Does heater tubes in fired heaters require ASME stamp?

have seen one fired heater with asme u stamp. ASme recogbnises DF, direct firing however it excludes tube heaters per the follwoing form ASME VIII-1.

U-1(c)(2) Based on the Committee's consideration, the following classes of vessels are not included in the scope of this Division; however, any pressure vessel which meets all the applicable requirements of this Division may be stamped with the Certification Mark with the U Designator:

(a) those within the scope of other Sections;

(b) fired process tubular heaters;

(c) pressure containers which are integral parts