Joint Efficiency for Seamless head 1

[PV design Engr]

I have a column to be designed with spot radiography requirements. My vendor has considered joint efficiency as 0.85 for both shell and head in calculation. The head is seamless. My client is asking J.E=1 for head but my vendor claims that for spot radiography vessels JE to be considered as 0.85 as we did not request for any additional spot radiography requirements as UW-11(a)(5)(b) Please advise if my vendor's consideration is correct.

 

[SnTMan]

PV design Engr, if the head-shell seam was not independently spotted your vendor is correct, see UW-12(d).

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

What is your job between your Vendor and your Client?
What about your technical opinion?

Regards

 

[david339933]

Your vendor is correct. Spot RT for the entire vessel or RT3 does not include the spot(s) required to satisfy UW-12(d)/UW-11(a)(5)(b). If the UW-11(a)(5)(b) shots are completed, it becomes RT-4.

 

[mechengineer]

Too late, but just intrested.
J.E=1 is correct because there is no any weld in the ellipsoildal portion of the head. Client is correct.
The staight flange of the head is a cylinder shape. The circumferential wled seam, a longitudinal stress is not the basis of governing thickness calculated. Vendor request J.E=0.85 for the head thickness calculation is incorrect.

 

[r6155]

Vendor is correct. Clear is in Appendix L Figure L-1.4-2

Regards

 

[XL83NL]

When it comes to discussions like this one on JE, NDE and Code rules - discussions which I by the way always follow with great interest since I learn a lot - I’m also amazed by the (apparent) complexity which this ASME Code section has gathered over the years. Even though we have appendix L and PTB-4, I’ve found EN 13445 to be much more user friendly and efficient in this regard.

Huub
- You never get what you expect, you only get what you inspect.

 

[mechengineer]

Appendix L Figure L-1.4-2:
UW-11(a) (5) (-b) MET, E = 1.0
UW-11(a) (5) (-b) not MET, E = 0.85 [Note (1)]

UW-11 (a) (5) (-b):
“Category B or C butt welds ... heads of vessels or connect seamless vessel shell or heads shall, as a minimum, meet the requirements for spot radiography ... “,
Spot RT performed on the joint weld (category B) of shell and head, so it met the requirement of UW-11(a)(5)(-b). It shall be considered as (a) column in UW-12 Table, E=1.
The elliptical head has a cylindrical shape of 50 mm S.F, so the thickness formula of the elliptical head is not directly related to the welding joint between the head and the shell. It is an ‘additional’ consideration of weld joint(Category B) of shell and head for J.E in the elliptical head formula, but it is not the weld in the elliptical shape of the head.