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Black stove pipe first then double wall...why?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by wg_bent, Jan 5, 2006.

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  1. wg_bent

    wg_bent Minister of Fire

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    I notice in pretty much all the free standing stove installations that they use black stove pipe, then switch to double wall stainless or better going through walls and then outside.

    Why isn't a stainless pipe required similar to a chimney liner? I guess another way to ask this... why isn't stove pipe o.k. as a chimney liner? Just curious.

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  2. Willhound

    Willhound Feeling the Heat

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    Warren
    I'm no expert and I'm sure Elk or one of the stove/tech guys will chime in, but my understanding is that black wall stove pipe is thinner guage, and not as robust as SS, but this is not as much of an issue where the pipe is exposed to the air and can release some of it's heat. A lot of older stoves wouldn't have much heat except for what was thrown off the pipe. Inserts, etc. where the pipe is usually closed in would not allow the heat to dissipate fast enough off this thin stuff and it would fail.

    Willhound
  3. Todd

    Todd Minister of Fire

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    I was told black stove pipe will rust through in a couple years, and wont hold up to a chimney fire if used as a liner.
  4. Michael6268

    Michael6268 Feeling the Heat

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    Rust- absolutely! It would rot out in a couple of years. As far as holding up to a chimney fire, not as good as a ss, but I often wondered, why wouldnt one be concerned with a chimney fire in the black pipe that leads from the stove to a masonry flue, or to a double wall chimney atop a catherdral ceiling, but would be concerned with a black pipe in a masonry chimney that has the added protection of a clay liner, bricks and mortar?? I dont burn wood (other than in fireplace) but I assume that most woodburners leave there stove on overnight and when the are not home?? Why is no one concerned of a chimney fire in the black pipe that is inside their home, which if burnt out could have a high potential of starting the inside of the house on fire?
  5. wg_bent

    wg_bent Minister of Fire

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    Exactly!!!! I have stainless from stove up, but....
  6. rmcfall

    rmcfall Feeling the Heat

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    So what is the best solution in the case of a freestanding stove?

  7. elkimmeg

    elkimmeg Guest

    I was hoping Craig piped in. I do not want to dominate the forum but here goes.
    First of all a chimney system is supposed to vent exhaust as safely and efficiently as possible. Heat is required for assention. If heat is lost threw dissipation in a single wall pipe the assention is not possible. This heat loss also leads to condensation and creosote build up. That is why c single wall connector pipe length are required to be the shortest straightest possible run. The pipe is not designed to stand up to chimney fires another reason to run it as short and straight as possible. A chimney has to have many properties. One: insulation to reduce clearances and reduce temp to exposed combustibles Two, Insulation also holds heat in to prevent heat loss and conducive to positive draft.. Three, A chimney also has to be corrosive resistant and weather resistant. Four a chimney must be durable enough to resist the heat of a chimney fire { HT 2100} ( Enter Stainless steel and clay) All properties and safety factors not found in single wall connector pipe.

    There are two common forms of single wall connector pipe snap fit 24 gage and welded seam 22 gage. 22 gage is far superior. In liner installations the single wall stainless steel liner can be used. It does not have the insulating properties of chimney pipe to enhance draft and reduce creosote build up. What about double wall connector pipe? Remember it is defined as connector pipe Its clearance is reduced to combustibles but not equal to chimney specs 6” to combustiables, is triple of the 2” most chimney pipe is spected out to. It does prevent heat loss to enhance draft in comparison to single wall pipe. It is not corrosion resistant nor is it HT 2100 compliant, but more protection than single wall connector pipe. Some stove manufactures spect single wall pipe to assist heat dissipation from the stove they are actually tested that way. Using double wall pipe in this instance could be detrimental to the longevity of the stove. One has to follow manufactures specs.

    Monetary expense also factors into the equation. It is a lot cheaper to use single wall connector pipe that doubles as your chimney. Stainless steel can cost more than $75 per section. Single wall connector pipe cost about $6 per same length section. When passing threw a combustible wall or ceiling, the single wall pipe must be 18” or more away from that transition area. Double wall 6 to 9” depending upon their listing requirement. . Once they enter chimney pipe that is the actual start of the chimney. Meaning single wall connector pipe cannot be used again (connector pipe as explained is not chimney pipe)

