SIST EN ISO 7278-2:2023 PDF

Overview

SIST EN ISO 7278-2:2023 (ISO 7278-2:2022) is the international standard for pipe provers (also called displacement provers) used in petroleum measurement systems. It describes the types, design, calibration and operation of provers - including sphere (ball) provers and piston provers in both unidirectional and bidirectional forms - and covers conventional, reduced-volume and small-volume modes. The standard applies primarily to crude oil and light hydrocarbon liquids at ambient conditions, with principles that also extend to water, low vapour pressure, chilled and cryogenic products (with additional guidance needed for those cases).

Key technical topics and requirements

• Design classification: Common features, sphere provers, piston provers, and operational classifications (conventional, reduced-volume, small-volume).
• Prover barrel and run-in length: Guidance on end chambers, barrel construction, internal finish and run-in requirements.
• Sizing and calibrated volume: Principles for selecting prover length, diameter, velocity and calibrated volume for accurate measurement.
• Displacers and detectors: Requirements for spheres/pistons, displacer velocity limits, and detector placement and performance.
• Ancillary equipment: Temperature and pressure measurement, calibration connections and system control considerations.
• Installation and traceability: Mechanical/electrical installation recommendations for fixed and mobile provers and traceability for calibration.
• Calibration methods: Detailed calibration circuits and equipment, including water-draw and volumetric calibration procedures (see Annex A).
• Prover–flowmeter interaction: How pipe provers interface with different types of flowmeters and the calculations used to derive liquid volumes.
• Acceptance criteria for fiscal/custody transfer: Guidance on expected acceptance criteria for fiscal and custody-transfer applications and calibration acceptance (see Annex C).

Practical applications

• Proving and verifying flowmeters used in custody transfer, fiscal metering, custody reconciliation and product custody accounting.
• Calibration of metering systems at terminals, refineries, pipelines and bulk loading/unloading stations.
• Design and procurement guidance for manufacturers and system integrators of pipe provers.
• Operational procedures and quality assurance for measurement service providers and calibration laboratories.

Who should use this standard

• Petroleum companies, pipeline operators and terminal managers
• Flowmeter and prover manufacturers
• Metrology and calibration laboratories
• Custody transfer engineers, measurement and instrumentation specialists
• Regulators and auditors responsible for fiscal measurement compliance

Related standards and references

• Other parts of the ISO 7278 series (pipe prover and petroleum measurement system standards)
• Industry measurement standards and guidelines from API, OIML and national metrology institutes for custody transfer and flowmeter performance

Keywords: pipe prover design, pipe prover calibration, piston prover, sphere (ball) prover, petroleum measurement systems, displacement prover, custody transfer, fiscal metering, flowmeter proving, reduced volume prover, small volume prover.