For Category C joint, detail is given in

FIG. NB-4243-1 ACCEPTABLE FULL PENETRATION WELD DETAILS FOR CATEGORY C JOINTS
(NB-3352.3)

The above figure shows only corner full penetration joint and not showing any pure butt joint but the reference of using a butt joint is given in NB-4243.
Can I use a single-V butt joint from outside without making any coller of tube sheet ?
Should I need to do strength calculations for that full penetration butt weld?

Thanking in anticipation!

Faisal

Faisal,
the title means SOME acceptable weld details.
Certainly Full penetration Butt welds can be made for Cat C welds. A Tubesheet may have a welding hub forged on it and properly machined, so it can be butt welded to the shell. This would be cat c butt weld. Full RT is required, There we go.

DK