DUCT LENGTH CHART
Duct Fitting
8" Diameter 90° Elbow
6" Diameter 45° Elbow
Air Flow
Air Flow this direction not recommended.
6" to 3
(15.24 cm to 8.26 cm x 25.4 cm)
Air Flow
3
(8.26 cm x 25.4 cm to 15.24 cm)
Air Flow
Air Flow
6" to 3
(15.24 cm to 8.26 cm x 25.4 cm)
(8.26 cm x 25.4 cm to 15.24 cm)
Air Flow
5" to 3
Air Flow
(12.7 cm to 8.26 cm x 25.4 cm)
Air Flow this direction not recommended.
6" Diameter Straight Duct–Feet
(For flex duct multiply by 2.)
"x10" Straight Duct–Feet
3
1
⁄
4
5" to 6" Transition
(12.7 cm to 15.24 cm)
"x10" 90° Elbow
⁄
1
4
"x10" to 6" 90° Elbow
1
⁄
4
"x10" 90° Elbow
1
⁄
4
"x10" to 6" Transition
3
1
⁄
4
"x10" 90° Elbow
1
⁄
4
"x10" 90° Elbow
3
1
⁄
4
(8.26 cm x 25.4 cm)
"x10" Flat Elbow
3
1
⁄
4
(8.26 cm x 25.4 cm)
6" Wall Cap
(15.24 cm)
"x10" Wall Cap
3
1
⁄
4
(8.26 cm x 25.4 cm)
10"x10" Roof Jack
(25.4 cm x 25.4 cm)
Thermal Break
Duct Fitting
Equivalent Length
5'
(1.52 m)
2.5'
(.76 m)
1.0'
(.30 m)
5'
(1.52 m)
9'
(2.75 m)
1'
(.30 m)
4.5'
(1.37 m)
6'
(1.83 m)
5'
(1.52 m)
12'
(3.66 m)
28'
(8.53 m)
20'
(6.10 m)
0'
(0 m)
2'
(.61 m)
1'
(.30 m)
1'
(.30 m)
Number
Total Equivalent
of Fittings
Length–Fitting
System Total
(continued next page)
25