ISO/FDIS 14532

Natural gas — Vocabulary

ISO 14532:2014 establishes the terms, definitions, symbols, and abbreviations used in the field of natural gas. The terms and definitions have been reviewed and studied in order to cover all aspects of any particular term with input from other sources such as European Standards from CEN (The European Committee for Standardization), national standards, and existing definitions in the IGU Dictionary of the Gas Industry. The definitive intention of ISO 14532:2014 is to incorporate the reviewed definitions into the ISO/TC 193 source standards.

Gaz naturel — Vocabulaire

L'ISO 14532:2014 a pour objet de donner les définitions, symboles et abréviations utilisés dans le domaine du gaz naturel. Les termes et définitions ont été étudiés et revus de manière à couvrir toutes les acceptations particulières des termes provenant également d'autres sources telles que les normes européennes du CEN (Comité Européen de Normalisation), les normes nationales et les définitions existantes dans le dictionnaire U.I.I.G de l'industrie du gaz. L'intention définitive de ce document est d'intégrer les définitions révisées dans les normes source de l'ISO/TC 193.

General Information

• Status: Not Published
• ICS: 01.040.75 - Petroleum and related technologies (Vocabularies)
• ICS: 75.060 - Natural gas
• Technical Committee: ISO/TC 193 - Natural gas
• Drafting Committee: ISO/TC 193 - Natural gas
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 23-Apr-2026
• Completion Date: 23-Apr-2026

Relations

• Consolidates: FprEN ISO 14532 - Natural gas - Vocabulary (ISO/FDIS 14532:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO/IEC 30105-8:2022 - Information technology — IT Enabled Services-Business Process Outsourcing (ITES-BPO) lifecycle processes — Part 8: Continual performance improvement (CPI) of ITES-BPO
• Effective Date: 08-Jul-2023
• Revises: ISO 14532:2014 - Natural gas — Vocabulary
• Effective Date: 02-Jul-2022

Overview

ISO/FDIS 14532:2025, Natural gas - Vocabulary is an international standard developed by ISO Technical Committee 193. This standard establishes comprehensive terminology, including terms, definitions, symbols, and abbreviations, widely adopted across the field of natural gas. By integrating input from leading national and regional standards bodies, such as CEN (The European Committee for Standardization) and references like the IGU Dictionary of the Gas Industry, ISO/FDIS 14532:2025 ensures unified language and clear communication in natural gas industries.

The vocabulary forms a fundamental cornerstone for professionals, regulators, and organizations working in natural gas production, processing, transport, and end-use sectors. Clear definitions help enable compliance, technical accuracy, and effective cross-border collaboration.

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Key Topics

ISO/FDIS 14532:2025 organizes terminology essential for all facets of the natural gas sector, including:

• Comprehensive Definitions: Inclusion of terms related to natural gas, its substitutes, gas mixtures, and wet gas.
• Standardized Symbols & Abbreviations: Ensures consistency across documents and technical communications.
• Reviewed and Updated Terms: Aligns industry vocabulary with the latest advances, incorporating relevant definitions from ISO/TC 193 standards as well as deleting overly general or highly specialized terms to improve clarity.
• References to Source Standards: Highlights terms adopted from other international or regional standards, providing authoritative context for each definition.
• Alphabetized Presentation: Easy searching and referencing for users and stakeholders.
• Coverage of Analytical and Operational Terms: Includes definitions around gas composition, sampling, calibration, measurement, and analysis techniques, supporting quality control and precision.
• Inclusion of Evolving Concepts: Addresses renewable gas, biogas, biomethane, and unconventional gas terms, reflecting the transition to sustainable energy sources.

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Applications

The ISO/FDIS 14532:2025 vocabulary is vital across the entire natural gas industry, with practical benefits including:

• Technical Consistency: Harmonizes terminology among international companies, regulatory agencies, suppliers, and end users.
• Regulatory Compliance: Facilitates reference in national and international regulations, aiding uniform policy implementation and enforcement.
• Product and System Development: Supports engineers, designers, and manufacturers in the development and certification of equipment, appliances, and systems handling natural gas.
• Operational Efficiency: Enables clear communication for plant operators, gas analysts, and laboratory technicians, reducing misunderstandings and process errors.
• Training & Education: Provides an essential learning resource for technical training, professional development, and academic programs.
• Quality and Safety: Supports robust documentation of gas quality, composition, and related properties, which is key for safety and accurate energy accounting (e.g., calorific value, Wobbe index, methane number).

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Related Standards

ISO/FDIS 14532:2025 is referenced throughout the international standards landscape. Related standards that frequently utilize or complement its terminology include:

• ISO 13686 - Natural gas - Quality designation
• ISO 6974 series - Natural gas - Determination of composition
• ISO 20765-2 - Natural gas - Calculation of thermodynamic properties
• ISO 10715 - Natural gas - Sampling guidelines
• EN 16723-1 - Natural gas and biomethane for use in transport and biomethane for injection in the natural gas grid
• ISO/IEC Guide 98-3 & Guide 99 - Uncertainty of measurement; International vocabulary of metrology

By adhering to ISO/FDIS 14532:2025, organizations ensure precise terminology and support global best practices throughout the natural gas value chain-an essential step toward unified international communication, improved safety, and environmental responsibility.

Standards Content (Sample)

DRAFT
International
Standard
ISO/DIS 14532
ISO/TC 193
Natural gas — Vocabulary
Secretariat: NEN
Gaz naturel — Vocabulaire
Voting begins on:
2025-05-15
ICS: 75.060; 01.040.75
Voting terminates on:
2025-08-07
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 14532:2025(en)
DRAFT
ISO/DIS 14532:2025(en)
International
Standard
ISO/DIS 14532
ISO/TC 193
Natural gas — Vocabulary
Secretariat: NEN
Gaz naturel — Vocabulaire
Voting begins on:
ICS: 75.060; 01.040.75
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 14532:2025(en)
ii
ISO/DIS 14532:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Annex A (Normative) List of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 .19
Bibliography .21

iii
ISO/DIS 14532:2025(en)
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 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).
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 193, Natural gas.
This third edition cancels and replaces the second edition (ISO 14532:2014), which has been technically
revised.
The main changes are as follows:
— All general and well known terms that are not specific for natural gas and can be found in publicly
available sources have been deleted.
— All terms that are too specific to a certain topic in the field of natural gas have been deleted.
— Some definitions have been modified, generalized with the aim to avoid becoming too specific to a
certain topic in the field of natural gas.
— Relevant terms from all ISO/TC 193 standards published since 2014 have been added.
— All terms are listed in alphabetical order.
— The Annex containing the alphabetical index has been deleted.
— The Annex containing the indices, symbols and units has been deleted.
— An Annex containing a list of terms defined in ISO/IEC Guide 98-3:2008 Uncertainty of measurement
(GUM) or ISO/IEC Guide 99:2007 International vocabulary of metrology (VIM) has been added.
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
ISO/DIS 14532:2025(en)
Introduction
ISO/TC 193 Natural Gas has been established in May 1988, its current scope being:
— to standardize terminology, quality specifications, methods of measurement, sampling, analysis, and
testing including thermophysical property calculation and measurement, for
— natural gas
— natural gas substitutes
— mixtures of natural gas with other gaseous fuels (such as unconventional and renewable gases), and
— wet gas
in all its facets from production to delivery to all possible end users across national boundaries.
— to standardize methods of analysis of liquefied natural gas (LNG).
As the aim is to create a coherent body of standards which support each other with regard to their
definitions, common and unambiguous terms and definitions used throughout all International Standards is
the starting point for the understanding and application of every International Standard.
The definitive intention of this document is to incorporate the reviewed definitions into the ISO/TC 193
standards.
The presentation of this document has been arranged to facilitate its use as follows:
— All terms are listed in alphabetical order
— Notes are given under numerous definitions where it was deemed important to give informative guidance
for a given definition. The Notes are not considered a part of the definition.
The terms and definitions have been reviewed and studied in order to cover all aspects of any particular
term with input from other sources such as European Standards from CEN (The European Committee for
Standardization), standards from ASTM, national standards, and existing definitions in the IGU Dictionary
of the Gas Industry.
v
DRAFT International Standard ISO/DIS 14532:2025(en)
Natural gas — Vocabulary
1 Scope
This document establishes the terms and definitions, used in the field of natural gas, natural gas substitutes,
mixtures of natural gas with gaseous fuels (such as unconventional and renewable gases) and wet gas.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
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/
3.1
absorption
retention, by physical or chemical forces of gas molecules, dissolved substances, or liquids by the bulk of
solids or liquids with which they are in contact
Note 1 to entry: The process causes (or is accompanied by) a physical or chemical change, or both, in the sorbent
material.
EXAMPLE Retention of siloxanes by charcoal.
3.2
adsorption
retention, by physical or chemical forces of gas molecules, dissolved substances, or liquids by the surface of
solids or liquids with which they are in contact
EXAMPLE Retention of methane by carbon.
[SOURCE: ISO 10715:2022, 3.2]
3.3
amount of substance fraction
amount fraction
mole fraction
quotient of amount of substance of a component and total amount of substance in the mixture
[SOURCE: ISO 80000-9, 9.13, modified. Original definition: for substance X in a mixture, quotient of amount
of substance nX of X and total amount n of substance in the mixture: X = n /n]
x x
3.4
analysis function
analyte content expressed as a function of instrumental response
[SOURCE: ISO 6143:2001]
ISO/DIS 14532:2025(en)
3.5
assigned value
value attributed to a particular property of a proficiency test item
[SOURCE: ISO 6974-3:2018, 3.11]
3.6
availability (of a measuring system or instrument)
probability, at any time, that the measuring system, or a measuring instrument forming part of the measuring
system, is functioning according to specifications
[SOURCE: ISO 15112:2018, 3.4]
3.7
biogas
gas, comprising principally methane and carbon dioxide, obtained from the anaerobic digestion of biomass
[SOURCE: EN 16723-1:2016, 3.1]
3.8
biomass
biological material from living, or recently living organisms, typically this may be plants or plant-derived
materials
[SOURCE: EN 16723-1:2016, 3.2]
3.9
biomethane
gas comprising principally methane, obtained from either upgrading of biogas or methanation of bio-syngas
[SOURCE: EN 16723-1:2016, 3.3]
3.10
bracketing
establishment of a straight-line calibration function using two calibration points defining a range
Note 1 to entry: The range is established so that the content of a component is expected to lie between the contents of
the component in the calibration gas mixtures.
3.11
bridge component
component selected to allow the combination of results for components measured by different analytical
operations
[SOURCE: ISO 6974-1:2012, 3.18, modified – ‘Bridging’ between the words ‘combination’ and ‘of’ has been
deleted.]
3.12
bubble pressure
pressure at which an infinitesimal amount of vapour is in equilibrium with a bulk liquid for a specified
temperature
[SOURCE: ISO 20765-2:2015, 3.1]
3.13
bubble temperature
temperature at which an infinitesimal amount of vapour is in equilibrium with a bulk liquid for a specified
pressure
[SOURCE: ISO 20765-2:2015, 3.2]

