This system is used in situations where the spread of fire is expected to be high and fast, and where it is desired to apply water to the entire area where the fire occurs and spreads. Open-type sprinklers are connected to the pipe system. The pipes are not pressurized with water or air. The main alarm valve is activated by a suitable automatic detection system. At least one manual release station must be provided to activate the main alarm valve in emergencies. Automatic detection systems should be installed in all rooms and compartments protected by the main sprinkler system. Detection systems must comply with the EN54 Standard. High Hazard Class Operation Group 4 areas are generally protected by main systems. Rules provided for sprinkler system designs are not applicable in main system designs due to the separate design approach taken for main systems.
