Circular equivalent diameters of rectangular ducts
Width
(in)
Height (in)
6
8
10
12
14
16
18
20
22
24
26
28
30
Circular equivalent diameters of flat oval ducts
Major Axis
(in)
Minor Axis (in)
6
8
10
12
14
16
18
20
22
24
26
28
30