Remember when doing inspections to check out the fire department connection. We all do that pretty well for the most part, making sure that nothing is blocking it and noting where it is for tactical reasons. However, I have seen crews miss checking the Post Indicator Valve when checking the FDC/Sprinkler System. It is just as important.
The biggest reason this is missed is because they are usually a little ways from the building and are not right next to the FDC, but it they are not checked and are SHUT, it could have grave circumstances if there is a fire.
These PIV control the water to the system. They should always be open and the window on the PIV will read OPEN or SHUT. Look around, usually these are on large industrial complexes and some high rise buildings.