Gives the geometry and method of use of square-edged orifice plates, nozzles and Venturi tubes when they are inserted in a conduit running full, to determine the rate of the fluid flowing in the conduit. It gives necessary information for calculating the flow-rate and its associated uncertainty. Applies only to pressure difference devices in which the flow remains subsonic throughout the measuring section, is steady or varies only slowly with time and the fluid is single-phased. Each device can only be used within limits which are specified. Does not apply for pipe sizes less than 50mm or more than 1,200mm or for pipe Reynolds numbers below 3150.

BS 1042-1(1964) : LATEST

BS 1042-1.1(1992) : 1992 AMD 9332

BS EN ISO 5167-1 : 2003