Full Description ADOPTED_FROM:EN 723:2009 This European Standard specifies a combustion method for determining the carbon content, if any, on the inner surface of tubes of copper or fittings of copper or copper alloys. This standard applies only to seamless, round copper tubes as specified for example in EN 1057 and EN 13348 or fittings of copper or copper alloys as specified in EN 1254 (all parts).