ASME VIII div.1 - Code Requirements for Reinforcements on Heads

[Fabrikk]

Hi Everybody,

I was looking for a clarification regarding ASME VIII div.1 code requirements.
Under UG-37 is written "when the opening and its reinforcement are in an ellipsoidal head and are located entirely
within a circle the center of which coincides with the center of the head and the diameter of which is equal to 80% of the shell diameter, t r is the thickness required for a seamless sphere of radius K 1 D, where D is the shell diameter and K 1 is given by Table UG-37."

As far as I have understood, is not advisable to have an opening outside the 80% of head diam. moreover the portion of R.F. that falls outside 80% cannot be calculated as reinforcements in the same way of the "inner" portion. (right?)

So, basically my questions are:
- Can Nozzle openings Reinforcements on head go beyond 80% of head dia?
- If yes, where I can find the formulas to calculate them? (is a FEA analysis mandatory?)
- One more: Lifting Lugs, Pipe Clips, Top Platform Clips (and relevant RF Pads) can be attached (even partially) outside the 80% of an ellipsoidal head? is there any additional requirement or calculation that shall per performed in this case?

Thanks a lot.
Best Regards

 

[SnTMan]

Fabrikk, this subject has been discussed previously, a site search might provide you with fuller information, but:

Openings and reinforcement may exceed the 80% figure, in which case the formula used for tr of the head is per UG-32 for internal pressure, which gives a larger tr than that per UG-37(a). You can easily demonstrate this by comparing the equations. And no, FEA is not mandatory.

Attachements may be placed (nearly) anywhere. Lugs, clips, etc. are not generally subject to Code design rules, but are usually analyzed per WRC-107 or its successors. The geometries within the scope of these methods may impose restrictions on the analysis, and in turn on the placement of the attachment.

Regards,

Mike