How Heat Works

[slschoming]

There is a short paragraph or two in the original plans that discuss adding an extra layer of firebrick under the floor to achieve more thermal mass, and therefore, longer cooking times. The downside is that this takes more time to heat up when you are not planning on extended cooking times.

I do not know if this would be a practical solution, but my thought was to keep a handful of firebricks that I could (in theory) lay out a smaller floor on top of my permanent cooking floor when I want to do longer days of bread baking. Nothing fancy, just a layer of firebrick or firebrick splits that don't have to conform to the shape of my floor (maybe a smaller square that doesn't have to touch dome walls) that would be easy to install / remove when the oven is cool.

[ThaiCapp]

Well I like the graphic

I'm in the early planning stages, and while I love pizza, I'm more excited about baking bread and I'm willing to spend a bit more time heating up to get to do multiple batches of bread and slow roast some meats.

[david s]

Re: How Heat Works

No, nothing really wrong with two hemispheres joined by a straight barrel. I was simply trying to clarify the geometry. A string that is movable between the three points would give you a true ovoid form.

[wotavidone]

Re: How Heat Works

Unless you have a string connecting the two pivot points with the inner dome contact point you'll end up with two hemispheres joined by a barrel arch. Another simpler way is to shape the oval dome in sand and build against the sand form.

So the shape will be two half hemispheres joined by a straight section rather than a true oval. So what?
I didn't explain my idea in much detail, but I believe I could make the whole dome in running bond, no centre arch making up the straight section.
I wanted to try it on my mates oven but he vetoed it on account of his short arms.
Maybe I'll get to try it on oven number three.

[david s]

Re: How Heat Works

If using an indispensable tool, you could easily build an oval oven simply by using two pivot points.

Unless you have a string connecting the two pivot points with the inner dome contact point you'll end up with two hemispheres joined by a barrel arch. Another simpler way is to shape the oval dome in sand and build against the sand form.

[wotavidone]

Re: How Heat Works

Sorry for the late reply.
You will come across many reports that say oval ovens work fine.
I offered to build my mate an oval one but he felt he would not be able to reach the back.
Our hosts, FB, offer an oval oven.
Artigiano120 Brick Oven Specifications

If using an indispensable tool, you could easily build an oval oven simply by using two pivot points.

[kira]

Re: How Heat Works

Hello,

Im working on an oven that is set on a trailer... WOrking with the size trailer bed we have 46x48" I had decided on an oven diameter of 32"... now looking at it, it seems small... I wanted to change the shape a bit to make it 35x38" oblong/oval but am afraid that will mess up the heat flow etc... can anyone share their experience with a non-perfect circle oven? Or their thoughts on how this small difference will affect the cooking of pizzas? This oven is intended for that, not baking. thank you!!!

[meranteboys@comcast.net]

Re: How Heat Works

To help, we need all of the details.
What kind, round/barrel?
What size?
How tall will the chimney be (from top of oven to end cap)?
Are we talking a straight up run or will you need curves?
Every detail you can include.

Also, being indoors you are going to have to follow local building codes, so that would be a good place to start.

please help, can you give us your number so that we can contact you on this. I am only relaying info from my husband and I think he needs to personally talk to someone over the phone to get a better understanding of this job. My personal email is meranteboys@comcast.net Thanks, Domenica

[wlively]

Re: How Heat Works

Also need to know the area of your oven opening, as proper sizing of the chimney is related to oven opeing size. The rule of thumb is a max of 1/10 ratio, meaning that the fireplace opening can be 10 times as large as the flue cross section. This ratio applies to the diameter of the flue, so if you use a square flue you will calculate the dia of the circle inside, as the corners will not flow much due the dynamics of circular airflow.

The good news is taller is better, so you should have a good draw. You want the vent opening in your arch to be as wide as possible to scavenge as much flow as possible. You want the area of the vent opening larger (at least 30%) than the area of the flue. Make the vent to flue transition as smooth as you can, a smooth and easy airflow path leads to more volume of flow and higher speed. You definietely want insulated chimney, at 30' I am sure Duravent is out of the question, but it may make good sense to use it for the first section. Just by going on oven size since opening is unkown, you might be able to use 6" (113 sq in), but 8" (201 sq in) is probably a better choice. Just remember as you go up any transitions need to be the same area or smaller, do not go larger.

Again, make sure you know what the code requirements are, as they may make a lot of the decisions for you.

Hope that helps.

[meranteboys@comcast.net]

Re: How Heat Works

Thanks for getting back to me. To give you all of the information that I have it is a rounded oven, with a 40 inch floor space and it is a 30' straight run from the top of the oven to the chimney cap. If you can help in any way I would appreciate it.

[wlively]

Re: How Heat Works

To help, we need all of the details.
What kind, round/barrel?
What size?
How tall will the chimney be (from top of oven to end cap)?
Are we talking a straight up run or will you need curves?
Every detail you can include.

Also, being indoors you are going to have to follow local building codes, so that would be a good place to start.

[meranteboys@comcast.net]

Re: How Heat Works

I'm having trouble with my indoor basement oven installation. I have a chimney top that is 30 feet from the basement where the oven is. What diameter flue do i need to feed through there to get the right flow for the oven to work properly. Anyone out there please help!!!!!!

[meranteboys@comcast.net]

Re: How Heat Works

Do you know of anyone who can help me with calculating flue size when it comes to my indoor pizza oven that is in the process of being built!!!! HELP!!!!!!!!!

[reid]

Re: How Heat Works

I just finished three hours at our local farmers market baking 90 pizzas and the oven was still doing great.

This is a refractory barrel style oven with 3" of refractory. outside of the dome was 160 degrees F.

[maver]

This is a nice graphical illustration of the theories of brick ovens we've talked about here. The question - for James or other bread oven owners with thermocouples - is what the oven is like at 3 hours - is it getting to suitable pizza temps then?