Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels — Dimethylether (DME) — Measurement and calculation on board ships
ISO 16384:2012 provides guidance on the practices for custody transfer of dimethylether (DME) on board ships, at both the loading and the discharging ports. It covers such aspects of volumetric calculation on board as measurement of liquid volume, vapour volume, temperature and pressure; and accounting for the total quantity of DME on board before and after loading/discharging, regardless of the type of ship's tank.
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base non pétrolière — Diméthyléther (DME) — Mesurage et calculs à bord des navires
Standards Content (Sample)
Refrigerated hydrocarbon and non-
petroleum based liquefied gaseous
fuels — Dimethylether (DME) —
Measurement and calculation on
Hydrocarbures réfrigérés et combustibles gazeux liquéfiés à base
non pétrolière — Diméthyléther (DME) — Mesurage et calculs à
bord des navires
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ii © ISO 2012 – All rights reserved
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1 Scope . 1
2 Terms and definitions . 1
3 Characteristics and properties of DME . 2
3.1 General . 2
3.2 General characteristics . 2
3.3 Chemical and physical properties . 2
4 General precautions . 3
4.1 General . 3
4.2 Equipment precautions . 3
5 Tank capacity table . 4
5.1 General . 4
5.2 Contents of tank capacity table . 4
6 Level gauges . 4
6.1 Type of level gauges . 4
6.2 Accuracy of level gauge . 4
6.3 Use of designated level gauge. 5
7 Temperature measuring equipment . 5
7.1 Type of temperature sensor . 5
7.2 Accuracy of temperature measuring equipment . 5
7.3 Number and position of temperature sensors . 5
8 Pressure gauge . 5
8.1 Type and number of pressure gauges . 5
8.2 Accuracy of pressure gauge . 5
9 Preparation for custody transfer . 6
9.1 Facilities for cargo operation . 6
9.2 Pipelines . 6
9.3 Ship/shore meeting . 6
10 Custody transfer measurement . 7
10.1 General . 7
10.2 Measurement of liquid level . 7
10.3 Measurement of temperature . 7
10.4 Measurement of vapour pressure . 7
11 Quantitative calculation . 8
11.1 General . 8
11.2 Concept of quantitative calculation . 8
12 Preparation for sailing . 9
12.1 Pipelines and other facilities . 9
12.2 Ship/shore meeting . 9
12.3 Information to cargo receiver . 9
Annex A (informative) Estimation of density of DME .10
© ISO 2012 – All rights reserved iii
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ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16384 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants,
Subcommittee SC 5, Measurement of refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels.
iv © ISO 2012 – All rights reserved
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Measures for environmental protection are required on a global scale. In this connection, various
methods of achieving these aims have been independently studied or undertaken in many countries.
One such project, the development of the use of dimethylether (DME) as a new form of energy has been
undertaken in several countries. Use of DME generates neither sulfur-oxide nor any other particulate
matter known to cause environmental pollution at the time of combustion.
Another benefit of the use of DME as a petroleum alternative is that it can be produced easily from
natural gases, coals and biomasses with only slight additional development of the existing techniques of
production, transportation, storage and consumption.
In international trade, liquefied gases in bulk are carried by specialized ships which are equipped with
fully refrigerated or semi-refrigerated type tanks, or pressurized type tanks. For assessing the quantity,
measurement on board these ships is preferable because shore tanks at loading/discharging ports usually
engage in transferring to/from tank cars by pipelines, etc. simultaneously with the delivery/receipt of
the cargo to/from the ships.
To prevent dispute over the delivered quantity of DME, uniform practice of volumetric measurement
and consequent calculation methods is called for.
Since detailed requirements on installation, calibration and verification of level gauges and thermometers
are standardized in their own respective International Standards, this International Standard focuses
on the practice of custody transfer and subsequent calculation of DME.
