ISO 23219:2026

• Abstract:

  This document specifies a text file format − XML file format − for reporting natural gas analysis results and other data relevant to natural gas, natural gas substitutes and other combustible gaseous fuels. The file name is applicable when it includes the extension of .XML (case insensitive). The XML file format is useful for output from, for example, ISO 6974-1 for composition, ISO 19739 for sulfur compounds and ISO 6974-2 for uncertainty, as input for ISO 6976 for properties calculation or ISO 10723 for performance evaluation. Typically, these are the gas composition as provided on an analysis certificate. The format can also be used for the results of properties calculation or a performance evaluation that can be read into a spreadsheet editor or data processing.

• Status: Published
• Publication Date: 20-Oct-2026
• ICS: 35.240.50 - IT applications in industry
• ICS: 75.060 - Natural gas
• Technical Committee: ISO/TC 193 - Natural gas
• Drafting Committee: ISO/TC 193 - Natural gas
• Current Stage: 6060 - International Standard published
• Start Date: 21-Oct-2026
• Completion Date: 21-Oct-2026

• Revises: ISO 23219:2022 - Natural gas — Format for data from gas chromatograph analysers for natural gas — XML file format
• Effective Date: 08-Jul-2023

ISO 23219:2026 is an ISO standard for an XML file format used to report natural gas analysis results and related data from gas chromatograph analysers. It gives a common structure for gas composition, sulfur compounds, uncertainty, and calculated properties so the data can move between analyser output, properties calculations, performance evaluation, and spreadsheet or data-processing tools.

What does ISO 23219:2026 specify?

ISO 23219:2026 specifies a text file format in XML for data about natural gas, natural gas substitutes, and other combustible gaseous fuels. The file name applies when it uses the .XML extension, case insensitive.

The document is organized into a scope, normative references, basic instructions, general comments on keywords and units, and three annexes.

Annex	What it covers
Annex A	Normative XML tags, schema example, and the structure of <measurements> and <properties>
Annex B	Informative software and code examples for XML file processing
Annex C	Informative International Chemical Identifier (InChI) values for natural gas components

In practice, the standard is meant to make gas chromatograph data easier to exchange between the instrument, calculation software, and downstream users. It is especially relevant where the same data may be used for composition reporting, sulfur compound analysis, properties calculation, or analyser performance evaluation.

What are the key requirements of ISO 23219:2026?

ISO 23219:2026 defines how the XML file is structured, how values are written, and how key gas-analysis data are identified. The main rules are in Clause 4 and Clause 5, with the detailed tag structure in Annex A.

XML structure and tag rules

Clause 4 says XML is hierarchical and uses opening and closing tags. Element names shall be lowercase, and multiword names shall use underscores, such as <retention_time>.

Clause 4.3 and 4.5 say tags shall not contain attributes, and the schema in Annex A defines the permitted structure. For implementers, this means the file needs a predictable layout that parsing software can validate without relying on tag attributes or case variants.

Dates, numbers, and units

Clause 4.6 requires <date_time> to follow ISO 8601-1. Clause 4.7 requires decimal numeric values with a period as the decimal separator, no digit grouping, and E-notation where needed. Clause 4.8 requires units without spaces and with either a solidus or exponent style, and unit case is significant.

For daily use, this means data must be written in a machine-readable form that avoids ambiguity between regional number formats or inconsistent unit spelling. Clause 5.3 adds that volume-based units must include reference conditions, and for sulfur compound analyses those conditions must align with the related ISO practice, including 101,325 kPa and 273,15 K for a dry, real gas.

Measurements, components, and properties

Clause 4.9 and Annex A place component data in <peak> blocks. Each peak can carry component identification, amount, retention time, peak height, peak area, and optional component parameters.

Clause 4.10 requires component names to use InChI (International Chemical Identifier). Annex C gives commonly used natural gas components and their InChI values. In practice, this reduces naming ambiguity across software, laboratories, and reports.

Clause 4.11 separates calculated bulk properties into a <properties> block, with each property in its own <property> block. Annex A also lists example property names and units, including property sets linked to ISO 6976 and ISO 20765-2.

