6
EQUIVALENT DUCT LENGTH CHART
Broan Model 407
Straight Duct
7-in. round x 2-ft. long
Equivalent length
2 ft.
Broan Model 418
10-in. Round Elbow
Equivalent length
10 ft.
Broan Model 427
4 ½-in. x 18 ½-in. to
10-in. Round, 6-in. High
- Lateral Transition
Equivalent length
2 ft.
Broan Model 647
7-in. Round
Wall Cap
Equivalent length
30 ft.
(15-ft. w/o damper)
Broan
Model 634 or 644
Roof Cap
(7-in. round)
Equivalent length
30 ft.
(7-ft. w/o damper)
Kenmore range hoods are designed to perform efficiently when attached to long runs of duct. As a point of reference, this hood
will function at approximately 80% of its rated air performance when 100 equivalent feet of 7" round ductwork is attached (for
600 cfm blowers) or 125 equivalent feet of 10" round duct is attached (for 1200 cfm blowers). Use this chart to calculate the
equivalent duct length of your system. Note that 7" round is the minimum recommended duct size for 600 cfm blowers, and 10"
round is the minimum recommended duct size for 1200 cfm blowers.
Broan Model 410
Straight Duct
10-in. round x 2-ft. long
Equivalent length
2 ft.
Broan Model 415
7-in. Round Elbow
Equivalent length
8 ft.
Broan Model 423
4 ½-in. x 18 ½-in. to
10-in. Round - Vertical
Transition
Equivalent length
2 ft.
Broan Model 424
4 ½-in. x 18 ½-in. to
10-in. Round - Horiz.
Front / Rear Transition
Equivalent length
10 ft.
Broan Model 454
4 ½-in. x 18 ½-in. to
10-in. Round - Horiz.
Right Transition
Equivalent length
12 ft.
Broan Model 453
4 ½-in. x 18 ½-in. to
10-in. Round - Horiz.
Left Transition
Equivalent length
12 ft.
Broan Model 437
10-in. Round
Roof Cap
Equivalent length
40 ft.
(25-ft. w/o damper)
Broan Model 441
10-in. Round
Wall Cap
Equivalent length
40 ft.
(25-ft. w/o damper)
