25
DUCT LENGTH CHART
Duct Fitting Number Total Equivalent
Duct Fitting Equivalent Length of Fittings Length–Fitting
8"Diameter 90° Elbow 5'
(1.52 m)
6"Diameter 45° Elbow 2.5'
(.76 m)
5"to 6"Transition 1.0'
(12.7 cm to 15.24 cm) (.30 m)
6"to 31⁄4"x10"90° Elbow 5'
(15.24 cm to 8.26 cm x 25.4 cm) (1.52 m)
31⁄4"x10"to 6"90° Elbow 9'
(8.26 cm x 25.4 cm to 15.24 cm) (2.75 m)
6"to 31⁄4"x10"90° Elbow 1'
(15.24 cm to 8.26 cm x 25.4 cm) (.30 m)
31⁄4"x10"to 6"Transition 4.5'
(8.26 cm x 25.4 cm to 15.24 cm) (1.37 m)
5"to 31⁄4"x10"90° Elbow 6'
(12.7 cm to 8.26 cm x 25.4 cm) (1.83 m)
31⁄4"x10"90° Elbow 5'
(8.26 cm x 25.4 cm) (1.52 m)
31⁄4"x10"Flat Elbow 12'
(8.26 cm x 25.4 cm) (3.66 m)
6"Wall Cap 28'
(15.24 cm) (8.53 m)
31⁄4"x10"Wall Cap 20'
(8.26 cm x 25.4 cm) (6.10 m)
10"x10"Roof Jack 0'
(25.4 cm x 25.4 cm) (0 m)
Thermal Break 2'
(.61 m)
6"Diameter Straight Duct–Feet 1'
(For flex duct multiply by 2.) (.30 m)
31⁄4"x10"Straight Duct–Feet 1'
(.30 m)
System Total
Air Flow
Air Flow
Air Flow
Air Flow
Air Flow
Air Flow
Air Flow this direction not recommended.
Air Flow this direction not recommended.
(continued next page)