Uncertainty, correlation, and checksum

Clause 5.5 says every measurement should have an associated uncertainty, and the uncertainty shall be given as an absolute value in the same units as the measurement. It also requires a coverage factor, and allows a distribution description.

Clause 5.6 and Annex A provide a <correlation_coefficients> block for correlated amount fractions. This matters when normalized compositions are reported, because the fractions sum to unity and are not independent.

Clause 4.13 requires a checksum at the end of the file as an XML comment. It is a confidence check against file corruption, not a security feature.

What terms does ISO 23219:2026 use?

ISO 23219:2026 uses a small set of recurring terms that matter for reading or producing the file.

• XML - A hierarchical text markup format used here to store gas analysis data in tagged elements.
• InChI - The International Chemical Identifier used to name components unambiguously and in a non-proprietary way.
• Checksum - A short end-of-file value used to check whether the XML text has been altered or corrupted.
• Normalized - A description of amount fractions that sum to unity.
• Coverage factor - The factor used with uncertainty values to express the intended confidence interval.
• Correlation coefficients - Values used to describe how amount fractions vary together in normalized compositions.
• Properties - Calculated bulk results derived from the measurement data, such as calorific value, density, or Wobbe index.
• Peak - The XML block used to hold one chromatographic peak and its associated component and amount data.

Who uses ISO 23219:2026?

ISO 23219:2026 is used by laboratories and operators that produce gas chromatography results for natural gas and related fuels. It is also relevant to analyser suppliers and software developers who need to export or import consistent XML data.

Quality managers, buyers, and technical reviewers use it when they need data that can be exchanged between certificates, calculation software, and evaluation tools without rekeying. The introduction also points to its use where different analysers should report comparable data in a uniform format.

The standard is particularly useful for:

• gas composition reporting
• sulfur compound analysis
• properties calculation
• analyser performance evaluation
• reading data into spreadsheet editors or data-processing tools

What changed in ISO 23219:2026 from the previous edition?

ISO 23219:2026 is the second edition and cancels and replaces ISO 23219:2022. The foreword says it has been technically revised.

The stated changes are:

• XML tags for sulfur compound determination by gas chromatography were added to the text and Annex A.
• Annex B, Annex C, and Annex D were removed and converted into an XML file in the ISO Maintenance Portal in electronic format.
• An example of a gas certificate for sulfur compound analysis and an example of sulfur compound analysis were added to the ISO Maintenance Portal in electronic format.
• Annex B was updated to reflect the added sulfur compound XML tags.
• Information on InChI for several sulfur compounds was added to Annex C.

Which standards are used with ISO 23219:2026?

ISO 23219:2026 cites ISO 8601-1 as a normative reference for date and time representation. It is the direct basis for the <date_time> format in Clause 4.6.

The document also names related standards and guides that provide the analytical context:

• ISO 6974-1 - composition and associated uncertainty by gas chromatography
• ISO 19739 - determination of sulfur compounds using gas chromatography
• ISO 6974-2 - uncertainty calculations for composition results
• ISO 6976 - calculation of calorific values, density, relative density, and Wobbe indices from composition
• ISO 10723 - performance evaluation for analytical systems
• ISO 20765-2 - thermodynamic properties for single-phase natural gas
• ISO/IEC Guide 98-3 - guidance for expressing measurement uncertainty

These references show how the XML file can carry the output of composition work, sulfur analysis, uncertainty calculations, and property calculations in a form that other standards can use.

What does the ISO 23219:2026 document contain?

Annex A contains the core XML schema and the tag descriptions for the root element, measurements, component data, uncertainty, correlation coefficients, and calculated properties. It also includes example names and units for component parameters and property values.

The annex provides the structure needed for implementation and validation, so software can read or write files in the same way. Clause 4 adds the writing rules for tags, numbers, units, date and time, and checksums.

Annex B gives example software approaches for XML file processing, including standalone code and Excel VBA examples. These are practical aids for reading data into spreadsheets or extracting values from XML files.

Annex C gives a table of InChI values for common natural gas components and several sulfur compounds. That table supports consistent component naming in certificates, software, and calculations.

