.... (2) "Closed controlled combustion wood-burning appliance" means a wood stove or pellet stove or fireplace capable of efficient heating and controlled combustion. The appliance must include doors with gaskets or flanges that permit tight closure and glass or ceramic panels which must be tightly sealed or gasketed in their frames.
What is the point here? Are they concerned about efficiency? If so why not specify the minimum efficiency acceptable like they do for gas fired appliances? Or are they concerned about back drafting? If so, why not specify the maximum combustion and excess air needs and the maximum negative pressure in which the appliance can vent flue gasses? The intent seems to be confused. The "table of appliances" shows that "closed combustion chamber wood-burning appliances" and "decorative wood-burning appliances" are permitted at negative indoor pressures that are essentially the same in that they are barely within the measurable tolerances. Rather than describe appliances with subjective characteristics and endorse favored appliances by innuendo, require the manufacturer or builder to test and demonstrate compliance with meaningful objective standards.
"Heating wood-burning appliance" means any wood stove, insert, masonry heater, pellet stove or fireplace shown by tests performed by an accredited independent testing laboratory to have an overall thermal efficiency of at least 50%. Site-built appliances are permitted provided the manufacturer or builder provides documentation from an accredited laboratory that the appliance has substantially the same core construction as a model tested and shown to meet the standard.
"Controlled combustion wood-burning appliance" means a wood stove, insert, masonry heater, pellet stove or fireplace shown by tests performed by an accredited independent testing laboratory to require less than 150 CFM in combined combustion and excess air and to exhaust all flue gasses in an environment within the dwelling that is negatively pressurized at 15 Pascals with respect to the ambient outdoor pressure. The appliance builder or manufacturer is permitted, in order to attain these results, to test and install the appliance with a make-up air system or barometric damper.
This, of course, is the catch-all for all appliances that don't meet the standards, whatever they are, and the penalty will be high - requiring expensive performance testing at least. Even if the drafters intend this section to all but outlaw fireplaces, it will be more objective, if not altogether toothless, if it's possible to include efficient fireplaces in a revised paragraph 2 above.
Table seems to allow fireplaces in prescriptive path 2 (5 Pascals), prescriptive path 3 (2 Pascals) and the "performance" path, provided the results don't exceed 5 Pascals negative pressure. In prescriptive path 1 (which I take to be the default path because builders won't want to test) everything has to work at negative 25 Pascals. See "table to size passive make-up air openings"
A table of appliances lists direct venting appliances as able to work up to 25 Pascals. "Thermal mass wood-burning appliances" are permitted in negative pressures up to 15 Pascals. "Closed controlled combustion wood-burning appliances" are only permitted at up to negative 7 Pascals and "decorative wood-burning appliances" up to negative 5 Pascals. [What is the method used to determine at what negative pressure various appliances draft adequately? Were masonry heaters, wood stoves or fireplaces actually tested?]. All except "decorative wood-burning appliances" are allowed to be excepted if they have a "manufacturer-certified negative pressure tolerance rating". [What's that and why can't fireplace manufactures provide it?]
Users of open fireplaces, masonry heaters and EPA certified stoves alike can do things to cause spillage. To a large extent, spillage is under the control of the user. Therefore, hand-fed woodburning systems should be permitted without fancy make-up air systems provided a CO detector/alarm is installed to give warning should spillage occur. Under this type of provision, there should be no health or safety risk.
1) What are the differences between prescriptive paths 1,2, & 3 and the performance path? Bill Forder (612 635 0603 "email@example.com") says in Path 1 everything has to work at up to neg. 25 Pa and be power vented. Path 2 is 5 Pa, Path 3 is 2 Pa and allows naturally drafted water heaters and he thinks "everybody should take the Performance Path, get some air in these tight houses and make sure everything works."
2) Where in the dwelling do they measure the depressurization? There is probably a 10 Pascal difference in pressure between the first and second stories in a two story house. The hot water heater in the basement is probably in a negative 10 Pa. environment when it's neg. 2 Pa on the first floor.
3) What is a "manufacturer-certified negative pressure tolerance rating" and why are they denied to fireplaces?
4) Why aren't "Thermal mass wood-burning appliances" defined in Subp 8?
5) What is the method used to determine at what negative pressure various appliances draft adequately? Were masonry heaters, wood stoves or fireplaces actually tested? If so, which models? For naturally drafting appliances, the one with the highest flue temperature - i.e. the least efficient - should "draw" the best.
As written, this proposed energy code is prejudicial toward masonry fireplaces, masonry heaters, wood stoves and, for that matter, all naturally drafting appliances. The code should strive for neutral indoor pressure and balancing the various air handling systems - not making them compete and overpower other systems for inadequate or non-existent makeup air. At least the language should be objective and measurable. Masonry fireplaces should have to meet the same standards that any other wood-burning appliance has to meet. We still might have to test for efficiency and air requirements and sell fireplaces with CO detectors or some sort of tested exterior air supply to the room in which the fireplace is built.
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