ISO/DIS 14532:2025(en)
3.14
calculated methane number
MN
C
numerical rating index obtained by a calculation, indicating the knock resistance of a gaseous fuel, according
to ISO 17507-1
Note 1 to entry: This analytical estimate of a methane number is based on using volume fraction gaseous fuel
composition as input.
[SOURCE: ISO/DIS 17507-1:2024, 3.2]
3.15
calibration function
instrumental response expressed as a function of analyte content
[SOURCE: ISO/DIS 6143:2024, 3.4.1]
3.16
calibration gas mixture
gas mixture of known stability and homogeneity whose composition is well established for use in the
calibration or verification of a measuring instrument or the validation of a measurement
[SOURCE: ISO 7504:2015, 5.1]
3.17
calorific value
heating value
amount of heat which would be released by the complete combustion with oxygen of a specified quantity of
gas, in such a way that the pressure at which the reaction takes place remains constant, and all the products
of combustion are returned to the same specified temperature as that of the reactants
[SOURCE: ISO 13686:2013, 3.8]
3.18
chromatographic resolution
resolution column efficiency characteristic describing the degree of separation of two adjacent peaks in the
chromatogram
Note 1 to entry: The resolution is measured as twice the distance between the maximum of the named peaks, divided
by the sum of the intercepts on the baseline made by tangents drawn to the peaks at half the height.
3.19
coal based synthetic natural gas
gaseous mixture synthesized from coal, comprising primarily methane and hydrogen, but generally also
includes ethane and some non-combustible gases such as nitrogen and carbon dioxide
[SOURCE: ISO/TR 17910:2023, 3.18]
3.20
combustion reference conditions
specified temperature and pressure at which a fuel is notionally burned
3.21
component
chemical compound
3.22
compressed natural gas
CNG
natural gas that has been compressed after processing for storage and transportation purposes
Note 1 to entry: CNG is mainly used as a fuel for vehicles, typically compressed up to 20 000 kPa in the gaseous state.

ISO/DIS 14532:2025(en)
Note 2 to entry: Usually the maximum pressure for natural gas stored in a container is 25 000 kPa.
3.23
compression factor
compressibility factor
quotient of the volume of an amount of gas at a specified pressure and temperature, and the volume of the
same amount of ideal gas at the same pressure and temperature
3.24
condenser
apparatus used to transform the condensable fraction (consisting of water vapour and/or of the higher
hydrocarbons) of the vapour phase present in natural gas into a liquid phase by cooling
3.25
contaminant
constituent in very low levels, such as particulates, glycol, compressor oil, etc., that are assumed to be
intrusive
[SOURCE: ISO 10715:2022, 3.3, modified - At the end of the definition ’and not part of the gas to be sampled’
has been deleted.]
3.26
cricondenbar
maximum pressure at which two-phase separation can occur
[SOURCE: ISO 20765-2:2015, 3.3]
3.27
cricondentherm
maximum temperature at which two-phase separation can occur
[SOURCE: ISO 20765-2:2015, 3.4]
3.28
critical point
unique saturation point along the two-phase vapour-liquid equilibrium boundary where both the vapour
and liquid phases have the same composition and density
[SOURCE: ISO 20765-2:2015, 3.5]
3.29
custody transfer point
location between two pipeline systems where the quantity of energy of the natural gas has to be accounted for
Note 1 to entry: At such location a change of pressure regime can also occur.
3.30
density
quotient of the mass of a gas and its volume
3.31
density ratio (of a fluid)
quotient of gas density and a liquid density of a fluid at line conditions
[SOURCE: ISO 12748_2015, 2.6, modified - “Ratio” has been replaced by “quotient”.]
3.32
desorption
removal of a sorbed substance by the reverse process of adsorption or absorption
[SOURCE: ISO 10715:2022, 3.4, modified; Note 1 to entry was deleted.]

ISO/DIS 14532:2025(en)
3.33
dew pressure
pressure at which an infinitesimal amount of liquid is in equilibrium with a bulk vapour for a specified
temperature
[SOURCE: ISO 20765-2:2015, 3.6]
3.34
dew temperature
temperature at which an infinitesimal amount of liquid is in equilibrium with a bulk vapour for a specified
pressure
[SOURCE: ISO 20765-2:2015, 3.7]
3.35
direct measurement (of a component content)
measurement in which the content of individual components or group of components are determined by
comparison with the content of identical components in the reference gas mixture
3.36
direct sampling
sampling in situations where there is a direct connection between the natural gas to be sampled and the
analytical unit
[SOURCE: ISO 10715:2022,3.5 ISO/TR 7262:2022, 3.3]
3.37
dry gas
gas containing a mole fraction of water and/or hydrocarbons that are not expected to condense at pipeline
conditions
Note 1 to entry: The water content and/or hydrocarbons content for dry gas are mostly defined by users or
transporters.
Note 2 to entry: The correlation between water content and water dew point is given in ISO 18453.[17]
3.38
equation of state
EoS
mathematical relationship between state variables of a gas or homogeneous gas mixture
EXAMPLE For an ideal gas, the equation of state is the ideal gas law. More complicated equations of state have
been developed to model the behaviour of actual gases over a range of pressures and temperatures, e.g. Benedict,
Webb, Rubin (BWR equation), Redlich, Kwong and Soave (RKS equation) and the GERG 2008 equation.
3.39
family of gases
gas family
group of combustible gases with similar burning behaviour linked together by a range of Wobbe indices
3.40
fast loop
sampling system that takes more sample from the process than is needed to make the measurement so as to
reduce the residence time
3.41
flash back
situation where the flame velocity exceeds that of the air gas mixture, resulting with the combustion taking
place before the burning port
Note 1 to entry: It generally results in an extinction of the flame and can damage the burner of the appliance.

ISO/DIS 14532:2025(en)
3.42
floating piston cylinder
container that has a moving piston separating the sample from a buffer gas
3.43
flow-proportional incremental sampler
sampler that collects a series of spot samples over a period of time with the spot samples taken in such a
manner as to ensure the incremental sample is proportional to the incremental totalised flow
Note 1 to entry: This is normally achieved by varying the frequency of extraction of a constant volume spot sample (grab).
3.44
gas analysis
measurement methods and techniques for determining the gas composition
[SOURCE: ISO 13686:2013, 3.17, modified - “Use of test methods” has been replaced by “measurement”, and
“other” before “techniques” has been deleted.]
3.45
gas composition
fractions or concentrations of all the components in a mixture
3.46
gas hydrates
solid crystalline substance resembling ice formed by gas molecules and water molecules
3.47
gas quality
set of attributes of a gas that characterises important aspects of its production, transportation or use
Note 1 to entry: Examples of attributes include composition, calorific value, Wobbe index, methane number, relative
density and dew points.
3.48
gas sorption effect
physical process whereby some gases are adsorbed onto or desorbed from the surfaces of a solid without
transformation of the molecules
Note 1 to entry: Note to entry: The force of attraction between some gases and solids is purely physical and depends
on the nature of the participating material. Natural gas can contain several components that exhibit strong sorption
effects. Special care should be taken when determining trace concentrations such as heavy hydrocarbons, water,
sulfur compounds, mercury and hydrogen.
[SOURCE: ISO 10715:2022, 3.7]
3.49
gas to oil ratio
ratio of gas volume flow rate to hydrocarbon liquid volume flow rate
[SOURCE: ISO/TR 12748:2015, 2.21]
3.50
gaseous fuel
fuel gas
any gaseous material that can be oxidized with the intent to release energy
Note 1 to entry: Examples of gaseous fuels include, but are not limited to, natural gas, digester gas, landfill gas, process
gas, hydrogen gas and their liquefied forms such as liquefied petroleum gas or liquefied natural gas.

ISO/DIS 14532:2025(en)
3.51
gross calorific value
superior calorific value
higher heating value
calorific value when the combustion products are in the gaseous state, except for water, which is condensed
to the liquid state
3.52
group of components
set of components whose content is measured not individually, but for the group as a whole
3.53
hot loop
sampling configuration that returns the sample to the pipeline
Note 1 to entry: The loop requires a pressure differential from collection point to discharge so as to ensure a constant
and steady flowrate through the sampling equipment located in the loop.
3.54
hydrocarbon dew temperature
hydrocarbon dew point (HCDP)
temperature at which an infinitesimal amount of liquid hydrocarbons is in equilibrium with a bulk vapour
for a specified pressure
3.55
incremental sampler
sampler that accumulates a series of spot samples into one composite sample
[SOURCE: ISO 10715:2022, 3.10]
3.56
indirect measurement (of a component)
measurement in which individual components or groups of components are determined using relative
response factors to a reference component in the reference gas mixture
3.57
indirect sampling
sampling in situations where there is no direct connection between the natural gas to be sampled and the
analytical unit
[SOURCE: ISO 10715:2022, 3.11 ISO/TR 7262:2022, 3.2]
3.58
in-line instrument
instrument whose active element is installed inside the pipeline and makes measurements under pipeline
conditions
3.59
interchangeability
characteristic of gases where one gas is compatible with another gas with regard to combustion
Note 1 to entry: Two gases are said to be interchangeable when one gas can be substituted for the other gas without
interfering with the operation of gas-burning appliances or equipment.
3.60
interference
negative or positive effect upon the response of the measuring system, due to a component of the sample
that is not the analyte
[SOURCE: ISO 2612:2023, 3.7 modified: ”measurand” is replaced by “analyte”]

ISO/DIS 14532:2025(en)
3.61
interfering substance
substance present in the sample under investigation, other than the analyte, that affects the response
[SOURCE: ISO 2612:2023, 3.8]
3.62
laboratory bias
difference between the result from a particular laboratory and an accepted reference value
[SOURCE: ISO 6974-3:2018, 3.5, modified - “Expectation of the test” before “result” has
...