International
Standard
ISO 23219
Second edition
Natural gas — Format for data from
2026-10
gas chromatograph analysers for
natural gas — XML file format
Gaz naturel — Format pour les données des analyseurs de
chromatographie en phase gazeuse pour le gaz naturel —
Format de fichier XML
Reference number
© ISO 2026
All rights reserved.
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued by ISO,
an ISO member body, or an authorized third-party distributor.
Except as required for implementation or expressly permitted by a separate licence, no part of this ISO publication may be
reproduced, distributed, modified, used, or made available in any form or by any means – electronic or mechanical, including
photocopying, scanning, recording, or posting on internal or external digital platforms.
Any use beyond the scope of the granted rights is prohibited and may result in legal action.
ISO copyright office
CP 401 • CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Basic instructions . 1
4.1 Syntax .1
4.2 Element names.1
4.3 Attributes .2
4.4 Element data .2
4.5 Schema .2
4.6 Date and time .2
4.7 Numeric datatype .2
4.8 Units .3
4.9 Component data .3
4.10 Components names .3
4.11 Properties .3
4.12 Example keywords .3
4.13 Checksum .3
4.14 Software .3
5 General comments to keywords and units . 3
Annex A (normative) XML tags . 5
Annex B (informative) Software suitable for XML file processing .16
Annex C (informative) International Chemical Identifier (InChI) .20
Bibliography .22

iii
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 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 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO /TC 193, Natural gas.
This second edition cancels and replaces the first edition (ISO 23219:2022), which has been technically
revised.
The main changes are as follows:
— XML tags for the determination of sulfur compounds by gas chromatography have been added to the text
and Annex A;
— Annex B, Annex C and Annex D have been removed and converted into an XML file in the ISO Maintenance
Portal in electronic format;
— “Example of a gas certificate for sulfur compound analysis” and “Example of sulfur compound analysis”
have been added to the ISO Maintenance Portal in electronic format;
— Annex B has been updated based on the addition of XML tags for sulfur compound analysis;
— information on InChI for several sulfur compounds has been added to Annex C.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
There are multiple suppliers of analysers for the measurement of natural gas composition and sulfur
compounds. If correctly set up, there is no reason to prefer any one in particular, since they give comparable
results. However, this gives rise to a variety of methods of reporting data, which can create confusion over
the use of such data for offline calculation of properties or evaluation of analyser performance.
Therefore, a uniform method of data presentation, independent of the source of the analyser, as presented in
this document is considered valuable.

v
International Standard ISO 23219:2026(en)
Natural gas — Format for data from gas chromatograph
analysers for natural gas — XML file format
1 Scope
This document specifies a text file format − XML file format − for reporting natural gas analysis results and
other data relevant to natural gas, natural gas substitutes and other combustible gaseous fuels. The file
name is applicable when it includes the extension of .XML (case insensitive).
The XML file format is useful for output from, for example, ISO 6974-1 for composition, ISO 19739 for sulfur
compounds and ISO 6974-2 for uncertainty, as input for ISO 6976 for properties calculation or ISO 10723 for
performance evaluation. Typically, these are the gas composition as provided on an analysis certificate. The
format can also be used for the results of properties calculation or a performance evaluation that can be
read into a spreadsheet editor or data processing.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 8601-1, Date and time — Representations for information interchange — Part 1: Basic rules
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org
4 Basic instructions
4.1 Syntax
XML is composed of a hierarchical structure of elements which contain text data.
Elements are defined by an opening tag which comprises the element name enclosed in angular bracket, e.g.
and a closing tag with / in front of the element name, e.g. .
4.2 Element names
Element names shall be lowercase (including inchi, which is usually written as InChI).
Any multiple word element names shall be concatenated with underscore, e.g. .
In general, element names should be complete words, rather short forms or acronyms.

4.3 Attributes
Tags shall not contain attributes, i.e. do not use:


mg/m3
….


Instead, use:

391.043

mg/m3
….


