Heatilator • CST42A • 4012-012 Rev J • 08/06
12
E. Construct the Chase
A chase is a vertical boxlike structure built to enclose the
fi
replace and/or its vent system. Vertical chimneys that run
on the outside of a building may be, but are not required to
be, installed inside a chase.
Construction of the chase may vary with the type of build-
ing. These instructions are not substitutes for the require-
ments of local building codes. Local building codes MUST
be checked.
Chases should be constructed in the manner of all outside
walls of the home to prevent cold air drafting problems. The
chase should not break the outside building envelope in any
manner.
Building codes require false ceiling and ceiling
fi
restops at
each
fl
oor of the chase or every 10 ft (3.05 m) of clear space
to control spread of
fi
re.
Walls, ceiling, base plate and cantilever
fl
oor at the
fi
rst level
of the chase should be insulated. See Figure 3.5. Vapor and
air in
fi
ltration barriers should be installed in the chase as per
regional codes for the rest of the home. Additionally, Hearth
& Home Technologies recommends that the inside surfaces
be sheet rocked and taped for maximum air tightness.
Attic
Insulation
Shield
Chimney
Ceiling
Firestop
Tabs
False Ceiling
False Ceiling
Insulation
Insulation
Ceilng
Firestop
Metal Chase Top
Round Termination Cap
False Ceiling
Figure 3.5 Chase Assembly
F. Chimney Requirements
When planning your
fi
replace location, the chimney con-
struction and necessary clearances must be considered.
The
fi
replace system and chimney components have been
tested to provide
fl
exibility in construction. Vertical distances
are measured from the base of the
fi
replace as shown in
Figure 5.2.
1
2
Figure 3.6 Chase Constructions
1. Chimney offset through exterior wall and enclosed in
chase.
2. Chase constructed on roof.
Gas line holes and other openings should be caulked with
high temperature caulk or stuffed with unfaced
fi
berglass in-
sulation. If the
fi
replace is being installed on a cement slab,
we recommend that in cold climates, a sheet of plywood or
other raised platform be placed underneath to prevent con-
ducting cold up into the room.
Two examples of chase applications are shown in Fig-
ure 3.6.
ft
meters
a. Minimum overall straight height
14.0
4.27
b. Minimum height with offset/return
16.5
4.93
c. Maximum height
90.0
27.43
d. Maximum chimney length between an offset and
return
20.0
6.1
e. Maximum distance between chimney stabilizers
35.0
10.67
f. Double offset/return minimum height
22.0
6.71
g. Maximum unsupported chimney length between the
offset and return
6.0
1.83
h. Maximum unsupported chimney height above the
fi
replace
35.0
10.67
i. Maximum unsupported chimney above roof
6.0
1.83
Note:
A maximum of two pairs offsets and returns may
be used.