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Vertical Terminations
Locate and mark the center point of the venting pipe. Using a nail
on the underside of the roof and drive this nail through this center
point. Make the outline of the roof hole around this center point.
NOTE: Size of the roof hole dimensions depend on the pitch of the
roof. There must be a 1 inch clearance (25 mm) to the vertical pipe
sections. This clearance is to all combustible material.
Cover the opening of the vent pipe and cut and frame the roof hole.
Use framing lumber the same size as the roof rafters and install the
frame securely. Flashing anchored to frame must withstand high
winds. The storm collar is placed over this joint to make a watertight
seal. Non-hardening sealant should be used to completely seal this
flashing installation.
Determining Minimum Vent Height Above the Roof.
Major U.S. building codes specify minimum chimney and/or
vent height above the roof top. These minimum heights are
necessary in the interest of safety. These specifications are
summarized in Figure 20.
ROOF PITCH
FLAT TO 6/12
6/12 TO 7/12
OVER 7/12 TO 8/12
OVER 8/12 TO 9/12
OVER 9/12 TO 10/12
OVER 10/12 TO 11/12
OVER 11/12 TO 12/12
OVER 12/12 TO 14/12
OVER 14/12 TO 16/12
OVER 16/12 TO 18/12
OVER 18/12 TO 20/12
OVER 20/12 TO 21/12
42603-4-0421
VERTICAL TERMINATION
WARNING
H (MINIMUM
FEET
METER
1.0
0.30
1.25
0.36
1.5
0.46
2.0
0.61
2.5
0.76
3.25
0.99
4.0
1.22
5.0
1.52
6.0
1.83
7.0
2.13
7.5
2.27
8.0
2.44
Figure 20
Figure 21
Note that for steep roof pitches, the vent height must be increased.
In high wind conditions, nearby trees, adjoining roof lines, steep
pitched roofs, and other similar factors can result in poor draft, or
down-drafting. In these cases, increasing the vent height may solve
this problem.
When terminating the vent cap near an exterior wall or overhang,
maintain minimum clearances as shown in Figure 20.
General Maintenance
Conduct an inspection of the venting system semi-annually.
Recommended areas to inspect are as follows:
1.
Check areas of the venting system which are exposed to
the elements for corrosion. These will appear as rust spots
or streaks and, in extreme cases, holes. These components
should immediately be replaced.
2.
Remove the cap and shine a flashlight down the vent. Remove
any bird nests or other foreign material.
3.
Check for evidence of excessive condensate, such as water
droplets forming in the inner liner and subsequently dripping
out at joints. Continue condensate can cause corrosion of caps,
pipe and fittings. It may be caused by having excessive lateral
runs, too many elbows and exterior portions of the system being
exposed to cold weather.
4.
Inspect joints to verify that no pipe sections or fittings have been
disturbed and, consequently, loosened. Also, check mechanical
supports, such as wall straps or plumbers' tape for rigidity.
Venting terminal shall not be recessed into a wall or siding. A
removable panel or other means must be provided in the enclosure
for visual inspection of the flue connection.
Installing the Vent System in a Chase
A chase is a vertical box like structure built to enclose the gas
appliance and/or it's vent system. Vertical vent runs on the outside of
a building may be, but are not required to be installed inside a chase.
Treatment of firestop spacers and construction of the chase
may vary with the type of building. These instructions are
not substitutes for the requirements of local building codes.
Therefore, your local building codes must be checked to
determine the requirements for these steps.
Figure 22
CAUTION
Page 19
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