Patent ID: 7857069

Claim:
A method for activating a sprinkler system having sprinklers, pipes and a system valve that controls the flow of a liquid extinguishant under an operating pressure from a source to the pipes and sprinklers, the sprinklers being connected to the pipes, comprising: maintaining a liquid extinguishant in the pipes under a standby pressure that is less than the operating pressure, whereby opening of at least one sprinkler connected to one of the pipes causes a drop in pressure in said one of the pipes; determining an arrangement of the sprinklers that is less than all of the sprinklers of the sprinkler system and will control a fire, wherein the arrangement includes sprinklers connected to a plurality of the pipes; and opening the system valve in response to a drop in pressure in each of the plurality of the pipes to which at least one of the sprinklers of the arrangement is connected.