It is well known that the best material for the sanitary network is the ceramic materials, As it has the best chemical resistance for the wastewater that contains sulfuric and nitric acids, salts, BOD and organic gases. All these items, which perform an aggressive environment inside the carrier pipes. That is the main reason for the use of the Vitrified Clay pipes for the sanitary network for the pipes for the diameters less than 1000 mm.

As for the pipes bigger than 1000mm diameter, which are mainly produced as reinforced Concrete pipes, it has to be protected from inside by a ceramic elements . This protection is a vitrified clay elements of dimensions 24OmmXll5mmXl5mm. These elements have a smooth surface from one side and a tee lock shape from the other side to insure the best adhesion between the elements and the concrete. These elements are assembled in sheets called the KERALINE.