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INDUSTRIAL NOISE

INDUSTRIAL NOISE. …the nature & effects of exposure to excessive noise…..I SAID, THE NATURE & EFFECTS OF EXPOSURE TO EXCESSIVE NOISE. What is sound?. “… any pressure variation that the human ear can detect”

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INDUSTRIAL NOISE

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  1. INDUSTRIAL NOISE …the nature & effects of exposure to excessive noise…..I SAID, THE NATURE & EFFECTS OF EXPOSURE TO EXCESSIVE NOISE

  2. What is sound? • “… any pressure variation that the human ear can detect” • “…..sensation produced through the organs of hearing usually by vibrations transmitted in a material medium, commonly air.” • If a tree falls in a forest… • Noise = unwanted sound!

  3. What is the need? • Estimates show that 16.9% of the working population are employed in jobs where noise levels exceed 85 dB. • It is estimated that 1.7 million workers in the US between 50 and 59 years of age have compensable noise-induced hearing loss. The potential cost to industry could exceed $500 million.

  4. Properties of Sound • WAVELENGTH • FREQUENCY • PITCH • INTENSITY • PRESSURE

  5. HOW DO WE HEAR? • OUTER EAR (funnels waves to eardrum) • MIDDLE EAR (transfers sound energy from outer to inner ear) • INNER EAR (has receptors for hearing and position sense)

  6. THE COCHLEA • Sensory organ for hearing • Organ of Corti • Frequency is a function of position; i.e.., hairs at base respond to high frequencies

  7. EAR’S NATURAL DEFENSES • Secretion of wax • Hairs in outer ear • Bent ear canal • Contractile muscle in eardrum/middle ear • Air-filled middle ear

  8. NON-NOISE-INDUCEDHEARING LOSS • Physical blockage of auditory canal • Traumatic damage • Disease damage • Hereditary or prenatal damage • Drug-induced damage • Presbycusis

  9. NOISE-INDUCED DAMAGE • Physiological • Temporary & permanent threshold shifts • Acoustic trauma vs. noise-induced hearing loss • Psychological • Cardiovascular • Speech interference • Other

  10. The effect that excessive noise has on an individual’s hearing... • Noise intensity (sound pressure level) • Frequencies/pitch • Time/type relationship (continuous/intermittent) • Duration of exposure episodes • Total work duration • Individual susceptibilities

  11. Common sounds in decibels • Sound is measured in decibels (dB) • 10 dB – human breathing, rustle of leaves • 20 dB – average whisper • 30 dB – average residence w/o stereo playing • 50 dB – average office • 60 dB – near freeway auto traffic • 80 dB – school cafeteria • 90 dB – noise factory, noisy urban street • 100 dB – loud horns at 10 feet away • 110 dB – accelerating motorcycle at a few feet away • 120 dB – hard rock band • 130 dB – threshold of pain • 140 dB – near jet engine

  12. Common industries… • Construction • Mining • Agriculture/forestry • Manufacturing • Textile, food, lumber, furniture, paper, printing, chemicals, petroleum, leather, metal, machinery, electronics etc. • Services • Auto repair, other repair services, etc. • Transportation • Passenger transit, trucking and warehousing, transportation by air, electric, gas, and sanitary services

  13. Steps in identification • Preliminary noise survey • Carried out at work areas where it is difficult to communicate in normal tones • When workers notice that sounds are muffled or they develop ringing in their ears • Detailed noise survey • How noisy is each work area? • What equipment or process is generating noise? • Which employees are exposed to the noise? • How long are they exposed?

  14. TLV’s for Noise 8 hrs 85 dB 4 hrs 88 dB 2 hrs 91 dB 1 hr 94 dB .5 hr 97 dB .25 hr 100 dB PELs for Noise 8 hrs 90 dB 4 hrs 95 dB 2 hrs 100 dB 1 hr 105 dB .5 hr 110 dB .25 hr 115 dB TLVs and PELs

  15. Impact Noise • Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level

  16. Permissible Exposure Levels • 90 dB is established PEL • However, at 85 dB one must implement an effective hearing conservation program

  17. OSHA Hearing Conservation Program (29 CFR 1910.95) • Noise monitoring • Audiometric testing program • Employee follow-up and referral • Hearing protection • Employee training • Recordkeeping

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