5
must be installed with refractory mortar. There must
be at least ½” air space between the flue liner and
chimney wall.
• The fireclay flue liner must have a nominal size of 8” X
8”, and should not be larger than 8”X 12”. If a round
fireclay liner is to be used it must have a minimum
inside diameter of 6” and not larger than 8” in
diameter. If a chimney with larger dimensions is to be
used, it should be relined with an appropriate liner that
is code approved.
• The masonry wall of the chimney, if brick or modular
block, must be a minimum of 4” nominal thickness. A
mountain or rubble stone wall must be at least 12”
thick.
• A newly-built chimney must conform to local codes
and in their absence must recognize national
regulations.
• When using an existing chimney, it must be inspected
by a professional licensed chimney sweep, fire official,
or code officer, to ensure that the chimney is in proper
working order.
• No other appliance can be vented into the same flue.
• An airtight clean-out door should be located at the
base of the chimney.
Prefabricated Chimneys
If a prefabricated metal chimney is to be used it must be a
chimney type that is tested and listed for use with solid
fuel burning appliances. High Temperature (HT) Chimney
Standard UL 103 for the U.S. and High Temperature
Standard ULC S-629 for Canada.
The manufacturer’s installation instructions must be
followed precisely. Always maintain the proper clearance
to combustibles as established by the pipe manufacturer.
This clearance is usually a minimum of 2”, although it may
vary by manufacturer or for certain chimney components.
Chimney Height
Whether a masonry chimney or prefabricated metal
chimney is used it must be the required height above the
roof line.
The requirement is:
The chimney must be at least 3 feet higher than the
highest point where it passes through the roof and at least
2 feet higher than the highest part of the roof or structure
that is within 10 feet of the chimney, measured
horizontally. See figure 3.
Chimneys shorter than 14 feet may not provide adequate
draft. This could result in smoke spilling into the room
from the stove when loading the stove, or when the door
is open. In addition, inadequate draft can cause back
puffing, which is a build up of gases inside the firebox.
Other times, chimney height can create excessive draft
which can cause high stove temperatures and short burn
times. Excessive drafts can be corrected by installing a
butterfly damper. If you suspect you have a draft problem,
consult your dealer.
Wall Pass Throughs
When your installation unavoidably requires the chimney
connector to pass through a combustible wall to reach the
chimney, always consult your local building officials, and
be sure any materials to be used have been tested and
listed for wall pass-throughs.
In the U.S.
The National Fire Protection Association’s publication,
NFPA 211, Standard for Chimneys, Fireplaces, Vents and Solid
Fuel Burning Appliances permits four methods for passing
through a combustible wall. Before proceeding with any
method be sure to consult with your local building officials
to discuss any local code requirements.
Common Method
When passing through a combustible wall to a masonry
chimney this method requires the removal of all
combustible materials from at least 12” around the
chimney connectors proposed location. With a 6” round
liner the minimum area required would be 31” x 31” square.
The space is then filled with at least 12” of brick around a
fireclay liner. Remember, the liner must be ASTM C35 or
equivalent, with a minimum wall thickness of 5/8”.
It is important to remember to locate the pass-through
at least 18” from the ceiling for proper clearance to
combustibles.
It will be necessary to cut wall studs, install headers, and
construct a sill frame to maintain the proper dimensions
and to support the weight of the brick.
The bricks must be solid brick with a minimum of
3 ½ “ thick (4” nominal).
Refractory mortar must be used at the junction of the
chimney and the pass-through liner. The pass-through
liner must not penetrate the chimney liner beyond the
inner surface of the chimney liner. Use extreme care when
constructing the hole in the chimney liner, the tiles can
shatter easily. See figure 3.
In Canada
The Canada the standard has been established by the
Canadian Standard Association. The installation must
conform to CAN/CSA-B365, Installation Code for Solid Fuel
Burning Appliances and Equipment.
Before proceeding be sure to consult your local building
inspector.
USA
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