Appendix P

Having recently read appendix P and running
the example appendix s from the COADE Downloads,

I get the following.

Max Op stress =192.34 n/2mm (node 39)
SoA = 205n/2mm

Then the stress ratio is 94% of the allowable.
Which, due to the variances that creep in during manufacture of piping, we would deem to be very high.

(we like to be below 90%)

i am assuming the stress range for comparison
is from T2P2 to T1P1, NOT ambient to T1P1 which is a 'cycle'

Comments appreciated.

(i just know i'm gonna be flamed for this!)

Regards.

Congratulations,

You are the very first poster to discuss this appendix and it appears as feared you have missed some of the finer points that TG B of B31.3 had for publishing this.

Salient points:
99.9999% of a code stress allowable value complies with the Codes numeric requirements. Any added allowances are at the option of the individual designer and while perhaps warranted for “unknowns” are not a direct code requirement. (Interestingly when discussed by the members of TG B some felt that 99.99% was overstressed, some felt that 101.999% would still be in compliance) Mathematically speaking however 99.99% of an allowable value is less than that value. I suggest you may want to prepare a code inquiry on this for further clarification. Please follow the format as spelled out in Appendix Z

The numeric values in this appendix are approximations of the results from various commercially used pipe stress programs. It was never intended as a “benchmark” See note1 of Table S301.5.1, Table S301.5.2

As stated in S301.7 SE as well as SA has been accounted for in a CAESAR II setup the two distinct OPE cases (T1/P1 vs T2/P2) would be algebraically summated.

Thanks to the Rev. Dr. Luf.

Chuck doesn't seen to get over to this board very often but readers might be interested in looking at this site:

http://www.bechtengineering.com/processPower/articles/ASME-B31.3TechnicalChanges2004.htm

There is always something of interest over there.

Regards, John.

Hi John,

The Synopsis by Chuck is well done... and it managed to be published long before the actual code!!!!

Fine Point Hint:Look @ the temperatures closely in the sample problem and take note of how they are used or not used as the case may be.