UW-14(b) clarification

[Jordan123]

UW-14-b states that single openings meeting UG-36(c)(3) requirements may be located in Category B or C butt welded joints.
Can a single opening meeting UG 36 (c)(3) be located in a Category A butt welded joint? If so under what conditions/requirements?

 

[RPRad]

Jordan

UW-14(b) says before this that it may be located in a head to shell weld, which is considered a Cat A joint. Given that, my interpretation would be that while a nozzle meeting UG-36(C)(3) can be installed in a head to shell weld (Cat A), it cannot be installed in a Cat A shell longitudinal joint or head seam weld.

According to UW-14(b) the weld joint into which the nozzle is installed must be 100% radiographed "for a length 3 times the diameter of the opening with the center of the hole at midlength"

A warning however if its an existing vessel and the weld was never radiographed originally or only spot radiographed initially you could find yourself doing numerous weld repairs on the existing seam welds. For a new vessel you would use that location as a spot radiograph location and kill two birds with one stone.

R

 

[Jordan123]

According to UW 3, shell to head welds are only Cat A with a hemispherical head.
I'm specifically interested in a longitudinal Cat A shell joint. I may have thrown off the question referencing only UW-14(b). UW-14(a) says any type opening that meets the reinforcement requirements given can be located in a welded joint (it doesn't limit joint category). My take is that even thoughUG-36(c) doesn't require reinforcement calculations, if I go ahead and perform them, I can place the opening in a Cat (A) joint under UW-14(a).

 

[jamesl]

UW-14(a) states any opening that meets UG-37 or UG-39 can be located in a weld joint. Therefore opening meeting UG-36(c)(3)can be located on a shell long seam as long as UG-37 is met.

Most client specs will require RT of shell or head seam when a nozzle is located on the seam.

 

[Jordan123]

James thanks, this was my read and I thought this would provide the pathforward. However it now seems to be more complicated. What I have is jacket penetration, consistent with App 9 Fig 9-6 (b). on a Cat A seam.
9-6 (b) would suggest that reinforcements of the opening are not required for Fig 9-6 penetrations since the opening is stayed by the closure member. It is silent on whether the opening is in a seam. UW-14 for opening in welds would seem to lead to UG-37, but UG-37 does not apply to stayed openings. Therefore 9-6 (b) would seem to be on point but is my read that a stayed jacket penetration falls under 9-6 and can be made in a weld seam without reinforcement calcs?

 

[RPRad]

James / Jordan

While its really splitting hairs, what UW-14(b)is saying is you can put a nozzle which meets the requirements of UG36(C)(3)(ie does not require reinforcement calcs be submitted) in to a head to shell, B or C welds providing you do the radiography...(Ie without having to check reinforcement).

If you want to put a UG36(C)(3) nozzle into a longitudinal weld you you must check the reinforcement calcs for these nozzles, which, as James indicated, makes them then comply with UG37 and UW14(a)...I am sure there is a good reason for this but it escapes me now...most of these types of nozzles seldom fail reinforcement calcs.

I agree with James its is standard practice to spot radiograph the seam weld location where you are going to put the nozzle. I am actually I surprised that it does not require it in UW14(a)...I would always take the calcs over
having to do the radiography if I am given a choice...but it depends upon the vessel.

As to your current situation I think you still have to do the reinforcement calcs. Para 9-6(b) is essentially saying that nozzle configurations shown in Fig 9-6 are exempt from reinforcement calcs, as UG36(C)(3) nozzles would be if they were installed in a jacket (as permitted by 9-6(a)). Once you put the nozzle in a weld seam Para UW-14 comes into play....you do the reinforcement calcs if you are going to stick it into a longitudinal weld or you do the radiography if you want to avoid the calc and stick it into a head to shell weld or Cat B or C Weld

That would be my take, I agree its a bit gray but I dont think you can ignore UW14 because Appendix 9 doesnt specifically reference it.