API 650 Flange class selection 2

[RBKN]

I am designing an API 650 tank for the first time and have loads given for a 4" nozzle with RFWN flange. Is there a section in API 650 giving guidelines to select the class of flange to be used?( if it were ASME section VIII Div 1 I would have to use a 300# under these conditions) I looked at Appendix - P but I cant see how it will help in selecting which class of flange should be used? I want to check if I can get away with 150# by API 650 standards.

 

[RBKN]

@TGS4

Sorry I can't share the calculations but Fx, Fy, Fz are 1300, 2500,1800 (N) resp. and Mx, My, Mz are 1100, 1350, 900 (N-m) resp. on a 4" RFWN.

 

[TGS4]

What's the design pressure for the flange? (Not the rating pressure). For a tank, it can't be more than the static pressure in the tank...

What's the temperature?

(FYI - I am intimately familiar with this Code Case - I wrote it and got it passed through the ASME Code Committees. The more real-world examples that I have, the better the calculation and it's implementation can be made.)

 

[LittleInch]

If your nozzle satisfies the requirements of App P then API 650 has no further design information about the flange on a nozzle. It is irrelevant to the tank so could be class 150, 300 or even 900.

Up to you.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RBKN]

@TGS4

It is ambient + 4.034psi ( liquid static head ). @ 203degF

 

[RBKN]

@LittleInch

Okay. That was all I wanted to know. Thank you, I am glad you finally understood my question.