53D9025
17
CHIMNEY OFFSET INSTALLATION
Elbow Installation
The following are important points that should be observed when installing elbows on the fireplace:
1. The support straps of all elbows not installed directly on top of the fireplace should be nailed se-
curely to the surrounding structure. This allows the support strap to carry the weight of the chim-
ney above the elbow and prevents this weight from breaking the elbow or chimney sections apart.
2. Elbows should not be used in any combination that inclines the chimney more than 30 degrees
from vertical.
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Figure 18
Inlet Air
Pipe
Flue
All four (4) support straps
must be nailed on to fram-
ing member around the
elbow with a minimum of
two (2) 8-Penny nails per
strap
NOTE:
Although both halves of the
elbow set may have tie straps, only
the top half must be secured. The
bottom elbow half is not required to
be secured for added stabilization of
pipe.
3. The limitations on the quantity of elbows per chimney are as follows: If the total height of the
fireplace and chimney is—12’ - 2” or more — two elbows may be used in the chimney. 21’ - 0” or
more — four elbows may be used in the chimney.
4. The inclined portions of chimneys that pass through living spaces likely to be used for storage
should be enclosed to avoid contact with and possible damage to the chimney. The minimum air
space of two inches between the chimney and enclosing materials must be maintained.
5. The length of the inclined portion of chimney between elbows must not exceed 6 feet when unsup-
ported or 20 feet if the chimney is supported at six-foot intervals with support such as metal sup-
port straps.
6. When enclosing the elbows and inclined portions of the chimney, enclosing materials must be
installed vertically to maintain the required two-inch minimum air space clearance to the chimney
at the extremities of the offset. It is recommended that enclosing material not follow the inclined
portions of the chimney.
Offset Installation Sequence
1. Determine the location and amount of offset required, then select the combinations of chimney
sections and elbows required from the offset chart. Refer to Page 19.
2. Install the first LE30 elbow by placing the extended flue into the mating part of the fireplace or
chimney section. Push down until the outside or inlet air duct of the elbow overlaps and the snaps
lock the elbow into the fireplace or chimney section.
3. Nail the support straps to the framing member with a minimum of two 8-penny nails per strap.
4. Install the sections of pipe between elbows until the proper number of chimney sections have been
installed.
5. Install the second elbow to return the run of the chimney to vertical.
6. Nail the support straps of the second elbow to a building frame member.
7. Continue installing the vertical portion of the chimney.
NOTE:
If the inclined portion of the chimney passes through a floor or ceiling, an LF-FS-30 firestop
spacer should be installed to provide the firestop and support required. Be sure proper spacing in
maintained between the chimney and combustibles.
