20
‘H’
Horizontal
overhang
Vertical
wall
Termination
cap
Storm
collar
Roof
flashing
Plumber’s tape
fixed to wall strap
Wall strap
Ceiling
firestop
Ceiling
support
Offset elbows
Min.
18”
Overhang should
not extend beyond
vent if within 48” of
termination cap
Min. 24”
(unvented soffit)
Min. 36”
(vented soffit)
Joists
10”
(254 mm)
10”
(254 mm)
Through-the-roof installation
Firestop hole
Co-Axial Vertical Installations
• Check the roof pitch to determine which roof
fl
ash-
ing will be needed. See
Approved Venting Components
pages 41–42 for allowable components.
• The distance from the roof to the lowest terminal
discharge opening (“H” in
fi
gure) depends on the roof
pitch and must be in accordance with the manufac-
turer’s instructions supplied with the termination unit.
Note: The venting system for these appliances is consid-
ered to be
Special Venting System
.
The rule in the CAN/
CGA-B149 Installation Code requiring a minimum vent
height of 2 feet above any portion of a building within
10 feet does not, therefore, apply.
• The minimum clearances to combustible materials
all round the vent pipes must be in accordance with
the dimensions shown in
Venting Con
fi
gurations—With
Vertical Rise
page 18 of this manual.
• Drop a plumb from the ceiling to the center of the ap-
pliance vent opening. Mark the position on the ceiling.
Drill a small hole at the marked position.
• Determine the position where the vent will pass
through the roof. If directly above the position where
it penetrates the ceiling, drop a plumb from the roof
to the small hole in the ceiling and mark the roof at
this spot.
If rafters or other obstructions will prevent a vertical
exit or if clear attic space is desired, the roof outlet
can be offset using 45 degrees elbows.
Drill a small hole at the marked position.
• A ceiling firestop must be installed at the second floor
and higher floors.
A ceiling support should be used below the flat ceiling.
To install the firestop and support, cut and frame a
10 inches (254 mm) square hole centered on the small
hole previously drilled.
• Fit vent accessory elbows a pipe lentghs as required
up through ceiling support boxes and firestops.
If installation includes offset, support the offsetting
pipes every 3 feet (1 m) with wall straps as shown.
• Cut a hole in the roof centered on the small hole. The
hole must allow for the minimum clearrences to com-
bustible materials. See Venting section in this manual.
• Fit pipe lengths through the roof. Fit roof flashing
securing it with roofing nails.
• Fit storm collar and termination cap.
Venting
Co-Axial
Roof Pitch
Minimum
"H" [feet]
Flat to 7/12
1'
Over 7/12 to
8/12
1.5'
Over 8/12 to
9/12
2’
Over 9/12 to
10/12
2.5’
Over 10/12 to
11/12
3.25’
Over 11/12 to
12/12
4’
Over 12/12 to
14/12
5’
