87D0176
17
B36LA8 & B36RA8 Woodburning Fireplaces
PLANNING INFORMATION
Preplanning an installation is very important to ensure
safety and to save time and money. An installer must
predetermine where a fireplace will be set and how the
chimney system will be run.
NOTE:
The B36RA8 and B36LA8 models use MHSC
SK8 (2-wall) chimney systems.
MOUNTING THE FIREPLACE
A fireplace may only be mounted on the following sur-
faces:
1. A flat combustible surface.
2. A raised wooden platform.
3. A concrete block or other solid object placed beneath
each of the four (4) corners of the fireplace.
The fireplace
must
be spaced 1/2" (13 mm) from a com-
bustible back wall and 1/2" (13 mm) from a combustible
side wall or support. (Page 14, Fig. 20)
PLANNING THE CHIMNEY RUN
Determine how the chimney will be run, length of run
and chimney components required to complete the job.
(Fig. 6)
Never
install a chimney below minimum heights.
Figure 6 -
Installed lengths of chimney sections
FP705
L1
L1
LT
MODEL SK &
2 WALL CHIMNEY
TOTAL
LENGTH
(LT)
INSTALLED
LENGTH
(L1)
SK81
SK818
SK83
SK84
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
FP705
STR/CVR-CHIM SECT. INSTALLED LENGTH
5/28/98
AC246
Figure 7 -
Ten Foot Rule illustration
2' Min.
2' Min.
3'
Min.
0 To 10'
3'
Min.
0 To 10'
AC246
4/1/96
Reference
Point
In planning a chimney system, it is important to know:
1. The height of a chimney is measured from the hearth
to the exit point on the termination.
2. A chimney cannot be offset more than 30° from a
vertical plane.
3. A chimney may run straight up or it may be necessary
to offset it to avoid obstructions.
4. The maximum length of an angled run (total chimney
system) is 20' (6 m).
5. No more than 2 offsets (4 total 30° elbows in U.S./or
2 total 45° elbows in Canada) per fireplace may be
used.
6. A guy wire stabilizer is required for chimneys extend-
ing more than 6' (1.8 m) above a roof line.
THE TEN FOOT RULE
Major U.S. building codes specify a minimum chimney
height above the roof top. The “Ten Foot Rule” is a fire
safety rule and not a draft rule. To ensure proper draft,
it is recommended that you always meet or exceed the
“Ten Foot Rule,” especially when installing a termination
on a high pitch roof. (Fig. 7)
The key points of the "Ten Foot Rule" are:
1. If the horizontal distance from the chimney to the peak
of the roof is 10' (3 m) or less, the top of the chimney
must be at least 2' (610 mm) above the peak of the
roof, but never less than 3' (914 mm) in height above
the highest point where it passes through the roof.
2. If a horizontal distance from the chimney to the peak
of the roof is more than 10' (3 m), a chimney height
reference point is established on the surface of the
roof a distance of 10' (3 m) from the chimney in a hori-
zontal plane. The top of the chimney must be at least
2' (610 mm) above the reference point, but never less
than 3' (914 mm) in height above the highest point
where it passes through the roof.
CHIMNEY SUPPORTS
The chimney system is supported by the fireplace for
vertical chimney heights less than 20' (6 m) above the
hearth. Chimney supports are required if the vertical
height exceeds 20' (6 m). Locate chimney supports
at ceiling holes or other structural framing at 20' (6 m)
heights. Spacing between chimney supports
must not
exceed 20' (6 m). Use Chimney Support Model SKCS8
for SK8 chimney.
(NOTE: the chimney support can
not be mounted directly to the fireplace.)
Support
provided by elbow straps fulfills the support requirement
only if they are spaced as previously described. (A chim-
ney support is 2
Z\x
" (64 mm) long when installed.)
Angled chimney runs require a support every 6' (1.8 m)
in addition to the elbow straps. Chimney supports are
used for this function. (Fig. 9)