Section 56.70-20 - Qualification, general(a) Qualification of welding procedures and welders is required, and must comply with the requirements of Section IX of the ASME BPVC (incorporated by reference; see § 56.01-2 ) as modified by part 57 of this subchapter.(b) Each butt-welded joint of Class I of Class I-L piping must be marked with the welder's identification symbol. Dies must not be used to mark the pipe where the pressure exceeds 600 psig or the temperature exceeds 750 °F or in Class I-L systems.CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by USCG-2003-16630, 73 FR 65184, Oct. 31, 2008