R1002.5, Chapter 44
Proponent: Timothy N. Seaton, B.S.C.E., Empire Masonry Heaters LLC (firstname.lastname@example.org)
Revise as follows:
1002.5 Masonry heater clearance. Combustible materials shall not be placed within 36 inches (914 mm) or the distance of the allowed reduction method
2. When masonry heaters are listed and labeled in accordance with UL 1482
TRVB 105 - Fireplaces for Solid Fuels
Reason: Make masonry heater clearances safe and rational!
North American masonry heater technology is virtually all sourced in Europe where the devices have been built for centuries. In conformance with typical European standards, ASTM E1602, Standard Guide for Construction of Solid Fuel Burning Masonry Heaters, does not stipulate masonry heater wall thickness nor relate it to clearances to combustibles. In contrast to masonry fireplace construction and operation, masonry heater wall thickness is not the critical design feature but instead material thermal conductivity. Greater wall thicknesses actually create a more dangerous situation by creating more thermal storage with eventual radiation.
Heat storing masonry heaters are being designed and installed at the same clearances as fireplaces which are not designed to store heat. Until recent IBC and IRC code revisions, all minimum masonry heater clearances were 4" (102 mm) to surface wall or protective shield as per ASTM E1602. Although I can locate no documented examples of wall ignition from masonry heaters of any wall thickness at this clearance:
2. no UL 1482 testing exists for any masonry heater with this low of a clearance.
3. ASTM E1602 mentions safety shielding but gives no prescription for use.
4. TRVB 105 remedies this by establishing greater safety clearances and outlining reduction strategies.
2. no European country stipulates masonry heater clearances to combustibles anywhere near 36".
3. UL 1482 masonry heater testing is not yielding clearances anywhere near 36".
4. NFPA 211 has recently moved masonry heaters from the chapter on solid fuel burning appliances to their own chapter, recognizing the difference in the devices.
Cost Impact: The code change proposal will not increase the cost of construction.
MACS NO POSITION
Public Hearing: Committee: D - on motion by Bob Eugene, UL
Assembly: ASF AMF DF
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