​This specification applies to cast iron pressure pipes up to 24 inches nominal diameter centrifugally cast in metal moulds. The pipes are intended primarily for the conveyance of water, gas and sewage under pressure. Provision is made for pipes of Classes B, C and D on the basis of wall thickness, buth the specification does not imply any correlation between the classes and any particular working pressures. The specification also applies to joints for use with the pipes.