Training Series (Year 2)

1.    What is Hearing Conservation ?

Protecting your hearing from potentially damaging levels of noise.

2.   Why should I know about Hearing Conservation ?

Your hearing is priceless and a noise induced hearing loss is never reversible but, it is stoppable.

3.   How does the ear work ?

Sound waves enter the ear and cause the eardrum to vibrate.
Vibrations pass through 3 connected bones in the middle ear.
This motion sets fluid moving in the inner ear.
Moving fluid bends thousands of hair cells that convert the vibrations into electrical impulses.
The electrical impulses are carried to the brain by the auditory nerve.
In the brain these impulses are converted into what we "hear" as sound.

4.   How do loud noises damage my hearing ?

Continuous loud noises or extremely loud impact noise can damage these hair cells. Without the hair cells there is nothing that can convert the vibrations into what we perceive as sound.

5. What is noise ? Unwanted sound.

6.   When do I need to protect my hearing ?

Anytime background noises keep you from hearing or understanding normal speech from three feet away and anytime noises cause your ears to ring.

7.     If I wear my hearing protection devices, HPDs, around loud noises will they keep me from losing my hearing ?

It will reduce the risk of noise induced hearing loss to almost zero.

8.      It I start to lose my hearing will I notice it right away ?

Generally not, it happens so gradually you probably will not notice it until it has become extensive and by then it is too late to get back what you have already lost.

9.   Will all damaging noises be painful ?

No, not until it is extremely loud, 140 dB+ and by then, damage is probably already done. Normally, your ear will start to ring, buzz, crackle or even shut down to warn it is being damaged.

10.   What would be considered some loud noises and how loud are they ?

20 dB Very quiet room
30 dB Soft whisper
60 dB Normal Conversation
70 dB-(10 X louder than 60 dB) One kitchen appliance
80 dB-(100 X louder than 60 dB) Levels above this are loud
85 dB Prolonged exposure is dangerous, HPDs recommended, i.e., alarm clock
90 dB-(1000 X louder than 60 dB)-
90 dB to 100 dB		 A vacuum cleaner, power equipment, general workshop, sheet metal shop, and lawnmower
100 dB-(10,000 X louder than 60 dB) 100dB to 110 dB Riveting, locomotives, ship engine room and highways
110 dB-(100,000 X louder than 60 dB) 110 dB to 115 dB Drop forges, textile and concrete industries, payloaders, and 410 shotgun
120+-dB Forest machineery, pneumatic drills and 12 ga. shotguns
130+-dB Dual protection recommended: mining, and chainsaws
140+-dB Start feeling pain: airfields, jet engines, and 357 mag.
150+-dB Deck of aircraft carrier, 44 mag., and rock concert

11.     What is the best type of hearing protection device, HPD, for me to wear ?

The best one is the one that you will and can comfortably wear the entire time you are exposed and one that will get your exposure below the 85 dB level.

12.     How do I know when I am under the 85 dB level ?

Find out the level of noise you work in, find the NRR of the HPDs and subtract 7 from that number, then subtract that number from your work level.  Answer should be below 85.

Example: Work level 100 dB
  - [NRR(28)-7] -21 dB
  Exposure  79 dB