Up-draft kiln: It is used in one of the oldest methods of firing. This kiln is round, made with bricks and narrows at the top to form a chimney. It has a floor and underneath which the wood is burned. The air enters through the doors, the pressure of the air pushes the heat and the gases up through the floor, round the ware being fired and up and out of the vent at the top. The vent is narrow so the heat collects and intensifies round the work and fires it.