ISO 6919:2024

Overview

ISO 6919:2024 specifies procedures and requirements for dynamic measurement of liquefied natural gas (LNG) delivered by truck-to-ship (TTS) bunkering. The standard mandates the combined use of a Coriolis mass flowmeter (MFM) and gas chromatography (GC) to determine transferred mass and fuel calorific value. It also provides guidance for portable packaging of the combined measurement system so mobile units minimize facility footprint and speed deployment. Output in calorie units is suitable for commercial transactions between LNG suppliers and ship operators.

Key topics and technical requirements

• Measurement system combination: Use of Coriolis MFM for mass and online GC for composition/quality measurement.
• Metrological requirements: Installation, calibration, verification and uncertainty management for both MFM and GC (see clauses on MFM system verification and GC system verification).
• Portable packaging: Guidance for mobile, compact measurement systems that reduce storage needs and streamline TTS operations.
• Measurement procedures: Detailed steps for MFM quantity measurement, GC quality measurement, documentation, calibration and handling of MFM failures or quantity disputes.
• Energy calculation: Methods for calculating net/gross calorific values and density to produce energy results (J/kg or calorie units) for commercial use.
• System tests and maintenance: Requirements and test methods for routine verification, maintenance and sealing of the custody-transfer system.
• Safety and operational controls: General safety precautions, PPE, alcohol/drug-free requirements, and references to TTS bunkering checklists (Annex D) and risk assessment expectations.

Practical applications and users

ISO 6919:2024 is intended for practical implementation in commercial LNG bunkering operations where truck deliveries fuel vessels. Primary users include:

• Bunker suppliers and mobile metering system providers deploying TTS units
• Ship operators and chief engineers accepting LNG bunkers and reconciling energy/quantity for voyage planning and fuel accounting
• Port authorities and terminal operators managing TTS operations and safety zones
• Meter manufacturers, calibration labs and metrologists responsible for verification, installation and certification of MFM/GC systems
• Independent bunker surveyors and auditors performing custody-transfer verification and dispute resolution

Related standards

Key referenced standards include ISO 22192 (MFM bunkering), ISO 10790 (Coriolis flowmeter guidance), ISO 6974-1 and ISO 6976 (gas composition and calorific calculations), ISO 21903, and ISO 6578. These provide complementary requirements for installation, analysis and energy calculations.

Keywords: ISO 6919:2024, LNG, truck-to-ship, TTS bunkering, Coriolis mass flowmeter, gas chromatography, portable measurement system, calorific value, metrological requirements, bunkering measurement.