table i
Sub table A: Sound power levels (L
w
) in dB
Sound power is a measure of sound energy per time unit. For a sound source, unlike sound pressure, sound power is neither room
dependent nor distance dependent. Sound power is a theoretical value that is not measurable. It is calculated and expressed in
watts and as sound power level L
W
in decibels.
The table below shows the sound power levels in dB calculated according to AMCA Standard 301.
static
pressure
(in. Wg)
Airflow
(cFM)
Octave band number & center frequency number (Hz)
1
2
3
4
5
6
7
8
63
125
250
500
1000
2000
4000
8000
FUA-1800
0
836
109
100
91
91
87
86
82
76
2.4
715
105
98
89
88
83
83
78
71
4.8
530
100
99
87
86
81
80
74
68
7.15
331
104
97
81
82
79
76
70
65
FUA-2100
0
1115
97
98
91
93
88
88
83
80
2.5
890
90
95
91
93
86
84
79
75
5
660
95
96
89
90
84
81
75
71
7.62
447
88
94
89
89
83
79
72
70
FUA-2700
0
1107
78
88
90
89
86
84
83
80
2.95
900
79
87
89
87
85
81
79
74
5.35
700
83
84
88
84
83
79
76
71
7.75
500
80
82
88
87
85
79
74
70
FUA-3000
0
1818
89
91
97
99
94
90
84
81
2.2
1570
95
91
98
100
91
87
81
78
4.4
1320
88
90
98
96
88
84
78
75
6.66
977
89
91
95
94
86
82
75
72
FUA-4700
0
2614
99
93
92
93
92
91
87
86
2.4
2343
98
95
94
93
92
90
85
83
5
2040
98
95
93
92
89
87
82
80
8.05
1528
95
92
96
91
86
85
80
77
Sub table B: Conversion of sound power level (L
w
) to sound pressure level (l
p
)
A sound source produces sound power, which generates a sound pressure fluctuation in the air. Sound power is the distance-
independent cause of this, whereas sound pressure is the distance-dependent effect.
The table below shows the dB value to be deduced from the values of sub table A to the achieve the sound pressure level at a
certain distance.
sound pressure level
At a distance of:
1 m (3.3 ft)
2 m (6.5 ft)
3 m (9.8 ft)
4 m (13.1 ft)
Ref.: sound power levels (L
w
) in sub table A
‒11 dB
‒17 dB
‒21 dB
‒23 dB
Sub table C: A-weighting of sound pressure level
The most common weighting that is used in noise measurement is A-weighting. Like the human ear, this effectively cuts off the
lower and higher frequencies that the average person cannot hear.
The table below shows the A-weighting related to the different frequencies.
Octave band number
1
2
3
4
5
6
7
8
Frequency (Hz)
63
125
250
500
1000
2000
4000
8000
A-weighing
‒0.8
‒0.2
0
0
0
‒0.2
‒0.8
‒3.0
Note: dB(A) levels are not licensed by AMCA International.
0000103355/240315/A FUA-1800/2100/2700/3000/4700 (60Hz)
9
