System valve activation methods for deluge-like wet pipe sprinkler system

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 sprinkler system downstream of the system valve under a standby pressure that is less than the operating pressure;
• determining a first number of sprinklers in an arrangement of the sprinklers that can control a fire;
• providing a bypass around the system valve to provide fluid communication between the source of liquid extinguishant under operating pressure and the pipes and sprinklers;
• reducing the pressure of the liquid extinguishant in the bypass to the standby pressure;
• calculating the total flow rate of liquid extinguishant that can flow, at the standby pressure, through a second number of the sprinklers, when actuated, that is fewer than the first number of sprinklers;
• limiting the flow of liquid extinguishant through the bypass at the standby pressure to a flow that is equal to the calculated total flow rate of liquid extinguishant through the second number of the sprinklers, whereby the pressure of liquid extinguishant in the sprinkler system downstream of the bypass falls below the standby pressure when a number of the sprinklers actuate that exceeds the second number of the sprinklers;
• and
• opening the system valve in response to (1) a flow of liquid extinguishant through the bypass that is at least equal to the calculated total flow rate of liquid extinguishant through said second number of the sprinklers and (2) a drop in pressure in the sprinkler system below the standby pressure.

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 sprinkler system downstream of the system valve under a standby pressure that is less than the operating pressure;
• determining the number of sprinklers in an arrangement of the sprinklers that can control a fire;
• providing a bypass around the system valve to provide fluid communication between the source of liquid extinguishant under operating pressure and the pipes and sprinklers;
• reducing the pressure of the liquid extinguishant in the bypass to the standby pressure;
• calculating the total flow rate of liquid extinguishant that can flow, at the standby pressure, through said number of the sprinklers, when actuated;
• and
• opening the system valve in response to a flow of liquid extinguishant through the bypass that is at least equal to the calculated total flow rate of liquid extinguishant through said number of the sprinklers.