    A real side story about codes and consequences when they are not followed:. Remember codes are implemented to protect the public. They are really minimum tested safety standards. I got a call for the neighboring town today and the State for my opinion concerning a tragedy involving a wood stove and carbon monoxide poisoning. A direct connect insert was just installed into a clay 12/12 masonry clay lined chimney. The damper was not sealed with a metal blocking plate but a couple pieces of fiberglass insulation. Three issues factored into exhaust entering into the living space. One the weather is warmer not draft conducive. The cross- sectional area in warmer weather and being 12/12 flue was too large for marginal draft conditions to positive draft correctly. The damper block off using insulation did not afford the safety, a sealed metal damper block off would have. End result one dead cat a dead dog the 8 year old daughter will recover. The father is in guarded condition, My prayers are that he fully recovers and not suffer permanent brain damage. No carbon monoxide sensors. The pets died to save the occupants. Codes are minimum requirements tested and proven. Unfortunately dire consequensence can result when they are compromised. This installation passed inspection.
    All I can do is to keep watch on my town and make sure the residences that pay for my inspections are safe. The other thing I can do, is to post on this forum so that others learn safety, even if their inspectors are delinquent in knowledge of safe installations. To those who want to re-engineer their stoves or duct systems or compromise them. Not in my town, not on my watch .
    I hope this answered your questions and to warn others not to compromise their personal safety for a few $$$. Feel free to correct my grammar and punctuation or add to this post so that others can be safer. I feel it is important enough to be brought forward as needed
  8. minesmoria

    minesmoria New Member

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    ELK, your wrong about the double wall pipe it is listed the same as chimney pipe!!

    I have excel ultra black double wall pipe it is stainless steel pipe which meets the canadian ulc s629 for 3 chimney fires at 2100f liftime warranty same as the selkirk chimney.

    I would never use single wall pipe that stuff should not be allowed to be use 18" clearence rust out fast, heck i seen new single wall pipe at the store with rust spots on it.

    You must have single wall pipe as you dont know much about the good safer better double wall pipe!
  9. elkimmeg

    elkimmeg Guest

    First of all I did not mention (black) double wall connector pipe. Conector pipe is connector pipe is connector pipe. As such chimney pipe double wall is listed to be chimney pipe. You are correct double wall connector pipe is a better application. 22 gage welded seal connector pipe is better than snap seam 24 gage No arguement their
  10. wg_bent

    wg_bent Minister of Fire

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    Thanks for the brain dump Elk, it's exactly what I was hoping for, and I must admit, I was baiting a bit. Someone at work was suggesting that sections of black pipe through a 0 clearance fireplace chimney was just fine...I said "no" but other than saying it didn't meet code, I didn't have a lot to back it up...not I do...Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  11. elkimmeg

    elkimmeg Guest

    Tell them like Clint Eastward said Hey punk do your feel lucky. When that first chimney fire occures ( And it will happen with single wall pipe a lot sooner) and it blows threw that pipe and back flashes into the home. Ask them, if they survive, how that single wall black connector pipe worked out for them? They can apply the money saved, buying cheap single wall pipe, to help offset the cost of the fire restoration efforts.
  12. Michael6268

    Michael6268 Feeling the Heat

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    Not to be repetitive but can anyone answer why single wall pipe is then allowed as connector pipe. In my previous post I mentioned a typical set up of lets say 15' cathedral ceilings with single wall pipe up to the box in the ceiling. Knowing that single wall wouldnt stand up to a chimney fire as a "liner" in a masonry chimney, what would happen to that 15' from the stove to the ceiling in the event of a chimney fire? Assuming the characteristic described previously are correct, that pipe would melt away and a house fire and possible loss of life would result. Therefore how/why would "any" code in any state allow such a dangerous situation to exist "inside the home", but not "outside the home" in a "liner type" situation? Someone help! My head hurts.........
  13. elkimmeg

    elkimmeg Guest

    Mike you have read enough of my post to know where I stand But I cannot make up code as I see fit.
    Eventhough we know the limitations of single wall pipe. Code allow x length per manufactures specs. It has been tested safe by the manufacturer. I know this is not good enough you want the reasons. So I am going to take a stab at it
    These set of conditions exist . 1# all connector pipe are inside the heated area 2# the are limited by manufactures specs to their length and bends. 3# being inside and closest to the stove they are extremely hot. ( stack thermo prove this)
    Since they remain hot inside the conditioned space and are staight as possible, Cresote does not build up as quickly. Straight runs no bends even less chance for cresote buildup. With minuimal build up there is less fuel for the chimney fire or little fuel (cresote) in the single wall pipe to see that insense fire. The cresote build up will occure from bends and when the chimney enters into the unconditioned space in the attic and to the outside. The Temperature difference there is greatest. cooling the pipe enhancing cresote buildup. It is there the fuel for the chimney fire resides and there it will be the most insense. Since heat rises the fire will blast upward and not downward towards the connector pipe unless it follows the fuel source or gets blocked above. All are welcome to correct me if I have not stated anything correctly I was trying. There is a difference knowing code and not knowing all the resaons code evolved.
  14. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I can't help ya because I agree. Even when people talk about rust. 15' of single wall to the ceiling and then 6' of double wall insulated stainless up and out sounds like as big a rust risk as putting it in a masonry flue.

