Manhole in ASME VIII Div.1 Pressure Vessels 2

[MaxCarb]

Hi all.
I have to design some separators with ASME VIII Div. 1. One of these is 20" ID.
My Owner wants the possibility to have access to the internals (vane packs) for maintenance. So i need a manhole at least of 18-20 inches and of course it's impossible for a vessel with 20" ID.
The question is this: Does the ASME VIII Div.1 give a limitation to the diameter of manholes taking in consideration the diameter of the vessel?
If the Code doesn't give any limitation, is it possible to design a vessels like a tee with caps and flanges?

Thanks for your answers

 

[JStephen]

See UG-36(b), perhaps other limitations as well.

Can you just flange one end (or both) of the separator and use that for a manway?

 

[jte]

JStephen has it exactly right. Hopefully you have the flexibility to use a 20" OD shell. Then you can buy an off the shelf flange pair and just split the shell either above or below the internals. If you need a 20" ID, then you'll have to design the flanges and get them custom made. Put some lifting lugs on the upper section for easy removal. One way to think of this is that it is exactly like a shell and tube heat exchanger without the tubesheet and tube bundle.

Technically I believe you could use a 20" x 20" x 20" B16.9 tee without having to calculate the opening reinforcement since it is a part certified by another standard. But the body flange is by far the superior option from the perspective of plot space and ease of accessibility to the internals.

jt

 

[jehan17718]

for such a small dia vessel manway will not be practical. provived main/girth flanged joints in the vessel. In fact many client specification explicitly state that vessels with ID less than 900 mm should have main/ flanged flanges.

-jehan

 

[MaxCarb]

Maybe the body flange is the better solution.
I'll go in that way.

Thanks for your answers!