Email from Jim Buckley, April 7, 1999
(private discussion snipped)
1) (snip)
In general the code is for site-built non proprietary
construction - like the kind of
construction done by members of the MHA - and a listing of some
sort is for
manufactured and proprietary products. (snip).
2) "Minimum fire and safety standards" really don't
involve flue sizes,
efficiency or how many turns the flue channels take. The code
committees
will be more interested in clearance to combustibles and seismic
reinforcing. Maybe the "compromise" should be to
shorten the definition of
a masonry heater in the code and see it's purpose as one of
identification
- not performance characteristics. Get all the controversial
language out
of the code and deal with the finer points of the definition
somewhere else.
The IBC Committee approved the "short version" which
referenced ASTM E 1602
but does not mention flue size. It could be stripped down even
more to
eliminate the words "heating appliance" "at least
180 degrees" and "the
surface temperature not to exceed 230 degrees". In the code,
the
definition is just for identification purposes.
The IRC Committee, on the other hand, approved the "long
version" which is
basically the whole ASTM E 1602 and does include the flue sizes
and
anything else Walter might object to.
Since masonry heaters are in the IBC and IRC differently, it
would be
appropriate for the MHA or MACS or even me (as the original
proponent) to
quietly challenge the code change for the purpose of coordinating
the
language between the two codes. They would especially like it if
there was
less language. (snip)
Best,
Jim Buckley
(SHORT VERSION)
SECTION 2112
MASONRY HEATERS
2112.1 Definition. A masonry heater is a heating appliance
constructed of
concrete or solid masonry, hereinafter referred to as masonry,
having a mass of at least 800 kg (1760 lbs.), excluding the
chimney and
foundation, which is designed to absorb and store heat from a
solid
fuel fire built in the firebox by routing the exhaust gases
through
internal heat exchange channels in which the flow path downstream
of the
firebox includes at least one 180 degree change in flow direction
before
entering the chimney and which delivers heat by radiation from
the
masonry surface of the heater which shall not exceed 230 degrees
F (110
degrees C) except within 8 inches (203 mm) surrounding the fuel
loading door(s).
2112.2 Installation. Masonry Heaters shall be listed or
installed in
accordance to ASTM E-1602
2112.3 Seismic reinforcing. Seismic reinforcing shall not be
required
within the body of a masonry heater whose height is equal to or
less than 2.5 times it's body width and where the masonry chimney
serving
the heater is not supported by the body of the heater. Where the
masonry chimney shares a common wall with the facing of the
masonry heater,
the chimney portion of the structure shall be reinforced in
accordance with Section 2113.
2112.4 Masonry heater clearance. Wood or other combustible
framing shall
not be placed within 4 inches (102 mm) of the outside
surface of a masonry heater, provided the wall thickness of the
firebox is
not less than 8 inches (203 mm) and the wall thickness of the
heat
exchange channels is not less than 5 inches (127 mm). A clearance
of at
least 8 inches (203 mm) shall be provided between the gas tight
capping slab of the heater and a combustible ceiling. The
required space
between the heater and combustible material shall be fully vented
to
permit the free flow of air around all heater surfaces.