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NOISE. Noise - what is it?. Unwanted sound sound is vibrations in air Sound Pressure Level decibels (dB) - sound loudness Frequency hertz (Hz) - vibrations per second Good human ears hear sounds between 20 to 20,000 Hz. Types of Noise . Continuous same noise level over long periods
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Noise - what is it? • Unwanted sound • sound is vibrations in air • Sound Pressure Level • decibels (dB) - sound loudness • Frequency • hertz (Hz) - vibrations per second • Good human ears hear sounds between 20 to 20,000 Hz.
Types of Noise • Continuous • same noise level over long periods • Intermittent • periods of quiet interrupted by noise • most noise exposures are intermittent • Impact or impulsive • nail gun • Most jobs have combinations of all noise types
Is noise a big problem? • 28 Million Americans affected • NIOSH says 2.5 million workers/year are affected • Over 500,000 construction workers are overexposed. • 50% of construction workers may have some job-related hearing loss • 33% of hearing loss is from NIHL • A 25 year old construction worker has the hearing of a 50 year old without noise exposure • Once hearing is gone, it is lost forever
Construction Workers • What does that mean to our workers • How do we protect them • Hierarchy of controls • Common exposures • jackhammer • power tools • heavy machinery
You • What does that mean to you? • Loss of hearing through aging (presbycusis) • Born with ~ 40,000 cilia in ear canal • Common Exposures • iPods, headphones • loud music/concerts • hunting • other
Decibels Noise levels are measured in decibels (dBA) • A small increase in decibels equates to a large increase in noise (logarithmic) • An increase of just 3 dB doubles the amount of sound 88 dB can do twice as much harm to your ears as 85 dB. An increase of 10 dB means it is 10 times louder • Typical levels: • 65- normal conversation • 75- busy street corner • 85- background noise on a construction site
How Do We Hear? • Outer ear collects sound and vibrates eardrum • Eardrum vibrates bones in middle ear • Bones transmit vibrations to cochlea (inner ear) • Cochlea hair cells are connected to auditory nerve that runs to the brain
Effects of Noise • Temporary Threshold Shift (TTS) • temporary hearing loss • early sign of a hearing problem • recovery within hours after exposure
Effects of Noise • Permanent Threshold Shift • permanent hearing loss • destroys hair cells • no treatment or cure • gradual
Effects of Noise • Tinnitus - ringing in the ears • Non-auditory problems • Constant state of “alert” • Disturbed sleeping patterns • Increased blood pressure • Presbycusis • hearing loss from aging • may be compounded by excess noise
Effects of Hearing Loss • Hearing loss makes it harder to communicate on the job, with friends and family, especially in noisy places like jobsites and restaurants • Hearing loss can make it difficult to hear warning signs like back up alarms or traffic on a street
Other Health Effects • Make you feel tired/fatigued • Heighten nervousness • Raise in blood pressure • Increase risks of heart problems • May also effect sense of balance • These effects are permanent
What can you do? • Turn down the volume • When listening to music on earphones at a medium volume, the noise generated reaches up to 100dBA • Loud enough to cause permanent damage after just 15 minutes/day • Use hearing protection • Walk away • 3 Foot Rule
OSHA Requirements • Construction 90 dBa • General Industry 85 dB • Hearing Conservation Program (1926.52)
Task-Based Method • ANSI A10.46-Hearing Loss Prevention in Construction and Demolition Workers • When equipment or tasks expose workers to sound levels exceeding 85 dBA, engineering or administrative controls should be implemented • Where controls are infeasible or fail to reduce sound levels below 85 dBA, HPD’s shall be provided and used by employees
Effective Hearing Conservation Program • Monitoring of employees’ noise exposures, • Engineering, work practice, and administrative controls, • PPE • Employee training and education • Baseline and annual audiometry, • Procedures for preventing further occupational hearing loss • Recording Keeping
Hearing Protectors • Ear Plugs • Semi-Inserts • Ear Muffs • Attenuation
Ear Plugs • Formable • Pre-molded • Custom-molded • Pros • cooler in hot weather, cheaper • Cons • attenuation varies with fit • easier to lose • hygiene problems
Ear Plugs • To fit correctly, ear plugs must be inserted snugly into the ear canal. • Make sure the foam plugs are rolled up tight and is crease free. Use the Roll model for practicing. • Pull back gently on the ear with your opposite had to straighten out the canal while inserting the plug.
Proper Fit • Ear plug is snug in the ear canal
Incorrect Fit • Ear plug is not in snug and protection level is much lower
Semi-Inserts • Ear plug connected by headband • Insert into the canal or cap over it • Intended to be worn for short duration • Pros • easier to take on and off • Cons • uncomfortable for extended use • smaller attenuation
Ear Muffs • Plastic cups attached by headband • Pros • easier to fit to most people, more consistent attenuation than plugs, can be fitted hardhats • Cons • heavier/hotter than plugs, • headband pressure can make long wear uncomfortable