5 x 90º ELBOWS
MAXIMUM
Restrictor 75
NO
RESTRICT
ORS
Example 1
NO INSTALLATION
NO INSTALLA-
TION
V3
Restrictor 50
2
4
6
8
10
12
14
16
18
20
23
23
Venting
Allowable Vent
Con
fi
gurations
Example 1
V Value = V1 (6’) + V2 (6’) + V3 (2’)= 14’
H Value = H1 (3’) + H2 (3’) = 6’
75% restrictor required
VERTICAL
RISE
(ft)
HORIZONTAL RUN
(ft)
Not to scale
Roof termination
Wall termination
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.
7. Co-linear rear venting
in existing chimney systems is
limited to 40 feet vertical rise.
8. Restrictors are not required
for co-linear
installations.
1” clearance
to combustible
at bottom and
sides of hori-
zontal pipe
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
How to Read the Venting Chart
The chart below applies to top or rear outlet, roof or
wall termination
with a vertical rise
.
All rear outlet venting without a vertical rise must
be terminated by a snorkel
.
1. The total length of the vent pipe cannot exceed 40
feet (12.2 m).
2. The minimum vertical height with roof termination is 8
feet (2.45 m).
3. Any combination of rise and run can be used as long
as they are within the allowable limits shown on the
chart below.
4. A maximum of 5 x 90 degrees elbows or equivalent (2
3” clearance
to combustible
above horizon-
tal pipe
1” clearance
to combustible
around vertical
pipe
QUALIFIED
INSTALLER