A seamless pipe shell welded to a seamless pipe cap on one end and an slip on flange on the other end. Spot RT is performed on the shell/pipe cap weld seam per UW-11(A)(5)(-b) in order to use a joint efficiency of 1.0 on the shell for the circumferential stress calculation. Since the shell can be considered equivalent to welded parts of the same geometry where cat A welds are type 1, I believe the vessel will be marked RT-2. Is this correct or does this vessel require RT-4 marking?