4.4 Element data
The text content of elements, e.g. keywords, are case insensitive. Leading and trailing spaces are ignored.
4.5 Schema
The format of the XML file is defined in the schema given in Annex A.
The element names in the tags defined in the schema are case sensitive (they are all lowercase) and have no
leading or trailing spaces. The tags have no attributes, i.e. no name=”value” within the tag.
4.6 Date and time
Date and time are tagged and shall use the convention specified in ISO 8601-1, e.g. time>2018-07-10T13:59:00+01
This data may be used for:
— date and time of sample registration;
— date and time when the results were produced;
— date and time when the results were validated;
— date and time when the report was issued.
4.7 Numeric datatype
The numeric datatype decimal (type xs: decimal or xs: float/ xs: double) shall be chosen. Numbers shall not
contain spaces and shall use a period as the decimal separator; they shall not use grouping of digits, i.e. no

thousands separator (e.g. comma). E-notation shall be used for powers of 10, e.g. 34; 12,3; −3,4567; 5,6E3;
and 7,8E-2.
4.8 Units
Units shall use a single solidus or -exponent, e.g. MJ/m3 (see annexes), or MJ·m-3. Units shall not contain
spaces. Units should be considered case sensitive and case used e.g. to distinguish the International System
of Units prefixes of m (milli) and M (mega).
4.9 Component data
Component data shall be contained in blocks (see Annex A).
4.10 Components names
Component names shall use the InChI (International Chemical Identifier) used by the International Union
of Pure and Applied Chemistry (IUPAC). See Annex C for commonly used natural gas components. This is
unambiguous, reasonably concise, non-proprietary and, since the chemical formula is part of the InChI, it is
often clear what the component is. The alternative of using Chemical Abstracts Registry Number (CAS RN) is
not so understandable and is proprietary.
4.11 Properties
Properties shall be contained in a block, with each individual property in a separate
block. The property is identified with a keyword rather than by an XML tag (see Annex A).
4.12 Example keywords
Example keywords and units are given in Annex A.
In general, any keywords and units should be agreed between writing and reading applications.
Reading applications should ignore any keyword sections that are not relevant to their operation.
4.13 Checksum
The XML file shall have a checksum, e.g. CRC-16 check (hexadecimal) sum as displayed by ZIP programs,
at the end of the file as an XML comment, e.g. . This is not intended for security purposes,
merely as a confidence check that the file contents have not been corrupted.
4.14 Software
Software, capable of processing XML data to a spreadsheet editor and vice versa, is listed in Annex B.
5 General comments to keywords and units
5.1 Possible keywords and units are given in Annex A (see also example XML files on ISO Maintenance
Portal).
5.2 Example gas component names are specified in Annex C.
5.3 Amount units:
— The amount of substance may be expressed as a fraction or percentage with an appropriate multiple or
submultiple prefix.
— It should be indicated whether the amount fractions are normalised or non-normalised.

— Where volume-based concentration units (e.g. mg/m ) are used, the reference conditions for the volume
(i.e. pressure and temperature) and whether the volume amount includes the named component or not
shall be given in the units. When used for sulfur compound analyses, the reference conditions shall
be consistent with the corresponding ISO standards (ISO 19739), the normal reference conditions of
pressure, temperature and humidity (state of saturation) equal to 101,325 kPa and 273,15 K for a dry,
real gas.
NOTE Fraction or percent can be mole basis or mass basis.
5.4 For calorific value (CV), the following definitions should be used:
— gross CV is the same as superior CV and higher CV;
— net CV is the same as inferior CV and lower CV.
3 3
NOTE Common units for calorific value include MJ/m , kJ/mol, MJ/kg, Btu/ft .
Along with any physical properties, all necessary metadata should be included. For example, for ISO 6976,
this encompasses the metering and combustion temperatures, the pressure, and whether the properties are
real or ideal.
5.5 According to ISO/IEC Guide 98-3, every measurement should have an associated uncertainty.
Uncertainty shall be specified using the tag as an absolute value in the same units as the
measurement value (i.e. not as a relative percentage). The coverage factor for the uncertainty value shall
be specified using the tag. The form of the distribution may be specified using the
tag. If omitted, the distribution is assumed to be Normal (Gaussian).
5.6 For normalised compositions, the amount fractions shall sum to unity, hence there will always be
correlation between the amount fractions. The block is to allow for this.
NOTE See ISO 6976 for correlation matrix calculation.
5.7 Peak height and area have no need for units, only that the units should be consistent for that analyser
and analysis. Retention time units can be seconds or minutes.

