|
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
|
|
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
|
| 80 dB |
City traffic
Loud music from radio
|
| 75 dB |
Kitchen appliances |
| 70 dB |
Crowded restaurant |
| 65 dB |
Conversation speech |
| 60 dB |
Sewing machine
Typewriter |
| 50 dB |
Average home interior |
| 40 dB |
Quiet residential community |
| 30 dB |
Whisper at five feet |
| 20 dB |
Leaves rustling in a breeze |
| 10 dB |
Normal breathing |
| 0 dB |
Faintest sound heard by a human ear |
|
