Formula for internal pressure t-min of butt welded elbow fittings? 2

[FIS4224]

Can someone help me out with the formula for internal pressure t-min calcs.
I need to perform t-min calcs on 45, 90, & 180 degree buttwelded elbows for both B31.3 and ASME SEC VIII div 1 codes. I have wall losses in both piping elbows and nozzle elbows.

I did find the fromula in B31.3 304.2.1 where do I find the radius of the elbows? I looked in B16.9 & B16.28 for the radius which is not listed. Do I have to calculate the radius?

Also it is not clear what "Y" is in the formula. Is it the values in table 304.1.1 for temp coefficients or as shown in fig. 304.2.1??

What about elbow nozzles in SEC VIII Div 1?? Please help

 

[C2it]

Now would be a good time to employ a piping engineer.

 

[FIS4224]

Thats why I am here

 

[SNORGY]

I think you can still treat them as straight pipe if they are to a recognized fabrication standard. It would strike me as contradictory if you could treat them as straight pipe in the new condition but then have to start treating them differently from piping after some corrosion as occurred.

Barring that, you can apply the "Lorenz Factors" (as they are sometimes called) for bends...even though they probably aren't "bends" by pure Code definition. The equations are in B31.3.

They are *probably* 1.5 x D radius; if in doubt, repeat the calculation for 1.0 x D and 5.0 x D and make the acceptance / rejection determination afterwards.

Regards,

SNORGY.

 

[ione]

http://www.red-bag.com/jcms/index.p...b-eg-ue301-comparison-asme-b311-b313-and-b318

and for buttwelding elbows dimensions

http://www.prochem.com.au/cache/25766a6d66ecb3f3ce8b34c16021de67/Buttweld_Fittings_Download.pdf