49-80267 Rev. 4
5
DUCT FITTINGS
This Hood Must Use an
6”
Round Duct.
It Can Transition to a
3-1/4
”
x 12
”
Duct.
Use this chart to compute maximum
permissible lengths for duct runs to
outdoors.
NOTE:
Do not exceed maximum
permissible equivalent lengths!
Maximum duct length:
100 foot for 6” round duct
75 foot for 3-1/4” x 12” duct
Flexible ducting:
If flexible metal ducting is used,
all the equivalent feet values in
the table should be doubled. The
flexible metal duct should be straight
and smooth and extended as much
as possible.
DO NOT use flexible plastic ducting.
NOTE:
Any home ventilation
system, such as a ventilation hood,
may interrupt the proper flow of
combustion air and exhaust required
by fireplaces, gas furnaces, gas
water heaters and other naturally
vented systems. To minimize the
chance of interruption of such
naturally vented systems, follow the
heating equipment manufacturer’s
guidelines and safety standards
such as those published by NFPA
and ASHRAE. When applicable,
install any makeup (replacement)
air system in accordance with
local building code requirements.
Visit
Monogram.com
for available
makeup air solutions.
Installation Preparation
Equivalent
Duct Piece
Dimensions
Equivalent
Length*
Quantity
Used
Total
Equivalent
Length
Round, straight
1 ft.
(per foot length)
3-1/4” x 12”, 3-1/4” x 24”
straight
1 ft.
(per foot length)
6” Round
90° elbow
15 ft.
6” Round
45° elbow
8 ft.
3-1⁄4” x 12”
90° elbow
11 ft.
3-1/4” x 12”or
45° elbow
6 ft.
3-1/4” x 12”
90° flat elbow
24 ft.
6” round to
3-1/4” x 12” transition or
3-1/4” x 24” transition
1 ft.
3-1/4” x 12” to 6”
round transition
8 ft.
6” round to 3-1/4” x 12” or
transition 90° elbow
16 ft.
3-1/4” x 12” to 6”
round transition 90° elbow
17 ft.
6” Round wall cap
with damper
30 ft.
3-1/4” x 12” wall cap
with damper
30 ft.
6” Round roof cap
26 ft
6” Round roof vent
26 ft
* Actual length of straight duct plus duct fitting equivalent. Equivalent
length of duct pieces are based on actual tests conducted by
GE Appliances Evaluation Engineering and reflect requirements for
good venting performance with any ventilation hood.
Total Duct Run
1” = 2.5 cm; 1’ = 0.3 m
