Describes requirements for plain end, seamless and welded, carbon and alloy steel tubes and for cold finished seamless austenitic steel tubes, not exceeding 127 mm outside diameter and not exceeding 12.5 mm thickness for use in boilers and superheaters. Covers information to be supplied by the purchaser and options to be documented, manufacture of the steel, manufacture of the product, chemical analysis, final supply condition, mechanical properties, visual inspection and appearance, tolerances, tests, number, selection and preparation of samples and test pieces, test methods, test certificate, protective coating and marking.