SIST EN ISO 14532:2017
(Main)Natural gas - Vocabulary (ISO 14532:2014)
Natural gas - Vocabulary (ISO 14532:2014)
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.
Erdgas - Begriffe (ISO 14532:2014)
Diese Internationale Norm legt Ausdrücke, Begriffe, Symbole und Abkürzungen fest, die auf dem Gebiet des Erdgases angewendet werden.
Die Ausdrücke und Begriffe wurden in der Absicht überprüft und untersucht, alle Bedeutungen jedes einzelnen Ausdruckes abzudecken, wobei andere Quellen wie Europäische Normen des CEN (Europäisches Komitee für Normung), nationale Normen und im IGU-Wörterbuch der Gasindustrie aufgeführte Begriffe einbezogen wurden.
Mit Hilfe des vorliegenden Dokuments ist letztlich beabsichtigt, die überprüften Begriffe in die von ISO/TC 193 herausgegebene Quellnormen einzuarbeiten.
Gaz naturel - Vocabulaire (ISO 14532:2014)
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.
Zemeljski plin - Slovar (ISO 14532:2014)
Standard ISO 14532:2014 določa pogoje, definicije, simbole in okrajšave, ki se uporabljajo na področju zemeljskega plina.
Izrazi in definicije so bile pregledane in preučevane ter zajemajo vse vidike posebnih izrazov, ki zajemajo podatke iz drugih virov, kot so evropski standardi Evropskega odbora za standardizacijo (CEN), nacionalni standardi in slovar IGU plinske industrije.
Dokončen namen standarda ISO 14532:2014 je vključiti pregledane definicije v izvorne standarde ISO/TC 193.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2017
1DGRPHãþD
SIST EN ISO 14532:2005
Zemeljski plin - Slovar (ISO 14532:2014)
Natural gas - Vocabulary (ISO 14532:2014)
Erdgas - Begriffe (ISO 14532:2014)
Gaz naturel - Vocabulaire (ISO 14532:2014)
Ta slovenski standard je istoveten z: EN ISO 14532:2017
ICS:
01.040.75 Naftna in sorodna tehnologija Petroleum and related
(Slovarji) technologies (Vocabularies)
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 14532
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2017
EUROPÄISCHE NORM
ICS 01.040.75; 75.060 Supersedes EN ISO 14532:2005
English Version
Natural gas - Vocabulary (ISO 14532:2014)
Gaz naturel - Vocabulaire (ISO 14532:2014) Erdgas - Begriffe (ISO 14532:2014)
This European Standard was approved by CEN on 13 September 2016.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14532:2017 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
The text of ISO 14532:2014 has been prepared by Technical Committee ISO/TC 193 “Natural gas” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 14532:2017 by
Technical Committee CEN/TC 238 “Test gases, test pressures, appliance categories and gas appliance
types” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2017, and conflicting national standards shall
be withdrawn at the latest by August 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 14532:2005.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 14532:2014 has been approved by CEN as EN ISO 14532:2017 without any modification.
INTERNATIONAL ISO
STANDARD 14532
NORME
Second edition
Deuxième édition
INTERNATIONALE 2014-06-15
Natural gas — Vocabulary
Gaz naturel — Vocabulaire
Reference number
Numéro de référence
ISO 14532:2014(E/F)
©
ISO 2014
ISO 14532:2014(E/F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2014
The reproduction of the terms and definitions contained in this International Standard is permitted in teaching manuals, in-
struction booklets, technical publications and journals for strictly educational or implementation purposes. The conditions for
such reproduction are: that no modifications are made to the terms and definitions; that such reproduction is not permitted for
dictionaries or similar publications offered for sale; and that this International Standard is referenced as the source document.
