18
Standard Horizontal Terminations
90º OR 45°
ELBOW
12" MIN. TO GRADE OR
HIGHEST ANTICIPATED
SNOW LEVEL
6” MAX
10”- 24”
4” MIN
(Dual Pipe)
Figure 15
90°
ELBOWS
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
3” - 24”
Alternate Horizontal Vent Termination (Dual Pipe)
Figure 16
90°
ELBOWS
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
3” - 24”
(Dual Pipe)
Figure 17
Direct Vent (Dual Pipe) Piping
Direct vent installations require both a combustion air intake
and a vent/flue pipe. The pipes may be run horizontally
and exit through the side of the building or run vertically
and exit through the roof of the building. The pipes may
be run through an existing unused chimney; however, they
must extend a minimum of 12 inches above the top of the
chimney. The space between the pipes and the chimney
must be closed with a weather tight, corrosion resistant
flashing. Both the combustion air intake and a vent/
flue pipe terminations must be in the same atmospheric
pressure zone. Refer to
Vent/Flue and Combustion Air Pipe
- Termination Locations
or
Concentric Vent Termination
for specific details on termination construction. For details
concerning connection of pipes to the furnace, refer to the
Vent/Flue Pipe and Combustion Pipe - Standard Furnace
Connections
or
Alternate Furnace Connections
.
90°
ELBOWS
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
3”-24” BETWEEN PIPES
Combustion Air Intake may also be snorkeled to
obtain 12” min ground clearance.
Alternate Vent Termination Above Anticipated
Snow Level
Termination of Multiple Direct Vent Furnaces
Figure 18
Vent/Flue & Combustion Air Pipe Lengths &
Diameters
Refer to the following table for applicable length, elbows,
and pipe diameter for construction of the vent/flue and
combustion air intake pipe systems of a direct vent
(dual pipe) installation. The number of elbows tabulated
represents the number of elbows and/or tees in each (Vent/
Flue & Combustion Air Intake) pipe. Elbows and/or tees
used in the terminations must be included when determining
the number of elbows in the piping systems.
If the combustion air intake pipe is to be installed above a
finished ceiling or other area where dripping of condensate
will be objectionable, insulation of the combustion air pipe
may be required.
Use ½” thick closed cell foam insulation such as Armaflex™
or Insultube™ where required.
