Masonry Magazine February 1983 Page. 25
FIRE CLAY FLUE LINER
NOMINAL 1 IN. (25 mm)
AIR SPACE
REFRACTORY
CONCRETE SLAB
BAFFLE CHAMBER
FIRE BRICK
FIREBOX
EXTENDED HEARTH,
MINIMUM 16 IN. (400 mm)
BOTH SIDES AND BACK
1990000 10000
EXTERIOR WYTHE OF MASONRY
SHOWN WITH METAL TIES
AND JOINT REINFORCEMENT
NOMINAL 1 IN. (25 mm)
AIR SPACE
ASHPIT
(FRONT SECTION)
Brick Masonry Heater with Vertical Baffles
FIG. 2
surface temperatures of the walls are normally between
100°F (38°C) and 130°F (54°C), but temperatures as
high as 190°F (88 °C) have been reported. Although these
temperatures are much lower than those achieved with
metal wood-burning stoves, sufficient clearances to
combustibles should be maintained. A minimum 36-in.
(900 mm) clearance is usually required between metal
wood-burning stoves and combustibles. A minimum
12-in. (300 mm) clearance is recommended between the
sides and back of the brick masonry heater and combus-
tibles. At the floor line, this may be achieved by pro-
viding a 12-in. (300 mm) extended hearth. In front of the
heater, a 20-in. (500 mm) extended hearth should be
used. This is easily achieved when the heater is properly
positioned in the room for maximum heating. This posi-
tion is in the center of the room so that all four walls of
the heater are providing radiant heat to the room. The
brick masonry heater may also be installed against inte-
rior brick masonry walls.
DESIGN AND CONSTRUCTION
General
The brick masonry heater should always be positioned
entirely inside the building. It should never be located on
an exterior wall. When incorporated into an exterior
REINFORCED
CONCRETE SLAB
wall, much of the radiant heat being supplied will be lost
to the exterior. In addition, the location on an exterior
wall will usually result in at least one cold surface on
which a considerable amount of creosote may form. A
creosote fire can reach temperatures which could result in
cracks within the heater that may become too large to
allow safe operation because combustion gases may leak
into the room.
The actual dimensions of the masonry heater are
limited by the available firebox door sizes, the number of
baffles, and the height of the heater. For best perfor-
mance, the heaters should not be more than one story in
height, nor should they contain more than five baffle
chambers. This is because the increased distances that the
hot combustion gases must flow will result in a cooling of
the gases. This causes a reduction in their heating capac-
ity and could result in increased creosote deposits which
may lead to potential fires.
There are two types of Russian-style brick masonry
heaters: the vertically baffled heater shown in Figures 1
and 2, and the horizontally baffled heater shown in Fig-
ures 3 and 4. Many of the features are similar for both.
The most critical factors for the proper performance
of brick masonry heaters are the gas flow through the
baffle system and the draft of the chimney. All openings
between the baffles and the area enclosed by the baffles
3