With the sole exceptions noted above, no other part of this publication may be reproduced or utilized otherwise in any form or
by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior writ-
ten permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of the
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La reproduction des termes et des définitions contenus dans la présente Norme internationale est autorisée dans les manuels
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À la seule exception mentionnée ci-dessus, aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque
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Published in Switzerland/Publié en Suisse
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ISO 14532:2014(E/F)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
2.1 General conditions . 1
2.2 Measurement methods . 4
2.3 Sampling . 6
2.4 Analytical systems . 8
2.5 Analysis.11
2.6 Physical and chemical properties .20
2.7 Interchangeability .24
2.8 Odorization .25
2.9 Thermodynamic properties .26
Annex A (informative) Indices, symbols, and units .27
Annex B (informative) Alphabetical index .30
Bibliography .36
ISO 14532:2014(E/F)
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 193, Natural gas.
This second edition cancels and replaces the first edition (ISO 14532:2001/Cor. 1:2002).
iv © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
Introduction
ISO/TC 193 Natural Gas was established in May, 1989, with the task of creating new standards and
updating existing standards relevant to natural gas. This includes gas analysis, direct measurement of
properties, quality designation, and traceability.
In these activities, a comprehensive and uniform review of the definitions, symbols, and abbreviations
used in the standards was not previously systematically pursued. The development of standards
with terminology created to suit specific purposes often resulted in the detriment of uniformity and
cohesiveness between standards.
Thus, there is the need for a work of harmonization of the terminology used in the standards pertaining
to natural gas. The intention of this International Standard is to incorporate the reviewed definitions
into the ISO/TC 193 source International Standard.
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 presentation of this International Standard has been arranged to facilitate its use as follows:
— Major headings pertain to specific fields of the natural gas industry. All definitions that fall under
these headings, as gleaned from ISO International Standards issued through ISO/TC 193, are listed
under that heading. A review of the contents will serve to facilitate finding specific terms.
— 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.
INTERNATIONAL STANDARD ISO 14532:2014(E/F)
Natural gas — Vocabulary
1 Scope
This International Standard 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 this document is to incorporate the reviewed definitions into the
ISO/TC 193 source standards.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 General conditions
2.1.1 Natural gas
2.1.1.1
natural gas
NG
complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane
and higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide
Note 1 to entry: Natural gas can also contain components or containments such as sulfur compounds and/or other
chemical species.
2.1.1.2
raw gas
unprocessed gas taken from well heads, through gathering lines, to processing or treating facilities
Note 1 to entry: Raw gas can also be partially processed well-head gas taken from basic upstream processing
,
facilities.
2.1.1.3
substitute natural gas
SNG
gas from non-fossil origin which is interchangeable in its properties with natural gas
2.1.1.4
manufactured gas
synthetic gas
gas which has been treated and can contain components that are not typical of natural gas
Note 1 to entry: Manufactured (synthetic) gases can contain substantial amounts of chemical species that are not
typical of natural gases or common species found in atypical proportions as in the case of wet and sour gases.
Note 2 to entry: Manufactured gases fall into two distinct categories, as follows:
a) those that are intended as synthetic or substitute natural gases, and that closely match true natural gases in
both composition and properties;
ISO 14532:2014(E/F)
b) those that, whether or not intended to replace or enhance natural gas in service, do not closely match natural
gases in composition.
Case b) includes gases such as town gas, coke oven gas (undiluted), and LPG/air mixtures. None of which
is compositionally similar to a true natural gas (even though, in the latter case, it can be operationally
interchangeable with natural gas).
2.1.1.5
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.
2.1.1.6
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.
2.1.1.7
wet gas
gas which falls short of qualifying as pipeline quality natural gas by the inclusion of undesirable
components such as free water, water vapour and/or high hydrocarbons in such amounts that they can
condense at pipeline conditions
2.1.1.8
sour gas
gas containing significant amount of acid gases such as carbon dioxide and sulphur compounds
Note 1 to entry: The presence of acid compounds is more detrimental in wet gases.
