Noise And Vibration Hazards - NOISEANDVIBRATION

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Click to edit Master subtitle style   NOISE AND VIBRATION Occupational Safety and Health Alex Proaps April 15th
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  Overview Hearing Loss Prevention Characteristics of Sound Hazard Levels and Risks Standards and Regulations Workers’ Compensation and Noise Hazards Identifying and Assessing Hazardous Noise Conditions Noise Control Strategies Vibration Standards Other effects of Noise Hazards Corporate Policy
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  Characteristics of sound Sound Any change in pressure detected by the ear Air pressure is most common Can be water or any pressure-sensitive medium Vibration Inaudible Perceived through the sense of touch Sound waves compressions and rarefactions of air molecules
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  Characteristics of sound cont. DeciBel unit of measurement to express the intensity of sound DeciBel (dB) = 20 log10(P/Po) P  = amplitude of sound wave Po  = reference point (1,000 Hz tone at sea level -.0002 dynes/cm2) dynes/cm2  = measure of power/pressure against a flat surface dB SPL  = Sound Pressure Level physical measure of sound dB SL  = Sensation Level
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  Characteristics of sound cont. Source (distance) Decibels (Db) Human whisper (at 1 m) 20 dB Human conversation (at 1 m) 60-70 dB Power saw (at 1 m) 110 dB Yelling in someone's ear 114 dB Threshold of pain to human ear 120-130 dB Sirens (at 1 m) 134 dB Jet engine (at 20 m) 140 dB Peak of rock music (at 5 m) 150 dB Blue whale 188 dB Hearing threshold level (HTL) hearing level when a specified sound or ton is heard  by an ear during a specified fraction of trials
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  Characteristics of sound cont. Hertz (Hz) unit of measurement for audio frequencies Ranges from 20 Hz to 20k Hz Three broad types of industrial noise Wide band noise Narrow band noise Impulse noise
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  Hazardous sound Any sound for which any combination of frequency,  intensity or duration is capable of causing  permanent hearing loss in a specified population Hearing loss is the fundamental hazard associated  with excessive noise
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  Hearing loss risk factors Intensity of noise (sound pressure level) * Type of noise (frequency) * Duration of daily exposure * Total duration (yrs) of exposure * Age of individual Coexisting hearing diseases Nature of environment in which exposure occurs Distance of the individual from source of noise
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  Types of hearing loss Conductive hearing loss affects the outer or middle ear Sensorineural hearing loss affects inner ear or auditory nerve
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This note was uploaded on 04/21/2011 for the course PETROLEUM PET 532 taught by Professor Moazzam during the Spring '11 term at University of Karachi.

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Noise And Vibration Hazards - NOISEANDVIBRATION

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