FINAL DRAFT
International
Standard
ISO/TC 193
Natural gas — Vocabulary
Secretariat: NEN
Gaz naturel — Vocabulaire
Voting begins on:
2026-04-23
Voting terminates on:
2026-06-18
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 193
Natural gas — Vocabulary
Secretariat: NEN
Gaz naturel — Vocabulaire
Voting begins on:
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to gas composition and properties .1
3.2 Terms related to sampling and measurement techniques .6
3.3 Terms related to analytical and calibration methods .8
3.4 Terms related to equipment and instrumentation .10
3.5 Terms related to thermodynamic and phase behaviour .10
3.6 Terms related to odorization and safety .11
3.7 Terms related to operational and process conditions . 12
3.8 Terms related to gas chromatography . 13
3.9 Miscellaneous terms .14
Annex A (informative) List of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 .16
Bibliography .18

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 193, Natural gas.
This third edition cancels and replaces the second edition (ISO 14532:2014), which has been technically
revised.
The main changes are as follows:
— All general and well-known terms that are not specific for natural gas and can be found in publicly
available sources have been deleted.
— All terms that are too specific to a certain topic in the field of natural gas have been deleted.
— Some definitions have been modified or generalized to avoid becoming too specific to a certain topic in
the field of natural gas.
— Relevant terms from all ISO/TC 193 documents published since 2014 have been added.
— The index has been deleted.
— The annex containing the indices, symbols and units has been deleted.
— An annex containing a list of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 has been added.
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
ISO/TC 193 Natural gas was established in May 1988. Its current scope is:
— to standardize terminology, quality specifications, methods of measurement, sampling, analysis and
testing, including thermophysical property calculation and measurement, from production to delivery
to all possible end users across national boundaries, for:
— natural gas;
— natural gas substitutes;
— mixtures of natural gas with other gaseous fuels (such as unconventional and renewable gases);
— wet gas.
— to standardize methods of analysis of liquefied natural gas (LNG).
The aim is to create a coherent body of standards which support each other with regard to their definitions.
Common and unambiguous terms and definitions are the starting point for understanding and applying
International Standards.
The intention of this document is to incorporate the reviewed terms and definitions into ISO/TC 193
standards.
The presentation of this document has been arranged to facilitate its use as follows:
— All terms are listed in alphabetical order.
— Notes are given under numerous definitions where it was deemed important to give informative guidance
for a given definition. The notes are not considered a part of the definition.
The terms and definitions have been reviewed and studied in order to cover all aspects of any particular
term with input from other sources such as European Standards from the European Committee for
Standardization (CEN), standards from ASTM International, national standards and existing definitions in
the International Gas Union (IGU) Dictionary of the Gas Industry.
Terms used in the field of gas analysis that are well defined by either ISO/IEC Guide 98-3 or ISO/IEC Guide 99
are included in Annex A.
v
FINAL DRAFT International Standard ISO/FDIS 14532:2026(en)
Natural gas — Vocabulary
1 Scope
This document establishes the terms and definitions that are used in the field of natural gas, natural gas
substitutes, mixtures of natural gas with gaseous fuels (such as unconventional and renewable gases) and
wet gas.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
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/
3.1 Terms related to gas composition and properties
3.1.1
amount of substance fraction
amount fraction
mole fraction
quotient of amount of substance of a component and total amount of substance in the mixture
[SOURCE: ISO 80000-9:2019, 9-13, modified — "For substance X in a mixture" has been deleted. Terms n
x
and X in "amount of substance n of X" and n in "total amount n" have been deleted. The formula x = n /n has
x x x
been deleted.]
3.1.2
biogas
gas, comprising principally methane and carbon dioxide, obtained from the anaerobic digestion of biomass
[SOURCE: EN 16723-1:2016, 3.1]
3.1.3
biomass
biological material from living or recently living organisms
Note 1 to entry: Typically, biomass comes from plants or plant-derived materials.
[SOURCE: EN 16723-1:2016, 3.2, modified — Note 1 to entry has been added; the content was taken from the
original term definition.]
3.1.4
biomethane
gas comprising principally methane, obtained from either upgrading of biogas or methanation of bio-syngas
[SOURCE: EN 16723-1:2016, 3.3]

3.1.5
calculated methane number
MN
C
numerical rating index obtained by a calculation, indicating the knock resistance of a gaseous fuel, according
to ISO 17507-1
Note 1 to entry: This analytical estimate of a methane number is based on using volume fraction gaseous fuel
composition as input.
3.1.6
calorific value
heating value
amount of heat released by the complete combustion with oxygen of a specified quantity of gas in such a way
that the pressure at which the reaction takes place remains constant and all the products of combustion are
returned to the same specified temperature as that of the reactants
3.1.7
combustion reference conditions
specified temperature and pressure at which a fuel is notionally burned
3.1.8
component
chemical compound
3.1.9
compression factor
compressibility factor
quotient of the volume of an amount of gas at a specified pressure and temperature and the volume of the
same amount of ideal gas at the same pressure and temperature
3.1.10
contaminant
constituent in very low levels, such as particulates, glycol, compressor oil, etc., that are assumed to be
intrusive
3.1.11
density
quotient of the mass of a gas and its volume
3.1.12
density ratio
quotient of the gas density and the liquid density of a fluid at line conditions
3.1.13
equation of state
EoS
mathematical relationship between state variables of a gas or homogeneous gas mixture
Note 1 to entry: For an ideal gas, the equation of state is the ideal gas law.
EXAMPLE Equations of state have been developed to model the behaviour of real gases over a range of pressures
and temperatures. See References [13] to [16].
3.1.14
gas analysis
measurement methods and techniques for determining gas composition
3.1.15
gas composition
fractions or concentrations of all the components in a mixture

3.1.16
gas hydrates
solid crystalline substance resembling ice formed by gas molecules and water molecules
3.1.17
gas quality
set of attributes of a gas that characterises important aspects of its production, transportation or use
EXAMPLE Composition, calorific value, Wobbe index, methane number, relative density and dew points.
3.1.18
gross calorific value
superior calorific value
gross heating value
higher heating value
calorific value when the combustion products are in the gaseous state, except for water, which is condensed
to the liquid state
3.1.19
hydrocarbon dew temperature
hydrocarbon dew point
HCDP
temperature at which an infinitesimal amount of liquid hydrocarbons is in equilibrium with a bulk vapour
for a specified pressure
3.1.20
interchangeability
characteristic of gases where one gas is compatible with another gas with regard to combustion
Note 1 to entry: Two gases are said to be interchangeable when one gas can be substituted for the other gas without
interfering with the operation of gas-burning appliances or equipment.
3.1.21
lean gas
natural gas having a relatively low energy content, close to or lower than that of pure methane
Note 1 to entry: Lean gas typically contains high amounts of nitrogen and carbon dioxide.
3.1.22
mass concentration
quotient of mass of a substance and volume of the mixture
[SOURCE: ISO 80000-9:2019, 9-10, modified — "For a substance X in a mixture" has been deleted. Terms for
mass m , substance X and volume V have been deleted. The formula γ=m /V has been deleted.]
x x
3.1.23
mass fraction
quotient of mass of a substance and total mass of the mixture
[SOURCE: ISO 80000-9:2019, 9-11, modified — “For substance X in a mixture” at the beginning of the
definition has been deleted. “m (ISO 80000-4)” after mass has been deleted. “X” after "substance" has been
X
deleted. “m” after "total mass" has been deleted. The formula after the definition has been deleted.]
3.1.24
metering reference conditions
specified temperature and pressure at which a volume of gas is expressed

3.1.25
methane number
MN
numerical rating indicating the knock resistance of a gaseous fuel
Note 1 to entry: The methane number is analogous to the octane number for petrol. The methane number is the volume
fraction expressed as the percentage of methane in a methane-hydrogen mixture, that in a test engine under standard
conditions has the same knock resistance as the gaseous fuel to be examined.
3.1.26
molar mass
quotient of mass and amount of substance
[SOURCE: ISO 80000-9:2019, 9-4, modified — "For a pure substance X" has been deleted. Terms for mass
m(X) and amount n have been deleted. The formula M=m/n has been deleted.]
3.1.27
molar volume
quotient of the volume of a substance and amount of substance
[SOURCE: ISO 80000-9:2019, 9-5 modified — "For a pure substance" has been deleted. Terms for volume V
and amount n have been deleted. The formula V =V/n has also been deleted.]
m
3.1.28
natural gas
NG
naturally occurring mixture of hydrocarbon and non-hydrocarbon gases found in porous geological
formations (reservoirs) beneath the earth’s surface
Note 1 to entry: Natural gas contains primarily methane, but generally includes ethane, propane and higher
hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide. Natural gas can also contain
components such as either sulfur compounds or other chemical species or both.
3.1.29
net calorific value
inferior calorific value
net heating value
lower heating calorific value when the combustion products are in the gaseous state
3.1.30
normal pressure
pressure at which appliances operate under nominal conditions when they are
supplied with the corresponding reference gas
3.1.31
normal reference conditions
conditions equal to 101,325 kPa for pressure and 273,15 K for temperature for a real gas in the dry state
3.1.32
other component
other constituent
component in the gas sample which either is not subject to analysis in accordance with the ISO 6974 series
or can be regarded as being present at a constant mole fraction or both
3.1.33
PKI methane number
MN
PKI
numerical rating index obtained by a calculation, indicating the knock resistance of a gaseous fuel, according
to ISO 17507-2
Note 1 to entry: This analytical estimate of a methane number is based on using mole fraction gaseous fuel composition
as input.
3.1.34
reference conditions
conditions of temperature, pressure and humidity (state of saturation) to be used for measurements and
calculations carried out on natural gases, natural gas substitutes and similar fluids in the gaseous state
3.1.35
relative density
quotient of the density of a gas and the density of dry air of standard composition at the same specified
conditions of pressure and temperature
3.1.36
relative humidity
quotient of the actual vapour pressure and the saturation vapour pressure over a plane liquid water surface
at the same temperature
Note 1 to entry: The phrase "relative humidity" is commonly abbreviated to RH although this is not a recognised
abbreviated term.
Note 2 to entry: Values of relative humidity are commonly expressed as a percentage.
3.1.37
rich gas
natural gas having a relatively high energy content, higher than that of pure methane
Note 1 to entry: Rich gas typically contains high amounts of ethane or propane or higher hydrocarbons.
3.1.38
standard reference conditions
conditions equal to 101,325 kPa for pressure and 288,15 K for temperature for a real gas in the dry state
3.1.39
substitute natural gas
SNG
manufactured or blended gas with properties which make it interchangeable with natural gas
Note 1 to entry: This also includes gases manufactured by thermal process from biomass.
3.1.40
volume fraction
φ
quotient of product of amount of substance fraction x and molar volume V of the pure substance X at
x mx
the same temperature and pressure, and the sum over all substances i of products of amount of substance
fractions x of substance i and their molar volumes V
i mi
xv
xmx
 
