2'-0"
3'-0" MIN.
ROOF RIDGE
WORK POINT
CRICKET
CHIMNEY
SECTION
THRU ROOF
LESS THAN 10'-0"
10'-0"
2'-0"
3'-0" MINIMUM
WORK
POINT
CRICKET
SECTION
THRU ROOF
CHIMNEY
40
DM 54 Chimney System: Height Requirements
Chimney Height Requirement:
The required minimum chimney height above the roof
and adjacent walls and buildings is specified by all major build
-
ing codes and is summed up in what is known as “the 2 foot in
10 foot rule”:
(1) If the horizontal distance from the roof ridge to the opening
of the chimney is less than 10’, the top of the chimney must be
at least 2’ above the roof ridge (Figure 69).
(2) If the horizontal distance from the opening of the chimney
to the roof ridge is more than 10’ then a chimney height “work
point” is established on the roof surface 10’ horizontally from
the opening of the chimney. The top of the chimney must be at
least 2’ above this work point (Figure 70).
(3) In all cases, the chimney cannot be less than 3’ above the
roof at the edge of the chimney (Figure 69 & 70).
A simple example of this would be if the roof is flat
then the chimney would need to be at least 3’ above the roof
surface. Or, if the chimney penetrates the roof at the ridge then
the chimney must be at least 3’ above the ridge. (Figure 71)
Note:
The “2 foot in 10 foot rule” is necessary in the interest
of fire safety but does not ensure smoke-free operation of the
fireplace. Trees, buildings, adjoining roof lines, adverse wind
conditions, etc. may require a taller chimney for the fireplace to
draft properly.
Chase Enclosures:
DM 54 chimneys can be enclosed within a
wood framed chase at zero clearance to wood framing members.
Chase enclosures need to be built to local wind load require
-
ments and shall be structurally independent of the Isokern
chimney. As with all chimney installations, avoid overhead
obstructions such as trees, power lines, etc.
CAUTION:
If insulation is used in chase walls the fireplace
and chimney must not be placed directly against it and must be
kept a minimum 3” from all fireplace and chimney components.
It is recommended that where fireplace and chimney chases are
insulated or have vapor barriers that the inside face of the chase
first be covered with gypsum board, plywood, particle board or
other sheathing material to assure that insulation and vapor bar-
riers remain in place and a minimum 3” away from the unit.
WARNING:
Do not pack insulation around the Standard fire
-
place or chimney. Do not insulate the chase cavity with blown or
loose-fill type insulation materials.
Chase Top Flashings:
Non-combustible, weather tight chase flashing must be
used to cover the top of the chimney chase. Be sure to seal the
joint where the DM 54 liner passes through the chase top flash
-
ing for positive weather seal. Chase flashings may be supplied
by others.
FIGURE 69
FIGURE 70
FIGURE 71
