In South Asia, the most widely used technology for firing bricks is the Fixed Chimney Bull’s Trench Kiln (FCBTK). It involves a continuous, moving fire kiln in which the fire is always burning and moving forward in the direction of air flow, due to the draught provided by a chimney. The bricks are warmed, fired and cooled simultaneously in different parts of the kiln.
There are basically two types of FCBTKs in operation: Forced or induced draught and natural draught. In forced or induced draught, a fan is provided to create the draught from the chimney, whereas in natural draught, the chimney itself creates the required draught.