This European standard specifies materials, assembly dimensions and tolerances and test requirements for fittings of copper and copper alloys with or without plating or coating. Maximum permissible temperatures and pressures are also established. This part of prEN 1254 specifies connection end dimensions of compression ends for the purposes of joing copper tubes specified in EN 1057. Fittings may comprise a combination of any of the end types specified in prEN 1254-1 to prEN 1254-5 or other standards. The standard establishes a designation system for the fittings.