Appendix
Typical 'A' Weighted dB levels
140
50 HP Siren (100')
130
Jet take-off (200')
Riveting machine
110
100
Subway (20')
Pneumatic drill (50')
Vacuum cleaner (10')
Large store
Small office
Residential area
(night)
Whisper (5')
10
Threshold of hearing
0
50
40
30
Sound studio
20
70
60
Speech (1')
Large Office
Residence
90
Boiler room
80
Freight train (100')
Chain saw
120
Frequency Weighting Graph
Frequency Weighting
5
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
10
100
1000
Frequency (Hz)
10000
dB (relative)
'A' Weighting
'C' Weighting
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407768 Version 2.0 06/06