Pressure t-min for in-service nozzle elbows on Sec VIII Div 1 vessels

[FIS4224]

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

I did find the formula 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? The thinnest area found is typically on the extrados of the elbow where do I find that 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? Is the info in the B codes applicable to Sec VIII elbows?

Any help is appreciated.

 

[EnergyMix]

Perhaps you measure them?

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