25
system or a common venting system, consult with your local
architect, planner, or building official.
Specifying Chimney Heights
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.
LISTED
VENT
CAP
"H"
8 FL MIN
12
x
ROOF PITCH x/12
LISTED CLEARANCE
LISTED
GAS
VENT
LOWEST
DISCHARGE
OPENING
(MIN HT
FROM ROOF)
Figure 32
Though there are many configurations in meeting these
requirements, chimney height cannot be fewer than 3 feet
above the roof at the edge of the chimney.
If the roof is flat, the chimney must extend no fewer 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 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
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
appliance 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.
Wall Mounting of Chimney Fan
Wall Mounting of Chimney Fan
When mounting the chimney fan on a wall, the installation
instructions for installation on a steel chimney should be followed.
Use of the adapter SCA can make the installation easier but is
not a requirement.
To ease installation, detach the fan base by removing the bolts
holding the hinges together. Center the fan base over the outlet
and bolt the base onto the wall with the hinges pointing upwards.
After mounting the base securely, attach the fan motor housing
by reassembling the fan hinges. Seal with silicone all around the
fiber mat to prevent rain from entering the flue.
Vent runs are approved for up to 70 feet with a qty. of six (6) 90°
elbows with use of an Enervex Fan and ADC100 Controller.
Please refer to Enervex Installation Instructions.
Figure 33
Non-Combustible
Cement Board
30”
30”
ROOF PITCH
FEET
METERS
FLAT TO 7/12
1
0.3
OVER 7/12 TO 8/12
1.5
0.46
OVER 8/12 TO 9/12
2
0.61
OVER 9/12 TO 10/12
2.5
0.76
OVER 10/12 TO 11/12
3.25
0.99
OVER 11/12 TO 12/12
4
1.22
OVER 12/12 TO 14/12
5
1.52
OVER 14/12 TO 16/12
6
1.83
OVER 16/12 TO 18/12
7
2.13
OVER 18/12 TO 20/12
7.5
2.29
OVER 20/12 TO 21/12
8
2.44
Gas vent systems using vent caps listed by Underwriters Laboratories may
terminate in accordance with this vent termination table.
TABLE 2
MINIMUM HEIGHT
Summary of Contents for Mason-Lite LMFP-108
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