Page 15 - Donaldson - Exhaust product guide for medium and heavy-duty vehicles and equipment

Shoptalk
General Exhaust Facts, Maintenance Tips and Product Features

Five Major Sources of Noise in Trucks Rules of Thumb

Combining Two Equal Noise SHOPTALK
Sources Increases Sounds
Exhaust 5 Fan Noise Level by 3 dBA
System
1 Two equal noise sources combine to
create a sound level 3 dBA greater
than either source.
2

83 83
Air Intake dBA dBA
4 3
Tires Mechanical Noise

Easy Maintenance Tips Reduce Exhaust Noise

1 Check the exhaust tubing. Repair or replace worn or leaking components.

2 Make sure your exhaust system is properly supported. 86
dBA
3 Installing a resonator or wye connector muffler is an economical way to
reduce noise.
4 Modify a single exhaust system to a dual. Twice the Loudness is a
10 dBA Increase
Check stack and tailpipe position. A straight stack will be quieter than a
5 curved stack on vertical exhaust systems. Turn your horizontal tailpipes The increases are not linear!
toward the center of the road. Increasing noise by 10 dB sounds
twice as loud.
Familiar Sounds on the dBA Noise Scale 80

dBA
Other examples of sound levels: 70 dB Traffic jam; 90 dB Heavy
machinery, 130 dB Jet engine at 10 meters. 70
dBA
Threshold of Pain
Siren (100 feet) 140
Jet Plane (50 feet)
130
Automobile Horn (3 feet)
120 Sound Pressure Level
Chain Saw (50 feet)
110 Changes With Distance
Commercial Airliner (inside) 100 Motor Cycle (50 feet) Doubling the distance to a noise
90 source decreases its sound level by
Snowmobile (50 fet)
80 Over Road Truck 6 dB. Halving the distance to a noise
Conversation (3 feet) 70 (50 feet) source increases its sound level by
60 6 dB.
Business Office
50 6 dBA Decrease
Soft Whisper (4 feet) 40
30 10 Feet 20 Feet
86 dBA 80 dBA
20
Recording Studio
10
Threshold of Hearing 0 6 dBA Increase
dBA
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