ASME VIII-1 joint efficiency Questions 1

[aregularengineer]

For a certain project, we are using a 20" SA-333-GR6 seamless pipe as the shell with SA-420-WPL6 seamless cap fittings. There is no radiography for this vessel.

According to here (assuming the information here is correct)

https://www.pveng.com/joint-efficiency/

, shouldn't the joint efficiencies be 0.85 for category A longitudinal welds and 0.7 for category B circumferential welds?

My boss is convinced that it should be 1.0 for the category B circumferential welds and he's convinced that the information in

https://www.pveng.com/joint-efficiency/

is for plate shells only, and that a different set of joint efficiencies apply for pipe vessels. But I don't see that indicated anywhere, and it should apply to seamless pipe since it is my understanding that you cannot have a seamless plate vessel (it has to be rolled and welded), or else why would it indicate "seamless"?

Any answers would be appreciated.

 

[david339933]

There is a difference between Circ Seam efficiency and the efficiency used in the head calculation. Efficiency used in the head calc is per UW-12(d), same as for a seamless shell. So if you do no RT, the long seam efficiency and the efficiency used for the head thickness are both .85. The efficiency of the actual circ seam is still .70. Two different things altogether.

 

[aregularengineer]

So the circumferential seam JE is 0.7, as I thought. For some reason, my supervisor is convinced that the circumferential JE is 1.0.

I appreciate the reply.

 

[cbPVme]

Review UW-12(d) with your supervisor. This addresses the longitudinal efficiency on seamless components.