 xv
ii m
i
[SOURCE: ISO 80000-9:2019, 9-14 modified — "For substance X" at the beginning and "of X" after "substance
fraction" have been deleted. "Substance" after "over all" has been written in plural.]
3.1.41
water content
quantity of water contained in unit quantity of gas
Note 1 to entry: Water content can be expressed as a concentration or as a mole or volume fraction.
3.1.42
water dew temperature
water dew point
temperature at which an infinitesimal amount of liquid water is in equilibrium with a bulk vapour for a
specified pressure
3.1.43
wet gas
gas containing water or condensable components such as either water vapour or hydrocarbons, or both, in
such amounts that they can condense or are already condensed at pipeline conditions
3.1.44
Wobbe index
quotient of the calorific value on a volumetric basis at specified reference conditions and the square root of
the relative density at the same specified metering reference conditions
Note 1 to entry: The Wobbe Index is said to be gross or net according to whether the calorific value used is the gross or
net calorific value.
3.2 Terms related to sampling and measurement techniques
3.2.1
absorption
retention, by physical or chemical forces of gas molecules, dissolved substances or liquids, by the bulk of
solids or liquids with which they are in contact
Note 1 to entry: The absorption process causes (or is accompanied by) a physical or chemical change, or both, in the
sorbent material.
EXAMPLE Retention of siloxanes by charcoal.
3.2.2
adsorption
retention, by physical or chemical forces of gas molecules, dissolved substances or liquids, by the surface of
solids or liquids with which they are in contact
EXAMPLE Retention of methane by carbon.
3.2.3
desorption
removal of a sorbed substance by the reverse process of adsorption or absorption
3.2.4
direct measurement
measurement in which the content of individual components or group of
components is determined by comparison with the content of identical components in the reference gas
mixture
3.2.5
direct sampling
sampling in situations where there is a direct connection between the natural gas to be sampled and the
analytical unit
3.2.6
fast loop
sampling system that takes more sample from the process than is needed to make the measurement to
reduce the residence time
3.2.7
floating piston cylinder
container that has a moving piston separating the sample from a buffer gas

3.2.8
flow-proportional incremental sampler
sampler that collects a series of spot samples over a period of time with the spot samples taken in such a
manner as to ensure the incremental sample is proportional to the incremental totalised flow
Note 1 to entry: This is normally achieved by varying the frequency of extraction of a constant volume spot sample
(grab).
3.2.9
gas sorption effect
physical process whereby some gases are adsorbed onto or desorbed from the surfaces of a solid without
transformation of the molecules
Note 1 to entry: The force of attraction between some gases and solids is purely physical and depends on the nature of
the participating material. Natural gas can
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ISO /TC 193/WG 4
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Secretariat: NEN
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Date: 2026-01-2704-08
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Natural gas - — Vocabulary
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St l D fi iti
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
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or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
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at the address below or ISO’s member body in the country of the requester.
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ISO copyright office
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ii
Contents Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
Foreword . iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to gas composition and properties . 1
3.2 Terms related to sampling and measurement techniques . 6
3.3 Terms related to analytical and calibration methods . 9
3.4 Terms related to equipment and instrumentation . 11
3.5 Terms related to thermodynamic and phase behaviour . 11
3.6 Terms related to odorization and safety . 12
3.7 Terms related to operational and process conditions . 13
3.8 Terms related to gas chromatography . 14
3.9 Miscellaneous terms . 15
Annex A (informative) List of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 . 18
Bibliography . 20

Foreword . 3
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
3.1 Terms related to gas composition and properties . 6
3.2 Terms related to sampling and measurement techniques . 11
3.3 Terms related to analytical and calibration methods . 14
3.4 Terms related to equipment and instrumentation . 16
3.5 Terms related to thermodynamic and phase behaviour . 16
3.6 Terms related to odorization and safety . 17
3.7 Terms related to operational and process conditions . 18
3.8 Terms related to gas chromatography . 19
3.9 Miscellaneous terms not categorized . 20
Annex A (normative) List of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 . 23
Bibliography . 25

iii
Foreword Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
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).
Formatted: English (United Kingdom)
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.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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee 193, Natural gas.
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
This third edition cancels and replaces the second edition (ISO 14532:2014), which has been technically
Formatted: Default Paragraph Font
revised.
Formatted: Default Paragraph Font
The main changes are as follows:
Formatted: Default Paragraph Font
— All general and well-known terms that are not specific for natural gas and can be found in publicly Formatted: No bullets or numbering
available sources have been deleted.
— All terms that are too specific to a certain topic in the field of natural gas have been deleted.
— Some definitions have been modified or generalized to avoid becoming too specific to a certain topic
in the field of natural gas.
— Relevant terms from all ISO/TC 193 documents published since 2014 have been added.
Formatted: Default Paragraph Font
— The index has been deleted.
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
— The annex containing the indices, symbols and units has been deleted.
Formatted: Default Paragraph Font
— An annex containing a list of terms defined in ISO/IEC Guide 98-3 and ISO/IEC Guide 99 has been
Formatted: Default Paragraph Font
added.
Formatted: Default Paragraph Font
Formatted: Default Paragraph Font
iv
Any feedback or questions on this document should be directed to the user’s national standards body. A
Formatted: Adjust space between Latin and Asian text,
complete listing of these bodies can be found at www.iso.org/members.htmlwww.iso.org/members.html. Adjust space between Asian text and numbers
v
Introduction
ISO/TC 193 Natural gas was established in May 1988. Its current scope is:
— — to standardize terminology, quality specifications, methods of measurement, sampling, analysis and
testing, including thermophysical property calculation and measurement, from production to delivery to
all possible end users across national boundaries, for:
— — natural gas;
— — natural gas substitutes;
— — mixtures of natural gas with other gaseous fuels (such as unconventional and renewable
gases);
— — wet gas.
— — to standardize methods of analysis of liquefied natural gas (LNG).
The aim is to create a coherent body of standards which support each other with regard to their definitions.
Formatted: Adjust space between Latin and Asian text,
Common and unambiguous terms and definitions are the starting point for understanding and applying Adjust space between Asian text and numbers
International StandardStandards.
The intention of this document is to incorporate the reviewed terms and definitions into ISO/TC 193
standards.
The presentation of this document has been arranged to facilitate its use as follows:
— — All terms are listed in alphabetical order.
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
— — Notes are given under numerous definitions where it was deemed important to give informative
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
guidance for a given definition. The Notesnotes are not considered a part of the definition.
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
The terms and definitions have been reviewed and studied in order to cover all aspects of any particular term
Formatted: Adjust space between Latin and Asian text,
with input from other sources such as European Standards from the European Committee for Standardization Adjust space between Asian text and numbers
(CEN), standards from ASTM International, national standards and existing definitions in the International
Gas Union (IGU) Dictionary of the Gas Industry.

