Potential Fire Hazard?

BigV Posted By BigV, Oct 5, 2006 at 11:07 AM

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  1. BigV


    Oct 1, 2006
    Akron, OH
    I converted my fireplace late last year and installed a small cast iron wood burner on the hearth. I was not happy with the stove and this year purchased a new Regency. I also extended my hearth out 20 inches to insure proper distance from carpeting. Here is my question, please no flaming. My current fireplace has 8” double walled flue pipe for the chimney. During the installation I ran 6” black pipe up 24” inside the 8” pipe inside the fireplace. After reading this forum for a little over a week, it sounds like I should have run a 6” flex pipe through my existing chimney pipe and connect to it my new stove.
    I have used the stove about a dozen times so far this year and everything seems to work well (great draw, no smoking). Have I created a potential for a fire hazard inside my chimney pipe, or will this installation work?
  2. paulgp602


    Jan 7, 2006
    Is it an insert or freestanding stove? When you sweep the 8" , the soot will fall out onto your hearth or stovetop(if its an insert). Which overtime can build up (if the insert isnt pulled out and cleaned).
  3. wg_bent

    Minister of Fire

    Nov 19, 2005
    Poughkeepsie, NY
    Yes. From what I'm reading here, your installation is not adequate. But I'm making assumptions.

    Is the original firplace a zero clearance metal fireplace, and the chimney is the 8" double wall attached to it?

    If so, that chimney, in 99% of the cases will not tolerate the current code requirements of 2100 degree. You need to run a flex liner inside that chimney.

    Take a look at the manual and look under installation in 0 clearance fireplaces.

    No flame...just facts.
  4. BigV


    Oct 1, 2006
    Akron, OH
    Your assumptions are correct. Zero clearance metal fireplace with 8” double walled flue pipe.
    The stove is an insert, but will sit outside the fireplace on the hearth.
    Thanks for the facts, looks like I need to use a flex liner. Any tips or advice on the type of liner, or are they all pretty much the same.
    Thanks all that took the time to respond.
  5. Corie

    Minister of Fire

    Nov 18, 2005
    Halifax, VA
    You know what I don't get about the codes, and this is a bit orthogonal to the thread, but I still want to say it.

    How does a ZC chimney, which isn't rated to 2100 degrees somehow become a safe installation when a thin layer of stainless steel is added between the hot flue gases and the old pipe. Stainless steel has an emormous thermal conductivity (k), so it really does almost nothing to change the temperature of the flue system. What gives, is that really a safe and permissible way for things to be done?

    And warren, that isn't aimed at you! I'm just curious.
  6. MountainStoveGuy

    Minister of Fire

    Jan 23, 2006
    Boulder County
    it doenst corie, it gets safe when you add the insulation. Insulation is always required to make a 1800* chimney a 2100* chimney.
  7. webbie

    Seasoned Moderator
    Staff Member

    Nov 17, 2005
    Western Mass.
    First of all, part of the reason for relining ZC's is that the seams can tend to fail. A reline will fix this problem. Then, when you install a 6" liner (for instance) in an 8 to 10 inch interior, the new liner can only rest against the old one for a small surface area. Therefore the potential heat transfer is vastly less, even at the highest temperatures....with or without insulation.

    When you consider that most newer prefab chimneys are tested to UL 103, (1800 degrees) - which for many years was the top standard for class A insulated chimney, it would be my guess that such a chimney lined with 6" pipe would easily withstand another 300 degrees (for a few minutes as per test).

    Also, many prefabs were originally tested WITHOUT liners for prefabs. The test labs recinded these listing - but the reason was the vast difference among prefabs as opposed to a number of fires, etc.

    Prefabs vary greatly. Older ones nearing or at the end of their 25 year design life were not even tested to the UL 103, rather they were tested as a stand alone system. Newer ones are tested to more stringent standards.

    There are already a number of threads here about the concerns of pre-fabs and a search will find some of those LONG conversations.
  8. elkimmeg


    Corie you have the AShe Hand book what does it say about the use of common connector pipe. a liner must resist the ability to corrode. With chimney condensttion heat and contraction what is the life expectancy of common connector pipe a couple of years at best?. Then what about pulling out an insert and installing it like a free standing stove? Where is that practice in the hand book?

    What about the hearth extention the original one is concerte not bricks on top of the wooden sub floor. What about thermal protection? You are installing an insert designed to be installed in a NFPA code compliant fire place? Part of your install tells you your fireplace might not be up to snuff so you pull an insert forward. AAgain read your manufacture's installation manual and is this a recomended installation. Why not a free standing stove designed to be installed that Way? How did you even get a permit for that install. there are so many possible code violations there? Not flaming you read your manual. I am just telling you the same as if I walked in to do an inspection on your stove. Probably not what you wanted to hear, but your tax dollar appointed me to protect people from these situations A job I take serious and I am helping you now. This may sound flaming to you now, but if you were in my town, I would be condeming that installation and ordering its removal or giving you 15 days to comply before removal. I cannot knowingly allow that type of setup to exist.
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