UW-11(a)(5)(-b) Spot
UW-11(a)(5)(-b) Spot
(OP)
Apologies for another UW-11(a)(5)(-b) post. All the threads on this website and other documentation I've read (such as Pastor's Pressure Points Newsletter) haven't quite covered my situation though.
I am reviewing the design of an existing VIII-1 vessel from the 2001 ed. It has the following RT & E details and is stamped RT-4:
X-RAY
Shell Long Joints
E Factor
Shell Long Joints
All the examples I've seen discuss when the Category A long seams are either seamless or full RT. It seems to me that UW-12(d) is satisfied because the Category B welds have been spot radiographed as per UW-11(a)(5)(-b), even though the Category A welds haven't been Fully RT'd as per UW-11(a)(5).
Can I use E=1 in the UG-32 calculation for a 2:1 seamless head if spot RT was done on both the Category A and B (Table UW-12 Type 1) welds?
I am reviewing the design of an existing VIII-1 vessel from the 2001 ed. It has the following RT & E details and is stamped RT-4:
X-RAY
Shell Long Joints
SPOT UW-11(b)
Head/Shell JointsSPOT UW-11(a)(5)(-b)
Joints in HeadsSMLS
E Factor
Shell Long Joints
0.85
Head/Shell Joints0.85
Joints in Heads1.00
All the examples I've seen discuss when the Category A long seams are either seamless or full RT. It seems to me that UW-12(d) is satisfied because the Category B welds have been spot radiographed as per UW-11(a)(5)(-b), even though the Category A welds haven't been Fully RT'd as per UW-11(a)(5).
Can I use E=1 in the UG-32 calculation for a 2:1 seamless head if spot RT was done on both the Category A and B (Table UW-12 Type 1) welds?





RE: UW-11(a)(5)(-b) Spot
Looks correct....spot on Long Seams, Spot on Circ Seams, + Spot for Head thickness (UW-11(a)(5)(b)). Must be RT-4 as you cannot have E=1 for head thickness with RT-3.
RE: UW-11(a)(5)(-b) Spot
RE: UW-11(a)(5)(-b) Spot
edit: Or are you referring to UW-11(a)(5)(-b) where it says that the spot radiographs shall not be used to satisfy the spot radiography rules as applied to any other weld increment? i.e. one spot RT is required to satisfy UW-11(a)(5)(-b) and a second spot RT is required to satisfy the circ seam joint efficiency.
RE: UW-11(a)(5)(-b) Spot
I had been thinking about the Category A weld mentioned in UW-12(d) as the long seam, but this link explains that I should consider an "imaginary" Category A weld in the seamless head instead. Which, therefore, lines up with david339933's post that RT of the long seam is irrelevant to UG-32 calculations.
RE: UW-11(a)(5)(-b) Spot
RE: UW-11(a)(5)(-b) Spot
I think interpretation VIII-79-85 will answer all your queries.
RE: UW-11(a)(5)(-b) Spot
RE: UW-11(a)(5)(-b) Spot
After the fact, when you're looking at a pre-existing vessel and you have the U-1 Manufacturer's Data Report, is it supposed to indicate somewhere on the form that uw11a5b was satisfied and that the head JE can be taken as 1.0?
Thanks
RE: UW-11(a)(5)(-b) Spot
RE: UW-11(a)(5)(-b) Spot
The value of "E" for the thickness of a seamless head is 1, if the requirements of UW-12 (d)and UW-11 (a)(5)(b) are met. The joint efficiency of the head to shell joint is still .70.
RE: UW-11(a)(5)(-b) Spot
I understand that. My question was about if the U-1 was supposed to indicate UW-11a5b.
Coincidentally, I came across a U-1 this morning that actually does list "UW-11(a)(5)(b)" in the additional remarks section. I've been operating under the assumption that if it doesn't say it, then it wasn't performed and the head E cannot be claimed as 1.0.
RE: UW-11(a)(5)(-b) Spot
A Clark is just pointing out that you mentioned ".....and that the head JE can be taken as 1.0?". This is usually referred to as efficiency for head thickness calculations rather than Joint Efficiency....so as not to confuse with head to shell circ.
RE: UW-11(a)(5)(-b) Spot
There are a lot of Certificate holders that still do not understand the meaning of UW-11 (a)(5)(b). When I was a ASME Team Leader I had to educate many Certificate Holders on this subject.