vi
Terms used in the field of gas analysis that are well defined by either ISO/IEC Guide 98-3 or ISO/IEC Guide 99
are included in Annex A.
vii
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Natural gas – — Vocabulary
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between Asian text and numbers
1 Scope
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This document establishes the terms and definitions that are used in the field of natural gas, natural gas
1.27 cm, Footer distance from edge: 0.5 cm
substitutes, mixtures of natural gas with gaseous fuels (such as unconventional and renewable gases) and wet
gas. Formatted: Adjust space between Latin and Asian text,
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2 Normative references
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There are no normative references in this document.
Formatted
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3 Terms and definitions
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ISO and IEC maintain terminology databases for use in standardization at the following addresses:
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— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
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— — IEC Electropedia: available at https://www.electropedia.org/  https://www.electropedia.org/
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Terms used in the field of gas analysis that are well defined by either ISO/IEC Guide 98-3 or ISO/IEC
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Guide 99 are included in Annex A.
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3.1 Terms related to gas composition and properties
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3.1.1 3.1.1
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amount of substance fraction
amount fraction
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mole fraction
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quotient of amount of substance of a component and total amount of substance in the mixture
Formatted: Font: Not Italic
[SOURCE: ISO 80000-9:2019, 9-13, modified — ”for"For substance X in a mixture”" has been removeddeleted.
Formatted: Font: Not Italic
Terms n and X in ”"amount of substance n of X”" and n in ”"total amount n” and the" have been deleted. The
x x
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formula x = n /n have alsohas been removeddeleted.]
x x
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3.1.2 3.1.2
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biogas
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gas, comprising principally methane and carbon dioxide, obtained from the anaerobic digestion of biomass
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[SOURCE: EN 16723-1:2016, 3.1]
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3.1.3 3.1.3
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biomass
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biological material from living, or recently living organisms,
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Note 1 to entry: Typically, biomass comes from plants or plant-derived materials.
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[SOURCE: EN 16723-1:2016, 3.2, modified — Note 1 to entry has been added; the content was taken from the
original term definition.]
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3.1.4 3.1.4
biomethane Formatted
...
gas comprising principally methane, obtained from either upgrading of biogas or methanation of bio-syngas
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ISO #####-#:####(X/FDIS 14532:2026(en)
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[SOURCE: EN 16723-1:2016, 3.3]
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3.1.5 3.1.5
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calculated methane number
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MN
C
numerical rating index obtained by a calculation, indicating the knock resistance of a gaseous fuel, according Formatted: Default Paragraph Font
to ISO 17507-1
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Note 1 to entry: This analytical estimate of a methane number is based on using volume fraction
gaseous fuel composition as input.
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3.1.6 3.1.6
calorific value
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heating value
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amount of heat released by the complete combustion with oxygen of a specified quantity of gas, in such a way
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
that the pressure at which the reaction takes place remains constant, and all the products of combustion are
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
returned to the same specified temperature as that of the reactants
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and Asian text, Adjust space between Asian text and
3.1.7 3.1.7
numbers
combustion reference conditions
specified temperature and pressure at which a fuel is notionally burned
3.1.8 3.1.8
component
chemical compound
3.1.9 3.1.9
compression factor
compressibility factor
quotient of the volume of an amount of gas at a specified pressure and temperature, and the volume of the
same amount of ideal gas at the same pressure and temperature
3.1.10 3.1.10
contaminant
constituent in very low levels, such as particulates, glycol, compressor oil, etc., that are assumed to be intrusive
3.1.11 3.1.11
density
quotient of the mass of a gas and its volume
3.1.12 3.1.12
density ratio
< of a fluid> quotient of the gas density and the liquid density of a fluid at line conditions
3.1.13 3.1.13
equation of state
EoS
Formatted: Note
mathematical relationship between state variables of a gas or homogeneous gas mixture
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and Asian text, Adjust space between Asian text and
Note 1 to entry:  For an ideal gas, the equation of state is the ideal gas law.
numbers
EXAMPLE Equations of state have been developed to model the behaviour of real gases over a range of pressures Formatted: Font: 10 pt
and temperatures [11] to [14]. See References [13] to [16].
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3.1.14 3.1.14
gas analysis
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measurement methods and techniques for determining the gas composition
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2 © ISO 2025 2026 – All rights reserved
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3.1.15 3.1.15
gas composition
fractions or concentrations of all the components in a mixture
3.1.16 3.1.16
gas hydrates
solid crystalline substance resembling ice formed by gas molecules and water molecules
3.1.17 3.1.17
gas quality
set of attributes of a gas that characterises important aspects of its production, transportation or use
EXAMPLE Composition, calorific value, Wobbe index, methane number, relative density and dew points.
Formatted: Example, Adjust space between Latin and
Asian text, Adjust space between Asian text and
3.1.18 3.1.18
numbers, Tab stops: Not at 0.7 cm + 1.4 cm + 2.1 cm
gross calorific value
+ 2.8 cm + 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3
superior calorific value
cm + 7 cm
gross heating value
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higher heating value
and Asian text, Adjust space between Asian text and
calorific value when the combustion products are in the gaseous state, except for water, which is condensed
numbers
to the liquid state
3.1.19 3.1.19
Formatted: Dutch (Netherlands)
hydrocarbon dew temperature
hydrocarbon dew point
HCDP
Formatted: English (United Kingdom)
temperature at which an infinitesimal amount of liquid hydrocarbons is in equilibrium with a bulk vapour for
a specified pressure
3.1.20 3.1.20
interchangeability
characteristic of gases where one gas is compatible with another gas with regard to combustion
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Note 1 to entry: Two gases are said to be interchangeable when one gas can be substituted for the other
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gas without interfering with the operation of gas-burning appliances or equipment.
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.1.21 3.1.21 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
lean gas
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natural gas having a relatively low energy content, close to or lower than that of pure methane
and Asian text, Adjust space between Asian text and
numbers
Note 1 to entry: Lean gas typically contains high amounts of nitrogen and carbon dioxide.
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3.1.22 3.1.22
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
mass concentration
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
quotient of mass of a substance and volume of the mixture
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and Asian text, Adjust space between Asian text and
[SOURCE: ISO 80000-9:2019, 9-10, modified — ‘for"For a substance X in a mixture’mixture" has been deleted.
numbers
TermTerms for mass mx, substance X. and volume V have been removed. deleted. The formula γ=mx/V has
also been removed]deleted.]
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...
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...
3.1.23 3.1.23
mass fraction Formatted: Font: 10 pt
quotient of mass of a substance and total mass of the mixture
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[SOURCE: ISO 80000-9:2019, 9-11, modified: “for — “For substance X in a mixture” at the beginning of the
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definition has been deleted;. “mX (ISO 80000-4)” after mass has been deleted . “X” after "substance" has been
;
deleted;. “m” after "total mass" has been deleted; the. The formula after the definition has been deleted].]
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© ISO 2026 – All rights reserved
ISO #####-#:####(X/FDIS 14532:2026(en)
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3.1.24 3.1.24
metering reference conditions
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...
specified temperature and pressure at which a volume of gas is expressed
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...
3.1.25 3.1.25
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...
methane number
Formatted
...
MN
Formatted
numerical rating indicating the knock resistance of a gaseous fuel
...
Formatted
...
Note 1 to entry: The methane number is analogous to the octane number for petrol. The methane
Formatted
number is the volume fraction expressed as the percentage of methane in a methane-hydrogen mixture, that in a test .
engine under standard conditions has the same knock resistance as the gaseous fuel to be examined.
Formatted
...
Formatted
3.1.26 3.1.26 .
molar mass
Formatted
...
quotient of mass and amount of substance
Formatted
...
Formatted
[SOURCE: ISO 80000-9:2019, 9-4, modified — ‘"For a pure substance X’,X" has been deleted. Terms for mass .
m(X) and amount n have been deleted. The formula M=m/n has also been removeddeleted.]
Formatted
...
Formatted
3.1.27 3.1.27 .
molar volume
Formatted
...
quotient of the volume of a substance and amount of substance
Formatted
...
Formatted
[SOURCE: ISO 80000-9:2019, 9-5 modified — ‘"For a pure substance’,substance" has been deleted. Terms for
...
volume V, and amount n have been deleted. The formula Vm=V/n has also been removed]deleted.]
Formatted
...
Formatted
3.1.28 3.1.28 .
natural gas
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...
NG
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...
naturally occurring mixture of hydrocarbon and non-hydrocarbon gases found in porous geological
Formatted
formations (reservoirs) beneath the earth’s surface .
Formatted
...
Note 1 to entry: Natural gas contains primarily methane, but generally includes ethane, propane and higher
Formatted
...
hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide. Natural gas can also contain
components such as either sulfur compounds or other chemical species, or both.
Formatted
...
Formatted
...
3.1.29 3.1.29
net calorific value Formatted
...
inferior calorific value
Formatted
...
net heating value
Formatted
...
lower heating calorific value when the combustion products are in the gaseous state
Formatted
...
3.1.30
Formatted
...
3.1.30
normal pressure Formatted
...
pressure at which appliances operate under nominal conditions when they are
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...
supplied with the corresponding reference gas
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...
3.1.31 3.1.31
Formatted
...
normal reference conditions
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...
conditions equal to 101,325 kPa for pressure and 273,15 K for temperature for a real gas in the dry state
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...
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...
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...
4 © ISO 2025 2026 – All rights reserved
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3.1.32 3.1.32
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other component
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other constituent
component in the gas sample which either is not subject to analysis in accordance with the ISO 6974 series or
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can be regarded as being present at a constant mole fraction or both
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3.1.33 3.1.33
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PKI methane number
MNPKI
numerical rating index obtained by a calculation, indicating the knock resistance of a gaseous fuel, according
to ISO 17507-2
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Note 1 to entry: This analytical estimate of a methane number is based on using mole fraction gaseous
fuel composition as input.
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3.1.34 3.1.34
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reference conditions
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
conditions of temperature, pressure and humidity (state of saturation) to be used for measurements and
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
calculations carried out on natural gases, natural gas substitutes and similar fluids in the gaseous state
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and Asian text, Adjust space between Asian text and
3.1.35 3.1.35
numbers
relative density
quotient of the density of a gas and the density of dry air of standard composition at the same specified
conditions of pressure and temperature
3.1.36 3.1.36
relative humidity
quotient of the actual vapour pressure and the saturation vapour pressure over a plane liquid water surface
Formatted: Adjust space between Latin and Asian text,
at the same temperature
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
Note 1 to entry: The phrase "relative humidity" is commonly abbreviated to RH although this is not a
