ISO 7278-2:2022

Overview

ISO 7278-2:2022 - "Petroleum measurement systems - Part 2: Pipe prover design, calibration and operation" is an international standard that describes the design, calibration and operational requirements for pipe provers (displacement provers) used in petroleum measurement systems. It covers the common types of provers in current use - sphere (ball) provers and piston provers - in both unidirectional and bidirectional forms and in conventional, reduced-volume and small-volume modes. The standard focuses on applications for crude oils and light hydrocarbon liquids (ambient, chilled and some low-vapour-pressure products), with principles applicable to a wider range of liquids including water.

Key technical topics and requirements

• Design classification: detailed descriptions of sphere provers and piston provers, including end chambers, run-in length, barrel and internal finish.
• Operational classification: conventional, reduced-volume and small-volume prover modes and related design implications.
• Sizing and calibrated volume: guidance on selecting prover volume, length between detectors, pipe diameter and velocity and pressure loss considerations.
• Displacers and detectors: requirements and considerations for spheres, pistons, detector types and pulse interpolation.
• Calibration methods: prescribed approaches such as the water draw calibration method, master meter methods (sequential and concurrent), calibration circuits and procedural requirements.
• Ancillary equipment: temperature and pressure measurement, calibration connections and system control important for traceable measurement.
• Installation and operation: mechanical and electrical installation guidance, meter proving operation, stabilizing temperature and periodic checks.
• Traceability and documentation: requirements to ensure measurement traceability for calibration and custody transfer.
• Acceptance criteria and calculations: guidance for fiscal and custody transfer applications (Annex C) and volume/mass calculation methods (Annex A).
• Safety and troubleshooting: safety procedures for prover operation (including LPG and cryogenic considerations) and troubleshooting guidance (Annex D).

Practical applications and who uses this standard

• Terminal and pipeline operators performing flowmeter proving and custody transfer measurement.
• Refineries, tank farms and custody transfer facilities requiring traceable volume measurement for fiscal accountability.
• Calibration laboratories and service providers performing prover calibration (water draw, master meter).
• Manufacturers of provers, flowmeters and custody transfer systems designing equipment to meet recognized international practice.
• Metrology and inspection bodies developing acceptance criteria and performance specifications.

Related standards

• ISO 7278-2:2022 complements other parts of the ISO 7278 series and broader flow-measurement and petroleum measurement standards. Consult ISO’s catalogue for related ISO/TC 28 publications on petroleum measurement systems.

Keywords: ISO 7278-2:2022, pipe prover, pipe prover design, calibration, operation, displacement prover, sphere prover, piston prover, flowmeter proving, custody transfer, petroleum measurement systems.