A question about chimney insulation and draft:
As best I can tell, any type of Class A, Type HT, All Fuel chimney pipe that meets the UL 103 standard protects your house from an over-firing stove up to the limits of the standard. The standard seems to include 1,000 F continuous, 1,400 F for one hour, and 2,100 F for 10 minutes. It seems that there are several designs to achieve those ends. One type is the Ameri-Tec triple wall with 1/2 inch of insulation and the Amerivent - Hart and Cooley TLC and/or the Duratech that all seem to be double walled with 1 inch of insulation. It does not seem that any triple wall non-insulated pipe meets the UL 103 standard.
All that being said, once the pipe is capable of keeping my house safe, how well does it keep my flue warm? From everything that I have learned in my extensive internet studies, draft is almost entirely related to two factors. 1: The temperature differential between the beginning of the chimney and the outlet of the chimney 2: The height of the chimney. Both factors seem to be directly proportional-double the temperature differential-double the draft. Double the height-double the draft.
As to temperature:
With a medium bed of coals, I measured my stove pipe inside the house (single wall 8 inch), testing with an infrared laser type instrument, and the temperature goes from 430 F on the stove top, to 260 F 6" from the stove top, to 110 F 10 feet up the pipe right before it goes into the thimble in the ceiling. So, I lost over 150 F (58%) in about 7 feet of travel. The underside of my chimney cap measured the 99 F. It does not seem as if I am losing too much heat in the outside portion of the chimney (8" Ameri-Tec triple wall with 1/2" insulation).
My stove pipe (15 feet total) is exposed for the last 6 feet.
Does anyone have any knowledge of how much heat various designs of pipe LOSE when exposed to cold outside temperatures? It would seem that the pipe with 1" of insulation would stay warmer than the one with only 1/2 inch of insulation if they used the same type of insulation.
As a slight side bar, can a modern wood stove be so efficient that not enough heat is sent up the pipe to make it draw correctly? Seems like I read somewhere that the newer EPA stoves are so efficient that a smaller chimney is needed to keep the inside of the pipe warm. That would be compared to the old "smoke dragon" days. If the stove is 80% efficient, only 20% goes up the flue.
How's that for a brain teaser on a New Year's Day?
As best I can tell, any type of Class A, Type HT, All Fuel chimney pipe that meets the UL 103 standard protects your house from an over-firing stove up to the limits of the standard. The standard seems to include 1,000 F continuous, 1,400 F for one hour, and 2,100 F for 10 minutes. It seems that there are several designs to achieve those ends. One type is the Ameri-Tec triple wall with 1/2 inch of insulation and the Amerivent - Hart and Cooley TLC and/or the Duratech that all seem to be double walled with 1 inch of insulation. It does not seem that any triple wall non-insulated pipe meets the UL 103 standard.
All that being said, once the pipe is capable of keeping my house safe, how well does it keep my flue warm? From everything that I have learned in my extensive internet studies, draft is almost entirely related to two factors. 1: The temperature differential between the beginning of the chimney and the outlet of the chimney 2: The height of the chimney. Both factors seem to be directly proportional-double the temperature differential-double the draft. Double the height-double the draft.
As to temperature:
With a medium bed of coals, I measured my stove pipe inside the house (single wall 8 inch), testing with an infrared laser type instrument, and the temperature goes from 430 F on the stove top, to 260 F 6" from the stove top, to 110 F 10 feet up the pipe right before it goes into the thimble in the ceiling. So, I lost over 150 F (58%) in about 7 feet of travel. The underside of my chimney cap measured the 99 F. It does not seem as if I am losing too much heat in the outside portion of the chimney (8" Ameri-Tec triple wall with 1/2" insulation).
My stove pipe (15 feet total) is exposed for the last 6 feet.
Does anyone have any knowledge of how much heat various designs of pipe LOSE when exposed to cold outside temperatures? It would seem that the pipe with 1" of insulation would stay warmer than the one with only 1/2 inch of insulation if they used the same type of insulation.
As a slight side bar, can a modern wood stove be so efficient that not enough heat is sent up the pipe to make it draw correctly? Seems like I read somewhere that the newer EPA stoves are so efficient that a smaller chimney is needed to keep the inside of the pipe warm. That would be compared to the old "smoke dragon" days. If the stove is 80% efficient, only 20% goes up the flue.
How's that for a brain teaser on a New Year's Day?