Note 2 to entry: Typically, wet and sour gases can be unprocessed (well head) or partially-processed natural
gases and can also contain condensed hydrocarbons, traces of carbonyl sulphide, and process fluid vapours such
as methanol or glycols.
Note 3 to entry: Carbon dioxide in the presence of free water can be an important cause of corrosion damage to
pipelines.
2.1.1.9
dry natural gas
natural gas containing a mole fraction of water of no more than 0,005 % [50 ppm (molar)] in the vapour
phase
Note 1 to entry: Water vapour content in natural gas can also be expressed in terms of water concentration
(mg/m ).
[17]
Note 2 to entry: The correlation between water content and water dew point is given in ISO 18453.
2.1.1.10
saturated gas
natural gas that at the specified conditions of temperature and pressure is at its water dew-point
2.1.1.11
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.
2 © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
2.1.1.12
liquefied natural gas
LNG
natural gas that has been liquefied after processing for storage or transportation purposes
Note 1 to entry: Liquid natural gas is revaporized and introduced into pipelines for transmission and distribution
as natural gas.
2.1.1.13
gas quality
attribute of natural gas defined by its composition and its physical properties
2.1.1.14
biogas
generic term used to refer to gases produced by anaerobic fermentation or digestion of organic matter,
and without further upgrading nor purification
Note 1 to entry: This can take place in a landfill site to produce landfill gas or in an anaerobic digester to produce
biogas. Sewage gas is biogas produced by the digestion of sewage sludge. Biogases comprise mainly methane and
carbon dioxide.
2.1.1.15
biomethane
methane rich gas derived from biogas or from gasification of biomass by upgrading with the properties
similar to natural gas
2.1.1.16
biomass
mass defined from a scientific and technical point of view as material of biological origin excluding
material embedded in geological formations and/or transformed to fossil
Note 1 to entry: Biomass is organic material that is plant-based or animal-based, including but not limited to
dedicated energy crops, agricultural crops and trees, food, feed and fibre crop residues, aquatic plants, alga,
forestry and wood residues, agricultural wastes, processing by-products and other non-fossil organic matter.
Note 2 to entry: See also herbaceous biomass, fruit biomass, and woody biomass.
2.1.2 Pipeline network
2.1.2.1
pipeline grid
system of interconnected pipelines, both national and international that serve to transmit and distribute
natural gas
2.1.2.2
local distribution system
LDS
gas mains and services that supply natural gas directly to consumers
2.1.2.3
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.
2.1.2.4
transfer station
system of pipelines, measurement and regulation (pressure control), and ancillary devices at a custody
transfer point necessary to account for the quantity of gases transferred and the adaptation to the
possible different pressure regimes of the networks
ISO 14532:2014(E/F)
2.2 Measurement methods
2.2.1 General definitions
2.2.1.1
absolute measurement
measurement of a property from fundamental metrological quantities
Note 1 to entry: For example, fundamental metrological quantities are length, mass, and time.
Note 2 to entry: For example, the determination of the mass of a gas using certified masses.
2.2.1.2
direct measurement
measurement of a property from quantities that, in principle, define the property
Note 1 to entry: For example, the determination of the calorific value of a gas using the thermometric measurement
of the energy released in the form of heat during the combustion of a known amount of gas.
2.2.1.3
indirect measurement
measurement of a property from quantities that, in principle, do not define the property, but have a
known relationship with the property
Note 1 to entry: For example, the determination of the calorific value from measurements of the air-to-gas ratio
required to achieve stoichiometric combustion that is related linearly to the calorific value.
2.2.1.4
lower range value
lowest value of a quantity to be measured (measurand) that a measuring system or transmitter is
adjusted to measure
2.2.1.5
upper range value
highest value of a quantity to be measured(measurand) that a measuring system or transmitter is
adjusted to measure
2.2.1.6
span
algebraic difference between the upper and lower range values
2.2.1.7
relative measurement
measurement of a property by means of comparison with a value of the property taken from an accepted
standard, for example, reference material
Note 1 to entry: For example, determining gas density from the quotient of the mass of gas contained in a given
volume to that of air contained in the same volume at the same temperature and pressure, and multiplying by the
density of air at that temperature and pressure.
