My question is the following:

Imagine the rising of a pipe, in the highest point of the rising we situate a +Y restraint (this support has being introduced for reducing the vertical deflection in sustained case)I analyze the piping and there is no overstress in any point,but when we observe the operational case, such point rises 3"(76,2 mm).

In order to verify there are no problems with the lift off, I delete such support and recalcule. I observe there is no overstress in the sustained case, for this, I think that the lift off is valid and I permit the pipe rises in such point and I will erect a rigid support.

Do you think this method of analysis being correct?
Do you believe it should be erected a spring support?
Would you follow the same steps I have followed to verify the location of such point?