Category B, Type 1, Sport RT....E = ???
Category B, Type 1, Sport RT....E = ???
(OP)
I hate to resurrect a topic that's been utterly beaten to death...but I will. Actually, I more so hate being "that guy" who brings the subject up AGAIN.
It's the dreaded UW-11(a)(5)(b) paragraph relating to the joint efficiency. Here's a very specific situation; Non-lethal, non-steam service, NPS 12 XH seamless shell section (SA-106-B) attached to a seamless formed, 0.500 in nominal, 2:1 ellipsoidal head (SA-516-70) with 2 inch straight flange. RT-2 is the claim. The circumferential joint will be of Type 1 and will be spot radiographed.
What joint efficiencies should be used to calculate the longitudinal stress calculations? My interpretation pushes me towards E = 0.85 but I suspect that a lot of folks would contest that for E = 1.0.
My rational is as follows.
UW-11(a)(5) applies to the full radiography requirements of Category A and D butt welds whereas the circumferential joint in question is a Category B butt weld.
UW-11(a)(5)(a) criteria is met because the Category B weld in question will be of Type 1.
UW-11(a)(5)(b) criteria is met because the Category B weld in question connects seamless vessel sections or heads and will be spot radiographed.
UW-12(d) throws out joint efficiencies (E) for calculations involving circumferential stress (longitudinal seams) NOT for longitudinal stress calculations (circumferential seams).
FIG. L-1.4-1 leads me to E = 0.85 for Category B, Type 1 butt welds because of the spot radiography.
FIG. L-1.4-2 implies E = 1.0 for a seamless head when UW-11(a)(5)(b) is met but may only apply to seamless hemispherical heads joined to main shell (Cat. A welds).
FIG. L-1.4-4 leads me to E = 0.85 because the joint is a Type 1 and will be spot radiographed.
Example L-1.5.2(b) supports the use of an E not equal to 1.0 for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b).
Example L-1.5.5(b) supports the use of an E not equal to 1.0 for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b).
Example L-1.5.5(f) supports the use of an E not equal to 1.0. However for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b) I would expect E = 0.80 instead of the given solution of E = 0.65 which implies no radiography...a possible mistake in the solution?!
Lastly but not imply that Code software packages are always correct...APV defaults to the same longitudinal stress E (0.85) for RT-2.
It's the dreaded UW-11(a)(5)(b) paragraph relating to the joint efficiency. Here's a very specific situation; Non-lethal, non-steam service, NPS 12 XH seamless shell section (SA-106-B) attached to a seamless formed, 0.500 in nominal, 2:1 ellipsoidal head (SA-516-70) with 2 inch straight flange. RT-2 is the claim. The circumferential joint will be of Type 1 and will be spot radiographed.
What joint efficiencies should be used to calculate the longitudinal stress calculations? My interpretation pushes me towards E = 0.85 but I suspect that a lot of folks would contest that for E = 1.0.
My rational is as follows.
UW-11(a)(5) applies to the full radiography requirements of Category A and D butt welds whereas the circumferential joint in question is a Category B butt weld.
UW-11(a)(5)(a) criteria is met because the Category B weld in question will be of Type 1.
UW-11(a)(5)(b) criteria is met because the Category B weld in question connects seamless vessel sections or heads and will be spot radiographed.
UW-12(d) throws out joint efficiencies (E) for calculations involving circumferential stress (longitudinal seams) NOT for longitudinal stress calculations (circumferential seams).
FIG. L-1.4-1 leads me to E = 0.85 for Category B, Type 1 butt welds because of the spot radiography.
FIG. L-1.4-2 implies E = 1.0 for a seamless head when UW-11(a)(5)(b) is met but may only apply to seamless hemispherical heads joined to main shell (Cat. A welds).
FIG. L-1.4-4 leads me to E = 0.85 because the joint is a Type 1 and will be spot radiographed.
Example L-1.5.2(b) supports the use of an E not equal to 1.0 for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b).
Example L-1.5.5(b) supports the use of an E not equal to 1.0 for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b).
