COHC flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- OSHA action level
- The OSHA hearing conservation action level is an 8-hour time-weighted average of 85 dBA, which triggers a hearing conservation program for exposed employees.
- OSHA permissible exposure limit
- The OSHA PEL for noise is 90 dBA as an 8-hour time-weighted average; engineering or administrative controls are required before relying on hearing protectors.
- Hearing conservation program elements
- Required elements include noise monitoring, audiometric testing, hearing protection, employee training, and recordkeeping; these components must be provided when exposures reach or exceed the action level.
- Baseline audiogram deadline
- A baseline audiogram must be obtained within six months of an employee's first exposure at or above 85 dBA, unless a mobile test van allows an extension under OSHA rules.
- Noise dosimeter
- A noise dosimeter is a wearable instrument that measures an individual's accumulated noise dose and time-weighted average over a work shift.
- Five-decibel exchange rate
- Under the OSHA 5 dB exchange rate, a 5 dBA increase doubles noise dose and halves the allowable exposure time; 90 dBA is allowed for eight hours.
- OSHA TWA formula
- For an eight-hour dose, OSHA calculates TWA as 16.61 times the base-10 logarithm of dose divided by 100, plus 90 dBA.
- Sound level meter
- A sound level meter measures sound pressure level at a location; it is used for area surveys but does not directly measure a worker's personal noise dose.
- Cochlear hair cells
- Cochlear hair cells are sensory cells in the inner ear that convert sound vibrations into nerve signals; noise damage to these cells is permanent.
- Noise notch
- A noise-induced hearing loss pattern often shows a notch at 3000 to 6000 Hz, commonly near 4000 Hz, with relative preservation of lower frequencies.
- Sensorineural hearing loss
- Sensorineural hearing loss results from damage to the cochlea or auditory nerve; most noise-induced hearing loss is sensorineural and irreversible.
- Temporary threshold shift
- A temporary threshold shift is a reversible hearing loss after noise exposure; repeated temporary shifts can lead to permanent threshold shift over time.
- Audiometric test frequencies
- OSHA audiograms test air-conduction thresholds at 500, 1000, 2000, 3000, 4000, and 6000 Hz in each ear.
- Audiometric booth requirement
- Audiometric testing must occur in a test environment whose background noise does not invalidate thresholds; OSHA Appendix D lists maximum permissible octave-band sound levels.
- Pure-tone threshold
- A pure-tone threshold is the lowest hearing level at which a listener responds to a tone at least 50 percent of the time during ascending presentations.
- Annual audiogram
- An annual audiogram is required for employees exposed at or above 85 dBA and is compared with the baseline to detect a standard threshold shift.
- Daily biological check
- Before daily audiometric testing, a person with stable hearing is tested to confirm that the audiometer and earphones produce expected thresholds.
- Annual audiometer calibration
- Audiometers must receive acoustic calibration at least annually to ANSI standards, verifying frequency, output level, attenuator linearity, and distortion.
- Audiometer listening check
- A listening check verifies that audiometer output is free of distortion, unwanted noise, or intermittent sound before testing employees.
- Earphone cushion inspection
- Inspect earphone cushions and headbands for cracks, hardening, or poor tension because defects can change attenuation and invalidate audiometric thresholds.
- Standard threshold shift
- An OSHA standard threshold shift is an average hearing loss of 10 dB or more at 2000, 3000, and 4000 Hz in either ear.
- STS retest interval
- When a standard threshold shift is found, the employer should retest within 30 days; if confirmed, the baseline may be revised and the shift recorded.
- Recordable hearing loss
- A standard threshold shift is recordable on the OSHA 300 log when the average hearing level at 2000, 3000, and 4000 Hz is 25 dB or more.
- Baseline revision
- A confirmed standard threshold shift may become the new baseline; if the retest does not confirm the shift, the original baseline remains in effect.
- Noise reduction rating
- The noise reduction rating is a single-number laboratory estimate of hearing protector attenuation; actual workplace protection is often lower.
- OSHA NRR formula
- For A-weighted exposure, OSHA estimates protected exposure as TWA minus the quantity NRR minus 7; for C-weighted exposure, subtract NRR directly.
- Personal attenuation rating
- A personal attenuation rating is a fit-test result showing attenuation for an individual worker with a specific protector and fit.
- Foam earplug insertion
- Roll the foam plug into a narrow cylinder, pull the pinna back, insert deeply, and hold until expansion to obtain a proper seal.
- Annual hearing training
- Employees in a hearing conservation program must receive annual training on noise effects, audiometric testing, hearing protector selection, fitting, use, and care.
- Audiometric record retention
- OSHA requires audiometric test records to be retained for the duration of employment plus 30 years, and noise exposure records for two years.
- Noise exposure record retention
- Noise exposure measurements must be retained for two years and made available to affected employees or their representatives.
- Program evaluation metrics
- Evaluate a hearing conservation program using standard threshold shift rates, dosimetry results, hearing protector use, training completion, and calibration records.