MHA Masonry Heater Definition
A masonry heater
1.) is a solid fueled heating system of predominantly masonry construction having a mass of at least 800 kg (1760 lb), excluding chimney and foundation.
2.) is designed to burn at a burn rate greater than 5 kg/hr. Burn rate is defined as the weight of fuel charge divided by the actual burn time. Standard masonry heater types, as illustrated in ASTM E1602-94, shall be deemed to attain this value.
3.) is deemed to meet EPA emissions requirements for woodstoves
by virtue of:
a) the above design principle
and
b) the substantial existing database of masonry heater PM-10 emissions
test results
4.) is equipped with doors that substantially enclose the firebox and which are intended to be in the closed position during the burn cycle.
5.) is designed, under normal operation, to burn with a maximum chimney entry temperature of 350C (662F)
6.) is constructed of sufficient mass such that under normal operating conditions the external surface of the heater, except in the region immediately surrounding the fuel loading door(s), does not exceed 110C (230F).
7.) achieves heat storage by routing of exhaust gases through internal heat exchange channels in which the flow path downstream of the firebox includes at least on 180 degree change in flow direction, usually downward, before entering the chimney.
8.) has a maximum chimney flue size of 8" x 12" (200 mm x 300 mm) or 8" (200 mm) round.
9.) has a maximum overall average wall thickness of 10" (250 mm).
10.) is capable of achieving a minimum average surface temperature of 50C (120F) with a design fuel load, on a design heating cycle.
11.) Shall not penetrate the house envelope.
