Dimensions summed up. Are these correct?

[sonomacast]

Is this correct
the height of the interior dome is 90% of the radius of the oven floor?
The Door opening height is 63% of the dome height?
The area of the flue is 10% of the area of the door opening?
The ideal door is 22" wide at the dome?
The flue should be 10% (area) of the area of the doorway
the ideal floor is 2 1/2" thick?
The minimum thickness of refractory (cast) concrete is 3"?
A floor cut inside the dome is far more efficient than a dome sitting on a floor?

I have now cut most of the forms for my newest oven project. In order to make things easier and also make the mould re-usable for future castings I plan to segment the oven, No -probs.
My question is this; Most of the modular ovens I see for sale are segmented also at the top. (A kind of keystone (Round)). Is there a reason for this, does it make the segments more secure and stronger or what? Thank you

Just want to make sure everything is correct before I start nailing things together. Thank you

[Neil2]

Re: Dimensions summed up. Are these correct?

"The ideal door is 22" wide at the dome? "

No particular "ideal" width. Nor is this a critical dimension in terms of the oven firing operation. Otherwise the various ratios seem right for a low dome style pizza oven.



"A floor cut inside the dome is far more efficient than a dome sitting on a floor? "

Two schools of thought on this one. As far as I am concerned it doesn't make much of a difference. Certainly not in terms of "efficiently". Dome-on-floor is probably easier to build. "Floor-inside-dome" may make it easier to replace damaged floor bricks. (Very unlikely occurrence, seems to me this has only happened once on this forum).

People have built them both ways with equal success.

[sonomacast]

Re: Dimensions summed up. Are these correct?

The 22" was something fb claim is essential in thier literature, funny though as when you check the fb oven plans the doors are smaller.. Forno Bravo Modena2G Oven Opening Size

Again here it says 2 1/2" is the best floor thickness but I just checked a few fb ovens and the floors are 2" and under... http://www.fornobravo.com/commercial...thickness.html

I am so confused now. Just take an average of everything I suppose

[GianniFocaccia]

Re: Dimensions summed up. Are these correct?

There really is no 'ideal' for an oven's dimensions, other than the 63% door height-to-dome height ratio, I believe. Just know that the more mass an oven has, whether it's in the dome, floor, or elsewhere, the more it will take to heat it up (wood and time) and the longer it will retain it's heat.
Only recently has anyone (mklingles) suggested that the difference between dome shape (flat vs hemi) and/or height (low/high) may have but a slight impact on the radiant heat distribution from dome to floor.

[sonomacast]

Re: Dimensions summed up. Are these correct?

The thing is some time ago I read in a few places that the Russians and the Finnish did a huge study on WFO's to find the best performing and economic dimensions but have never actually read the results. I'd love to see them and see what worked out to be the ultimate configuration. After more studying i have now deduced that 40.3% of the diameter is the average dome height when it comes to commercially sold ovens. i found this file in the forums http://www.fornobravo.com/forum/atta...g-analysis.pdf

[sonomacast]

Re: Dimensions summed up. Are these correct?

My doorway is 22" wide and 10 1/2" high. The door is a perfect semicircle so the door area is more or less 175" square so the flu would need to be 17 1/2" square area therefore the flue would have to be under 5" in diameter according to the info I have found on this forum.....(Ideal Flue is 10%area of the door area). This seems small for a 42" oven...any ideas? Thanks

[sonomacast]

Re: Dimensions summed up. Are these correct?

"A floor cut inside the dome is far more efficient than a dome sitting on a floor? "
Was something I read here Mugnaini Advantage | Mugnaini.com

[Neil2]

Re: Dimensions summed up. Are these correct?

"Was something I read here Mugnaini Advantage | Mugnaini.com"

I read that too. There is no logic to it. If your insulation completely surrounds the floor and dome its all one and the same.

[dmun]

Re: Dimensions summed up. Are these correct?

Again here it says 2 1/2" is the best floor thickness but I just checked a few fb ovens and the floors are 2" and under... http://www.fornobravo.com/commercial...thickness.html

Firebricks are 2 1/2 inches thick. Hence the floor recommendation. I seem to recall that my firebricks were 2 1/4. Use what you can get. This is nothing to loose sleep over.

[sonomacast]

Re: Dimensions summed up. Are these correct?

"Was something I read here Mugnaini Advantage | Mugnaini.com"

I read that too. There is no logic to it. If your insulation completely surrounds the floor and dome its all one and the same.

I thought the same myself, heat rises so to be honest I see little point even insulating the floor

[GianniFocaccia]

Re: Dimensions summed up. Are these correct?

mklingles, in his detailed thermal analysis reported:

I have not been able to find a reliable source of data on the amount of energy absorbed by fire brick vs the amount reflected. I believe from the numbers I have found that ~80%of the energy is absorbed and only 20% reflected.

It is this 80% of stored heat that allows a WFO floor to rebound in the cooking of multiple pizzas. It this this 80% of stored heat in the dome that provides the continuous radiation that makes for the wonderful golden-topped artisan hearth bread. Without proper insulation under the floor this stored heat would be leaked into the support slab upon firing and never allow the floor get to proper cooking temperatures. That is the point of insulating under the floor and a mighty big one.
Further, the way I understand it, the thicker one's floor, and the more heat storage capacity, the more floor insulation you need.