This European Standard is applicable to pipes and fittings of longitudinally welded stainless steel pipes with spigot and socket for wastewater systems. It specifies dimensions and tolerances for pipes, fittings, pipe connectors and seals of the System X and establishes a system of designations for the different pipe and fitting types that conform to the stated requirements. NOTE System X is a system of pipes and fittings of longitudinally welded stainless steel pipes with two-step sockets. This European Standard is only valid in connection with EN 1124-1. This European Standard does not apply to the marking of products. EN 1124-1 applies to the marking.