My issue is with the area of the piping. The area of the process piping is D^2pi/4, and the total piping area to the PSVs is 4 times that since all of the piping has the same 4" diameter.
I have 4 4x6 PSVs located on a 4" nitrogen line, and none of them are spares. As I understand it, all of these PSVs don't actually protect the line and downstream equipment. This is because the process piping area is less than the total area of all of the PSVs. Can credit be taken for just...