2.2.2 Specific methods
2.2.2.1
gas chromatographic method
method of analysis by which the components of a gas mixture are separated using gas chromatography
Note 1 to entry: The sample is passed in a stream of carrier gas through a column that has different retention
properties relative to the components of interest. Different components pass through the column at different
rates and are detected as they elute from the column at different times.
4 © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
2.2.2.2
potentiometric method
method of analysis by which a known quantity of gas is first passed through a solution, where a specific
gas component or a group of components is (are) selectively absorbed, then the absorbed analyte(s) in
the solution is (are) evaluated by potentiometric titration
Note 1 to entry: The result is a titration curve showing the potentiometric end points for the components being
sought versus the titration solutions required. From this data, the concentrations of the various components can
be calculated.
2.2.2.3
potentiometric titration
method where the amount of titrant consumed for reaction of the gas component with the titrant is
proportional to the gas component concentration, and the endpoint of reaction is determined by the
variation of potential inside the cell
Note 1 to entry: The volume increments of titrant (titration solution) added determine the difference in potential
to be measured. Different volume increments of titrant, specifically smaller volume increments close to end
points, can permit a better evaluation of the end points.
2.2.2.4
turbidimetric titration
method to determine the content of sulfate ions whereby a barium salt solution is added to an absorption
solution and the turbidity caused by the formation of any insoluble barium sulfate detected
Note 1 to entry: This method is valid for solutions having a total sulfur content below 0,1 mg.
Note 2 to entry: A photometer with galvanometer readout is employed with the titration procedure to determine
the inflection point. From these data, the total sulfur content in mg/m can be calculated.
2.2.2.5
combustion method
method by which a gas sample undergoes total combustion and the specific combustion products are
measured to determine the total concentration of an element in the sample, e.g. sulfur
Note 1 to entry: Wickbold method: the Wickbold combustion method uses the combustion and complete thermal
decomposition of compounds at a high temperature in a hydrogen/oxygen flame. It is performed with a special
[2]
instrument (see ISO 4260 ).
Note 2 to entry: Lingener method: the Lingener combustion method uses air, and it is performed using a special
[8]
instrument (see ISO 6326-5 ).
2.2.2.6
absorption
extraction of one or more components from a mixture of gases when brought into contact with a liquid
Note 1 to entry: The assimilation or extraction process causes (or is accompanied by) a physical or chemical
change, or both, in the sorbent material.
Note 2 to entry: The gaseous components are retained by capillary, osmotic, chemical, or solvent action.
EXAMPLE Removal of water from natural gas using glycol.
2.2.2.7
adsorption
retention, by physical or chemical forces of gas molecules, dissolved substances, or liquids by the surfaces
of solids or liquids with which they are in contact
Note 1 to entry: For example, retention of methane by carbon.
2.2.2.8
desorption
removal of a sorbed substance by the reverse process of adsorption or absorption
ISO 14532:2014(E/F)
2.3 Sampling
2.3.1 Sampling methods
2.3.1.1
direct sampling
sampling in situations where there is a direct connection between the natural gas to be sampled and the
analytical unit
2.3.1.2
indirect sampling
sampling in situations where there is no direct connection between the natural gas to be sampled and
the analytical unit
2.3.1.3
in-line instrument
instrument whose active element is installed inside the pipeline and makes measurements under
pipeline conditions
2.3.1.4
on-line instrument
instrument that samples gas directly from the pipeline, but is installed externally to the pipeline
2.3.1.5
off-line instrument
instrument that has no direct connection to the pipeline
2.3.1.6
spot sample
sample of specified volume taken at a specified place at a specified time from a stream of gas
2.3.2 Sampling devices
2.3.2.1
floating piston cylinder
container that has a moving piston separating the sample from a buffer gas. The pressures are in balance
on both sides of the piston
2.3.2.2
incremental sampler
sampler that accumulates a series of spot samples into one composite sample
2.3.2.3
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).
