Hearing Conservation Program Flashcards
OSHA action level for noise?
85 dBA
OSHA requires audiometric testing baseline on employees entered into hearing conservation program within what time frame?
6 months.
OSHA requires audiogram must be performed within 6 months of an employee’s first exposure at or greater than 85 decibels, 8 hours TWA) and annually thereafter.
OSHA PEL for noise
90 dBA 8 hour TWA
Short term exposure level (STEL) of 115 dBA
15 min
Hearing conservation program?
Work site surveillance: visual inspection & noise measurement and analysis Medical surveillance Audiometric testing Engineer control Hearing protection Record keeping
Which solvent has synergistic effect with noise to hearing lose?
Styrene
Physical or chemical agents that have synergistic effects on hearing loss?
Vibration Organic solvent (styrene) CO Ototoxic drugs eg. frusemide Certain metals
Conductive hearing loss?
Disruption of external or middle ear with normal inner ear function
Sensorineural hearing loss
Damage medial to stapedial plate -cochlear (inner ear) -retrocochlear (auditory nerve) Noise can irreversibly damage hair cells in Organ of Corti Greater hearing loss at higher frequency -usually starts at 4000 Hz (4K notch)
Unilateral hearing loss often seeing in what occupation?
Truck drivers (one window opens, close to one year) Military person or police using firearms
Medical disorder that could have unilateral hearing loss?
Acoustic neuroma
Meniere’s in adults
Hearing speech is related to a hearing thresholds of
500 to 2000 Hz
Noise induced hearing loss classically peaks at ?
4000 Hz
Human voice is in the range of ?
300- 700 Hz
Human ear can hear frequency in the range of?
20 - 20,000 Hz
Human ear is most sensitive in the range of
1000- 4000 Hz
The anatomical location of change that results in the Temporary threshold shift is at?
Organ of Corti
A chemical change in the composition of the fluid or a metabolic change in the hair cells themselves
What is a STS (standard threshold shift)?
An average shift in either ear of of 10 dB or more at 2000, 3000, and 4000 Hz.
At what frequency does noise induced hearing loss first show up on an audiogram ?
3k-6k Hz
Anatomical damage of noise induced hearing loss?
Hair cell of inner eat
What is the limit of hearing damage, currently suggested by AMA, before compensation should be awarded?
Average of 25 or less at 500, 1000, and 2000 Hz.
If >25 dB loss then compensation is suggested
Decibels are measured on a logarithmic scale
Every time you add 5 dB, you double the sound, you need to half the time limit according to OSHA: 90 dB 8 hr 95 dB 4 hr 100 dB 2 hr 105 dB 1 hr 110 dB 30 min 115 dB 15 min
Under OSHA standard, a STS (10dB) in either ear must be recorded on?
OSHA 300 log or MSHA Form 7000-1
Employer is responsible for record keeping regarding employee noise exposure. How long does the Noise monitoring results need to be kept?
For at least 2 years
How long has an employee’s Audio metric results be kept?
It must be maintained for the duration of the employment of the employee plus 30 years.
NRR
Noise reduction rating for hearing protection devices:
The higher the number, the greater the protection.
Noises reduction
= (NRR - 7)/2
After the determination that a employee’s audiometric test results show an STS, the employer must be notified within how many days?
21 days
Is age adjustment necessary for STS?
Yes
