Flange design ASME VIII DIV 1 Appendix 2

[JHJ086]

Dear all

We have got an ASME piping system design that needs to be continued from a SANS design. We are using ASME B16.5 flanges class 300 & class 150, drilled according to SANS 1123 T4000 to make the connection. I have to do flange calcs to qualify the altered ASME flanges for AIA approval.

I'm doing these flange calcs under ASME VIII DIV 1 Appendix 2 but have trouble with reading the required values of f, F and V from the charts and by following the formulas for these factors the values I get are of the charts. As hub length is a factor that influences the outcome of h/h_o, what is the value for h that I am to use in this formula, I have played around with options and arriving at some good looking wrong answers.

Please have a look at the calculations done(see link). one is in US customary units(this one actually worked out for values of f, F & V from the charts) the other tab didn't quite work out and resorting to the formulas also prove inadequate. I tried the calculations in both imperial and metric units but still get stuck at one point.

https://dl.dropbox.com/u/90777826/Flange design.xlsx

Am I on the right track with qualifying these flanges under altered conditions or is there another route I should be following?


Thank you in advance

 

[MikeG7]

Hi JHJ086

I've looked through your calcs (Metric) and run same to check, looks like you're on the right track as far as the calcs go treating this as Appendix 2 flange.
F is .61, V is .63.

Bolt up conditions are worst for your flange as bolts are large and many.
BTW, if the vessel is under 6in, per U-1(c)(2) it is outside of the scope of ASME VIII, Div.1.
Michael

 

[JHJ086]

Hi MikeG7

Thanx for your reply,how did you manage to solve for F & V in post above given the h / h_o ratio below as you won't be able to read values from the charts and the applicable formulas for F & V give of the chart values?

h_o (factor) h_o 24.77
ratio of hub length / h_o (factor) h / h_o 2.13
ratio of thickness of hub at back / - at small end g_1 / g0 2.73

Going on leave today so will tend to this matter again in the new year and do some reading on the applicabilty of the scope of ASME VIII Div 1 to our design in the mean time.

Happy festive season.

 

[C2it]

I checked out the 6" flange to Div 2. I agree with the g1/g0 value = 2.725 and h/h0 = 2.131

Evaluating the various factors:

T=1.4188
U=2.7959
Y=2.5443
Z=1.4932

F=0.5909
V=0.06097
f=1.0

So I would suggest your Excel spreadsheet needs some attention.

My value for V is far different to MikeG7's.

I checked the same geometry set to Div 1 and got the same results.

BTW ... It is always good to treat values that are off the charts with some care. In the given zones the graphs are quite linear, but they turn assymtotic both sides of the linear region and can thus give ridiculous results.

 

[MikeG7]

C2it
I mis-typed the value of "V" in my post , misplacing the point, should have read "0.063" not "0.63". There's a slight difference, as I was taking a manual reading, compared to one determined as yours by formula (?). I get exact match for T,U,Y,Z as you and ditto for g1/g0 value and h/h0.

 

[MikeG7]

JHJ086, I took another look at your spreadsheet and your "Y" value 6.614, looks high compared to those reported here and I see you have not limit "f" to a minimum of 1, which is how I read it. Besides that the spreadsheet looks like on the right track, good luck. Might just need some tweaking or do it by hand once or twice maybe you made a typo (quite easy to do as you see above!)
Happy holidays!