12
Venting
Co-Axial
Venting Chart
How to Read the Venting Charts
The chart below applies to co-axial roof or wall
termination in installations
with vertical rise.
All rear venting without a vertical rise must
be terminated by a snorkel
—see page 11.
1. The total length of the vent pipe cannot
exceed 40 feet.
2. The minimum vertical height with roof ter-
mination is 8 feet.
3. Any combination of rise and run can be
used as long as they are within the allow-
able limits shown on the chart.
4. A maximum of 5 x 90 degrees elbows—or
equivalent (2 x 45 degrees = 90 degrees)—
can be used.
5. Each 90 degrees elbow installed on the
horizontal plane is equivalent to a 3 feet
horizontal pipe; therefore, 3 feet must be
subtracted from allowable horizontal run.
(45 degrees elbow is equivalent to 18 inches
horizontal pipe.)
6. All horizontal pipe runs must be graded 1/4
inch per foot upwards in the direction of the
exhaust
fl
ow.
The
fi
nal pipe length, when terminating
through the wall may be graded downwards
slightly to prevent water migration.
7.
Maximum co-linear venting
in existing
chimney systems is limited to 40 feet
vertical rise.
8.
Restrictors are not required for co-linear
installations.
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
2 4 6 8 10 12 14 16 18 20
7RSRU5HDUWDNHR
Horizontal Run (ft)
Ve
rt
ica
l R
ise (
ft
)
Example 1
NO INSTALLATION
Restrictor 75
Restrictor 50
No restrictor
NO INSTALLATION
Allowable Co-Axial Vent Con
fi
gurations
with restrictor positions
