Overview
ISO 16384:2012 - Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels - Dimethylether (DME) - Measurement and calculation on board ships provides guidance for accurate custody transfer and volumetric accounting of dimethylether (DME) carried in bulk aboard ships. The standard sets out practices for measuring and calculating liquid volume, vapour volume, temperature and pressure during loading and discharging operations, and for determining total quantity on board before and after transfer - regardless of tank type (fully refrigerated, semi‑refrigerated or pressurized).
Key factual characteristics of DME cited in the standard include:
- Boiling point: −25.1 °C (atmospheric pressure)
- Saturated vapour pressure: 0.61 MPa at 25 °C
- Explosive range, gas density and liquid density (as reference for measurement and safety)
Key Topics
The standard addresses practical and technical topics essential to custody transfer of DME:
- Measurement scope: liquid level, liquid and vapour temperature, vapour pressure, and vapour volume.
- Tank data: tank capacity tables and heel accounting for pre/post-transfer quantity.
- Level gauges: permitted types (float, magnetic, radar/microwave, ATG), required accuracy and designated-use practices.
- Temperature measurement: sensor types, accuracy, and number/positioning of sensors.
- Pressure gauges: type, number and accuracy requirements for vapour pressure monitoring.
- Preparation & procedures: ship/shore meetings, pipeline checks, cargo operation facilities, and documentation.
- Equipment management: calibration, accuracy verification certificates, maintenance, operation by designated personnel, malfunction reporting and approval procedures for gauge changes.
- Quantitative calculation: principles for converting measurements to volumetric and mass quantities (including Annex A on estimating DME density).
Applications
ISO 16384:2012 is intended to prevent disputes in international trade by standardizing on‑board custody transfer practices for DME. Practical applications include:
- Performing opening and closing custody transfer measurements at loading/discharge
- Preparing shipboard documentation and tank capacity tables for commercial settlement
- Ensuring accurate metrology and traceable calibration for transfer instruments
- Operational checklists for pipelines, safety precautions and ship/shore coordination
Who uses this standard
- Ship operators and crew responsible for liquefied gas cargo operations
- Terminal and port operators handling DME transfers
- Cargo surveyors and metrological authorities verifying custody transfer
- Classification societies, flag administrations and auditors reviewing compliance
- Ship designers and equipment suppliers specifying gauges and tank instrumentation
Related standards
- ISO 29945 (DME properties reference)
- ISO 18132 series (automatic tank gauge definitions and performance)
- ISO 10976 (cargo terms such as heel)
Using ISO 16384:2012 supports reliable, auditable custody transfer of DME and helps align shipboard measurement practice with industry and regulatory expectations.