UG-34 ASMEVIII

[Cracenet]

Hello, Very new to pressure vessel design. Our AI has asked for UG-34 calculations on a manway blind. based on its type the UG-34 calculations button that usually is available is not for this opening. I have tried to just read the book and do the calculations by hand but I don't understand which equation to use. I figure it matches sketches j & k the best but the equation for them refers to a welded joint and this cover is bolted on. am I supposed to use the weld where the manway meets the head? can someone talk me through this. Compress photo below.

 

[Maslov]

Why do UG-34? Is this a custom blind? It looks like you could do a studded outlet with a standard B16.5 blind, in which case no UG-34 calc is needed (see UG-34(c)(1)).

As for your question, I assume you are confused by the joint efficiency. See UW-12(d):

 

[Cracenet]

Why do UG-34? Is this a custom blind? It looks like you could do a studded outlet with a standard B16.5 blind, in which case no UG-34 calc is needed (see UG-34(c)(1)).

As for your question, I assume you are confused by the joint efficiency. See UW-12(d):

View attachment 1202

Maslov,
It is a studding outlet and a standard B16.5 Blind however we apparently are lacking a certification from the company that made it stating they can make standard B16.5 blinds. the AI opening the job wants a UG34 calculation (in leu of a certificate) on the blind to prove it is acceptable? I don't really understand that because while I'm an engineer these regulations are all new to me and I'm more used to Roark's stress and strain calcs for determining thicknesses. Also the part about a joint efficiency confuses me because I thought this calculation is for the blind only however the nearest weld is on the studding outlet to the head. Thanks for your response though.

 

[Maslov]

Understood. Then yes, UG-34 is a pathway. Just to note, often UG-34 requires thicknesses above those of B16.5 standard flanges, so it may not be sufficient based on your design pressure/temperature.

I don't have access to COMPRESS right now, but it may allow the calc if you remove the B16.5 flange and add a custom flange with all the dimensions of a B16.5 flange. Otherwise, the hand calc isn't too bad. Fundamentally, the code formulas are "relatives" to Roark formulas with many simplifications and experimentally derived constants/charts, but they do get a bit complicated when you have to flip back and forth through multiple code sections to find definitions and tables.