ANSWERS
Unit of measurement for frequency (pitch) - Hertz (Hz)
Unit of measurement for intensity (loudness) - Decibel (dB)
Risk of damage from noise - How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator - Lasts 1 second or longer
Impulse or Impact nois...
Unit of measurement for frequency (pitch) - Hertz (Hz)
Unit of measurement for intensity (loudness) - Decibel (dB)
Risk of damage from noise - How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator - Lasts 1 second or longer
Impulse or Impact noise, e.g. gunfire or nail gun - Lasts less than one second
Parts of the outer ear - Pinna and external auditory canal
Parts of the middle ear - Tympanic membrane, ossicles, eustachian tube
Eustachian tube (auditory tube) - Tube connecting the middle ear to the pharynx and
equalizes middle ear space with atmospheric pressure
Conductive HL occurs here - Outer or middle ear
Sensorineural hearing loss - Hearing loss resulting from damage to the inner ear
(cochlea) or the auditory nerve
Noise-induced hearing loss (NIHL) - Condition caused by the destruction of hair cells,
the organs responsible for hearing, as a result of sounds that are "too long, too loud, or
too close"; a sensorineural hearing loss
Mixed hearing loss - Combination of conductive and sensorineural types in the same
ear
3 foot rule - Good rule of thumb to recognize hazardous noise exposure
levels/situations: the rule is: if you have to shout at arms length (~3ft), in order to be
understood over the background noise, then you're likely exposed to hazardous noise
levels & should be wearing hearing protection to prevent NIHL
OSHA (Occupational Safety and Health Administration) versus National institute of
Occupational Safety and Heath (NIOSH) - OSHA enforces regulation and NIOSH
recommends best practice based on science and research
Sound pressure level (SPL) versus hearing level (HL) - SPL describes noise
measurements taken with a sound level meter or dosimeter; HL describes Threshold
levels obtained with an audiometer; 0 dB HL is not equal to 0 dB SPL
Noise Dosimeter - A sound measurement device used to record the amount of sound
exposure over an extended period of
time (usually a work day)
Personal vs. Area
Sound level meter - Uses a microphone to sense pressure variations in sound waves;
the meter converts those pressures directly into decibels; provides a noise
measurement that is a snapshot in time.
Time Weighted Average (TWA) - An evaluation of exposures that is time-weighted over
an established period. It allow the exposure levels to be averaged generally over an
eight-hour time period.
OSHA exchange rate - 5 dB; for every 5 dB you go over the PEL of 90dBA TWA you
half the allowable time of exposure
OSHA Action Level for noise - 85dBA TWA
Sound Level Meter A-weighted Scale - OSHA requires this scale as it resembles how
the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz
Human Frequency Response at Birth - 20 Hz to 20,000 Hz (20 kHz)
Human speech frequency range - 250 Hz to 4000 Hz
Elements of a Hearing Conservation Program - Noise hazard assessment;
engineering/administrative controls; annual hearing monitoring; annual
training/education; hearing protection; recordkeeping
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