9
properly). Level the Support Box and secure
it to the framing using at least three 8-penny
nails per side (min. of 12 total). Wrap the
straps of the Support Box around the framing
members
(Fig 4)
, and secure with (2) 8-penny
nails per side. (eight nails total) Alternatively,
you may use 1-1/2” #8 wood screws (min. of
12 total for the Support Box, and 8 total for
the straps), instead of nails. Next, secure
the round or square Trim Collar to the ceiling/
framing members using (4) 1” long, round-
head wood screws.
4. Frame Openings:
Frame openings in
each ceiling or floor above the Support Box
(Fig 6)
. These openings are to hold the
Firestop Radiation Shield and Attic Insulation
Shield. Locate each opening by dropping a
plumb bob to the four corners of the opening
below. Maintain the minimum clearances and
dimensions as specified in
Table 2
. If Elbows
must be used to avoid an obstruction, refer to
the Offset Elbow Installation section.
5. Cut Roof Opening:
Cut an opening in the
roof directly above the opening below, and
at least 4 inches larger than the chimney’s
outside diameter to provide at least a
2-inch clearance all around the chimney.
The chimney must be centered within this
opening and maintain the 2-inch clearance to
combustibles.
Figure 7
Table 2
Inside Square Framing Dimensions
(X" x X")
Chimney Diameter
10"
12"
14"
16"
18"
20"
22"
24"
chimney inSide diameteR
16 1/4" 18 1/4" 20 1/4" 22-1/4" na
na
na
na
wall thimBle
16"
18"
20"
22"
na
na
na
na
FiReStop Radiation Shield
16"
18"
20"
22"
24 1/4" 26 1/4" 28 1/4" 30 1/4"
attic inSulation Shield
16 1/4" 18 1/4" 20 1/4" 22 1/4" 24 1/4" 26 1/4" 28 1/4" 30 1/4"
6.
Install Firestop Radiation Shield: A Firestop
Radiation Shield is required in multistory
installations at each floor penetration above
that where the Support Box is located.
Example: in a multistory home where the
appliance is on the ground floor (Support
Box is in the 1st floor ceiling), you would
need a Firestop Radiation Shield at the 2nd
floor ceiling, and at the 3rd floor ceiling, etc.,
including where the chimney penetrates into
the attic.
Figure 6
shows a typical 2-story
installation with an attic.
FRAMING
FIRESTOP
RADIATION
SHIELD
