Hi All,

I have a question related to internals on one of the vessel which I designed.

The vessels rating is 150 # and there is a 2" pipe (internal pipe) connecting two nozzles inside the vessel. As a process requirement a high pressure gas will be passed inside this pipe. By looking into the design condition of the gas passing in, i found that it falls under 900#. Hence i decided the nozzle to have 900#. My problem is that, if i provide break flanges for this internal pipe......can I go for a plate flange or should i go for a B16.5 flange?

If i am opting to go for plate flange, then how can i justify my client that its good enough to handle the dissimilar pressure?


SHARE YOUR THOUGHTS

Hello Shabeer,

if you go for a plate flange ,design it with the help of appendix 2 for both internal as well as external pressure ,which is the inside pressure of the vessel.

Also there is a clause in 2-11 in appendix 2 of ASME section VIII Div:01 which states that

[/b](b) When flanges are subject at different times during
operation to external or internal pressure, the design shall
satisfy the external pressure design requirements given in
(a) above and the internal pressure design requirements
given elsewhere in this Appendix.[b]

clause says "Different Times" ???

Hope this helps

Regards

ASD23789
(Beginner)

Dear Shabeen
as per our understanding, your concern is about flange material made from either forging or plate. pl. refer, Table 2-1.1 pressure-temperature rating for group 1.1 materail, both materail i.e forging & plate is acceptable as per B16.5(2003).