Annex A
(normative)
XML tags
A.1 General
This annex provides descriptions of the elements of the XML file and includes an example of the XML schema.
These descriptions and examples are intended to assist in the implementation and validation of the XML
format.
The following example XML and CSV files are available for download at https:// standards .iso .org/ iso/ 23219/
ed -2/ en as optional adjuncts to this document:
— example of a gas certificate for composition analysis in machine readable format;
— example of composition analysis in machine readable format;
— example of gas composition and properties;
— example of a gas certificate for sulfur compound analysis in machine readable format;
— example of sulfur compound analysis.
A.2 Root element
The root element of the XML file is which contains the two main blocks, and
.
A.3
A.3.1
The measurements block contains all elements related to the analysis of a sample.
A.3.2
A.3.2.1
The parameters block contains elements used to describe the sample.
A.3.2.2
See 4.6.
A.3.2.3
Text description of cylinder number.
A.3.2.4
Text description of certificate number.

A.3.2.5
Text description of sample point.
A.3.2.6
Text description of sampling location.
A.3.3
A.3.3.1
The instrument block contains elements used to describe the instrument.
A.3.3.2
Text description of instrument type.
A.3.3.3
Text description of manufacturer.
A.3.3.4
Text description of serial_no.
A.3.3.5
Text description of id_no.
A.3.4
A.3.4.1
The method block contains elements used to describe the method used for the analysis.
A.3.4.2
Text description of the method name.
A.3.5
A.3.5.1
The peak blocks contain elements used to describe a peak in the chromatographic analysis, including
information about the component identification, quantitative results (the amounts) and chromatographic
information (retention time, peak area, etc.). A new peak block is used for each peak in the chromatogram.
A.3.5.2
A.3.5.2.1
The component block contains elements used to contain information about the identified component for the
chromatographic peak.
A.3.5.2.2
Text description of the component name.
A.3.5.2.3
a)
The parameters blocks contain elements used to further characterize the component. A new parameters
block is used for each property of the component. These component properties can be required for the
calculation of bulk properties of the sample.
b)
Text description of the property. Example names (and units) are provided in Table A.1.
Table A.1 — Example names and units
Names Units Remarks
molar_mass [kg/kmol]
boiling_point [K] (normal, at 101,325 kPa)
o
specific_gravity [–] (60/60 F relative density)
critical_temperature [K]
critical_pressure [MPa]
critical_volume [m /kmol]
critical_density [kg/m ]
acentric_factor [-]
Where the chemical formula of the component is needed for a calculation, this can be obtained from the
InChI element (see A.3.5.2.4).
c)
Numerical value of the property.
d)
Text description of the property units.
A.3.5.2.4
Text InChI descriptor of the component (see Annex C).
A.3.5.2.5
a)
The amount block contains elements used to contain the quantitative results of the analysis for the peak (the
amount of substance).
b)
Numerical value of the amount.
c)
1)
The units block contains elements used to describe the amount units.

2)
Text description of amount unit (see Clause 5).
3)
Text description of the basis of the units e.g. mole or mass can be required for amounts expressed as a
percentage.
4)
Text describing if amount fractions are normalised or non-normalised; can be true or false.
5)
i)
Optional block to describe the reference condition for volume-based units.
ii)
Numerical value of the reference pressure.
iii)
Text description of reference pressure units.
iv)
Numerical value of the reference temperature.
v)
Text description of reference temperature units.
d)
1)
The uncertainty block contains optional elements used to contain data for the component amount’s
uncertainty.
2)
Numerical value of the uncertainty.
3)
Numerical value, e.g. for a 95 % confidence interval of a normal distribution, the value is 1,96. This value
is often taken as 2.
4)
Text description of the distribution (see 5.5). If absent, assumed normal.
5)
Integer value. The number of measurements used in the calculation of .
6)
Integer value. Unique value for or .

A.3.5.3
Numerical value of the peak retention time.
A.3.5.4
Numerical value with arbitrary units (consistent throughout the file).
A.3.5.5
Numerical value with arbitrary units (consistent throughout the file).
A.3.6
A.3.6.1
Optional block to describe the correlation between amount fractions. See also 5.6. If absent, assumed to be
an identity matrix.
A.3.6.2
A.3.6.2.1
The element block contains values for each unique element in the correlation matrix.
A.3.6.2.2
Integer value. (Referenced by .)
A.3.6.2.3
Integer value. (Referenced by .)
A.3.6.2.4
Numerical value (in the range −1 to +1).
A.4
A.4.1
A.4.2
A.4.2.1
The method block contains elements related to a specific method used for properties calculation. Multiple
method blocks can be included if properties are calculated by different methods, e.g. ISO 6976 and ISO 20765.
A.4.2.2
Text description of the method used.

