WRC-107 does not apply to attachments to flat plates (eg: bolted covers, etc). The bulletin provides method of analysis only for attachments to cylindrical and spherical shells.

For analysis of attachments to a flat plate you can perform analysis by hand using principles from theory of elasticity, etc (see "Theory of Plates and Shells" by Timoshenko).

You can also use the FEA-Nozzles feature in COMPRESS to analyze nozzles on bolted covers. This feature was formerly available only at additional cost. It is now part of the basic COMPRESS license.


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  Tom Barsh
  Codeware Technical Support

Of course, this presumes that the bolted cover has been designed, and is not a B16.5 blind flange. If it is, the limits of unreinforced hole size must be adhered to, as well as the opening being dead-center on the blind. If the opening is reinforced, it must be as called for in B16.5. If one chooses not to do so, then the entire blind becomes a designed component, not a standard one, and there's a good chance that it will not be thick enough.

jt

Good points. This issue (nozzle in standard blind flange) was discussed earlier in this forum in thread thread1259-161656: Nozzle through Blind Flange.

Hartford inspection had an article in the June, 1999 issue of their Pressure Points describing this situation. See www.hsbct.com/uploadedFiles/CTWeb/AllImages/PP-1999-06.pdf.

I just noticed a related Pressure Points article indicating that bolted covers with nozzles must fall under the Section VIII Code boundary. For an interesting discussion, see www.hsbct.com/uploadedFiles/CTWeb/AllImages/PP-2001-11.pdf.

The June, 1999 article leaves one wondering about the case where Table 7 (now Table 6) in ASME B16.5 permits an opening that is larger than the largest openings exempt from reinforcing requirements by UG-36(c)(3)(a). My opinion is that because the blind flange is a standard pressure part accepted by UG-44 then such an opening is acceptable without further investigation for UG-37 since the opening is permitted by B16.5.



"Although this forum is monitored by Codeware it is not intended as a venue for technical support and should not be used as the primary means of technical support."

  Tom Barsh
  Codeware Technical Support
 

Tom-

Good links, thanks! I agree with your view about the blind remaining a standard pressure component as long as the B16.5 limits are met. Thus, Section VIII-1 work is not necessary for this situation. Really, this is no different than if I use a piping tee as a part of my vessel. If I use a 12"x12"x6" B16.9 tee, the 6" branch opening is not subject to UG-37. Similarly, If I use a 16"x10" B16.9 reducer, I would not run VIII-1 conical transition calc's.

jt