The objective of this document is to provide guidance on the use of ISO 5167:2022 series. ISO 5167:2022 is an International Standard for flow measurement based on the differential pressure generated by a constriction introduced into a circular conduit (see ISO 5167‑1:2022, 5.1). It presents a set of rules and requirements based on theory and experimental work undertaken in the field of flow measurement.

For a more detailed description of the scope, reference is made to ISO 5167‑1:2022, Clause 1. Definitions and symbols applicable to this document are given in ISO 5167‑1:2022, Clauses 3 and 4.

Neither ISO 5167‑1:2022 nor this document gives detailed theoretical background, for which reference is made to any general textbook on fluid flow.