I´m calculating the ASME B31.4 alowable stress in a pipe system, but it´s always 0 or N/A in the code stress report.

I´m running a case with external forces (Ux,y,z), internal pressure (P) and thermal expansion (T).

I´ve set material properties, as said in para. 419.6 in the code.

My load cases are as follows:

OPE W+T1+P1
SUS W+P1
OPE W+T1+P1+U1
OPE W+T1+P1-U1
OPE W+T1+P1+U2
OPE W+T1+P1-U2
OPE W+T1+P1+U3
OPE W+T1+P1-U3
EXP L9=L1-L2
OCC L10=L3-L1
OCC L11=L4-L1
OCC L12=L5-L1
OCC L13=L6-L1
OCC L14=L7-L1
OCC L15=L8-L1
OCC L16=L9-L10
OCC L17=L9-L11
OCC L18=L9-L12
OCC L19=L9-L13
OCC L20=L9-L14
OCC L21=L9-L15

I´m newbie in pipe stress, and i´ve read the code, obviously there is something missing, if anyone could give me a clue, it would be a great help!

Thanks for your advice.

Read this earlier post .

thanks for your help, I wasn´t defining the water weight, that was the problem.

And your load cases L16 to L21 are wrong.