Example L-1.5.5(f) supports the use of an E not equal to 1.0. However for a Category B, Type 2, spot radiographed joint meeting UW-11(a)(5)(b) I would expect E = 0.80 instead of the given solution of E = 0.65 which implies no radiography...a possible mistake in the solution?!
Lastly but not imply that Code software packages are always correct...APV defaults to the same longitudinal stress E (0.85) for RT-2.





RE: Category B, Type 1, Sport RT....E = ???
if you put in a good type 1 seam
e=1.0 because seam is per ug-11(a)5(b) and not
the normal spot rt
RE: Category B, Type 1, Sport RT....E = ???
and the vessel is being stamped rt-2 but could also be using rt-4 if the head is the only thing that needs E=1.0
and the other category seams are also being spot x-rayed per UG-11(a)5(b) or enough x-rays being done to compensate
APV software should have a button for ug-11(a)5(b)
RE: Category B, Type 1, Sport RT....E = ???
RE: Category B, Type 1, Sport RT....E = ???
Because the head-to-shell seam is spot RT then E=0.85 is applicable to this joint when considering the required thickness of the cylinder based on longitudinal stress. This is assuming that this seam has spot RT in addition to the particular spot required to meet UW-11(a)(5)(b), but then this is implied by RT2.
RE: Category B, Type 1, Sport RT....E = ???
I know E=0.7 will be controversial. However read that article published in 2000 by Tom Pastor of HSB.
RE: Category B, Type 1, Sport RT....E = ???
TomBarsh...yes!
UW-11(a)(5)(a) and UW-11(a)(5)(b) identify criteria that must be met to allow "...Category A and D butt welds...joint efficiency permitted by UW-12(a)." I get the impression that some take the association of Type 1 and 2 Category B welds with UW-11(a) Full Radiography as allowing for E = 1.0 even though UW-11(a)(5)(b) states that those welds are (minimally) spot radiographed.
RE: Category B, Type 1, Sport RT....E = ???
Spot radiographs required by this paragraph shall not be used to satisfy the spot radiography rules as applied to any other weld increment.
See UW-52(b)(1) for the definition of a weld increment.
Note: The definition of a weld increment is not specific to any category of weld. A weld increment needs only to have a joint efficiency assigned per Table UW-12 and shall not exceed 50 ft in length and includes welders/operators as applicable...
FYI.......There are blocks in the Manufacturer's Data Report (Form) for the joint efficiencies applicable to the longitudinal and circumfirential welds....The AI should be able to clear up any confusion onemay have..
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RE: Category B, Type 1, Sport RT....E = ???
uw-12(d) explains it quite nicely for type 1 welds
for circumferential stress (long seams)
e = 1.0 when using uw-11(a)5(b)
e = .85 when uw-11(a)5(b) is not met
each circuferential seam (longitudinal stress)
is treated on it's own
e=1.0 when uw-11 is met
e=1.0 when uw-11(a)5(b)
e=.85 when uw-11(b)is used
that guy from HSB may be the greatest thing since sliced bread....but i will continue what is written in the code book
RE: Category B, Type 1, Sport RT....E = ???
UW-11(a)(5)(b) is meant to be used for Category A and D joints, not for Category B.
For Circumferential joints, if full RT, E=1; if spot RT (in addition to spot RT used for UW-11(a)(5)(b)), E=0.85; if no RT or spot RT only to satisfy UW-11(a)(5)(b), E=0.7.
RE: Category B, Type 1, Sport RT....E = ???
listed under full radiography
category b or c welds yada yada
I don't see how you can say does not apply to category b welds.
it's written for category b and c welds under full radiography.
it allows E=1.0 for non special service vessel as long as you follow it and stamp vessel RT-2
RE: Category B, Type 1, Sport RT....E = ???
There are two different joint efficiency here, one for long seam, the other for circum seam.
When you have full RT on long seam, no RT on circum seam, joint efficiency for long seam is E=0.85 (E=0.7 for circum seam). You then do UW-(a)(5)(b), E=1.0 for long seam (you can stamp RT-2), E=0.7 for circum seam. If you do additional spot RT on circum seam, E=0.85 for circum seam. Only after you have full RT on circum seam can you use E=1.0 for circum seam.