    Not to mention your chimney fire in the house scenario. The masonry flue tiles would damn sure contain disintegrating black pipe better than my living room would.
  15. Michael6268

    Michael6268 Feeling the Heat

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    Im glad someone see's my point of view. :)
  16. fbelec

    fbelec Minister of Fire

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    i've got a technical question i hope some could answer. i'll give a for instance also. back when i was about 19 or 20 i had this apartment that i installed a wood stove. now i was very dumb when it came to the codes about such things. i didn't know any existed. this stove was in the kitchen. i hooked it into a clay lined chimney 8x8. did i say (knowing what i know now) how lucky i am to be here asking this question? i'am lucky. anyway i hooked in the chimney to a metal (what i was told to be a thimble) metal sleeve with a rolled edge which was cut thru the plaster into the chimney. about 3 feet of smoke pipe (not black pipe) a 90 then 2 feet of smoke pipe into the stove.( a imitation of a jotul stove. that thing use to smoke out the the street when running which was 24/7
    about every week to week and a half the creosote in the pipe from the stove to chimney would light off after i got use to it when it did light off i would control it. it would make a glowing red ring starting a foot up and crawl up the pipe and usually stop before the chimney. when i would see it getting close i would shut the stove down and it would go out. every once and while i would pull of the pipe and check after the stove went out that next time and it would be clean as a whistle. the chimney had just a black color. nothing would scrap off. so here is my long drawn out question
    and i hope i ask it so that someone can understand.

    is it possible to wring out the creosote in a long piece of pipe before it reaches the chimney
    or was i just plain lucky

    btw let me just say that it was a inside chimney on the snd floor of a two family house that had two water heaters in the basement running up the same flue.

    thanks for your time:)
  17. rudysmallfry

    rudysmallfry Feeling the Heat

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    Warren, I completely agree with your question of why only single wall is required. Any system is only as good as it's weakest link. It's been bothering me since I put my stove in a few months ago. I simply ran out of money and went single for now, but will be upgrading to the good stuff as soon as money permits. Single wall pipe meets the most basic saftey standards, just like cars can protect you in a 35mph crash. But who crashes at 35mph? Fire is very powerful stuff. Overkill is better in this case.
  18. wg_bent

    wg_bent Minister of Fire

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    Yup...That's why I asked the question. I understand Elk's response, and he's right in that the double is required by code etc..., Even my neighbor was required by the building inspector to put in single wall up to the thimble, then double wall through the wall. Required??? It seems like doublewall insulated stainless would be better.

    In the case of my coworker, I know that again, the single piece stainless is better, and that's what I have from stove to above the existing chimney, so I did not install as he suggested he did in his install, but in years past there were plenty of folks who did less..(another "but") BUT, there were a lot more chimney fires.

    I believe that in my Engineering founded mind, that a single peice of pipe is better, and that stainless is better than rolled steel. But in the analogy of cars, a base Saturn is adequate, but a high end Mercedes with adaptive cruise, air bags all over, active roll over protection, a body structure worthy of a m1 tank, is clearly better. The final arbiter is the housing code, as Elk has stated as the basic minimum criteria. Now why is the minimum the way it is? It's based on statistics.

    All that said, I think it doesn't make sense... stove pipe, then the required switch? Elk, thanks for your response and I certainly will do as the code suggests, and I'm still a bit nervous having a 1200 degree thing in my livingroom.
  19. elkimmeg

    elkimmeg Guest

    I have often wondered why not use a tee instead of a 90 degree angle? With the tee, one can install a cover which can be removed for observation and cleanning. The tee will alllow one to be able to clean the connector pipe without diss-essembly. Me. I prefere the 22 gage welded seam connector pipe. I have not seen stainless steel avaible locally. It has peaked my interest it is better. I know it is rust resistant, Just wondering how easy it is to cut crimp and drill. One really notices the difference with 22 gage much harder to cut with tin snips. I use a dremmel with a metal cutoff wheel. I have also used a sawzall, but with one extra trick. I cut 2 round piece of wood spacer and place one each side of the cut . Helps keep its shape, with all the vibrations and makes it a lot easier to get a clean cut. Those round spacers also are great to support drilling the holes for the sheet metal screws. One other hint, those round spacers, I put a dry wall screw in the middle. Helps having them to manouver the spacers, something to grab onto
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