limits of reinforcement in shell, Type 12 nozzle

[RXer]

I'm working with a studded manway forging (Fig AD-612.1, sketch d-2) set into a hemi head using the 'Type 12' nozzle to evaluate it.

I note in the results that the barrel thickness, tn, is not included in determination of limits of reinforcement in the plane of the shell. The equation considers the corroded radius, shell (head) thickness and zero for the tn term for the ri+t+tn expression.

What would be the basis of not considering the barrel? If it tapered to a neck rather than being studded it would be considered. I'm not sure I understand why Compress treats this as it does. Any help?

 

[gr2vessels]

Refer to Fig. UG-40 (a-2)
Cheers.
gr2vessels

 

[gr2vessels]

Just a bit of correction, Fig. AD-612.1 (d-2) has been replaced by Fig. UG-40 (a-2) in ASME VIII-1 in 2007;- in the new code, the tn=0.
gr2vessels