ISO/TR 9464:2023

Overview

ISO/TR 9464:2023 - Guidelines for the use of ISO 5167:2022 - is a Technical Report that helps users correctly apply the ISO 5167 series for flow measurement in circular conduits using differential-pressure primary devices. The document explains how the six-part ISO 5167:2022 standard is structured, clarifies clauses, and gives practical guidance on implementation, calculation and uncertainty assessment. It complements the main standard by pointing to relevant theory, experimental basis and useful annexes (e.g., worked examples and gas compressibility).

Key topics and requirements

• Scope and relation to ISO 5167:2022: Guidance is organized to match each part of ISO 5167 (parts 1–6) so users can find advice tied to specific clauses.
• Primary devices covered: Orifice plates, nozzles and Venturi nozzles (guidance specific to parts dealing with these devices is included).
• Measurement and computation: References the formulae in ISO 5167‑1:2022 and provides worked examples and iterative computation guidance (Annex A).
• Installation requirements: Practical advice on positioning of primary devices, piping layout and secondary instrumentation installation to meet ISO 5167 requirements.
• Secondary instrumentation: Recommendations for pressure and differential-pressure measurement, temperature sensors, density transducers and signal connections.
• Density, temperature and pressure: Guidance on measuring and computing density (including compressibility factor methods in Annex B), sensing moving-fluid temperature, thermowell considerations and static/differential pressure measurement best practices.
• Uncertainty and calibration: Notes on estimating measurement uncertainty (consistent with ISO/IEC Guide 98‑3) and on flow calibration of meters.
• Electrical and safety considerations: Brief guidance on electrical supply, cabling and use in potentially explosive atmospheres.
• Informative annexes: Principles of measurement, compressibility factor computation for natural gas, and orifice plate assembly details (Annexes A–C).

Practical applications and users

ISO/TR 9464:2023 is useful for:

• Instrumentation and process engineers specifying differential‑pressure flowmeters
• Flowmeter manufacturers and calibration laboratories
• Pipeline and plant operators (oil & gas, chemical, water and utilities)
• Metrology specialists and consultants assessing measurement uncertainty and compliance The report aids in correct installation, accurate flow computation and consistent interpretation of ISO 5167:2022 requirements.

Related standards

• ISO 5167:2022 (six-part series) - primary measurement rules and formulae
• ISO 4006 - vocabulary and symbols for fluid flow measurement
• ISO/IEC Guide 98‑3 - guidelines for expressing measurement uncertainty

For implementation, consult ISO/TR 9464:2023 alongside the full ISO 5167:2022 parts and applicable industry regulations.