Case Study of Noise-Induced Hearing
Loss. The audiogram below belongs to a man whose hearing
loss was caused by gunfire while serving in World War II.
After the war, he continued to be active in shooting sports.
You can see that his hearing loss is most pronounced in the
areas critical to understanding speech.
Symptoms of Hearing Loss:
Hearing but not understanding
Turning up the volume on the TV
Must lip read to understand speech
Cannot hear environmental sounds such
as game calls, traps releasing, crickets, etc.
Strained personal relationships, denial
Social withdrawal
Fatigue and stress
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NOISE EXPOSURE TIME LIMITATIONS
Noise Level
Exposure Limits
90 dB
8 hrs
95 dB
4 hrs
100 dB
2 hours
105 dB
1 hour
110 dB
30 minutes
115 dB
15 minutes
GUNFIRE NOISE LEVELS
.38 Spl.
156 dB
.44 Mag
164 dB
ENVIRONMENTAL NOISE LEVELS
140 dB
Space rocket at blastoff
130 dB
Jackhammer
120 dB
Ambulance siren
Amplified rock band
Thunder clap
115 dB
Sandblasting
110 dB
Woodworking shop
100 dB
Pneumatic drill
Chainsaw
90 dB
Lawn mower
Disco dance music
Shop tools
Truck traffic
Noisy restaurant
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