Historical
ISO 2186:1973
Fluid flow in closed conduits - Connections for pressure signal transmissions between primary and secondary elements
Describes means whereby a pressure signal from a primary element can be transmitted by known techniques to a secondary device in such a way that the value of the signal is not distorted or modified even though it may be changed into a signal of a different nature. Is concerned only with the pressure difference techniques of flow measurement.
International Organization for Standardization [iso]