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Poll - Chimney/flue diameter - Forno Bravo Forum: The Wood-Fired Oven Community



I'm Peter Reinhart! Ask Me Anything! Monday, February 15, 2016 7:00-8:00 pm EST

To kick off our AMA feature, we have invited author, chef and master bread maker and host of Pizza Quest, Peter Reinhart, to be our first host! Peter will be in the Forum on Monday, February 15th, from 7:00 - 8:00 pm EST. If you are unable to be online during the live session, you can post your questions in the sticky post. Peter will answer those questions during the live session on February 15th. You can view Peter's answers to your questions as well as what happened during the live session in the session thread.

Ask Me Anything New Forum Feature

You will notice a new forum at the top of the main page called, "Ask Me Anything". This forum will be used for live one hour "Ask Me Anything" (AMA) sessions hosted by people who are knowledgeable in different areas pertaining to wood fired ovens. How it works:
- Each AMA will have a "sticky" thread where the community can post questions they would like answered during the live session. This will allow everyone to participate even if you can't be online for the live session. These questions will not be answered by the host until the live AMA; if you need an answer quickly, you should post it in the appropriate Forum area for the community to respond.
- Another thread will be posted for the live AMA. Registered users who are logged in during the live session can interact with the host by asking questions and receiving responses.
- The live thread will remain in the AMA forum to view after the session.

We hope you enjoy this new feature! Please let us know if there is a topic that you'd like to have as an AMA and we'll look for a host!

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Poll - Chimney/flue diameter

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  • Poll - Chimney/flue diameter

    reading the material on the FB Forum and web site one gets the notion that on the minimum the diameter of the chimney for a 42 inch oven should be no smaller than 8 inches, 50 square inches. I am searching for the largest cross sectional of the chimney that works.

    Has anyone used a larger dimension?
    How well does it draw?

    CanuckJim - same question jsut modify your answer as appropriate.

    Still herding those ants

  • #2
    Re: Poll - Chimney/flue diameter

    36" diameter, 8" square refractory flue tile, most likely 12-14 feet high when finished, draw to be determined.
    My geodesic oven project: part 1, part 2


    • #3
      Re: Poll - Chimney/flue diameter

      8 inch I.D. square clay tile. 42" oven. Expect to use 4 feet of flue. Draft TBD.

      The wooden box represents the location of the flue tile.
      I'm building a Pompeii Oven in Austin, Texas. See my progress at:
      Il Forno Fumoso


      • #4
        Re: Poll - Chimney/flue diameter

        39 inch oven, 7.7 inch diameter chimney.

        I want to extend my flue because I believe the more flue you have the better the draw becomes as it heats up. I'm also fighting nearby walls. As I recall some codes for house chimneys wanted them to be above the roofline....
        sigpicTiempo para guzarlos..... ...enjoy every sandwich!


        • #5
          Re: Poll - Chimney/flue diameter

          Muy buenas tardes, XabiaJim!

          Building a 39in (1m inner diameter) dome on a hearth 90 cm above ground level.

          I've checked with my local council what provisions they have for barbeques (this is an Australian national emblem for the backyard) because I didn't want to try getting approval for a pizza oven.

          Turns out you need NO building permit or whatever for a barbeque, provided it is no less than 3 m from the boundary line and is no higher than 1.8 m.

          That limits my flue to 50 cm - I guess that would still be o.k.? If not, I'd have to emply the sliding extension type of flue that I've seen mentioned on the Forno Bravo forum...

          Salud y pesetas - y putas para gastarlas!

          Last edited by carioca; 02-20-2007, 02:38 AM. Reason: dimensions of oven added
          "I started out with nothing, and I've still got most of it"


          • #6
            Re: Poll - Chimney/flue diameter


            It does seem that 8" square flue tile is the standard, not only for pizza ovens and bread ovens, but also for indoor fireplaces. Having said that, however, I used 7" round tile on my 3' x 4' bread oven and it draws exceptionally well, winter and summer. As for height stipulations, most building codes do specify that the chimney must extend above any roofline within 10' or so by as much as 3'. Depends on where you are. But, this is for fire hazard reasons, not draw. The chimney on my bread oven clears the peak by about 18". There is a pic of it in the photo gallery. There are many theories and, I believe, some formulas for the height and diameter of the chimney in relation to the size of the firebox, but these are mainly written for fireplaces and wood stoves, not ovens. Count Rumford of Revolutionary War fame is just such a mathematician.

            Of course, as the flue gasses rise, they begin to cool. In my experience, an exceptionally long flue contributes to creosote deposits, but this is based on fireplaces and woodstoves. Seems to me, at the heat our ovens burn, that the length of the flue is not as critical as in these other applications.

            I get zero smoke out the mouth of my oven, UNLESS the wind is blowing horizontally from the south, directly into the mouth itself. In these conditions, I shouldn't be outside anyway, because a howler is on its way. Essentially, I designed the total height of the chimney more for aesthetic than mathematical reasons, and it works just fine. The total flue is quite short, and this contributes to a clean interior.

            "Made are tools, and born are hands"--William Blake, 1757-1827


            • #7
              Re: Poll - Chimney/flue diameter

              My Casa110 [43" ID] has a 8" DuraTech SS dual-walled flue extending 6' above the oven.

              J W