I recently encoutered a situation where reinforcement installed on a vessel opening was inadequate per the requirements of UG-37. I have researched a bit on adding secondary reinforcement. I first found reference to it in the Pressure Vessel Design Handbook by Bednar and then I searched Code...
I believe 1.4tmin is meant to be 1.4tn as is required in B31.1-2004
Where tn is the nozzle or pipe wall thickness
Also worth noting another inconsistency in B31.3-2004 T overscore is used in the rule for xmin.
At any rate something for ASME to fix/clarify in the next edition or addenda of...