09A Slip-On Fillets & Setback UW-21 1

[BigTank]

Ch-ch-ch-changes.

Would you interpret the dimensions given in UW-21 as minimums with the maximums shown in appendix 2 for a loose-type arrangement? This appears to have been a hurried change when compared to the completeness in the '08 Addenda...and this interpretation seems consistent between the two addendas.

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Fitter, happier, more productive

 

[vesselfab]

weld is lesser 1/4" or thickness of nozzle. I think most use the nozzle thickness as many users don't like an unwelded corner and inside appendix 2 uses full pipe thickness

they are not addressing the standard 1/8" between toe of weld and the corner of raised face. but appendix 2 says max is 1/4" + wall of pipe.

we standardly use pipe wall + 1/8 for set back with a pipe wall + 1/4" max set back

Now that being said, we never weld a slip on flange in pressure situation, just internal non-pressure.

 

[SnTMan]

So what do you interpret to be the meaning of "tmin" in the note under the figure? t(required) of the neck? tr + CA?

Agree with BigTank, this looks a little hasty.

Regards,

Mike

 

[SnTMan]

My mistake, probably tmin per UG-16?

 

[BradLancour]

I believe 1.4tmin is meant to be 1.4tn as is required in B31.1-2004

Where tn is the nozzle or pipe wall thickness

Also worth noting another inconsistency in B31.3-2004 T overscore is used in the rule for xmin.

At any rate something for ASME to fix/clarify in the next edition or addenda of section VIII.

 

[InspectorByDay]

All,

Yes, this is an error which did not get caught prior to final printing.

The new weld dimension requirements in UW-21 were extracted from B31.1 and should mirror them in the upcoming Errata.

In the meantime, BradLancour is correct:

1.4t[sub]min[/sub] should read 1.4t[sub]n[/sub].

X[sub]min[/sub] = 1.4t[sub]n[/sub] or thickness of hub, whichever is smaller.

t[sub]n[/sub]= nominal pipe wall thickness.

Regards.