Noise and Hearing Conservation
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Transcript of Noise and Hearing Conservation
Noise and Hearing Conservation
UCOP Safety Meeting March 2010
Developed by Karen Hsi, UCOP EH&S Student Intern
Noise and Acoustics
Noise and Acoustics Hazardous noise exposures occur
On the job… And off the job…
Measuring Noise Sound Level Meter -
Instant reading› Quest 2200› Sound level range
from 30 to 140 decibels (dB)
Effects of Noise Temporary damage to sensorineural
system – temporary threshold shift (TTS)
Permanent threshold shift (PTS) is noise induced hearing loss
Loss of communication Physiological effects
Noise Induced Hearing Loss 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
Noise and Acoustics
Regulatory Levels Continuous Noise
- 85 decibel, 8 hour time-weighted average (TWA)- Action Level
~Hearing conservation programs~Training~Annual audiometric examinations
- 90 decibel, 8 hour TWA- Permissible Exposure Level
~Wear Earplugs
How do I know if the noise levels are hazardous?
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.
Time Weighted Average
Permissible Exposure Limits
Time Weighted Average
Permissible Exposure Limits
How We Hear…
How the Ear Works… Sound waves cause
the eardrum to vibrate Bones in middle ear
transmit vibrations to cochlea
Receptors (hair cells) in cochlea convert vibrations to electrical energy
Brain interprets these electrical impulses as sound
Reponses of the Cochlea Nerve cells in the
cochlea are tuned to specific frequencies
Base of the cochlea is sensitive to high frequency sounds
Tip of the cochlea is sensitive to low frequency sounds
Two Types of Hearing LossConductive Caused by damage to
or a malfunction of the outer and middle ear
Some causes› Excessive ear wax› Fluid in the ear› A torn eardrum› Colds
Usually hearing is restored once the cause is diagnosed and treated
Sensory Caused by damage to or a
malfunction of the inner ear, auditory nerve, or the brain
Causes of sensory hearing loss› 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
High-Frequency Sounds of Speech
K P
SH
STHTF
CH
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Let’s hear what it sounds like to have progressive hearing loss… Imagine you are at
a classical concert.. but you are experiencing progressive hearing loss during it. Listen to the difference!
Typical UCOP Noise Levels 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
Noise exposure from MP3 Players and/or i-Pods with headphones
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
rule
Other Options… Wear Noise- Cancelling
Headphones 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.
Other Types of Noise Exposures
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!!
Hearing Loss Due To Noise Exposure Is …
PainlessPermanentProgressive
… and very PREVENTABLE!