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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
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Noise and Hearing Conservation UCOP Safety Meeting March 2010 Developed by Karen Hsi, UCOP EH&S Student Intern
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
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 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 Loss Conductive • 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
CH P S K H TH T F SH High-Frequency Sounds of Speech
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 … Painless Permanent Progressive … and very PREVENTABLE!