5 x 90º ELBOWS
MAXIMUM
Restrictor 75
NO
RESTRICT
ORS
Example 1
NO INSTALLATION
NO
INSTALLATION
V3
Restrictor 50
2
4
6
8
10
12
14
16
18
20
13
Venting
Allowable Vent
Confi gurations
Example 1
V Value = V1 (6’) + V2 (6’) + V3 (2’)= 14’
H Value = H1 (3’) + H2 (3’) = 6’
75% restrictor required
VERTICAL
RISE
HORIZONTAL RUN
Not to scale
Roof termination
Wall termination
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.
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
horizontal 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.
3” clearance
to combustible
above
horizontal pipe
1” clearance
to combustible
around vertical
pipe
INSTALLATION
