Overview
ISO 24062:2023 - Measurement of fluid flow in closed conduits - Clamp-on ultrasonic transit-time meters for liquids and gases - is the international standard that specifies requirements and recommendations for non-intrusive (clamp-on) ultrasonic flowmeters (USMs). It covers transit-time measurement principles for volumetric flowrate in closed pipes, primarily for single‑phase liquids and gases (and situations with small amounts of secondary phases). The standard addresses performance, calibration, output characteristics and installation conditions for clamp-on ultrasonic transit-time meters.
Key topics and technical requirements
- Principle of measurement: transit-time ultrasonic method and generic meter description (transducers, path configurations, electronics).
- Transducer and path design: guidance on transducer types, orientations, coupling and multiple-path configurations to optimize accuracy.
- Electronic unit functionality: signal processing, timing measurements and outputs required for flow calculation.
- Special considerations: gas measurements, extreme temperatures, non-Newtonian fluids, stratification and contamination by secondary phases.
- Additional measurements: procedures for deriving standard volume flow, mass flow and heat flow from transit-time data.
- Test and calibration: laboratory flow calibration under flowing conditions and individual testing requirements for performance verification.
- Installation requirements: recommended upstream/downstream straight-pipe lengths, mounting methods, cable guidance and effects of thermal insulation or vibration.
- Operational diagnostics: recommended diagnostic parameters such as fluid speed of sound, gain and signal‑to‑noise ratio (SNR) to assess meter performance in situ.
- Uncertainty analysis: mathematical model and contributory variances affecting measurement uncertainty (cross‑sectional area, velocity profile, path geometry, time measurement, delay times, and effects of multiple paths).
Practical applications
ISO 24062:2023 is practical for:
- Flow measurement in process industries (chemical, water/wastewater, HVAC, utilities)
- Plant instrumentation and control where non‑intrusive mounting minimizes downtime and contamination risk
- Situations requiring wide rangeability without pressure loss or invasive pipe penetration
- Applications needing traceable calibration, documented uncertainty budgets and diagnostic capabilities
Who should use this standard
- Flow meter manufacturers and calibrators
- Instrumentation and process engineers
- Metrology laboratories and testing facilities
- Asset owners and operators in oil & gas, water, utilities and industrial process sectors
- Procurement and quality teams specifying clamp-on ultrasonic transit-time meters
Related standards and notes
- Prepared by ISO/TC 30 (Measurement of fluid flow in closed conduits). ISO 24062:2023 aligns with ISO/IEC editorial rules and references normative documents used for metrology and calibration practices. For implementation, consult national standards bodies and manufacturer documentation for product‑specific details.
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