ASME Section VIII Division 1 Corrosion Allowance on Internal Projection of Nozzle

[FoxRox]

I'm using COMPRESS for calculations and getting the following deficiency:

The area available in the nozzle internal projection (A3) is not contributing to the reinforcement as the nozzle
corrosion plus the vessel corrosion is larger than the nozzle thickness.

I understand what this means (A3 from Figure UG-37.1 is non-existent), but I'm unable to find why this should be a deficiency, because the internal projection and internal weld are not required at all. The joint is per Figure UW-16.1(d) with added internal projection and an internal fillet weld. It is a UG-36(c)(3) exempt opening. It works out fine with no internal projection. Why should adding more material be a deficiency? UW-16(c) does not prohibit internal projections or internal welds. In fact, it permits them to be used and considered as extra reinforcement as necessary. But I'm not trying to claim reinforcement. I'm just trying to ease fabrication by not requiring the extra steps for the flush internal mount. Is there a section or paragraph I'm missing, or is this perhaps an oversight in the COMPRESS programming? I have submitted an inquiry but won't hear back before Monday. I curious if anyone here has insights. Thanks!

 

[JStephen]

It sounds to me like they're just saying your nozzle is too thin in a poorly-worded way.
My thinking would be that extension may not be required, but if it's furnished, it must meet the code.
You could possibly get that clarified via an interpretation for future cases.

 

[david339933]

Interesting. I agree with what you stated. I could see this being a warning in Compress, but not a deficiency. The below interpretation rules out the fact that the internal pipe, since there must meet Code.
Please update once you receive an answer.


Standard Designation: BPV Section VIII Div 1
Edition/Addenda:
Para./Fig./Table No:
Subject Description: Section VIII, Division 1 (1998 Edition, 1999 Addenda); UG-45
Date Issued: 06/13/2000
Record Number: BC00-157
Interpretation Number : VIII-1-98-118
Question(s) and Reply(ies):

Question (1): Do the requirements of UG-45 in Section VIII, Division 1 apply to the external portion of the nozzle neck which is within, as well as beyond, the limits of reinforcement normal to the vessel wall [per UG-40(c)]?

Reply (1): Yes, except as allowed in UW-13(g).

Question (2): If a portion of a nozzle neck extends inside a vessel wall [term ti defined in UG-37(a)], do the requirements of UG-45 of Section VIII, Division 1 apply to the internal portion of the nozzle neck?

Reply (2): No.

 

[FoxRox]

Thank you for the replies. I got a reply from COMPRESS that it should be a warning instead of a deficiency. It will be updated in the next release.