Calculates the effect of Orifice plate bending due to the differential pressure. The uncertainty due to elastic bending shows the effect of plate buckling on the discharge coefficient. The “Plastic buckling limit” shows the pressure at which distortion becomes plastic.

References
British Standard BS1042:1987 Part 1: Section 1.5 Measurement of fluid flow in closed conduits - Part 1 Pressure differential devices. Section 1.5 Guide to the effect of departure from the conditions specified in Section 1.1.
Effect of Plate Buckling on Orifice Meter Accuracy, P. Jepson & R. Chipchase, Journal Mechanical Engineering Science, IMechE Vol 17 No. 6 1975.