P2904.6.2.1 Available Pressure Equation
The pressure available to offset friction loss in the interior piping system (Pt) shall be determined in accordance with the Equation 29-1.
Psup = Pressure available from the water supply source.
PLm = Pressure loss in the water meter. (Table P2904.6.2(2))
PLd = Pressure loss from devices other than the water meter.
PLe = Pressure loss associated with changes in elevation. (Table P2904.6.2(3))
Psp = Maximum pressure required by a sprinkler.