Studded opening fabricated from bar (UG-14)

[marty007]

Hello,

It seems as though every time I try and make sense of a specific paragraph in ASME VIII-1 I am left wanting for clearer writing...

Here's my newest question regarding UG-14:

Scenario: due to lead times, I've been asked by the fabrication shop if we can fabricate a studded opening from bar material rather than plate. The studded opening is per Fig. UG-40(a-2) with the following dimensions: 5.25"OD x 1.7"ID c/w drilled/tapped holes and facing to match a 1.5" 150# flange.

UG-14(b) states that bar stock can be used for hollow cylindrically shaped parts up to and including NPS4 (DN100) provided some conditions on metal flow lines are met. So, considering the studded opening design above, would you consider this a 1.5 NPS part, or would you compare the 5.25" OD to the OD of a 4 NPS pipe (4.5")?

Follow-up questions:
a) If we are comparing OD's, why doesn't the code just say the parts must be 4.5" OD or less... this would be must clearer?

Thank you!
Marty

 

[gr2vessels]

marty007, the UG-41(b) you mentioned states a bit more than you quoted;- it says 'Except for flanges of all types, hollow cylindrical parts may be machined from rod or bar...'.
'So, considering the studded opening design above,..', your item remains a flange which is excluded from using rod or bar material.
Cheers,
gr2vessels

 

[EnergyMix]

umm ... I'm reading this at home and so can't check the references. But Marty007 says UG 14 and gt2vessels says UG 41.

Is there a typo or are you two talking about two different sections?

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[gr2vessels]

Sorry, it is UG-14(b), not UG-41(b) as above. Thanks for correcting...

 

[SnTMan]

marty007, check with your supplier, it is possible that your bar is multiple certified, i.e., bar and forging. This is fairly common I think. If so, your problem goes away...

Regards,

Mike