17
apply to vents at 12” diameter or less and require a minimum
height in accordance with the roof pitch and a minimum of 8 ft.
distance from a vertical wall or obstruction (see Fig. 29).
Figure 29
TABLE I
Roof Pitch
Minimum Height
Feet
Meters
Flat to 7/12
1
0.3
7/12 to 8/12
1.5
0.46
8/12 to 9/12
2
0.61
9/12 to 10/12
2.5
0.76
10/12 to 11/12
3.25
0.99
11/12 to 12/12
4
1.22
12/12 to 14/12
5
1.52
14/12 to 16/12
6
1.83
16/12 to 18/12
7
2.13
18/12 to 20/12
7.5
2.29
20/12 to 21/12
8
2.44
If venting horizontally through a side wall becomes 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 an existing gas burning appliance. However, if
it becomes necessary to common vent this appliance, the
venting system must be sized and configured in accordance
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, planner, or building official.
Specifying Chimney Heights
If the horizontal distance from the mid-point of the
chimney to the peak of the roof ridge is less than 10 feet, the
top of the chimney must be at least 2 feet above the roof ridge.
This is called the “2 foot in 10 foot” rule.
If the horizontal distance from the chimney’s center
measured across to the ridge of the roof is more than 10 feet,
the top of the chimney still needs to be at least 2 feet above a
point measured from a distance of 10 feet horizontally along
the roof.
Though there are many configurations in meeting
these requirements, chimney height cannot be less than 3 feet
above the roof at the edge of the chimney.
If the roof is flat, the chimney must extend no less than
3 feet from where it intersects the roof.
If the chimney is entering the roof at an angle, measure
the shorter angle where the chimney intersects the roof which
should also be at least 3 feet.
Note: The previous guidelines do not take into consideration
outside conditions which may require a higher chimney due to
foliage, other buildings, power lines and weather conditions
in your area. Follow the chimney manufacturer’s installation
guide for further information.
Chimney Termination Units
You will be installing at or possibly near the top of the
chimney chase flashing. A top termination unit is the essential
piece of equipment in keeping sparks out of the atmosphere.
Before installing this important piece of equipment, you
will have to make a judgment call as to whether or not the
termination unit – like all the other exterior exposed chimney
components, for that matter – should be painted in order to
protect it/them from rusting and weathering. Particularly if you
are installing the fireplace and chimney near water or in a high
humidity area, the manufacturer recommends a top quality,
rust-proof paint especially formulated for metal. Follow the
paint manufacturer’s directions, applying the paint well before
you are scheduled to install the round top termination unit or
any of the flashings or flues that will be exposed to outside
weather conditions.
Venting terminals shall not be recessed into walls or
siding. This appliance, when installed, must be electrically
grounded in accordance with local codes and in the absence
of local codes, with the National Electrical Code, ANSI NFPA
70, or the Canadian Electrical Code, CSA C22.1.
