EN ISO 14912:2006

SLOVENSKI STANDARD
01-november-2006
Analiza plinov – Pretvorba podatkov sestave plinskih zmesi (ISO 14912:2003)
Gas analysis - Conversion of gas mixture composition data (ISO 14912:2003)
Gasanalyse - Umrechnung von Zusammensetzungsangaben für Gasgemische (ISO
14912:2003)
Analyse des gaz - Conversion des données de composition de mélanges gazeux (ISO
14912:2003)
Ta slovenski standard je istoveten z: EN ISO 14912:2006
ICS:
71.040.40
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 14912
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2006
ICS 71.040.40
English Version
Gas analysis - Conversion of gas mixture composition data (ISO
14912:2003)
Analyse des gaz - Conversion des données de composition Gasanalyse - Umrechnung von
de mélanges gazeux (ISO 14912:2003) Zusammensetzungsangaben für Gasgemische (ISO
14912:2003)
This European Standard was approved by CEN on 21 July 2006.
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 Central Secretariat 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 Central Secretariat has the same status as the official
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© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14912:2006: E
worldwide for CEN national Members.

Foreword
The text of ISO 14912:2003 has been prepared by Technical Committee ISO/TC 158
"Analysis of gases” of the International Organization for Standardization (ISO) and has been
taken over as EN ISO 14912:2006 by Technical Committee CEN/SS N21 "Gaseous fuels and
combustible gas", the secretariat of which is held by CMC.

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 February 2007, and conflicting national
standards shall be withdrawn at the latest by February 2007.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Endorsement notice
The text of ISO 14912:2003 has been approved by CEN as EN ISO 14912:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 14912
First edition
2003-03-15
Gas analysis — Conversion of gas
mixture composition data
Analyse des gaz — Conversion des données de composition de
mélanges gazeux
Reference number
ISO 14912:2003(E)
©
ISO 2003
ISO 14912:2003(E)
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ii © ISO 2003 — All rights reserved

ISO 14912:2003(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Terms and definitions .1
3 Symbols and units .4
4 Basic principles.6
4.1 Expression of gas mixture composition.6
4.2 Conversion between different quantities.8
4.3 Conversion between different state conditions.9
5 Main procedures.10
5.1 Conversion between different quantities of composition.10
5.2 Conversion to reference conditions.13
6 Practical implementation.13
6.1 Conversion between quantities of composition .13
6.2 Conversion of single analyte contents .14
6.3 Conversion of complete compositions.15
6.4 Conversion between state conditions .15
6.5 Simple approximations applicable to conversion .15
7 Input quantities and their uncertainties.16
7.1 Pure gas data.16
7.2 Gas mixture data .19
7.3 Rough uncertainty estimates.22
8 Conversion uncertainty .22
8.1 General considerations .22
8.2 Conversion of single analyte contents .23
8.3 Conversion of complete compositions.24
8.4 Uncertainty calculation using numerical differentiation.26
8.5 Variances and covariances of input composition data.27
9 Application recommendations.29
Annex A (normative) Assessment of state conditions .30
Annex B (normative) Summation relations for the expression of mixture properties .33
Annex C (informative) Mixture component data .34
Annex D (informative) Examples.40
Annex E (informative) Computer implementation of recommended methods.55
Bibliography.57

ISO 14912:2003(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14912 was prepared by Technical Committee ISO/TC 158, Analysis of gases.
iv © ISO 2003 — All rights reserved

ISO 14912:2003(E)
Introduction
The objective of gas analysis is to determine the composition of gas mixtures. Gas mixture composition is
expressed qualitatively in terms of specified mixture components of interest, called analytes, and the
complementary gas. Gas mixture composition is expressed quantitatively by specifying the amount of every
analyte in the mixture and the composition of the complementary gas.
For the purpose of specifying the amount of an analyte in a gas mixture, different quantities are in use. This
diversity is due to the fact that in different applications different quantities have decisive advantages.
Therefore procedures for conversion between different quantities are required.
In cases where these quantities involve the volumes of the analytes or the gas mixture or both, they depend
on the state conditions, i.e. pressure and temperature, of the gas mixture. For each of these quantities,
procedures for conversion between different state conditions are required.
As a crude approximation, all of the conversions referred to above can be performed on the basis of the Ideal
Gas Law. In most cases, however, an accurate conversion has to take into account the real gas volumetric
behaviour of the analyte and of the gas mixture. In particular, many conversions require values of the
compression factor (or of the density) of the gas mixture.
This International Standard provides formally exact conversion procedures, based on fundamental principles,
which fully account for real gas behaviour of pure gases and gas mixtures. In addition to these, approximate
procedures for practical applications are described, designed for different levels of accuracy and available
data. These approximations are necessary because measured gas mixture compression factors (or densities)
are rarely available and therefore have to be estimated from component data. Uncertainty estimates are given
which result from combining approximations in the conversion procedures with the uncertainties of the input
data. Where conversions require real-gas volumetric data of pure gases or gas mixtures, these are expressed
by compression factors. As equivalents, density data could be converted into compression factor data.
INTERNATIONAL STANDARD ISO 14912:2003(E)

Gas analysis — Conversion of gas mixture composition data
1 Scope
This International Standard defines the following quantities commonly used to express the composition of gas
mixtures:
 mole fraction,
 mass fraction,
 volume fraction,
and
 mole concentration,
 mass concentration,
 volume concentration.
For these quantities of composition, this International Standard provides methods for
 conversion between different quantities, and
 conversion between different state
...