but the ones we do with backflows and PIVs are designed so that when the fire department shows up they select the building on fire and pressurize it up to 200 PSI. This results in all the sprinkler heads in the building going off
I am sorry I really have to question that, I think you may have been given incorrect info or misunderstood the info.
That is what happens in the movies, I have worked a lot of commercial buildings and have never seen a sprinkler system operate in that way.
The FD may very well turn on fire pumps but I doubt highly that causes all sprinkler heads to let go.
Two problems with that.
1)You would be basically 'wasting' your water supply and your main would have to be sized to run all heads at the same time.
I doubt a sprinkler main can support all heads open any more than our service main can handle all circuits fully loaded.
2)Insurance Companies. As much as the insurance company wants the fire out they definitely do not want water damage in the entire building for a localized fire.