11
11
Minimum
Maximum
A:
From
fl
oor to top of vent duct
4’-3½”
(131 cm)
9’-3½”
(283 cm)
B:
Frame front face to outside
wall
-
12’-5½”
(380 cm)
C:
Frame front face to inside
wall
2’-5½”
(75 cm)
-
D:
Vertical pipe run between
elbows
12”
(30.5 cm)
6’
(183 cm)
E
1
+E
2
:
Total horizontal pipe
run including terminal pipe
but excluding adapter and
elbows
-
10’
(305 cm)
with no
elbows in
horizontal
run
F:
Clearance to combustible
materials above horizontal
pipe run inside building
(Outside wall shields/
thimbles)
1”
(2.5 cm)
-
G:
Clearance to combustible
materials below horizontal
pipe run
1-
5
⁄
16
”
(3.3 cm)
-
H:
Clearance to combustible
materials all round vertical
pipe run and at sides of
horizontal pipe run
2”
(5.1 cm)
-
Rear Vent Connection—Vertical Vent Rise with
Horizontal Rear Termination
See
fi
gure 7.
Can be used with either #551DVK standard vent kit or
another terminal cap and accessories.
Adapter #817VAK, two 90º elbows and pipe lengths will be
required. See venting accessories list on pages 39–40 for
allowable components.
The location requirements are shown in the table and graph
below and figure 7.
For installations with a horizontal rear termination, the
combination of horizontal and vertical vent pipes must
be within the allowed area shown in Graph 1. A minimum
vertical pipe run of 12” is necessary.
Example a: If a vertical rise of 3’ is required, the horizontal run must not be more than 7’9”.
Example b: If a horizontal run of 3’6” is required, the vertical run must be at least 1’9”.
If the horizontal pipe run is redirected using a further 90° elbow, the maximum total horizontal run allowed is
reduced by 3’ to 7’. Redirection using 45° elbows reduces the maximum total horizontal run by 18” per elbow.
Rear Vent Connection—Vertical Vent Rise with Horizontal Snorkel Termination
For “semi-basement” situations where a snorkel accessory alone does not raise the termination suf
fi
ciently above ground
level. The dimensional requirements in the section above,
fi
gure 7, and graph 1 apply.
Adapter #817VAK, two 90° vent elbows, pipe lengths and a snorkel termination will be required. A thimble kit may also be
necessary. See venting accessories list on pages 39–40 for allowable components.
14” (36 cm) max.
combustible wall
A
B
C
D
E
1
E
2
F
G
H
1
0
2
3
4
5
6
1
2
3
4
5
6
7
8
9
10
FORBIDDEN VENT PIPE
COMBINATIONS
Example b
Example a
ALLOWED VENT PIPE
COMBINATIONS
Maximum Horizontal Run (Ft) (E
1
+ E
2
in Fig. 7)
Vertical
Rise (Ft)
(D in Fig. 7)
Figure 7 Rear vent—Vertical rise, rear termination
Location
Graph 1
