Transcript Hearing Conservation

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How hearing works
Protecting your hearing
Health effects of noise
List of general sounds and their
associated dB level
Warning signs of potential hearing
damage
OSHA requirements
Types of protection devices
Audiometric testing
Benefits of a hearing conservation
program
Information from: http://upload.wikimedia.org/wikipedia/commons/7/7c/HumanEar.jpg
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Outer Ear
◦ The outer ear is the most external portion of the ear.
The outer ear includes the pinna, the ear canal, and
the very most superficial layer of the eardrum
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Middle Ear
◦ An air-filled cavity behind the ear drum, includes
three ear bones or ossicles: the malleus, incus, and
stapes. The opening of the Eustachian tube is also in
the ear.
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Inner Ear
◦ Includes the cochlea, vestibule, and semi-circular
canals
Sounds and the Cochlea
• The intensity of sound waves impact the hair
cells in the Cochlea
• If the hair cells are damaged, it impacts our
ability to hear
• Compare this diagram to your audiogram
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Outer Ear
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Middle Ear
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Inner Ear
◦ Pinna-Laceration from glass, knives, and bites,
avulsion injuries, cancer, frostbite, and burns
◦ Ear Canal- Firecrackers or explosives, and
mechanical trauma from placement of foreign
bodies into the ear
◦ Firecrackers or explosives, and mechanical
trauma from placement of foreign bodies into the
ear
◦ Exposure to elevated sound levels (noise trauma),
and exposure to drugs and other substances
(ototoxicity)
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Conductive hearing loss
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Sensory hearing loss
◦ Excessive ear wax
◦ Damaged ear drum or other structures of the ear
◦ Generally reversible by medical or surgical means
◦ Hair cell and nerve damage
◦ Irreversible
◦ Most often caused by noise exposure
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Hearing loss effects the ability to
communicate
Social interaction is affected
May impact the body’s reaction to stress
◦ Circulatory system
◦ Digestive and elimination system
◦ Immune system
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May impact sleep patterns
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Airboat 108 dBA
Band Saw 104 dBA
Blower 99 dBA
Concrete Saw 112 dBA
Chain Saw 110 dBA 32
Combine operator 95
dBA Compressed Air 92
dBA Edger 86 dBA
Fire Alarms 95 dBA
Front End Loader 95
dBA
Hedge Trimmer 103
dBA
Miter Saw 109 dBA
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Pneumatic Staking 103
dBA Pressure Washer
100 dBA
Radial Arm Saw 103
dBA
Riding Lawn Mower 90
dBA Sprayer, 1,000 gal.
101 dBA Table saw 93
dBA
Tractor 92 dBA
Vacuum 87 dBA
Weed eater 96 dBA
Wet/Dry Vac 94 dBA
From University of Florida information found at http://www.ehs.ufl.edu/OCCMED/noiselvl.pdf
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People seem to mumble more frequently
You experience ringing in your ears
You often ask people to repeat themselves
Your family complains that you play the radio or TV
too loudly
You no longer hear normal household sounds, such
as the dripping of a faucet or the ringing of a
doorbell
You have difficulty understanding a conversation
when in a large group or crowd
You have trouble understanding all the words in a
conversation
You find telephone conversation increasingly difficult
You have trouble hearing when your back is turned to
the speaker
You have been told you speak too loudly
Information from the Internet site: http://www.beltone.com/welcome/warningsigns.aspx
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Annual training
Area and personal noise monitoring
Audiometric testing and Standard Threshold Shifts
Hearing Protectors
Employee and Supervisor Responsibilities
Recordkeeping
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Area monitoring
◦ Conducted using a sound level meter and octave band
analyzer
◦ Noise maps show areas that are above 85 dBA with a
single hash mark and areas above 105 dBA with
double hash marks
 Corresponds to single and double hearing protection
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Personal monitoring
◦ Conducted using a noise dosimeter
◦ Reports are provided to employees to show their daily
peak noise exposure, time weighted average, and
exposure when wearing hearing protectors
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Annual requirements – within 12 months per
code
Testing is conducted from 500 to 8000 hertz
◦ Conversation range is 2000 – 4000 hertz
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Comparison with an employee’s baseline test
to watch for Standard Threshold Shifts
◦ If a shift is identified, another audiogram is
conducted within 30 days to confirm the shift
 loud noise exposure can cause a temp. shift
 congestion or a cold
 medical conditions such as ear infections
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A decrease in
hearing
ability
resulting in
an average
shift of 10dB
or more in
the 2000,
3000, and/or
4000 Hertz
range
Year
2000
3000
4000
Baseline
10
10
15
2008
10
20
35
Change
0
10
20
Average shift is 10 dB
0 + 10 + 20 = 30
30 / 3 = 10
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Based on an 8 hour time weighted average
Hearing Conservation Program with noise
exposure levels over 90 dBA
Hearing protectors required at 90 dBA
Annual audiograms (within 12 months)
Annual training
Noise Levels
OSHA
Noise Level
dBA
Time
(Hours)
90
8
95
4
100
2
105
1
110
½
115
¼
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Reduce the impact of sound waves to the
eardrum
Designed to reduce sound levels in the various
ranges of the work environment – especially the
4,000 Hz range.
◦ Much of the industrial noise levels are high in the 4000
Hz levels so there is a significant hearing loss called the
4000 Hz “notch”
◦ On the audiogram it is often noticed that there is a
notch at 4000 Hz
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Ear Muffs
◦ 23 to 30 dBA Noise Reduction Rating
◦ When used with other hearing protection an
additional 5 dB reduction is provided
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Ear Plugs
◦ DISPOSABLE!!!! Change them often
◦ 28 to 33 dBA Noise Reduction Rating (NRR)
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Molded Ear Plugs
◦ Made to fit in your ear
◦ 25 dBA Noise Reduction Rating but no human
error factor
General Areas of Hearing Loss
Information from: http://www.pacificaudiology.com/audiogram/uya.html
Audiogram
Notice the 4000 Hz notch
Information from: http://www.aafp.org/afp/20000501/2749.html
Moderate Hearing Loss
4000 Hz notch is still evident
Information from: http://www.aafp.org/afp/20000501/2749.html
Corresponding Sounds
with the Audiogram
Information from: http://www.hdhearing.com/learning/part2pdf.pdf
Sounds and the Audiogram
Information from: http://www.hdhearing.com/learning/part2pdf.pdf
Sounds and the Cochlea
• We learned the intensity of sound waves impact
the hair cells in the Cochlea, which then impacts
our hearing.
• Compare this diagram to your audiogram.
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Quality of life
◦ Ability to participate in conversations
◦ Ability to hear nature sounds – birds, deer, water
◦ Ability to hear a child speak – “Grandpa, I love you.”
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Job performance
◦ Ability to detect sounds for maintenance of
machinery
◦ Safety and security
◦ Reduce stress and fatigue
Wear hearing protection – it is worth the time.
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OSHA Hearing Conservation Standard
www.osha.gov
http://upload.wikimedia.org/wikipedia/com
mons/7/7c/HumanEar.jpg (Wikipidia)
http://www.hdhearing.com/learning/part2p
df.pdf (HD Hearing)
Workers Comp. for British Columbia