Efficiency of hillside drilled hole

[coolniks37]

I have a section 1 pipe, where holes are drilled hill side.
How do i calculate ligament efficiency for this design for calculation of min thickness?

 

[racookpe1978]

What are the dimensions (diameters OD, ID) of the two pipes, of the offset length between the two pipes (equal on both sides?), and of the primary PV?

In some cases, it will not matter very much. In others, the two pipes will be a major proportional of the entire wall of the PV.

 

[Jano6924]

It looks that in the vessel you have only two hillside openings. Assuming this is an ASME VIII-1 vessel take a look into UG-53(b): "When a cylindrical shell is drilled for tubes in a line parallel to the axis of the shell for substantially THE FULL LENGTH OF THE SHELL.....". If this is not your case then you don't need to use ligament efficiency to calculate Shell thickness. Otherwise you shall follow UG-53 rules.

Hope this helps.