Chris is on the right track, and without spending a lot of time doing a cut and paste from NFPA 99 Chapter 5:
There are 4 basic requirements of where the zone valve box are to be located.
#1 is to have an intervening wall between the zone valve box and the outlets
( NFPA 99 has a picture of this in the book - personally I’m not a big fan of it ).
#2 is for the zone valve box to be in the Corridor.
#3 fairly new to NFPA 99 - The zone valve box can not be in the same room as the outlets.
#4 if the zone valve box services-controls an anesthetizing location, it is to be immediately outside that location / space.
I was providing this information via voice to text sorry / if the format is a little strange.