RE: Category B, Type 1, Sport RT....E = ???
no problem
RE: Category B, Type 1, Sport RT....E = ???
I've read the article you referenced, but, don't see it as you do.
RE: Category B, Type 1, Sport RT....E = ???
Can you comment on my last post and point out which part you see differently? Thanks.
RE: Category B, Type 1, Sport RT....E = ???
As debatable as this topic is I put a lot of stock in the Appendix L examples...L-1.5.2, L-1.5.3, L-1.5.5, and L-1.5.6.
Good discussion and I hope no one goes home mad.
RE: Category B, Type 1, Sport RT....E = ???
There should be differentiation between the head "quality factor" E=1 for UW-11(a)5(b) and E=1 of the circ seam which is efficiency for long stress.
There is also an interpretation with respect to something like this but I do not know the number off hand. It is likely around 2004.
My 2 cents.
EJL
RE: Category B, Type 1, Sport RT....E = ???
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RE: Category B, Type 1, Sport RT....E = ???
get your qc manager and AI to read this old National board article. it pretty well sums up what i have been trying to say, not too eloquently, i should add
ht
RE: Category B, Type 1, Sport RT....E = ???
Still, the predominant topic in the examples (pages 3-5) involved efficiencies of seamless shell sections and seamless heads...not the welds joining them. The governing equations for thickness determination are UG-27(c)(1) for (circumferential stress) shell sections and UG-32(d) for 2:1 ellipsoidal heads, as an example. I don't dispute anything mentioned.
For shell sections there's still the need to evaluate, using a potentially different efficiency, the longitudinal stress, UG-27(c)(2) even though it doesn't usually influence the design (page 19, footnote 16).
Part of the answer to the article's 4th question completely blows my mind. I'm good with the 1.0 for the longitudinal cylinder joint and 0.85 for the nozzle joint but what he did with the circumferential (head-to-shell) joints has me stumped. They're Category B, Type 1, spot examined, butt welds so I would have selected 0.85 from UW-12 column (b). How he arrived at 0.70 from column (c) and why he multiplied it by 2 are complete mysteries to me.
RE: Category B, Type 1, Sport RT....E = ???
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RE: Category B, Type 1, Sport RT....E = ???
.0.7 for the circ joints is appropriate instead of 0.85 because spot RT [in addition to UW-11(a)(5)(b)] was not performed.
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RE: Category B, Type 1, Sport RT....E = ???
I get the x2 multiplier now that you reiterated the "equivalent longitudinal efficiency" term. It relates to the (now) footnote 16 on page 19, "...circumferential joint efficiency is less than one-half the longitudinal joint efficiency..." All I can say is that's one way to look at it.
With respect to the 0.70...I'm starting to see the light and can understand the rationale behind its selection in this article as well as in HSB article pointed out by jamesl.
If I may request one additional indulgence of you, please take a look at examples L-1.5.2 and L-1.5.5 in Sec. VIII's Appendix L. Specifically L-1.5.2(b) and L-1.5.5(b) identify Category B, Type 2, welds that have, "spot, meets UW-11(a)(5)(b)" radiography. The solutions identify efficiencies from column (b) in Table UW-12 rather than column (c). Does that imply that "spot, meets UW-11(a)(5)(b)" would be more accurately stated as "spot in addition to UW-11(a)(5)(b)?"
RE: Category B, Type 1, Sport RT....E = ???
I would agree that it would be more appropriate to use your words in the examples provided. Especially when providing them as examples.....But...... using the term "meets UW-11(a)(5)(b)"in addition to TABLE L-1.5-1 should be enough to clear up any misunderstanding.
Additionally, if I read on a drawing, calculation, design specification, or any other fabrication paperwork that a joint is called out for spot RT, I would know that I would have to check other documents to verify the spot RT in addition to that used for UW-11(a)(5)(b)was present and accounted for.
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RE: Category B, Type 1, Sport RT....E = ???
I appreciate the shared knowledge and experience.