Kostenloser Kanalquerschnitt-Rechner
Dimensionieren Sie Lüftungskanäle nach Luftvolumenstrom und Geschwindigkeit.
CFM
ft/min
Round Duct Diameter
10.2 in
Querschnittsfläche82.3 sq in
Actual Velocity at Next Size606 ft/min
Round Duct Diameter vs Airflow
Formel
## Duct Sizing by Velocity **A = CFM / Velocity** **Diameter = 2 x sqrt(A / pi)** Convert the area to diameter for round ducts. For residential trunk lines, maximum velocity of 700 ft/min keeps noise low. Branch runs can go up to 600 ft/min. Round up to the next standard duct size.
Lösungsbeispiel
400 CFM at a max velocity of 700 ft/min.
- 01Area = 400 / 700 = 0.571 sq ft = 82.3 sq in
- 02Diameter = 2 x sqrt(0.571 / pi) x 12 = 10.2 in
- 03Use a 10-inch round duct (or 12-inch for lower velocity).
Häufig Gestellte Fragen
What velocity is too high for residential ducts?
Above 900 ft/min in trunk lines and 700 ft/min in branches, duct noise becomes noticeable. Keeping velocities below these limits ensures quiet operation.
How do I convert round to rectangular ducts?
Use the equivalent diameter formula: De = 1.3 x (a x b)^0.625 / (a + b)^0.25, where a and b are the rectangular dimensions.
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