Affect More Than My Hearing?
•A ringing in the ears, called tinnitus, commonly occurs after noise exposure, and it often becomes permanent. Some people react to loud noise with anxiety and irritability, an increase in pulse rate and blood pressure, or an increase in stomach acid. Very loud noise can reduce efficiency in performing difficult tasks by diverting attention from the job. 

All such equipment is capable of producing loud and high pitch noise, which will eventually damage your hearing in the long run.  To address this health problem, below are some of the measures, which you can do to protect your hearing.
Noise is major health hazard. It may be defined as unwanted sound that disturbs the mind and causes deafness.

1.    There are number of processes in the workplace that produce excessive noise above the permissible level of 85 dB (A).For examples, the air compressor, forklift, crane, and gouging work.

2.   At such noise level, 2 persons, about 1 meter, away need to shout at each other to be heard.

3.    Excessive noise level (above 85 dB (A)) can cause deafness over a period of time, usually over 5 years.  This is called Noise Induced Deafness (NID) and is irreversible, thus the importance of prevention should not be overlooked.

4.    There are two methods of preventing NID, one is to control it at source, that is, at the point where noise is being generated; the other one is to protect the worker when the first method cannot be achieved.

5. Controlling noise at source includes regular maintaining and repairing machinery and equipment, use of anti-vibration mountings, use of silencer etc.

6.    Two ways of protecting the workers are:

·        Use of earplugs:       Reduce noises about 20 dB (A).

·        Use of earmuff:        Reduce noises about 40 dB (A).