I have a vessel with two conical transitions. The reinforcement is provided by 4x4x.25 angle that is welded with one side/leg against the vessel. The centoid of the angle is, at best, 1.09 inches from the junction [assuming that the leading edge of the angle is right at the junction]-- with the distance limit something like 0.95 in [~15% difference].


Supposedly, I can't take credit for any of the reinforcement. Of course there are some who say, "heck, it's not even a quarter inch off", and assume that we can take credit for the whole thing. Maybe they are correct. I don't understand the basis for the limit-- other than it makes sense that the reinforcement needs to be 'at' the junction.

Is this really an issue? If so, can I take credit for any of the reinforcement? For instance, can I assume it is instead a 4x0.25 flat bar-- which moves the centroid within the limit and lets me take credit for 1 in^2 of area? Or will this violate the intent?

I have an additional issue. Section VIII 1-5 and 1-8 indicates that the reinforcement must meet the requirements of UG-41. That is, primarily, that the reinforcement must an allowable stress value greater or equal to that of the vessel-- or the area of reinforcement must be increased in inverse proportion to the ratio of the allowable stress values. Of course the stiffener material has a lower allowable stress than the vessel material. If I do not take credit for all of the stiffener, then it is doubtful that I will meet UG-41.

The original vessel would not meet current code-And, as I am sure you have guessed, we have been running the vessel this way for thirty years-- but we are also corroding at about 3 mpy.

Any guidance or suggestions would be appreciated.

Best Regards,
Charles Babcock

This topic has been addressed elsewhere on the forum.