Noise and Hearing Conservation

Developed by Karen Hsi, UCOP EH&S Student Intern
Hazardous noise exposures occur
On the job…
And off the job…
Sound Level Meter Instant reading
› Quest 2200
› Sound level range from
30 to 140 decibels (dB)
Temporary damage to sensorineural
system – temporary threshold shift (TTS)
 Permanent threshold shift (PTS) is noise
induced hearing loss
 Loss of communication
 Physiological effects
Causes no pain
Causes no visible trauma
Leaves no visible scars
Is unnoticeable in its earliest stages
Accumulates with each over-exposure
Takes years to diagnose
Is permanent and 100% preventable
 Continuous
- 85 decibel, 8 hour time-weighted average (TWA)Action Level
~Hearing conservation programs
~Annual audiometric examinations
- 90 decibel, 8 hour TWA- Permissible
Exposure Level
~Wear Earplugs
If you must shout to be understood over the
background noise when standing about
one arm-length away from somebody,
that background noise is
potentially hazardous.
Permissible Exposure Limits
Permissible Exposure Limits
Sound waves cause
the eardrum to
Bones in middle ear
transmit vibrations to
Receptors (hair cells)
in cochlea convert
vibrations to
electrical energy
Brain interprets these
electrical impulses as
Nerve cells in the
cochlea are tuned
to specific
Base of the cochlea
is sensitive to high
frequency sounds
Tip of the cochlea is
sensitive to low
frequency sounds
Caused by damage
to or a malfunction of
the outer and middle
 Some causes
Excessive ear wax
Fluid in the ear
A torn eardrum
Usually hearing is
restored once the
cause is diagnosed
and treated
Caused by damage to or
a malfunction of the inner
ear, auditory nerve, or the
 Causes of sensory hearing
› Aging, Damage to fetus,
Hereditary, Noise, Disease,
Injury, Drugs
Cannot be corrected
medically or surgically
 Hearing loss in the
workplace is typically a
sensory hearing loss
Imagine you are at
a classical
concert.. but you
are experiencing
progressive hearing
loss during it. Listen
to the difference!
 Indoor (Office Environment)
› Office Background Noise–45 to 60 decibels
› Elevator-55 to 65 decibels
› Normal Conversation-60 to 65 decibels
› Copying Machine-65 to 70 decibels
 Outdoors (Street)
› Street Background Noise– 65 to 75 decibels
› Trucks, Buses Driving By-75 to 80 decibels
 All
noise levels found are within the
Cal/OSHA permissible exposure limits
Dr. Dean Garstecki, audiologist from
Northwestern University, suggests
that i-Pod users take precautions
Hearing loss found in younger
people that is normally found in
aging adults
› Listening to music at 110 to 120
decibel range
Earbuds can boost sound signal by
6-9 decibels
Follow the 60% volume/60 minute
Wear Noise- Cancelling
 Helps to cancel out
background noise and
prevents listeners from
cranking up the volume on
their i-pods/mp3 players.
 Also recommends use of older
style, larger headphones that
rest over the ear opening.
UC Site Visits
› Construction & Shops- Machinery, Backhoe,
Tools, Jackhammers, etc.
› Power Plants
Travel – Small Aircraft
 Personal Activities/Hobbies
› Gardening – Lawn Mower, Hedge Trimmer
› Carpentry/Tools, Shooting Range,
Wear earplugs or earmuff to protect your
Hearing Loss Due To
Noise Exposure Is …
… and very PREVENTABLE!

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