DP Flow - Origins of ISO 5167 Measurement of Fluid Flow by Means of Differential Pressure Devices

Monday, April 15, 2019 | Steve Clark
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ISO 5167 is at the heart of the Solartron ISA flow metering product range. Formally introduced in 1980 it superseded the 1967 ISO R-541 standard for differential pressure flowmeters. Prior to R-541, BS 1042 first published in 1942 under the title ‘Flow Measurement’ was the main reference for flow measurement engineers.


ISO 5167 focus is based on commonly used differential pressure primary elements, their geometry and methods of use as well as performance coefficients and uncertainty expectations. Split into 6 parts, it covers general requirements, orifice plates, nozzles, venturi tubes, cone meters and the recently released Part 6 on wedge meters.

In addition to ISO 5167, several technical reports have been released to support the user of differential pressure meters, including TR 9464 – Guidelines for the use of ISO 5167, TR 15377 – DP meters beyond the scope of ISO 5167, TR 12767 – Effects of departure from ISO 5167 and TR 11583 – Measurement of wet gas using DP meters.

For over 50 years, Solartron ISA have designed and manufactured single-phase differential pressure flowmeters and for the last 25 years we have taken the ISO 5167 venturi device and modified it for use on our range of wet gas flow meters.

Solartron ISA have been active participants for over 15 years in the ISO/TC 30/SC2 technical committee assigned to ISO 5167. The standard is due for ISO systematic review in 2019.