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
recognised abbreviated term.
Formatted: TermNum3, Adjust space between Latin
Note 2 to entry:  Values of relative humidity are commonly expressed as a percentage. and Asian text, Adjust space between Asian text and
numbers
3.1.37 3.1.37
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rich gas
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natural gas having a relatively high energy content, higher than that of pure methane
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
Note 1 to entry: Rich gas typically contains high amounts of ethane or propane or higher hydrocarbons.
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and Asian text, Adjust space between Asian text and
3.1.38 3.1.38
numbers
standard reference conditions
conditions equal to 101,325 kPa for pressure and 288,15 K for temperature for a real gas in the dry state
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3.1.39
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3.1.39
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substitute natural gas
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
SNG
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
manufactured or blended gas with properties which make it interchangeable with natural gas
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Note 1 to entry: This also includes gases manufactured by thermal process from biomass.
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© ISO 2026 – All rights reserved
ISO #####-#:####(X/FDIS 14532:2026(en)
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3.1.40 3.1.40
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volume fraction
and Asian text, Adjust space between Asian text and
φ
numbers
quotient of product of amount of substance fraction xx and molar volume Vmx of the pure substance X at the
same temperature and pressure, and the sum over all substances i of products of amount of substance
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fractions x of substance i and their molar volumes V
i mi
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xv
x mx
ϕ=
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Σ xv
i im
i
𝑥𝑥𝑣𝑣
x mx
𝜑𝜑 =
𝛴𝛴𝑥𝑥𝑣𝑣
𝑖𝑖 𝑖𝑖 m
𝑖𝑖
[SOURCE: ISO 80000-9:2019, 9-14 modified — ‘for"For substance X’X" at the beginning, and ‘"of X’X" after
Formatted: Adjust space between Latin and Asian text,
"substance fraction," have been deleted. ‘substance’"Substance" after ‘"over all’all" has been written in
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plural].]
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3.1.41 3.1.41
water content
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quantity of water contained in unit quantity of gas
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Note 1 to entry: Water content can be expressed as a concentration or as a mole or volume fraction. Formatted: Default Paragraph Font
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3.1.42 3.1.42
water dew temperature Formatted: Default Paragraph Font
water dew point
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temperature at which an infinitesimal amount of liquid water is in equilibrium with a bulk vapour for a
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specified pressure
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3.1.43 3.1.43
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wet gas
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gas containing water or condensable components such as either water vapour or hydrocarbons, or both, in
such amounts that they can condense or are already condensed at pipeline conditions
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3.1.44 3.1.44
Wobbe index
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quotient of the calorific value on a volumetric basis at specified reference conditions and the square root of
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the relative density at the same specified metering reference conditions
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
Note 1 to entry: The Wobbe Index is said to be gross or net according to whether the calorific value
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
used is the gross or net calorific value.
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and Asian text, Adjust space between Asian text and
3.2 Terms related to sampling and measurement techniques
numbers
3.2.1 3.2.1
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...
absorption
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...
retention, by physical or chemical forces of gas molecules, dissolved substances or liquids, by the bulk of solids
or liquids with which they are in contact
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...
Note 1 to entry: The absorption process causes (or is accompanied by) a physical or chemical change,
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or both, in the sorbent material.
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EXAMPLE Retention of siloxanes by charcoal.
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6 © ISO 2025 2026 – All rights reserved
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3.2.2 3.2.2
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adsorption
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retention, by physical or chemical forces of gas molecules, dissolved substances or liquids, by the surface of
solids or liquids with which they are in contact
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and Asian text, Adjust space between Asian text and
EXAMPLE Retention of methane by carbon.
numbers
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3.2.3 3.2.3
desorption
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removal of a sorbed substance by the reverse process of adsorption or absorption and Asian text, Adjust space between Asian text and
numbers
3.2.4 3.2.4
direct measurement
measurement in which the content of individual components or group of
components is determined by comparison with the content of identical components in the reference gas
mixture
3.2.5 3.2.5
direct sampling
sampling in situations where there is a direct connection between the natural gas to be sampled and the
analytical unit
3.2.6 3.2.6
fast loop
sampling system that takes more sample from the process than is needed to make the measurement so as to
reduce the residence time
3.2.7 3.2.7
floating piston cylinder
container that has a moving piston separating the sample from a buffer gas
Formatted: Adjust space between Latin and Asian text,
3.2.8 3.2.8 Adjust space between Asian text and numbers, Tab
flow-proportional incremental sampler stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
sampler that collects a series of spot samples over a period of time with the spot samples taken in such a 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
manner as to ensure the incremental sample is proportional to the incremental totalised flow
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and Asian text, Adjust space between Asian text and
Note 1 to entry: This is normally achieved by varying the frequency of extraction of a constant volume
numbers
spot sample (grab).
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3.2.9 3.2.9
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
gas sorption effect
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
physical process whereby some gases are adsorbed onto or desorbed from the surfaces of a solid without
transformation of the molecules Formatted: TermNum3, Adjust space between Latin
and Asian text, Adjust space between Asian text and
Note 1 to entry: The force of attraction between some gases and solids is purely physical and depends numbers
on the nature of the participating material. Natural gas can contain several components that exhibit strong sorption
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effects.
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.2.10 3.2.10
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
hot loop
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sampling configuration that returns the sample to the pipeline
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Note 1 to entry: The loop requires a pressure differential from collection point to discharge so as to
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ensure a constant and steady flowrate through the sampling equipment located in the loop.
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Line spacing: single, Tab stops: Not at 17.2 cm
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© ISO 2026 – All rights reserved
ISO #####-#:####(X/FDIS 14532:2026(en)
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3.2.11 3.2.11
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incremental sampler
and Asian text, Adjust space between Asian text and
sampler that accumulates a series of spot samples into one composite sample
numbers
3.2.12 3.2.12
indirect measurement
measurement in which content of the individual components or groups of
components is determined using relative response factors to a reference component in the reference gas
mixture
3.2.13 3.2.13
indirect sampling
sampling in situations where there is no direct connection between the natural gas to be sampled and the
analytical unit
3.2.14 3.2.14
purging time
period of time during which a sample purges a device or part of equipment
Note 1 to entry: The purging time can be much longer than the residence time and will be multiples of
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the residence time in sampling systems.
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.2.15 3.2.15
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
representative sample
Formatted: TermNum3, Adjust space between Latin
sample having the same composition as the gas from which it is taken when the latter is considered as a
and Asian text, Adjust space between Asian text and
homogeneous whole
numbers
3.2.16 3.2.16
residence time
time it takes for a sample to flow through a device or a part of equipment
3.2.17 3.2.17
sample container
a container for collecting the gas sample when indirect sampling is necessary
3.2.18 3.2.18
sample line
line provided to transfer a sample of the gas from the sampling point to the sampling device or the analytical
unit
Note 1 to entry: Devices necessary to prepare the sample for transportation and analysis (conditioning unit) can be
Formatted: Adjust space between Latin and Asian text,
part of ita sample line.
Adjust space between Asian text and numbers, Tab
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.2.19 3.2.19
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
sample probe
Formatted: TermNum3, Adjust space between Latin
device inserted into the gas source used to extract a sample and to which a sample line is connected
and Asian text, Adjust space between Asian text and
numbers
3.2.20 3.2.20
sampling place
whereabouts along the gas pipeline or on the process plant where the sample probe is located
3.2.21 3.2.21
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sampling point
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exact point in space defined by the sampling place, the sampling position and the location of the inlet on the
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sample probe
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spacing: single
8 © ISO 2025 2026 – All rights reserved
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3.2.22 3.2.22
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sampling position
Line spacing: single
location within the cross-sectional area of the gas pipeline or process plant at the sampling place from where
a sample is taken
3.2.23 3.2.23
sorption
process in which one substance takes up or holds another (by either absorption or adsorption)
3.2.24 3.2.24
spot sample
sample of specified volume taken at a specified place at a specified time from a stream of gas
3.2.25 3.2.25
wetted surface
surface of the material in contact with the sampled gas
3.3 Terms related to analytical and calibration methods
3.3.1 3.3.1
Formatted: TermNum3, Adjust space between Latin
analysis function
and Asian text, Adjust space between Asian text and
analyte content expressed as a function of instrumental response
numbers
[SOURCE: ISO 6143:2025, 3.4.2]
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3.3.2 3.3.2
calibration function Formatted: Default Paragraph Font
instrumental response expressed as a function of analyte content
[SOURCE: ISO 6143:2025, 3.4.1]
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3.3.3 3.3.3
calibration gas mixture Formatted: Default Paragraph Font
gas mixture of known stability and homogeneity whose composition is well established for use in the
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calibration (Annex A) or verification of a measuring instrument or the validation of a measurement
[SOURCE: ISO 7504:2015, 5.1, modified — Note 1 to entry has been removeddeleted.]
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3.3.4 3.3.4
molar composition Formatted: Default Paragraph Font
chemical compositions expressed in mole fractions
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3.3.5 3.3.5
multi-point calibration
establishment of a calibration function (Annex A) using more than two calibration points
3.3.6 3.3.6
normalization
adjustment of the mole fractions of all components so that their sum is adjusted to exactly unity by applying
the same proportional adjustment to all measured components
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3.3.7 3.3.7 Formatted: Font: 10 pt
normalized mole fraction
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processed mole fraction
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mole fraction of each component after the application of a process to correct the sum of the mole fractions to
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unity
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© ISO 2026 – All rights reserved
ISO #####-#:####(X/FDIS 14532:2026(en)
Formatted: Font: Bold
Formatted: Font: Bold
Formatted: HeaderCentered, Line spacing: single
3.3.8 3.3.8
raw mole fraction
unnormalized mole fraction
mole fraction of each component before the application of a process to correct the sum of the mole fractions
to unity
3.3.9 3.3.9
reference component
component present in the calibration gas mixture used as a reference to define the relative response factors
of sample components that are not present in the calibration gas mixture
EXAMPLE If the calibration gas mixture contains hydrocarbons up to and including n-butane, but no pentanes or
higher, then n-butane contained in the calibration gas mixture can be used as a reference component for the
quantification of pentanes and heavier components in the sample.
3.3.10 3.3.10
Formatted: TermNum3, Adjust space between Latin
reference gas mixture
and Asian text, Adjust space between Asian text and
calibration
...

