Appendix L Fig.L-1.4-1

[kormechanical3]

In Fig.L-1.4-1 in Appendix L of ASME Sect.VIII Div.1, 2005 Addenda. If my cylinder is seamless section, I will select RT of Category B and C butt joint, and the figure will shown joint efficiency of category A B and C.But cylinder is seamless section, why category A have Type 1 or Type 2.(In UW-12 (d): seamless section shall be considered equivalent to welded parts of the same goemetry in which all Category A welds are Type No.1)