ISO 29945:2016

INTERNATIONAL ISO
STANDARD 29945
Second edition
2016-11-15
Refrigerated non-petroleum
based liquefied gaseous fuels —
Dimethylether (DME) — Method of
manual sampling onshore terminals
Combustibles gazeux non pétroliers liquéfiés réfrigérés —
Diméthyléther (DME) — Méthode d’échantillonnage manuel sur des
terminaux à terre
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Chemical and physical properties of DME . 2
4.1 General characteristics . 2
4.2 Chemical and physical properties . 2
5 Precautions . 2
5.1 General . 2
5.2 Safety precautions . 2
5.3 General precautions for sample cylinders . 3
5.4 Sampling point . 3
6 Sampling system . 3
6.1 Apparatus used for sampling . 3
6.2 Materials and structure of sampling line and sample cylinders . 5
6.2.1 General. 5
6.2.2 Sampling line . 5
6.2.3 Sample cylinder . 5
7 Sampling . 6
7.1 Terminal in a loading port . 6
7.2 Terminal in an unloading port . 6
8 Preparation for sampling . 6
8.1 Visual inspection of sampling line and sample cylinder . 6
8.2 Connection of the apparatus . 6
8.3 Purging the sampling line and sample cylinder . 6
9 Sampling procedure . 7
9.1 General . 7
9.2 Two-valve sample cylinder with or without ullage tube . 7
9.3 Single-valve sample cylinder. 7
9.4 Two-valve sample cylinder with a siphon tube . 7
10 Adjustment of sample volume . 8
10.1 Two-valve sample cylinder without ullage tube . 8
10.2 Two-valve sample cylinder with ullage tube . 8
10.3 Single-valve sample cylinder. 8
10.4 Two-valve sample cylinder with a siphon tube . 8
11 Checking for leakage . 9
12 Number of samples . 9
13 Identification of sample cylinder . 9
14 Retention of samples .10
Bibliography .11
Foreword
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
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electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 28, Petroleum products and related products
of synthetic or biological origin, Subcommittee SC 5, Measurement of refrigerated hydrocarbon and non-
petroleum based liquefied gaseous fuels.
This second edition cancels and replaces the first edition (ISO 29945:2009), which has been technically
revised.
iv © ISO 2016 – All rights reserved

Introduction
Measures for environmental protection are required on a global scale. In this context, 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. The 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, especially bulk transportation by sea, DME is liquefied by either refrigeration
or pressurization and transported using ocean-going DME tankers and/or LPG tankers. To detect
qualitative deterioration of the DME that can take place during transportation or storage, the
establishment of an International Standard, agreed to by all concerned nations and parties, is required.
This document specifies a method of manual sampling of DME liquefied by refrigeration for analysis to
define and/or confirm adherence to contractual specifications.
INTERNATIONAL STANDARD ISO 29945:2016(E)
Refrigerated non-petroleum based liquefied gaseous
fuels — Dimethylether (DME) — Method of manual
sampling onshore terminals
1 Scope
This document specifies a manual sampling method for refrigerated liquefied DME at terminals in both
loading and unloading ports along with precautions.
This document does not include recommendations for the location of a sampling point in a line or vessel.
This document is also applicable to the following cases, with necessary modifications:
— sampling of DME on board liquefied gas tankers where appropriate sampling apparatus is provided;
— sampling of other refrigerated, non-petroleum-based, liquefied gaseous fuels whose chemical and
physical properties are similar to those of DME.
The detailed chemical and physical properties of DME differ from those of LPG, which suggests that
DME requires precautions different from those of LPG. However, their basic properties are similar to
each other and so general reference is made in this document to precautions for LPG that have been
applied in many countries. Reference can also be made to the appropriate individual items in this
document for precautions concerning the quality.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
sampling line
line used to connect a sample probe (3.2) and a sample cylinder
3.2
sample probe
device inserted into gas or liquid to be sampled from the transfer line or fitted to the transfer line for
collecting a sample
[SOURCE: ISO 1988-6:2000, 6.40.104]
3.3
ullage tube
outage tube
tube fitted in a sample cylinder in order to easily adjust volume of the DME vapour
4 Chemical and physical properties of DME
4.1 General characteristics
DME has the following general characteristics, which should be considered with respect to personal
safety precautions.
a) It is non-corrosive.
b) It has a relatively small coefficient of thermal expansion.
c) It acts as an effective solvent for many materials.
d) It is hydrophilic.
4.2 Chemical and physical properties
DME has the following general chemical and physical properties:
a) boiling point (at atmospheric pressure) −25,1 °C;
b) saturated vapour pressure (at 25 °C) 0,61 MPa;
c) explosive range 3,4 % to 27,0 % volume fraction;
d) gas density (relative to air) 1,59;
e) liquid density (at 20 °C) 670 kg/m ;
f) chemical structure (CH ) O;
3 2
−1
g) molecular weight 46,07 g mol ;
h) auto ignition temperature 350 °C.
5 Precautions
5.1 General
Clause 5 introduces
...