If you are seeking to make your own barrel oven, then you need to consider a number of factors. One of them is the intended use of the oven. The intended use of the oven is crucial because it determines the size of the oven. The barrel oven has a length and a width. For commercial purposes, the big size oven is appropriate. However, for the home-based oven, the standard size is 32" x 36" (82 cm x 92 cm) internal dimensions. The oven foundation should be set 20 cm from the ground and the internal height of the oven preferably 16”.
Further information: Make your own barrel brick pizza oven and outdoor setting