Section VIII Division 1 - Table UW-12 3

[IdanPV]

Hello all.

I have a question and I didn't find any answer here or in the Code interpretations website.

I am dealing with longitudinal joint in a vessel with diameter of 500mm, thickness is 3mm.
No Radiography is made.

Is it permissible to use a joint efficiency of E=0.6 for this kind of welded joint although it shall be classified as Type No. (1) joint?

Thank you very much

 

[SnTMan]

I suppose it's possible, but why would you use an efficiency lower than permitted?

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

 

[IdanPV]

SnTMan,
Thanks for your comment.
Do you have any refernce which stated that it is permissible?

The thing is someone made a mistake with the U-1A a lot of MDRs were fill as can be seen in this picture:

Now, the A.I asks to change the U-1A and I wanted to check if there are some interpretation or paragraph which allows me to leave it that way.

 

[mk3223]

Per ASME Code, the vessel can be made with the joint eff of 0.6. However, is it complied with the the Client Standard?
If it was only a typo on the U-1A, why not to have the Fabricator to correct it?

 

[Geoff13]

Very confused.
[ul]
[li]In your initial posting you said this was a Type 1 joint, but in your picture of the U-1A it's a Type 3 joint.[/li]
[li]A Type 3 joint has E=0.60, but it's only permitted on certain circumferential welds, and you've indicated this is a longitudinal weld.[/li]
[/ul]
I guess my one comment is that you can only know if E=0.60 is correct or a typo by reviewing the design calculations to see what was used. Without the calcs it's just guessing. If the U-1A is wrong, the fabricator should correct it.

 

[david339933]

Why would you want to leave it that way? It should have never been signed with a type 3 joint. Either your vessel doesn't comply with the Code or your data report doesn't. Non-Conformance the data report and sign a new one....and be happy your AI doesn't scrap the vessel. How are you proving it is a Type I?

 

[IdanPV]

Hello all,
Thank you all for your comments.

The MDRs will be corrected.

 

[tbeek]

I agree that you should fix the error, so that the MDR matches the calculations, but to answer the original question: Yes you can use a lower value of efficiency in your design. See UW-12(a),(b), and (c). They all begin with the words "A value of E not greater than that given in column... of Table UW-12 shall be used in the design calculations..."

For a joint with no radiography, UW-12(c) would apply.