ASME SectionVIII, Div 1 Small Openings 1

[PEIAI]

A 1" nozzle meeting all the requirements of UG-36(c)(3) is exempt from reinforcment calcs. However, if you wish to put this nozzle through the long joint of the shell you now must meet the requirements of UW-14. Am I forced to meet the radiographic requirements of UW-14(b)? As an option can I do the reinforcing calc as per UG-37 and not take the exemption allowed under UG-36(c)(3)?

 

[MarcoE]

Yes, RT is required but will not be easy because of the size of the opening.

Well...by doing reinforcement calcs of UG-37, you are not taking the exemption of UG-36(c)(3). In other words, ug 36-C3 says that since your nozzle is small, you don't have to show the calcs done in UG-37.

Hope this helps

 

[prex]

My opinion is that you can make the calculations per UG-37 (this would be anyway be necessary in case of rapid pressure fluctuations, so why not in a simpler case?) and so skip UW-14.
To MarcoE:
-it is not exact that one has not to show reinforcement calcs for small openings: they don't even require any reinforcement, other than what is inherent in the minimum neck thickness and weld size as specified by other rules
-the RT requirements per UW-14 need be satisfied before the opening is cut. prex

http://www.xcalcs.com

Online tools for structural design

 

[MarcoE]

The weld you are attaching the nozzle through will have to be RT'd per UW-14. The nozzle weld will require RT testing too unless it is a Fig. UHT-18.2 type of full pen. nozzle connection.
-to prex:I didn't say he had to do the calcs, but by doing them anyway (per UG37) you wouldn't be taking the exemption allowed by UG36c3. Just trying to save this guy some unecessary work.

 

[PEIAI]

MarcoE I really appreciate both you and prex responding to this question. To clarify the issue somewhat, the reason radiography is not something we want to do is because its a small shop which would have to contract out the work. The added expense is not something they are comfortable with, so we were trying to come up with ways of avoiding radiography if possible. Thanks for the responses, I'll let you know what we finally decide to do after the job meeting.

 

[deanc]

Suggest you all reread UW-14b. It does not mention Category
A joints{long seam}. UW-14d speaks of openings adjacent to
the butt welds. Refer to Interpretation VIII-1-83-208,Q-2.

The correct answer of course is to consult your AI and AIA.

 

[PEIAI]

We had our final job meeting on this today and decided that by doing calculations for the nozzle we would now be governed by UG-37, and therfore UW-14(a) would apply for the weld. By not taking the exemption from calculations granted in UG-36(c)(3) the paragraphs UW-14 (b) thru (c) no longer apply. The AIA agreed with this reasoning. We also agreed that the extra trouble of doing this is enough reason to not put a small opening in a shell joint. Thanks to you all for your help.