2.3.2.4
sample container
container that is used to collect a representative sample and maintain the sample in a representative
condition
Note 1 to entry: The sample container should not alter the gas composition in any way or affect the proper
collection of the gas sample. The materials, valves, seals, and other components of the sample container shall be
specified to maintain this principle.
6 © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
2.3.2.5
sample line
conduit to transfer a sample of gas from the sample place to the analytical unit or sample container
Note 1 to entry: Another word used for sample line is transfer line.
2.3.2.6
sample probe
device inserted into the gas pipeline so that a representative sample of the flowing gas can be taken.
The sample probe will have a conduit to convey the sample from the flowing gas to a point external to
the pipeline
2.3.2.7
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.
2.3.2.8
vent line
section of the sampling system that diverts a portion of the sampled gas away from the analyser/instrument
or sample container
Note 1 to entry: The flowrate and pressure loss in the open-ended line need to be controlled so as to ensure that
sample accuracy cannot be affected from any cooling and condensation.
2.3.2.9
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
2.3.3 Conditioning device
2.3.3.1
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
2.3.3.2
liquid separator
unit, in the sample line, used to collect liquid fall-out
2.3.3.3
pressure reducer
device used to reduce gas pressure immediately downstream of its installed position
Note 1 to entry: It has the ability to maintain a near constant outlet pressure within its design parameters
regardless of changes in pressure or flow in other parts of the system.
2.3.3.4
back-pressure regulator
device used to control/maintain gas pressure immediately upstream of its installed position
Note 1 to entry: It has the ability to maintain a near constant inlet pressure within design parameters, regardless
of pressure or flow fluctuations in other parts of the system.
ISO 14532:2014(E/F)
2.3.3.5
heating device
device to ensure that the sample gas remains at a temperature sufficient to avoid a change of its
composition due to condensation of some compounds
Note 1 to entry: Heating elements can be installed on the sample probe and sample lines. In some cases, heating
the sample cylinder is also required. It is particularly important where Joule-Thomson cooling occurs as a result
of pressure reduction.
Note 2 to entry: Heating devices are also used to maintain “wetted surface areas” at near constant temperatures to
avoid changes in gas sorption coefficients when measuring components that are prone to strong sorption effects.
2.3.4 Other definitions
2.3.4.1
purging time
residence time plus the time to insure that the sample in the sampling system is representative of the
gas stream
Note 1 to entry: The purging time can be much longer than the residence time and will be multiples of the residence
time in poorly designed sampling systems.
2.3.4.2
representative sample
sample having the same composition as the natural gas sample when the latter is considered as a
homogeneous whole
2.3.4.3
residence time
time it takes for a sample to flow through a piece of equipment
2.3.4.4
sampling point
point in the gas stream or vessel where a representative sample can be taken
2.3.4.5
sampling place
location of a sampling point along a stream, or the location of the vessel
2.3.4.6
gas sorption effects
physical processes 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 contain several components that exhibit strong sorption
effects. Special care should be taken when determining trace concentrations of heavy hydrocarbons, water, sulfur
compounds, and hydrogen.
2.4 Analytical systems
2.4.1
measuring system
complete set of measuring instruments and other equipment assembled to carry out specified
measurements
Note 1 to entry: System comprising, in general, a sample transfer and introduction unit, a separation unit, a
detector and an integrator or a data processing system.
8 © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
2.4.2
introduction unit
unit for introducing a constant, or a measured amount of material to be analysed into the analyser
Note 1 to entry: Gas chromatographic analysers are comparative rather than absolute. Therefore, the introduction
of equal quantities of a calibration mixture and of sample allows quantitative measurement of sample components.
