**Firebricks calculations**

One of the important purchases for the oven are the refractory bricks. You need to properly estimate the number of bricks based on the design you choose. A good idea is to roam around the different forums and see what people have used for similarly sized oven. This should give you a pretty good idea of what is needed. If you have a 3d model, that's even better, you can also do some calculations to get a rough estimate.

A rough estimate of the number of firebricks can be simply calculated with the following kindergarten formula:

*Num bricks = Area/brick area*

I used firebricks in three parts: the oven hearth, the dome and the door arches.

Depending on whether the bricks would be tapered on all four sides or not slightly influences the final count.

In my case, the bricks dimensions are 22x11x6 (units in cm - yes I'm using the ever popular metric system!) and I'm using mostly half bricks (up to the 10th layer), whose section would be 11x6

- oven hearth: Surface = Π* R
_{e}^{2}

with R_{e}: external radius = internal radius + brick width = 46cm + 11cm = 57cm

Surface = Π*57^{2}= 10201 cm^{2}

For the hearth, the bricks are laid on their wide surface whose area is 11cm x 22cm = 242cm^{2}. The number of bricks would then be = 10201/242 ≈ 42 full bricks - oven dome:

An ellipsoid surface can be calculated using this**ellipsoid area calculator**where you provide a=b (dome radius) and c for the dome height

There are two cases:**non tapered bricks**The bricks section fits the interior of the dome and in this case I have a=b=46 cm and c=38, which yields&nb p;for a half ellipsoid ≈ 23562/2 = 11781 cm^{2 }which corresponds to about 11781/(11*6) ≈ 179 half bricks = 90 full bricks**tapered bricks**

Here the bricks section fits the exterior of the dome and a=b=46+11=57

and c=38+11=49, which gives a dome surface of 18533 cm^{2}which corresponds to 18533/(11*6) ≈ 280 half bricks = 140 full bricks

- The door has an opening of 46 cm (w) x 25 cm (h), and requires two arches made with around 20 firebricks

The total number of bricks is approximately:

non tapered bricks: 42 + 90 + 20 ≈ 150 bricks

tapered bricks: 42 + 140 + 20 ≈ 200 bricks

**Firebricks calculator**

Now just for fun, here's a firebrick calculator I wrote, just enter your numbers and it will spit out an estimate of the number of bricks you need for the dome + hearth. The actual number will be slightly lower as it doesn't consider the entry area where there are no bricks. But this is slightly compensated by the entry arch bricks (the one supporting the dome) as they are not included in the calculations.

This works in any units, as long as you use the same for all dimensions. You can even use parsecs if you like, but that might not be practical.

Dome radius |
Dome height |
Brick width |
Brick height |
Brick depth |
Tapered bricks |

Dome area |
Dome bricks |
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Hearth area |
Hearth bricks |
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Total area |
Total bricks |