(at least - standards vary) but for incompressible fluids, including most liquids Overall pressure loss The overall pressure loss caused by an orifice plate is less than the differential pressure measured across tappings near the plate. For sharp-edged plates such as corner, flange or D and D/2 tappings, it can be approximated by the equation or See also Accidental release source terms Choked flow De Laval nozzle Flowmeter Pitot tube Restrictive flow orifice Rocket engine nozzle Torricelli's law Venturi effect Advantages and disadvantages of orifice meter and venturi meter References Notes Citations Sources Mathachan Online Tools Online Orifice Plate Calculator Fluid dynamics Chemical engineering Mechanical engineering Control devices Piping