Note 2 to entry: In gas analysis, the introduction device is frequently a multi-port valve, in which a fixed volume
of a calibration mixture or sample is isolated, and by operation of the valve, passed into the analyser.
Note 3 to entry: Equimolar quantities can be obtained by controlling the pressure and temperature of the
introduction device.
2.4.3
gas chromatograph
device that physically separates components of a mixture in the gaseous phase and measures them
individually with a detector whose signal is processed
Note 1 to entry: A chromatograph consists of the following main parts: an introduction unit, a separation unit,
and a detector. The separation unit consists of one or more chromatographic columns through which carrier gas
flows and into which samples are introduced. Under defined and controlled operating conditions, components
can be qualitatively identified by their retention time, and quantitatively measured by comparing their detector
response to that of the same or a similar component in a calibration mixture.
Note 2 to entry: In gas analysis, the range of components and their properties frequently cause more than
one separation mechanism to be required. These can be and often are combined in a single separation unit or
chromatograph.
Note 3 to entry: A gas chromatograph capable of temperature programming is a chromatograph whose columns
are placed in an oven whose temperature is programmable in a defined and repeatable manner over the period
of analysis.
2.4.4
carrier gas
pure gas introduced so as to transport a sample through the separation unit of a gas chromatograph for
analytical purposes
Note 1 to entry: Typical carrier gases are hydrogen, nitrogen, helium, and argon.
2.4.5
auxiliary gases
gases required for detector operation, e.g. hydrogen and air for flame detectors
2.4.6
chemiluminescence detector
CD
detector that uses a reducing reaction in which molecules give rise to characteristic luminous emissions
that are measured by a photomultiplier and the associated electronic devices
Note 1 to entry: A chemiluminescence detector is used in gas chromatography mainly to detect components that
contain particular elements, e.g. nitrogen (N) and sulfur (S).
2.4.7
electrochemical detector
ED
detector consisting of an electrochemical cell that responds to certain substances contained in the
carrier gas eluting from the column
Note 1 to entry: The electrochemical process can be an oxidation, reduction, or a change in conductivity. The
detection can be very specific depending on the electrochemical process involved.
ISO 14532:2014(E/F)
2.4.8
flame ionization detector
FID
detector in which hydrocarbons are burned in a hydrogen-air flame and the electrical current caused by
the resulting ions is measured between two electrodes
Note 1 to entry: The flame ionization detector is used in gas chromatography mainly to detect hydrocarbon
compounds.
2.4.9
thermal conductivity detector (TCD)
hot wire detector (HWD)
detector that measures the difference in thermal conductivity between two gas streams when a sample
(gas mixture) passes through the sample channel
Note 1 to entry: The HWD is a dual channel detector, requiring a reference flow of pure carrier gas through the
reference channel.
Note 2 to entry: The use of helium or hydrogen is recommended as carrier gas except when the sample contains
either of these two substances to be measured.
Note 3 to entry: The detector consists of a bridge circuit; the change in resistance in the sample channel during the
passage of the sample produces an out-of-balance signal that is the basis of the detection. The detector responds
to all components except the carrier gas and it is non-destructive.
2.4.10
flame photometric detector
FPD
detector that uses a reducing flame in which individual elements give rise to characteristic colours that
are measured by a photomultiplier
Note 1 to entry: The detector is used in gas chromatography mainly to detect components that contain particular
elements, e.g. phosphorous (P) and sulfur (S).
2.4.11
integrator
device that quantitatively measures the response signal of a detector to a component in a mixture
Note 1 to entry: By comparing the integrator output to the same component in a calibration mixture and in a
sample, the concentration in the sample can be calculated. If the detector response has a temporal dimension, as
in chromatography, then the instantaneous response is integrated with respect to time.
2.4.12
photometry
determination of the concentration of a dissolved substance in a solution by using the absorption of light
by this substance
2.4.13
absorption cell
device put into the light path of the photometer
Note 1 to entry: The lower the concentration of the dissolved substance, the greater path length of the absorption
cell has to be.
