UW-11 interpretation 5

[farzam]

Hello All

Would please let me know your technical interpretation of section UW-11(a,5).

Thank you

 

[SnTMan]

farzam, UW-11(a)(5) says if your vessel components are designed using joint efficiencies from Table UW-12 Column (a), you must full RT Cat A & D joints.

UW-11(a)(5)(a) says Cat A & B joints shall be full penetration butt welds.

UW-11(a)(5)(b) says (this is more tricky) that for Cat B & C which intersect the Cat A welds or for joining seamless sections, with an exception for smaller nozzles, must be spot RT'd. The last sentence says this spot RT cannot be used to meet the requirements of UW-52(b)(1) for extent of radiography.

UW-11(a)(5)(b) allows, for example, the use of a joint efficiency of 1 (for a double welded butt joint) for, say, attaching a seamless head to a seamless pipe, as long as one spot RT is performed on this seam.

UW-11(a)(5)(b) also exempts seams in smaller nozzles from the spot RT requirement, for example a pipe to flange buttweld.

Hope you find this useful.

Regards,

Mike

 

[dtn6770]

Well stated Mike.

 

[JoeTank]

SnTMan,
A star to you. That may be the simpliest explanantion that involved the dreaded UW-11(a)5(b) I have seen. In your fourth paragraph I might point out that it's UW-12(d) that gives us E=1.0 for seamless heads of the extra spot RT is done on the B seam. Also, I would point out that one spot is not always enough. For a large vessel additional shots on the round seam may be required.

Joe Tank

 

[SnTMan]

Thanks to dtn6770 and JoeTank, I agree that one spot is not enough, as hinted at in my third para. Also agree re UW-12(d), I was just limiting the scope of my post. Thanks again, and I hope the OP gets some good out of it.

Regards,

Mike

 

[SnTMan]

farzam, no disrespect intended. Sorry if it came across that way.