A.4.2.3
A.4.2.3.1
The parameters block contains elements for parameters that are relevant to the method. Examples are given
in A.4.2.3.2 to A.4.2.3.4.
A.4.2.3.2
Numerical value: <32 assumed oC, 32 to 100 assumed oF, >100 assumed K.
A.4.2.3.3
Numerical value: <32 assumed oC, 32 to 100 assumed oF, >100 assumed K.
A.4.2.3.4
Numerical value: >25 assumed kPa, <25 assumed psiA.
A.4.2.4
A.4.2.4.1
The property block contains elements describing the calculated property. Multiple property blocks can be
included.
A.4.2.4.2
Text description of the property. Example names (followed by possible units in [], and symbols) are given in
Table A.2.
Table A.2 — properties names and units
ISO 6976 properties Units Symbols
molar_mass [kg/kmol] M
gas_compression_factor [-] Z
volume_gross_calorific_value [MJ/m ] (Hv)
G
molar_gross_calorific_value [kJ/mol] (Hc)
G
mass_gross_calorific_value [MJ/kg] (Hm)
G
volume_net_calorific_value [MJ/m ] (Hv)
N
molar_net_calorific_value [kJ/mol] (Hc)
N
mass_net_calorific_value [MJ/kg] (Hm)
N
relative_density [-] G
gas_density [kg/m ] D
wobbe_index [MJ/m ] W
G
net_wobbe_index [MJ/m ] W
N
3 0
ideal_volume_gross_calorific_value [MJ/m ] (Hv)
G
3 0
ideal_volume_net_calorific_value [MJ/m ] (Hv)
N
ideal_relative_density [-] G
3 0
ideal_gas_density [kg/m ] D
3 0
ideal_wobbe_index [MJ/m ] W
G
3 0
ideal_net_wobbe_index [MJ/m ] W
N
ISO 20765-2 properties
temperature [K] T
pressure [MPa] p
molar_helmholtz_free_energy [kJ/kmol] a
second_virial_coefficient [m /kmol] B
molar_isobaric_heat_capacity [kJ/kmol·K] c
p
molar_isochoric_heat_capacity [kJ/kmol·K] c
v
isochoric_heat_capacity [kJ/kg·K] C
v
isobaric_heat_capacity [kJ/kg·K] C
p
molar_density [kmol/m ] d ρ
density [kg/m ] D
molar_gibbs_free_energy [kJ/kmol] g
gibbs_free_energy [kJ/kg] G
molar_enthalpy [kJ/kmol] h
enthalpy [kJ/kg] H
molar_entropy [kJ/kmol·K] s
entropy [kJ/kg·K] S
molar_internal_energy [kJ/kmol] u
internal_energy [kJ/kg] U
molar_volume [m /kmol] v
speed_of_sound [m/s] w
compression_factor [-] Z
isothermal_throttling_coefficient [m /kmol] ϕ

TTaabblle Ae A.2 2 ((ccoonnttiinnueuedd))
isentropic_exponent [-] κ
joule-thomson_coefficient [K/MPa] μ
viscosity [mPa·s] η
A.4.2.4.3
Numerical value of the property.
A.4.2.4.4
Text description of property units.
A.4.2.4.5
a)
The uncertainty block contains elements used to contain data for the property’s uncertainty.
b)
Numerical value, in the same units as the property value.
c)
Numerical value. If absent, one (1) is assumed, i.e. uncertainty is the standard deviation.
d)
Text description of the distribution. If absent, normal is assumed.
e)
Optional text description of the method used for the uncertainty calculation.
A.5 XML schema (ISO23219.XSD)
This clause contains an example schema for the content outlined in this annex.
It is permissible to add other tags that can be useful for a specific case, e.g. extra data not considered here,
images and pictures.