Vent Opening Sizing

[CapePizza]

I'm working on the design of the vent opening and running into some spacing issues. Is there a recommended opening size created by the bricks. I'll be using a 6" double walled flue pipe and the adapter plate with the flange that seems to be 10 inches square. Thanks!

[rwiegand]

What size oven? 6" seems extremely small for any open wood burning application. On my 42" oven I'm using a 10" round pipe and that is barely adequate-- a 10" pipe has ~3X the area of a 6" pipe. (78 vs 28 sq in) You need the brick opening to be at least as large as the pipe in sq in, it's helpful to create as large a smoke chamber as you can manage to improve the draw up the chimney.

I think a 6" pipe is asking for a lot of smoke in your face as it comes out the door. (not to mention the possibility of flame exiting if you get a little enthusiastic with your fire)

Your 100 sq in plate is a good size for a 10" pipe.

[CapePizza]

Thanks for the reply. I'm building a 32 inch oven. I had thought from what I've read, seems 6 inch diameter pipe seems typical (adequate) for this size oven. If I'm wrong, please let me know. Thanks!

[CapePizza]

Looked at your build. Nice! Taking a pix from your build, these 2 dimensions are what I'm looking to determine, keeping in mind for a 32" oven Thanks!

[Neil.B]

I'm also building a 32" and have what I believe will be a small landing. I was thinking of opening the front arch wider to make the vent wide at the front and meeting the inner arch. This would give a bigger angled opening somular to above.
I was also considering building the chimney above the inner arch the same way as I have planned for my grill.
Something similar to this, thick yellow bricks for inner arch and thin yellow for outer arch.

[mongota]

I have a 42" oven with an 8" chimney pipe.

My plan evolved as I built it, but for the 8" pipe I built my vent throat ~8" square. See pic #1.

To create a level brick landing for the chimney plate to anchor to, I did what was shown in the next three pics.

What I ended up with is not what I had planned in the design phase, but you learn and evolve as the build goes higher.

Good luck!

[CapePizza]

Thanks all for the replies and help. And thanks, Mongo, for the pix. Those were helpful and answered my question. I'm interpreting all this .....so if I use a 6 in diameter double walled flue, a 6x6 inch opening in the brick should do it.

[twistof8]

Hallo all, I wonder if anyone can help. I bought a house in Portugal that came complete with a pizza oven. To my surprise, it has no chimney!!! There is a small hole in the back about half way up (maybe higher) but is only the size of a pencil!! Was this a design flaw or how do I use it? I am too scared to make a fire in it since no exit!! See pic attached. Any advice would be great as I would love to make use of it.

[david s]

The oven would work ok without a chimney, but all the smoke would come out the door. As it appears to be indoors this would not be acceptable. As there’s no smoke staining around the top of the door it’s probably never been fired.
The tiny hole in the back is probably for a thermocouple (temperature probe)

As you don’t have any room in front of the oven for a flue gallery, you could get a hood fabricated in sheet steel over the top of the oven door like restaurants have over their stoves.