Vektor-CD Performance Catalog - Greenheck

SOUND DATA
How to Calculate Sound Performance
Once a Vektor-CD fan has been selected that meets performance specifications, use the following procedure to
attain sound data for the specific fan rpm and percent Wide Open Volume (%WOV). Interpolation will be used to
determine the eight sound power levels, the total sound power (LwA) and sound pressure (dBA) rating.
From the fan selection example on the AMCA 260 Air Test Procedure pages, the Vektor-CD Size 30, High
Velocity Nozzle is operating at 1,600 rpm and 68% WOV. Viewing the Size 30 Sound Power Table, interpolation
between 60 and 80% WOV is needed to find values for 68% WOV.
Example of Sound Performance:
Vektor-CD Size 30 (HV Nozzle)
Example
Sound Power by Octave Band
Inlet Sound Power
Outlet Sound Power
rpm %WOV 1 2 3 4 5 6 7 8 LwA dBA 1 2 3 4 5 6 7 8 LwA dBA
1600 100 96 98 102 95 91 88 81 75 98 86 101 101 104 99 97 90 85 78 102 90
1600 80 98 96 101 93 89 85 79 74 96 85 98 98 103 95 93 87 82 75 99 87
1600 60 104 104 100 93 87 84 78 73 96 85 103 104 101 94 91 85 80 75 97 86
1600 50 107 107 101 95 89 85 79 74 98 86 106 109 102 95 93 86 81 75 99 88
1600 40 110 108 102 95 89 86 79 74 99 87 109 113 102 96 93 87 82 79 101 90
2182 100 104 105 110 106 99 97 91 84 107 96 110 109 112 109 105 100 94 88 111 99
2182 80 107 104 109 104 97 94 88 83 105 94 107 106 111 106 101 96 91 85 108 96
2182 60 112 112 111 103 96 92 87 82 106 94 111 113 110 104 99 94 89 84 107 95
2182 50 114 116 113 104 97 94 88 82 108 96 114 118 112 105 100 96 90 85 109 97
2182 40 117 118 114 104 97 94 89 83 109 97 116 122 113 107 101 97 90 86 111 99
Interpolate the sound data at 1600 rpm between 80% and 60% WOV to find 68% WOV for
each octave band.
1st Octave Inlet Sound
[ {( 80% — 68% ) ( ) }]
1600 rpm @ 68% WOV, dB = 98 dB — ___________ x 98 dB — 104 dB = 102 dB
80% — 60%
2nd Octave Inlet Sound
[ {( 80% — 68% ) ( ) }]
1600 rpm @ 68% WOV, dB = 96 dB — ___________ x 96 dB — 104 dB = 101 dB
80% — 60%
The same procedure should be followed to calculate the remaining inlet and outlet sound values. If
the fan selection results in a fan RPM not shown, sound power levels are calculated at the next RPM
above and below the operating RPM, then interpolated to the operating RPM.
Results for above example are as follows:
Sound Power by Octave Band
Inlet Sound Power
Outlet Sound Power
rpm %WOV 1 2 3 4 5 6 7 8 LwA dBA 1 2 3 4 5 6 7 8 LwA dBA
1600 68 102 101 100 93 88 84 78 73 96 85 101 102 102 94 92 86 81 75 98 86
8