Abstract: A fire sprinkler system includes a plurality of sprinkler heads disposed at predetermined positions within a structure. Water in the system, on the system side, is isolated by a solenoid-activated valve from water on the municipal or street side. The water pressure on the system side is maintained at a lower pressure than the water pressure on the municipal side. In one embodiment, the sprinkler heads include a sprinkler head casing mated with a cover plate. The cover plate separates from the casing at a specified temperature. A switch compressed between the casing and the cover plate is activated by the separation of the cover plate. Activation of the switch opens the solenoid-activated valve of the fire sprinkler system, thereby releasing water at street pressure into the system.