A residential dwelling unit fire protection system for a residential dwelling unit (R). The fire protection system includes a pressurized liquid supply (10), a pressurized gas supply (28), a control valve (30) coupled to the liquid and gas supplies, the control valve (30) being biased in a closed position to prevent liquid flow through the control valve (30) based on a pressure differential between the liquid and gas supplies, a network of pipes (22, 22a, 22b, 23) coupled to the pressurized gas supply (28), a minimum quantity of residential fire sprinklers (40A, 40B, 40C), and an alarm (38) to indicate a flow of liquid through the network. Each of the quantity of residential fire sprinklers is coupled to the at least one pipe so that, upon actuation of at least one residential fire sprinkler, the control valve (30) is actuated to deliver liquid from the liquid supply (10) to at least one of the residential fire sprinklers for distribution over a protection area (A) at a predetermined density in at least one compartment.