Hello,

I have some questions regarding SA- expansion allowable stress.

1. The code (B31.1) provides two formulas Eq.1A and Eq.1B to calculate SA. Sometime the results from these two formulas are quite different, normally which one should be used for expansion (or displacement) stress reange verification?

2. Some people say that Eq.1A is for expansion (or displacement) stress range calculation and Eq.1B is for operating loads (expansion loads + sustained loads) calculation, Is that right? or the old codes were required this way?

Carter