SIF & Tees

Dear All,

In SIF & tees option in Caesar-II input, two type is mention for socket connection ( 8 & 9 no.)

Can anyone tell me that what is the difference between this two socket connection?

Refer CAESAR II Technical Reference Manual.

Also read appendix D from B31.1 (note 11) and appendix D from B31.3 (note 13)

Best regards,

The "help" explains this, push the [F1] key when the cursor is in that field.

8 SOCKET WELD (NO UNDERCUT) FILLET
9 SOCKET WELD (AS WELDED) FILLET

But I am not getting clear meaning of 8 & 9.
Also I am confused between 8 or 9 for socket connection in SIF & tees.
(when I will go for 8 or 9)

Undercut is term associated with welding. While providing circumferential weld on small bore pipes in field, welder usually stop and start welding at frequent intervals. Moreover the electrode angle is changed several times because it is difficult to weld small bore pipes with same electrode angle. Doing so there is a tendency to undercut the previous weld.
This tendency (undercut) can be eliminated by grinding the weld surface.
Note that weld with undercut have higher SIF values (refer B31.1 Appendix D Note 11).

Actually for both the case SIF value is same.

Which code you are using?
The above statement is applicable for B31.1 code.
For B31.3 refer Appendix D Notes.

I am using B31.3 code.
In my case, SIF value is same (2.1) for both the case.
I have checked in C-II for both the cases & it is same.

Dear shamaliabhavin,
You can validate higher SIF values once you select B31.1.
In B31.3 you saw same values because user need to mention SIF manually.
Presently, I don't have a copy of B31.3 with me but I remember (with my limited memory) that such condition is cited in B31.3, Appendix D Note 11 or 13. Hope this helps.

Just my opinion:

If the project is a Power Plant and the Client specified ASME B31.1 as the Design Basis Code then you must use B31.1 for all analysis.

If the project is a Refinery or Chemical plant and the Client specified ASME B31.3 as the Design Basis then you must use B31.3 for all analysis. The only exception here is if there is a Boiler included in the Refinery or Chemical plant and the Client defines the Boiler piping (only) as B31.1 then only that piping inside the primary isolation valves would be Boiler Code Piping.

You as the Pipe Stress Engineer does not get to pick and choose the "Code" for your analysis that gives you a "Good" answer.

You must use the "Code" that is specified by the Client for his project and do the analysis based on that code. If the configuration passes then that is good. If it fails you do not get to go and look for a different answer using a different Code. To get a problem to pass you must have the piping layout and routing revised to eliminate or mitigate the problem.

Jop,
After reading your opinion I realized that I should have written my previous post more comprehensibly.

My intent (in my previous post) was to clarify that B31.1 and B31.3 have different approach as far as SIF for socket weld connection is concern.

I totally agree with you that we as stress engineers need not pick code and apply as per our ease, and we should never mix codes.