10 © ISO 2014 – All rights reserved/Tous droits réservés
ISO 14532:2014(E/F)
2.5 Analysis
2.5.1 Calibration and quality control
2.5.1.1
calibration
operation, that under specified conditions in a first step establishes a relation between the quantity
values with measurement uncertainties provided by measurement standards and corresponding
indications with associated measurement uncertainties and, in a second step uses this information to
establish a relation for obtaining a measurement result from an indication
Note 1 to entry: A calibration can be expressed by a statement, calibration function, calibration diagram,
calibration curve, or calibration table. In some cases, it consists of an additive or multiplicative correction of the
indication with associated measurement uncertainty.
Note 2 to entry: Calibration should not be confused with adjustment of a measuring system, often mistakenly
called “self-calibration”, nor with verification of calibration.
Note 3 to entry: Often, the first step alone in the above definition is perceived as being calibration.
2.5.1.2
adjustment of a measuring instrument
operation of bringing a measuring instrument into a state of performance suitable for its use
Note 1 to entry: Adjustment can be automatic, semi-automatic, or manual.
2.5.1.3
volumetric conversion
determination of the volume at reference conditions from the volume at operating conditions
2.5.1.4
correction
value added algebraically to the uncorrected result of a measurement to compensate for systematic
error
Note 1 to entry: The correction is equal to the negative of the estimated systematic error.
Note 2 to entry: Since the systematic error cannot be known perfectly, the correction cannot be complete.
2.5.1.5
correction factor
numerical factor by which the uncorrected result of a measurement is multiplied to compensate for
systematic error
Note 1 to entry: Since the systematic error cannot be known perfectly, the correction cannot be complete.
2.5.1.6
calibration interval
period between routine calibrations over which the performance of the analyser meets specified
requirements
2.5.1.7
working range
range of parameters for which the calibration function has been developed and validated
2.5.1.8
extended working range
range of parameters for which the correlation has been developed, but outside the range for which the
calibration function has been validated
ISO 14532:2014(E/F)
2.5.1.9
single-point calibration
establishment of the calibration function using one (only) calibration point
Note 1 to entry: This is a calibration in which the response of the analyser to a measured component maintains an
exact proportion to the concentration of the component over the entire working range.
Note 2 to entry: The response can be described as being linear through the origin. A plot of the analyser response
against the concentration of the component would show a straight line intercepting the (0,0) point of the plot. In
such circumstances, the use of a single calibration mixture containing the component at a concentration within
the working range (single-point calibration) is appropriate, as the ratio of response to concentration remains
constant at all points.
Note 3 to entry: Where a more complex response function, first order not passing through the origin or second or
third order polynomial, has been defined by the use of multiple calibration mixtures, and the different elements
of this function, e.g. the coefficient of the polynomial, have been shown to maintain a constant relationship to each
other, then a single-point calibration can be used to adjust all the elements of the function on a short-term basis
(for example, daily).
2.5.1.10
bracketing
method consisting in principle in reducing the interval over which the linearity of the calibration
function is assumed as much as possible
Note 1 to entry: This leads to surrounding the value of the unknown quantity by two values of reference materials
(RMs) as tightly as possible (or bracketing).
2.5.1.11
multi-point calibration
establishment of a calibration function using more than two calibration points
Note 1 to entry: In multi-point (also called “multi-level”) calibrations, the response curves of the detector are
determined for each component over the ranges to be analysed using a series of certified reference gas mixtures.
Note 2 to entry: To define the response curves, it is necessary to obtain results at a number of different concentration
levels for each component. The number of concentration levels needed depends on the order of the polynomial
(response curve) that has to be fitted. For first order, the minimum number of concentration levels needed is
three, for second order is five, and for third order is seven. In most cases, the order of fit of the response curves is
unknown beforehand, in which cases; it is advisable to perform the analysis of at least seven concentration levels
so as to detect third order detector behaviour with a high degree of detection s
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