You might be interested in the new hybrid system of fire suppression by Victaulic. It combines an ultra-fine water mist and nitrogen to a) reduce the amount of O2 in the room to 16% which will extinguish a fire (a person remaining in the room can still breathe) and b) the fine mist will cool the heat of the fire and help extinguish it. Less water is used in this system, and it takes less time to suppress the fire than a traditional sprinkler system.
My client’s (a museum) collections storage area will probably have this Vortex system installed, and it will probably be combined with a wet pipe sprinkler system for less-vulnerable areas.
I saw the hybrid system in action last week at their plant in Easton, PA and was amazed by the technology and effectiveness. I would recommend you look into it. Victaulic Vortex