CFM Corporation WMC36 WMC42 - Manual (Page 6)

6
WMC Series Woodburning Fireplace
20000583
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.
Mounting the Fireplace
A fireplace may be mounted on the following surfaces:
1. A flat combustible surface.
2. A raised wooden platform.
3. A concrete block or other solid object placed be-
neath each of the four (4) corners of the fireplace.
The fireplace must be spaced 1/2" (13 mm) from a
combustible back wall and 1/2" (13 mm) from a com-
bustible side wall or support. Refer to Page 14, Figure
18.
Planning the Chimney Run
Determine how the chimney will be run, length of run
and chimney components required to complete the
job. (Fig. 4) Never install a chimney below minimum
heights.
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. It is recommended that
you always meet or exceed the “Ten Foot Rule,” espe-
cially when installing a termination on a high pitch roof.
(Fig. 6)
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' (609 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 that is on the surface of
the roof a distance of 10' (3 m) from the chimney in a
horizontal plane. The top of the chimney must be at
least 2' (609 mm) above the reference point, but never
less than 3' (914 mm) in height above the highest
point where it passes through the roof.
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 neces-
sary to offset it to avoid obstructions.
4. The maximum length of an angled run (total chim-
ney 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 (not provided) is required for
chimneys extending more than 6' (1.8 m) above a
roof line.
L1
L1
LT
MODEL SK
2 WALL
CHIMNEY
TOTAL
LENGTH
(LT)
INSTALLED
LENGTH
(L1)
SK81
SK818
SK83
SK84
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FP288A
MBUF-INSTALLED LENGTH
Triple wall
1/28/99 djt
TRIPLE
WALL
81
818
83
84
FP288A
Fig. 5 Installed lengths of chimney sections.
2' Min.
2' Min.
3'
Min.
0 To 10'
3'
Min.
0 To 10'
AC246
4/1/96
Reference
Point
AC246
Fig. 6 Ten Foot Rule illustration.