PROJET
Norme
internationale
ISO/DIS 14532
ISO/TC 193
Gaz naturel — Vocabulaire
Secrétariat: NEN
Natural gas — Vocabulary
Début de vote:
2025-05-15
ICS: 75.060; 01.040.75
Vote clos le:
2025-08-07
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ISO/DIS 14532:2025(fr)
ISO/DIS 14532:2025(fr)
Ȁ193
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ISO/DIS 14532:2025(fr)
Ȁ193
‡…”±–ƒ”‹ƒ–ǣNEN
Gaz naturel — Vocabulaire
Naturel gaz — Vocabulary

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ii
ISO/DIS 14532:2025(fr)
Sommaire Page
Avant-propos . iv
Introduction . vi
1 Domaine d'application . 1
2 Références normatives . 1
3 Termes et définitions . 1
Annexe A (normative) Liste des termes définis dans l'ISO/IEC Guide 98-3 et dans
l'ISO/IEC Guide 99 . 23
Bibliographie. 25

iii
ISO 14532:2025(fr)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes nationaux
de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est en général
confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude a le droit de faire
partie du comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l’ISO participent également aux travaux. L’ISO collabore étroitement avec
la Commission électrotechnique internationale (IEC) en ce qui concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont décrites
dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents critères
d'approbation requis pour les différents types de documents ISO. Le présent document a été rédigé
conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L'ISO attire l'attention sur le fait que la mise en application du présent document peut entraîner l'utilisation
d'un ou de plusieurs brevets. L'ISO ne prend pas position quant à la preuve, à la validité et à l'applicabilité
de tout droit de propriété revendiqué à cet égard. À la date de publication du présent document, l'ISO n'avait
pas reçu notification qu'un ou plusieurs brevets pouvaient être nécessaires à sa mise en application.
Toutefois, il y a lieu d'avertir les responsables de la mise en application du présent document que des
informations plus récentes sont susceptibles de figurer dans la base de données de brevets, disponible à
l'adresse www.iso.org/brevets. L'ISO ne saurait être tenue pour responsable de ne pas avoir identifié tout
ou partie de tels droits de brevet.
Les appellations commerciales éventuellement mentionnées dans le présent document sont données pour
information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion de
l'ISO aux principes de l'Organisation mondiale du commerce (OMC) concernant les obstacles techniques au
commerce (OTC), voir www.iso.org/avant-propos.
Le présent document a été élaboré par le comité technique 193, Gaz naturel.
Cette troisième édition annule et remplace la deuxième édition (ISO 14532:2014), qui a fait l'objet d'une
révision technique.
Les principales modifications sont les suivantes :
— tous les termes généraux et bien connus qui ne sont pas spécifiques au gaz naturel et qui peuvent être
trouvés dans des sources publiques ont été supprimés ;
— tous les termes qui sont trop spécifiques à un certain sujet dans le domaine du gaz naturel ont été
supprimés ;
— certaines définitions ont été modifiées, généralisées dans le but d'éviter de devenir trop spécifiques
à un certain sujet dans le domaine du gaz naturel ;
— les termes pertinents de toutes les normes ISO/TC 193 publiées depuis 2014 ont été ajoutés ;
— tous les termes sont listés dans l'ordre alphabétique ;
— l'Annexe contenant l'index alphabétique a été supprimée ;
iv
ISO/DIS 14532:2025(fr)
— l'Annexe contenant les indices, symboles et unités a été supprimée ;
— une annexe contenant une liste de termes définis dans l'ISO/IEC Guide 98-3:2008 Incertitude de
mesure (GUM) ou l'ISO/IEC Guide 99:2007 Vocabulaire international de métrologie (VIM) a été
ajouté.
Il convient que l'utilisateur adresse tout retour d'information ou toute question concernant le présent
document à l'organisme national de normalisation de son pays. Une liste exhaustive desdits organismes se
trouve à l'adresse www.iso.org/fr/members.html.
v
ISO 14532:2025(fr)
Introduction
L'ISO/TC 193 Gaz naturel a été établie en mai 1988, son domaine d'application actuel étant de :
— normaliser la terminologie, les spécifications de qualité, les méthodes de mesure, l'échantillonnage,
l'analyse et les essais, y compris le calcul et la mesure des propriétés thermophysiques, pour :
— gaz naturel ;
— substituts du gaz naturel ;
— mélanges de gaz naturel avec d'autres combustibles gazeux (tels que les gaz non conventionnels et
renouvelables) ; et
— gaz humide ;
sous tous ces aspects, de la production à la livraison à tous les utilisateurs finaux possibles au-delà des
frontières nationales ;
— pour normaliser les méthodes d'analyse du gaz naturel liquéfié (GNL).
Comme le but est de créer un ensemble cohérent de normes qui se soutiennent mutuellement en ce qui
concerne leurs définitions, des termes et définitions communs et sans ambiguïté utilisés dans toutes les
normes internationales sont le point de départ pour la compréhension et l'application de chaque Norme
internationale.
L'intention définitive de ce document est d'intégrer les définitions révisées dans les normes de l'ISO/TC 193.
La présentation du présent document a été conçue pour faciliter son utilisation comme suit :
— tous les termes sont listés dans l'ordre alphabétique ;
— des notes sont données sous de nombreuses définitions où il a été jugé important de donner des lignes
directrices informatives pour une définition donnée. Ces notes ne sont pas considérées comme faisant
partie de la définition.
Les termes et définitions ont été étudiés et revus de manière à couvrir toutes les acceptations particulières
des termes provenant également d'autres sources telles que les normes européennes du CEN (Comité
Européen de Normalisation), les normes de l'ASTM, les normes nationales et les définitions existantes dans
le dictionnaire U.I.I.G de l'industrie du gaz.
vi
PROJET de Norme internationale ISO/DIS 14532:2025(fr)

