Construct The Chase; Chimney Requirements - Heatilator ST42A Owner's Manual

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 fi restop spacers 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 infi 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.
Round Termination Cap
Metal Chase Top
Firestop
Spacer
False Ceiling
Insulation
Tabs
Insulation Insulation
False Ceiling
False Ceiling
Figure 3.5 Chase Assembly
12
Attic
Shield
Firestop
Spacer
Chimney
Heatilator • ST42A • 35038 Rev G • 02/05
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.
1. Chimney offset through exterior wall and enclosed in
chase.
2. Chase constructed on roof.
1
Figure 3.6 Chase Constructions
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.
a. Minimum overall straight height
b. Minimum height with offset/return
c. Maximum height
d. Maximum chimney length between an offset and
return
e. Maximum distance between chimney stabilizers
f. Double offset/return minimum height
g. Maximum unsupported chimney length between the
offset and return
h. Maximum unsupported chimney height above the
fi replace
i. Maximum unsupported chimney above roof
2
ft meters
14.0 4.27
16.5 4.93
90.0 27.43
10.0 3.05
35.0 10.67
22.0 6.71
6.0 1.83
35.0 10.67
6.0 1.83