System and methods for wet system fire protection

A method of providing a wet ceiling-only fire protection system having a supply portion and a demand portion including a plurality of sprinklers, each sprinkler having a minimum design operating pressure, the method comprising:

• determining a withholding period for withholding fluid pressure from the demand portion of the system following actuation of at least one sprinkler in the demand portion in response to a fire;
• specifying a design area of the demand portion, the design area being defined by a maximum number of sprinklers activated to one of control or suppress a fire in a fire test that incorporates the withholding period;
• and
• withholding, via a control device comprising a pressure sensor disposed in a main line between and coupled with the supply portion and the demand portion, fluid pressure from the demand portion following actuation of at least one of the plurality of sprinklers for a predetermined withholding period, the control device comprising:
• a valve having a standby state which prevents fluid communication between the supply portion and the demand portion and an operated state which permits fluid communication between the supply portion and the demand portion;
• and
• a timer configured to initiate countdown of the predetermined withholding period, the timer coupled to the valve to transition the valve from the standby state to the operated state upon expiration of the predetermined withholding period.

A wet ceiling-only fire protection system for the protection of a stored commodity, the system comprising a pressure control device, the pressure control device comprising:

• a pressure sensor disposed in a main line between and coupled with a fluid supply portion and a demand portion and configured to withhold fluid pressure from pressurizing a plurality of automatic fire protection sprinklers for a predetermined withholding period following thermal actuation of at least one of the plurality of automatic fire protection sprinklers, wherein the predetermined withholding period is a function of the thermal responsiveness of the plurality of automatic fire protection sprinklers;
• a valve having a standby state which prevents fluid communication between the fluid supply portion and the demand portion and an operated state which permits fluid communication between the fluid supply portion and the demand portion;
• and
• a timer configured to initiate countdown of the predetermined withholding period, the timer coupled to the valve to transition the valve from the standby state to the operated state upon expiration of the predetermined withholding period.