NOTE: If you need to install ducts, note that the total duct length of 31/4"x 10"rectangular or 6" diameter round duct
should not exceed 140 equivalent feet.
Outside ventilation requires a HOOD EXHAUST DUCT. Read the following carefully.
NOTE: It is important that venting be installed using the most direct route and with as few elbows as possible. This
ensures clear venting of exhaust and helps prevent blockages. Also, make sure dampers swing freely and nothing is
blocking the ducts.
Exhaust connection:
The hood exhaust has been designed to made with a standard 3
If a round duct is required, a rectangular-to-round transiting adaptor must be used. Do not use less than a 6"diameter
duct.
Maximum duct length:
For satisfactory air movement, the total duct length of 3
exceed 140 equivalent feet.
Elbows, transitions, wall and roof caps, etc.,
section of straight duct which is longer than their actual physical size. When calculating the total duct length, add the
equivalent lengths of all transitions and adaptors plus the length of all straight duct sections. The chart below shows you
how to calculate total equivalent ductwork length using the approximate feet of equivalent length of some typical ducts.
DUCT PIECES
Rectangular-to-Round
Transition Adaptor*
Wall Cap
90° Elbow
45° Elbow
90° Elbow
45° Elbow
Roof Cap
Straight Duct 6 " Round or
3¼" x 10" Rectangular
* IMPORTANT: If a rectangular-to-round transition adaptor is used, the bottom corners of the damper will
have to be cut to t, using the tin snips , in order to allow free movement of the damper. Equivalent
lengths of duct pieces are based on actual
with any vent hood.
General Information
"x10" rectangular duct.
1/4
"x10" rectangular or 6"diameter round duct should not
1/4
present additional resistance to
EQUIVALENT
x
LENGTH
5 Ft.
x
40 Ft.
x
10 Ft.
x
5 Ft.
x
25 Ft.
x
5 Ft.
x
24 Ft.
x
1 Ft.
x
Total Duct work
5
and are equivalent to a
NUMBER
EQUIVALENT
=
LENGTH
USED
( )
=
( )
=
( )
=
( )
=
( )
=
( )
=
( )
=
( )
=
=
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
F t.