Sec VIII-1 UW-13(d)
Sec VIII-1 UW-13(d)
(OP)
Hello,
I need some help with understanding applicability of UW-13(d). Does it apply to joints between shell and tubesheet of a heat exchanger with both tubesheets fixed and straight tubes? Should this tubesheet be treated as a stayed/supported plate, thus exempted from UW-13(d) ?
Thanks
Konrad
I need some help with understanding applicability of UW-13(d). Does it apply to joints between shell and tubesheet of a heat exchanger with both tubesheets fixed and straight tubes? Should this tubesheet be treated as a stayed/supported plate, thus exempted from UW-13(d) ?
Thanks
Konrad





RE: Sec VIII-1 UW-13(d)
RE: Sec VIII-1 UW-13(d)
Is it a good point to send a request for interpretation?
Konrad
RE: Sec VIII-1 UW-13(d)
Until recently, if memory serves, there used to be a statement in UW-13(e) that a tubesheet or head could be considered stayed if 80% of the pressure loads were carried by tubes, braces or stays. Rather than try to prove this point, it was simpler to just design the weld joint per UW-13.
At that time also, the 3X criteria applied to tubesheets with a bolting flange rather than just ring flanges I believe. It was fairly common to ignore the 3X criteria and use the 2X criteria to avoid the warpage to the tubesheet caused by the large welds. Anyway, that's what I heard ;)
Regards,
Mike
RE: Sec VIII-1 UW-13(d)
Thank you for the hint about 80% of load carried by tubes.
Konrad
RE: Sec VIII-1 UW-13(d)
Did you review Part UG-34? Continue reading Part UW-13 to (e) because you are dealing with a pressure part (tubesheet) that is being welded to a shell to form a corner joint. I believe this applies to your situation and refers you back to Figure 13.2.
RE: Sec VIII-1 UW-13(d)
Regards,
Mike
RE: Sec VIII-1 UW-13(d)
The 80% is gone from UW-13 because it addressed by UHX and this is not optional. You must address items per UW-13,UHX,and UG-34.
Suggest you visit with your AIA.
SnTMan: UG-93 deals with NDE---this must be tied in with UHX. Sounds good-but you cannot pick and choose.
RE: Sec VIII-1 UW-13(d)
Konrad
RE: Sec VIII-1 UW-13(d)
Regards,
Mike
RE: Sec VIII-1 UW-13(d)
I have not seen your design so I really have no opinion. All the paragraphs in the book are applicable. It is up to the designer/Eng. as to which apply. Have you spoken with your AIA?
SnTMan: No offense,but I have seen it happen too many times.
So,I am a bit gun shy.
Just remember you must address "all" of the requirements. Please review U-2 (b thru g) talk to your AIA.
RE: Sec VIII-1 UW-13(d)
RE: Sec VIII-1 UW-13(d)
Konrad
RE: Sec VIII-1 UW-13(d)
Please review U-2(g). There are exemptions in UHX if it does not fit.
Not wise to argue with the AI---see U-2(e). He may be trying to keep you out of trouble. Instead of arguing a point why not ask for some help from the same. Could even kick it up the ladder.
Can you design per TEMA? May be OK if you address all the Code requirements. You could even go with UG-101.
Guess the point I am trying to make is you must justify your design in an acceptable manner.
RE: Sec VIII-1 UW-13(d)
U-2(g) doesn't explain what kind of construction is covered, and what is not. Neither U-2(e)
Can I design per TEMA? I can design it per whatever methods people made, but the uncertainity of some BPVC rules' applicability still is an issue.
Konrad
PS. I'm preparing a request for interpretation.
RE: Sec VIII-1 UW-13(d)
It is my opinion that you could indeed use TEMA or for that matter any other design standard. IF! the ASME Code does not address your particular design and you cover any requiremnets that do. That is what U-2(g) is for.
Be careful---ask your AI that his Supv.or Eng.Group give an opinion. CYA you know.
Interpretation: Yes,it will take a while and you may not get the answer you want. There is likely one out there that already covers it.
RE: Sec VIII-1 UW-13(d)
You may find help in other standards. Maybe ASME Section 1 has something applicable, I'm not that familiar with it, boilers are all different shapes.
Regards,
Mike
RE: Sec VIII-1 UW-13(d)
Konrad
RE: Sec VIII-1 UW-13(d)
The 80% support statement is gone----Do you have stays or attached head or cover with ribs to stiffen the sheet?
Think if it was me I would consider it non-supported and move on. Read UW-13 part by part and if it does not apply your FEA may be acceptable(If the AI will buy it).
To really give an opinion on this,would need to see prints.