SIST EN ISO 5167-3:2023 PDF

Overview

EN ISO 5167-3:2022 - Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full (Part 3: Nozzles and Venturi nozzles) provides standardized geometry, installation and operating conditions for using nozzles and Venturi nozzles to determine flowrate from differential pressure. It is intended to be used together with ISO 5167‑1 and applies to single‑phase, subsonic flow in circular pipes within defined limits (pipe diameters 50–630 mm and Reynolds number ≥ 10 000). The standard excludes pulsating flows and supersonic conditions.

Key Topics

• Device types covered
  • ISA 1932 nozzle
  • Long‑radius nozzle
  • Throat‑tapped nozzle
  • Venturi nozzle (same upstream face as ISA 1932 but with a divergent section)
• Geometry and manufacture
  • Detailed profiles, material and manufacturing requirements for repeatable nozzle and Venturi nozzle construction
• Pressure tappings and locations
  • Specified tapping positions (upstream and downstream) for accurate differential pressure measurement
• Installation requirements
  • Minimum upstream/downstream straight lengths, flow conditioner guidance, pipe circularity/cylindricity, and mounting details
• Performance and calculation
  • Discharge coefficients, expansibility (expansion) factors, pressure loss characteristics, and background for computing flowrate from measured differential pressure
• Calibration and uncertainty
  • Requirements and guidance for flow calibration tests, reporting, and uncertainty analysis; coefficients are based on direct calibration experiments with known limits of uncertainty

Applications

EN ISO 5167-3:2022 is used wherever reliable differential‑pressure flow measurement with nozzles or Venturi nozzles is required:

• Industrial process control and plant monitoring (liquids and gases in closed conduits)
• Flowmeter manufacturers and calibration laboratories performing tracer or primary‑device calibrations
• Utilities and engineering firms specifying permanent or test metering installations
• Metrology and quality assurance where standardized measurement methods and uncertainty reporting are required

This standard is particularly useful for applications needing low uncertainty, repeatable flow measurement across 50–630 mm pipes and Reynolds numbers above 10 000.

Related Standards

• ISO 5167‑1 - General principles for measurement with differential pressure devices (to be used in conjunction with Part 3)
• Other parts of ISO 5167 (e.g., orifice plates, cones) cover alternate primary devices and complement Part 3 for a complete flow‑measurement strategy

Keywords: EN ISO 5167-3:2022, nozzles, Venturi nozzles, flow measurement, differential pressure, flowrate, circular conduits, ISA 1932, calibration, discharge coefficient, Reynolds number.