Bricks that are equal to or greater than 2000Kg/m3 are considered dense refractory bricks. They are used for lining melting furnaces or ovens which are exposed to significant mechanical or chemical dangers.
Insulating refractory bricks have a density of 1000 Kg/m3 or less. They are used to insulate dense bricks and concrete in fusion ovens. They are also used as a first layer insulation for the linings of heat treatment furnaces and various heating equipment.