© ISO 2012 – All rights reserved v
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INTERNATIONAL STANDARD ISO 16384:2012(E)
Refrigerated hydrocarbon and non-petroleum based
liquefied gaseous fuels — Dimethylether (DME) —
Measurement and calculation on board ships
This International Standard provides guidance on the practices for custody transfer of dimethylether
(DME) on board ships, at both the loading and the discharging ports. It covers such aspects of volumetric
calculation on board as measurement of liquid volume, vapour volume, temperature and pressure; and
accounting for the total quantity of DME on board before and after loading/discharging, regardless of
the type of ship’s tank.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
pressure in excess of a perfect vacuum, equal to the algebraic sum of atmospheric pressure and
automatic tank gauge
instrument that continuously measures liquid height (dip or ullage) in storage tanks
[ISO 18132-1:2011, definition 2.1.1 and ISO 18132-3:2011, definition 2.1.1]
NOTE 1 An automatic tank gauge usually includes a level sensor, a gauge head and associated mounting
hardware, and in some cases local display.
NOTE 2 Automatic tank gauges are also known as automatic level gauges (ALGs).
ATG that uses a float to detect the liquid level
[ISO 18132-1:2011, definition 2.1.5 and ISO 18132-3:2011, definition 2.1.4]
NOTE The float is guided by a tape or wire that is connected to a drum or a ratchet in the gauge head, where
the level measured is displayed locally and/or remotely.
ATG that measures the liquid level by magnetic reed switches with a float sensor including magnets, or
by magneto-strictive principle
[ISO 18132-3:2011, definition 2.1.7]
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ATG that utilizes an antenna to transmit electromagnetic continuous waves toward the liquid in a tank,
and to receive electromagnetic waves which are reflected at the surface of the liquid
[ISO 18132-1:2011, definition 2.1.7 and ISO 18132-3:2011, definition 2.1.8]
measurement of liquid level, liquid and vapour temperature, and vapour pressure of the DME to be
delivered to/from a tank, by which volume and other data are determined as the basis of payment or the
assessment of duty
closing custody transfer
custody transfer implemented after loading or discharging cargo from the tank(s)
opening custody transfer
custody transfer implemented before loading or discharging cargo from the tank(s)
amount of cargo retained in a cargo tank prior to loading or after discharge
[ISO 10976:2012, definition 3.1.16]
saturated vapour pressure
pressure exerted by the vapour above the liquid in equilibrium at a given temperature
3 Characteristics and properties of DME
DME has the following typical characteristics and properties (see ISO 29945), in consideration of which,
safety precautions should be taken.
3.2 General characteristics
DME has the following general characteristics, which should be considered with respect to personal
b) relatively small temperature coefficient of volume expansion;
c) acts as an effective solvent of many materials;
3.3 Chemical and physical properties
DME has the following general chemical and physical characteristics:
a) boiling point: −25,1 °C at atmospheric pressure;
b) saturated vapour pressure: 0,61 MPa at 25 °C;
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c) explosive range: 3,4 volume % to 27,0 volume %;
d) relative gas density: 1,59 relative to air;
e) liquid density: 677 kg/m at 15 °C.
4 General precautions
Nothing contained in this International Standard is intended to supersede any regulatory requirements
or recommended operating practices issued by organizations such as the International Maritime
Organization (IMO), International Chamber of Shipping (ICS), Oil Companies International Marine
Forum (OCIMF), International Association of Classification Societies (IACS) and individual operating
companies, nor is this International Standard intended to conflict with any safety or environmental
considerations, local regulations, or the specific provisions of any contract.
4.2 Equipment precautions
4.2.1 Accuracy inspection and verification of gauges
Level gauges, temperature measuring equipment and pressure gauges to be used for custody transfer
shall be subject to accuracy inspection at the time of installation on board and at subsequent periodic
inspections as required by regulation and/or the sales contract.
Certificates of these accuracy verifications shall document the inaccuracies of gauges and provide
statements with regard to their operational condition and suitability for use. They shall be dated and
indicate the person and company performing the verification. The most current cert