08/04
31068 Rev E
13
MHST36D INSTALLATION INSTRUCTIONS
Figure 6 - Chimney Height
3. Number of Sections Required
To determine the chimney components needed to
complete your particular installation, follow the steps
below:
a.
Determine the total vertical height of the fireplace
installation. This dimension is measured from the
base of the fireplace assembly to the point where
the smoke exits the termination cap.
b.
Subtract the effective height of the fireplace
assembly (47-1/4 in.) from the overall height of
the fireplace installation (measured from the
base of the fireplace to the bottom of the
termination cap).
c.
Refer to Table 2 to determine what components
must be selected to complete the fireplace
installation.
d.
Determine the number of firestop spacers, stabi-
lizers, roof flashing, etc. required to complete the
fireplace installation.
2. Chimney Height Requirements (above roof
line)
a.
Major building codes specify a minimum chimney
height above the roof top. These specifications
are summarized in what is known as the
Ten Foot
Rule
. This rule states:
“If the horizontal distance from the side of the
chimney to the peak of the roof is 10 ft or less, the
top of the chimney must be at least 2 ft above the
peak of the roof, but never less than 3 ft in overall
height above the highest point where it passes
through the roof.
“If the horizontal distance from the side of the
chimney to the peak of the roof is more than 10 ft,
a chimney height reference point is established
on the surface of the roof a distance of 10 ft from
the side of the chimney in a horizontal plane. The
top of the chimney must be at least 2 ft above this
reference point, but never less than 3 ft in height
above the highest point where it passes through
the roof.” See Figure 6.
b.
These chimney heights are necessary in the
interest of safety but do not ensure smoke-free
operation. Trees, buildings, adjoining roof lines,
adverse wind conditions, etc. may create a need
for a taller chimney should smoking occur.
Table 2
HEIGHT OF CHIMNEY COMPONENTS
Chimney Stabilizer
SL3
4-3/4 in.
Firestop Spacers
FS338
0 in.
FS339
0 in.
FS340
0 in.
Offsets/Returns
SL315
13-3/8 in.
SL330
14-1/2 in.
Roof Flashing
RF370
0 in.
RF371
0 in.
Chimney Sections*
SL306
4-3/4 in.
SL312
10-3/4 in.
SL318
16-3/4 in.
SL324
22-3/4 in.
SL336
34-3/4 in.
SL348
46-3/4 in.
* Dimensions reflect effective height
