UW-12(d) & (e) for pipe use - Joint Efficiency E value?
UW-12(d) & (e) for pipe use - Joint Efficiency E value?
(OP)
Hi,
I usually use pipe (both seamless or longitudinally welded) in the design of pressure vessels, and I do not fully understand UW-12(d) & (e) statements for E value: for the more conservative case of no RT, should I always use E = 0,85 for circumferential stress? Does not it collide with Table UW-12? Since circumferential stress is the controlling one over longitudinal stress, this decission on E value for shell calculations is crucial for me.
Best regards and thanks for your confirmation/comments!
I usually use pipe (both seamless or longitudinally welded) in the design of pressure vessels, and I do not fully understand UW-12(d) & (e) statements for E value: for the more conservative case of no RT, should I always use E = 0,85 for circumferential stress? Does not it collide with Table UW-12? Since circumferential stress is the controlling one over longitudinal stress, this decission on E value for shell calculations is crucial for me.
Best regards and thanks for your confirmation/comments!





RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
You would use 0.70 when making a shell from plates and welding your own category A welds. Note that when using welded pipe, UW-12(e) multiplies in another 0.85 factor, so the joint efficiency on welded pipe with no RT winds up being 0.85 X 0.85 = 0.72.
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
Yet, I do not fully understand your second paragraph: when talking about welded pipe, I always mean "bought as such" to my raw material supplier, not fabricated by me from plates. I reviewed my 2004 Ed. of ASME VIII Div.1 UW-12(e) and it simply states "Welded pipe or tubing shall be trated in the same manner as seamless, but with allowable tensile stress taken from the welded product values of the stress tables, and the requirements of UW-12(d) applied.". Why do you apply 0.85 factor twice? I figure out that first 0.85 factor comes from UW-12(d), but what about the second 0.85?
Best regards and thanks again,
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
Is full RT mandatory? No, proceed to next step. Is this a seamless section? YES per UW-12(e) (even if using SA-53 ERW Gr.B, or SA-312 Tp316L welded pipe). As trottiey pointed out, E=0.85 for your circ stress. For long stress, E will correspond to your RT on butt joints in Cat A, B, & C joints.
If you have corner joints on both ends of the pipe, E=0.85 for circ stress, and E=1.0 for long stress.
-TJ Orlowski
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
Thanks again,
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
Note that this line is the only one of the four which is permitted under Section III, which requires thorough examination of pipe anyway.
RE: UW-12(d) & (e) for pipe use - Joint Efficiency E value?
J.I.G.C.