Kevin,

You said that the redistrubted dead weight loads are primary. I disagree. Any difference between the two load cases is secondary. This fact is stated in the French piping code, CODETI.

If you disagree, read the section on "hot sustained stresses" in Chapter 6 of the Technical Reference Manual. This sets up a SUS load case the way Richard (Havard) lays out above.

In actual fact, as is pointed out in the newsletter article referenced above, you may need to evaluate the SUS stresses in more than one (boundary) condition of the piping system. Simply removing the +Y support may address (one) hot sustained condition, but the resulting expansion stresses are incorrect. This is why I used the word "wrong" above. You can't just remove the +Y from the model and call it quits.