Chapter 8 - Noise and OSHA's Hearing Conservation Program Flashcards
OSHA Hearing Conservation Program required when
an employee’s noise exposure equals or exceeds an 8-hr time-weighted average sound level of 85 dB on the A-scale (slow response) or equivalently a dose of 50%
Do you need to implement a hearing conservation program if sound level exceeds 85 dB, but this noise exposure is attenuated by devices such as earplugs, muffs, or bands?
Yes!
Monitoring program
required when information indicates that any employee’s noise exposure may equal or exceed an 8-hr. TWA
Monitoring sampling stragety
Designed to identify employees to be included in program
Continuous, intermittent, and impulsive sound levels from 80-139 dB shall be integrated into measurements
Monitoring shall be repeated whenever a change in production, process, equipment, or control occurs
Type 1 sound level meter
Used for precision measurements in the field
Accuracy of +/- 1 dB
Type 2 sound level meter
Used for general purpose measurement in the field
Accuracy of +/- 2 dB
minimum measuring device allowed for determining an employee’s noise level exposure under the OSGA Hearing Conservation Standard
Sound level meters used to
spot check employee exposures
identify potential noise sources needing further evaluation
Assist in the feasibility of engineering controls
Octave band analyzer
Sound level meter that measures noise levels at various frequencies
useful to analyze sources of noise on the basis of frequencies, determining specific noise attenuation devices to recommend
divide noise into frequency components
provide reading for 31.5 Hz, 63 125, 250, 500, 1000, 2000, 4000, 8000, 16000
Noise dosimeter
sound level meter worn by the employee for a period time- computes dose and overall noise exposure
Employee notification
required if employee is exposed at or above 8 hr TWA of 85 dbA
affected employee or representative must have opportunity to observe noise measurements conducted
Audiometric testing
must be performed on any employee in the program
must be conducted by an audiologist, otolaryngologist or a certified technician
Baseline audiogram
within 6 months of first exposure greater than 85 dBA
audiometric testing
Baseline shall be preceded by 14h without exposure
annually after baseline
Must be pure tone, air conduction tests in the 200, 1000, 2000, 3000, 4000, 6000 Hz
Standard Threshold shift
change in hearing threshold relative to that baseline audiogram of an average of 10dB or more at 2000, 3000, or 4000Hz in either ear
This is a recordable injury
Must make allowance for contribution of aging
Hearing Conservation Program Training
Enrolled employees must train within 30 days of exposure
Topics include:
effects of noise on hearing,
purpose of hearing protectors (advantages/disadvantages of various types),
selection, fit and use and care of hearing protectors
purpose of audiometric testing
Hearing Conservation Program Record Keeping
Audiometric test record -
Name and job classification of employee
date of audiogram
examiner’s name
date of the last acoustic calibration
employee’s most recent noise exposure assessment
Noise exposure measurements required every 2 years
Noise
Unwanted sound
Harmful to humans
Can create a hearing loss if uncontrolled
Continuous Noise
sound that has unbroken sound waves of one or more different frequencies
intermittent noise
sound that has broken sound waves or is non-continuous
Sound
Oscillations in pressure above and below the ambient atmospheric pressure, generated by a vibrating surface or turbulent fluid flow, causing high and low pressure areas to be formed, which propagate away from the source
Mechanical vibrations transmitted through an elastic medium.
A sensation is produced by stimulation of organs of hearing by vibration
Frequency
number of complete cycles of a sound wave in 1 second
measured in Hz
normal range of hearing for human is 20-20000 Hz
Period
time required for one cycle
Reciprocal of frequency
Speed or velocity of sound
wavelength * frequency depends upon the medium density and compressibility speed of sound in air = 332 m/s speed of sound in water = 1500 m/s speed of sound in steel = 6100 m/s
Wavelength
distance traveled during one pressure cycle