Gaz naturel — Vocabulaire
1 Domaine d'application
Le présent document établit les termes et définitions utilisés dans le domaine du gaz naturel, des
substituts de gaz naturel, des mélanges de gaz naturel avec des combustibles gazeux (tels que les gaz non
conventionnels et renouvelables) et du gaz humide.
2 Références normatives
Le présent document ne contient aucune référence normative.
3 Termes et définitions
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes :
— ISO Online browsing platform : disponible à l'adresse https://www.iso.org/obp
— IEC Electropedia : disponible à l'adresse https://www.electropedia.org/
3.1
absorption
rétention par action physique ou chimique, de molécules de gaz, de substances dissoutes ou de liquides
dans la masse de solides ou de liquides avec lesquels ils sont en contact
Note 1 à l'article : Le processus entraîne, subséquemment ou concomitamment, une modification physique,
chimique ou physico-chimique du sorbant.
EXEMPLE Rétention des siloxanes par le charbon de bois.
3.2
adsorption
rétention, par action physique ou chimique, de molécules de gaz, de substances dissoutes ou de liquides
sur la surface de solides ou de liquides avec lesquels ils sont en contact
EXEMPLE Rétention du méthane sur le carbone.
[SOURCE : ISO 10715:2022, 3.2]
3.3
fraction de quantité de matière
fraction molaire
quotient de la quantité de matière d'un composant sur la quantité totale de matière dans le mélange
[SOURCE : ISO 80000-9, 9.13, modifié. Définition initiale : pour un constituant X d'un mélange, quotient
de la quantité de matière nx du constituant X sur la quantité de matière n totale dans le
mélange : X = n /n]
x x
ISO 14532:2025(fr)
3.4
fonction d'analyse
la teneur de l’analyte, exprimée en fonction de la réponse instrumentale
[SOURCE : ISO 6143:2001, modifié]
3.5
valeur assignée
valeur attribuée à une propriété particulière d'une entité soumise à l'essai d'aptitude
[SOURCE : ISO 6974-3:2018, 3.11]
3.6
disponibilité (d'un système de mesure ou d'un instrument)
probabilité que le système de mesure ou qu'un instrument de mesure constituant une partie du système,
fonctionne, à tout moment, conformément aux spécifications
[SOURCE : ISO 15112:2018, 3.4]
3.7
biogaz
gaz, comprenant principalement du méthane et du dioxyde de carbone, obtenu à partir de la digestion
anaérobie de la biomasse
[SOURCE : EN 16723-1:2016, 3.1]
3.8
biomasse
matériau biologique issu d’organismes vivants ou récemment vivants, il peut typiquement s'agir de
plantes ou de matières d'origine végétale
[SOURCE : EN 16723-1:2016, 3.2]
3.9
biométhane
gaz comprenant principalement du méthane, obtenu soit à partir du traitement de biogaz ou de la
méthanation de bio-syngaz
[SOURCE : EN 16723-1:2016, 3.3]
3.10
encadrement
établissement d'une fonction d’étalonnage linéaire à partir de deux points d'étalonnage définissant une
plage
Note 1 à l'article : La plage est établie de façon que la teneur attendue d'un constituant soit censée se situer entre
les teneurs du constituant dans les mélanges de gaz d'étalonnage.
ISO/DIS 14532:2025(fr)
3.11
composé pont
composé sélectionné afin de permettre l'association des résultats des constituants mesurés par
différentes opérations analytiques
[SOURCE : ISO 6974-1:2012, 3.18, modifié — « Pontage » entre les mots « association » et « des » a été
supprimé.]
3.12
pression de bulle
pression à laquelle une quantité infinitésimale de vapeur est en équilibre avec une phase liquide à une
température spécifiée
[SOURCE : ISO 20765-2:2015, 3.1, modifié]
3.13
température de bulle
température à laquelle une quantité infinitésimale de vapeur est en équilibre avec une phase liquide à
une pression spécifiée
[SOURCE : ISO 20765-2:2015, 3.2, modifié]
3.14
indice de méthane calculé
MN
C
indice de valeur numérique obtenu par un calcul, indiquant la résistance au cliquetis d'un combustible
gazeux conformément à l'ISO 17507-1
Note 1 à l'article : Cette estimation analytique d'un indice de méthane est basée sur l'utilisation de la fraction
volumique de la composition du combustible gazeux comme entrée.
[SOURCE : ISO/DIS 17507-1:2024, 3.2]
3.15
fonction d'étalonnage
la réponse instrumentale exprimée en fonction de la teneur de l’analyte
[SOURCE : ISO/DIS 6143:2024, 3.4.1, modifié]
3.16
mélange de gaz d'étalonnage
mélange de gaz ayant une stabilité et une homogénéité connues, dont la composition est établie afin de
réaliser l'étalonnage ou la vérification d'un instrument de mesure, ou la validation d'un mesurage
[SOURCE : ISO 7504:2015, 5.1]
ISO 14532:2025(fr)
3.17
pouvoir calorifique
valeur calorifique
quantité de chaleur qui serait libérée par la combustion complète d’une quantité spécifiée de gaz dans
l'air, de manière telle que la pression à laquelle la réaction a lieu reste constante et que tous les produits
de la combustion soient ramenés à la même température spécifiée que celle des corps en réaction
[SOURCE : ISO 13686:2013, 3.8]
3.18
résolution chromatographique
caractéristique de l’efficacité de séparation d'une colonne chromatographique, décrivant le degré de
séparation entre deux pics adjacents dans le chromatogramme
Note 1 à l'article : La résolution est définie comme deux fois la distance entre les sommets des pics désignés divisée
par la somme des intersections avec la ligne de base des tangentes à la mi-hauteur des sommets.
3.19
gaz naturel synthétique à base de charbon
mélange gazeux synthétisé à partir de charbon, composé principalement de méthane et d'hydrogène,
mais comprend généralement aussi de l'éthane et certains gaz non combustibles tels que l'azote et le
dioxyde de carbone
[SOURCE : ISO/TR 17910:2023, 3.18]
3.20
conditions de référence de combustion
température et pression spécifiées auxquelles un combustible est théoriquement brûlé
3.21
composant
composé chimique
3.22
gaz naturel comprimé
GNC
gaz naturel qui a subi un traitement de compression pour pouvoir être stocké ou transporté
Note 1 à l'article : Le GNC est principalement utilisé comme carburant pour les véhicules, généralement comprimé
à l'état gazeux jusqu'à 20 000 kPa.
Note 2 à l'article : Généralement, la pression maximale pour le gaz naturel stocké dans un conteneur est de
25 000 kPa.
3.23
facteur de compression
facteur de compressibilité
quotient obtenu en divisant le volume d'une quantité de gaz, à une pression et température spécifiées,
par le volume de la même quantité de gaz parfait, à la même pression et température
ISO/DIS 14532:2025(fr)
3.24
condenseur
appareil utilisé pour faire passer, par réfrigération, la fraction condensable de la vapeur d'eau et/ou des
hydrocarbures plus lourds contenus dans le gaz naturel de l'état de vapeur à l'état liquide
3.25
contaminant
composé présent à de très faibles niveaux de concentration, tels que matières particulaires, glycol et huile,
etc., qui sont considérés comme gênants
[SOURCE : ISO 10715:2022, 3.3, modifié — À la fin de la définition « et distincts du gaz devant être
échantillonné » a été supprimé.]
3.26
cricondenbar
pression maximale à laquelle la séparation des deux phases peut se produire
[SOURCE : ISO 20765-2:2015, 3.3]
3.27
cricondentherme
température maximale à laquelle la séparation des deux phases peut se produire
[SOURCE : ISO 20765-2:2015, 3.4]
3.28
point critique
point de saturation unique sur la courbe d'équilibre liquide-vapeur où la phase vapeur et la phase liquide
ont des compositions et des masses volumiques identiques
[SOURCE : ISO 20765-2:2015, 3.5]
3.29
point interface transactionnel
emplacement entre deux systèmes de canalisations où la quantité d'énergie du gaz naturel doit être
comptée
Note 1 à l'article : À un tel emplacement, un changement de régime de pression peut également se produire.
3.30
masse volumique
quotient de la masse d'un gaz sur son volume
3.31
rapport de masse volumique (d'un fluide)
quotient de la masse volumique du gaz sur la masse volumique du liquide d'un fluide dans les conditions
opératoires
[SOURCE : ISO 12748_2015, 2.6, modifié — « rapport » a été remplacé par « quotient ».]
ISO 14532:2025(fr)
3.32
désorption
libération d'une substance sorbée par le processus inverse de l'adsorption ou de l'absorption
[SOURCE : ISO 10715:2022, 3.4, modifié; la Note 1 à l’article a été supprimée.]
3.33
pression de rosée
pression à laquelle une quantité infinitésimale de liquide est en équilibre avec une phase vapeur à une
température spécifiée
[SOURCE : ISO 20765-2:2015, 3.6, modifié]
3.34
température de rosée
température à laquelle une quantité infinitésimale de liquide est en équilibre avec une phase vapeur à
une pression spécifiée
[SOURCE : ISO 20765-2:2015, 3.7, modifié]
3.35
mesurage direct (de la teneur d'un constituant)
mesurage dans lequel la teneur des constituants individuels ou groupes de constituants sont déterminés
par comparaison avec la teneur des constituants identiques dans le mélange de gaz de référence
3.36
échantillonnage direct
échantillonnage dans des situations où il y a connexion directe entre le gaz naturel à échantillonner et
l'unité analytique
[SOURCE : ISO 10715:2022,3.5 ISO/TR 7262:2022, 3.3]
3.37
gaz sec
gaz contenant une fraction molaire d'eau et/ou d'hydrocarbures qui ne sont pas censés se condenser
dans les conditions observées en canalisation
Note 1 à l'article : La teneur en eau et/ou la teneur en hydrocarbures du gaz sec sont principalement définies par
les utilisateurs ou les transporteurs.
Note 2 à l'article : La corrélation entre la teneur en eau et le point de rosée de l'eau est donnée dans l'ISO 18453.[17]
3.38
équation d'état
EoS
équation mathématique établissant la relation entre les variables d'état d'un gaz ou d'un mélange gazeux
homogène
EXEMPLE Pour un gaz parfait, l'équation d'état est la loi des gaz parfaits. Des équations d'état plus complexes
ont été développées pour modéliser le comportement des gaz réels sur une plage de pressions et de températures,
par exemple Benedict, Webb, Rubin (équation BWR), Redlich, Kwong et Soave (équation RKS) et l'équation GERG
2008.
ISO/DIS 14532:2025(fr)
3.39
famille de gaz
ensemble de gaz combustibles ayant des caractéristiques de combustion similaires et liés par une plage
d'indice de Wobbe
3.40
boucle rapide
système d'échantillonnage qui prélève du procédé une quantité d’échantillon supérieure à celle
nécessaire pour effectuer la mesure de manière à réduire le temps de séjour
3.41
retour de flamme
situation dans laquelle la vitesse de flamme est supérieure à celle du mélange air gaz, entraînant une
combustion avant l'orifice du brûleur
Note 1 à l'article : Il se traduit généralement par une extinction de la flamme et peut endommager le brûleur de
l'appareil.
3.42
cylindre à piston flottant
récipient doté d'un piston mobile séparant l'échantillon d'un gaz tampon
3.43
échantillonneur par prélèvements élémentaires proportionnels au débit
échantillonneur qui recueille une série d'échantillons élémentaires sur une période de temps, ces
échantillons élémentaires étant pris de manière qu'il soit proportionnel au débit total élémentaire
Note 1 à l'article : Ceci est obtenu normalement en faisant varier la fréquence de l'extraction d'un échantillon
ponctuel de volume constant (grab).
3.44
analyse des gaz
méthodes et techniques de mesurage pour déterminer la composition du gaz
[SOURCE : ISO 13686:2013, 3.17, modifié — « utilisation de méthodes d'essai » a été remplacée par
« mesurage », et « autres » avant « techniques » a été supprimé.]
3.45
composition du gaz
fractions ou concentrations de tous les constituants d'un mélange
3.46
hydrates de gaz
substance solide cristalline ressemblant à de la glace formée par des molécules de gaz et des molécules
d'eau
3.47
qualité du gaz
ensemble d'attributs d'un gaz qui caractérise des aspects importants de sa production, de son transport
ou de son utilisation
Note 1 à l'article : La composition, le pouvoir calorifique, l'indice de Wobbe, l'indice de méthane, la densité relative
et les points de rosée sont des exemples d'attributs.
ISO 14532:2025(fr)
3.48
effet de sorption du gaz
phénomène physique d'adsorption ou de désorption observé entre certains gaz et la surface d'un solide
sans transformation des molécules
Note à l’article : La force d'attraction entre certains gaz et des solides est purement physique et dépend de la
nature du matériau en contact. Le gaz naturel peut renfermer un certain nombre de constituants présentant de forts
effets de sorption. Il convient de veiller à ces phénomènes, en particulier lors de la détermination des concentrations
d'éléments à l'état de traces, tels que les hydrocarbures lourds, l'eau, les composés soufrés, le mercure et
l'hydrogène.
[SOURCE : ISO 10715:2022, 3.7]
3.49
rapport gaz/pétrole
rapport entre le débit volumique de gaz et le débit volumique de liquide d'hydrocarbure
[SOURCE : ISO/TR 12748:2015, 2.21]
3.50
combustible gazeux
gaz combustible
toute matière gazeuse pouvant être oxydée dans l'intention de libérer de l'énergie
Note 1 à l'article : Les combustibles gazeux comprennent, sans s'y limiter, le gaz naturel, le gaz de digesteur, le gaz
de décharge, le gaz de procédé, l'hydrogène gazeux et leurs formes liquéfiées telles que le gaz de pétrole liquéfié ou
le gaz naturel liquéfié.
3.51
pouvoir calorifique supérieur
valeur calorifique supérieure
pouvoir calorifique lorsque les produits de combustion sont à l'état gazeux, à l'exception de l'eau qui est
condensée à l'état liquide
3.52
groupe de constituants
ensemble de constituants dont le contenu n'est pas mesuré individuellement, mais pour le groupe dans
son ensemble
3.53
boucle en charge
configuration d'échantillonnage qui retourne l'échantillon à la canalisation
Note 1 à l'article : Une différence de pression est nécessaire entre le point de collecte et le point de décharge pour
assurer un débit constant et stable dans les dispositifs d’échantillonnage situés sur la boucle.
3.54
température de rosée hydrocarbures
point de rosée hydrocarbures HCDP
température à laquelle une quantité infinitésimale d'hydrocarbures liquides est en équilibre avec une
phase vapeur à une pression spécifiée
ISO/DIS 14532:2025(fr)
3.55
échantillonneur par prélèvements graduels
dispositif qui accumule un certain nombre d’échantillons élémentaires pour former un échantillon
composite
[SOURCE : ISO 10715:2022, 3.10]
3.56
mesurage indirect (d'un constituant)
mesurage dans lequel les constituants individuels ou groupes de constituants sont déterminés en
utilisant des facteurs de réponse relatifs à un constituant de référence dans le mélange de gaz de
référence
3.57
échantillonnage indirect
échantillonnage dans des situations où il n'y a pas connexion directe entre le gaz naturel à échantillonner
et l'unité analytique
[SOURCE : ISO 10715:2022, 3.11 ISO/TR 7262:2022, 3.2]
3.58
instrument en ligne (in-line)
instrument dont la partie active est installée dans la canalisation et mesure dans les conditions de celle-ci
3.59
interchangeabilité
caractéristique des gaz où un gaz est compatible avec un autre en ce qui concerne la combustion
Note 1 à l'article : Deux gaz sont dits interchangeables quand l'un peut être substitué à l'autre sans perturber le
fonctionnement des appareils ou de l'équipement brûlant ce gaz.
3.60
interférence
effet positif ou négatif sur la réponse du système de mesurage du fait d'un composant de l'échantillon qui
n'est pas l’analyte
[SOURCE : ISO 2612:2023, 3.7 modifié : « mesurande » est remplacé par « analyte »]
3.61
substance interférente
substance présente dans l’échantillon analysé, différente de l’analyte, qui a un effet sur la réponse
[SOURCE : ISO 2612:2023, 3.8]
3.62
biais du laboratoire
différence entre le résultat d'un laboratoire particulier et une valeur de référence acceptée
[SOURCE : ISO 6974-3:2018, 3.5, modifié — « espérance des résultats d'essai » a été supprimé.]
ISO 14532:2025(fr)
3.63
gaz pauvre
gaz naturel ayant une teneur en énergie relativement faible, à proximité de ou inférieur à celui du
méthane pur
Note 1 à l'article : Le gaz pauvre contient généra
...