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117437-01F
10
In each case the offsets must be supported
and firestops must be positioned wherever
the vent must pass through a sub-floor, ceil
-
ing joist or an attic overhang. The vent pipe
must terminate vertically into a listed type vent
cap and extend a sufficient height through
an approved roof flashing, roof jack or a roof
thimble. At all points the listed clearances
must be maintained.
Vent terminations must be located in ac-
cordance with height and proximity rules of
NFPA No. 54
. These rules apply to vents at
12" diameter or less and require a minimum
height in accordance with the roof pitch and
a minimum of 8 foot distance from a vertical
wall or obstruction (see Figure 11).
If venting horizontally through a side wall be
-
comes necessary, a listed thimble approved
for use with B-type vent must be used. Check
with your local codes before venting through
a side wall.
Some codes areas allow the use of existing B-
type vent systems if the system is at or above
the recommended diameter of the flue.
The flue connection must be made using listed
B-type connectors and the existing system
must be code inspected for damage and proper
installation.
It is not recommended that this appliance be
common vented with and existing gas burning
appliance. However, if it becomes necessary
to common vent the appliance. The venting
system must be sized and configured in ac
-
cordance with the common venting guides
Appendix G of the current
National Fuel Gas
Code NFPA No. 54/ANSI Z223.1.
Note: Before connecting this appliance to an
existing vent system or a common venting
system consult with your local architect plan-
ner, or building official.
CHECKING FOR PROPER VENTING
VENTING INSTALLATION
Continued
Lowest
Discharge
Opening
Listed
Vent Cap
8 Ft. Min.
Roof Pitch x/12
Listed Clearance
12
x
Listed
Gas
Vent
H (Min)
Height
From Roof
Figure 11 - B-Vent Termination
Roof Pitch
H (Min.)
Flat to 6/12
1.0 ft (0.3 m)
6/12 to 7/12
1.25 ft (0.38 m)
Over 7/12 to 8/12
1.5 ft (0.46 m)
Over 8/12 to 9/12
2.0 ft (0.61 m)
Over 9/12 to 10/12
2.5 ft (0.76 m)
Over 10/12 to 11/12 3.25 ft (0.99 m)
Over 11/12 to 12/12 4.0 ft (1.22 m)
Over 12/12 to 14/12 5.0 ft (1.52 m)
Over 14/12 to 16/12 6.0 ft (1.83 m)
Over 16/12 to 18/12 7.0 ft (2.13 m)
Over 18/12 to 20/12 7.5 ft (2.27 m)
Over 20/12 to 21/12 8.0 ft (2.44 m)
Figure 10 - Typical B-Vent Configuration
Maintain
Listed
Clearance
Maintain
Listed
Clearance
12' Min.
12' Min.
45°
45
6'
8'
12' Min.
60
45
Position
Firestop
Position
Firestop
Position
Firestop
Listed
Vent Cap
Listed
Vent Cap
Listed
Vent Cap
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Support Each
Lateral At
Least Every
6 Feet
Maintain
Listed
Clearance
10'
EXAMPLE 3
EXAMPLE 2
EXAMPLE 1