# Calculation Methods - Sprinkler

For all phase states the pressure loss across a sprinkler is given by the equation for orifice flow. Rather than explicitly stating the area and discharge coefficient, sprinkler manufacturers usually employ a nominal size and a coefficient Ks. This coefficient should not be confused with the pressure loss coefficient K. The relationship between volumetric discharge flow and pressure is given by: Q = Ks (P)0.5 where: Q is the flow rate (l/min). Ks is the manufacturer's nozzle discharge coefficient. P is the pressure at the nozzle (bar). FluidFlow also allows sprinkler data to be expressed as a table of flow against pressure. If you define a sprinkler in this way FluidFlow interpolates between table values. Interpolation is made according to the sprinkler equation above.