The indirect heating system consists of 27 mm diameter and 4.5 mm thick annular pipes; these pipes are combined in modular ring-shaped tube nests and heat the floors and ceilings of the various baking chambers uniformly. This new construction system permits exploiting to the full the heat produced by combustion. The oven is also more sensitive to temperature changes and therefore more versatile and adaptable to different production needs. The baking chambers are completely closed and separate from each other. For a more traditional baking system we suggest the ANULAR oven ASTM with wooden working, masonry parts and furnace for solid fuels (as optional) placed in the front- or in the left-side of the oven.