EN ISO 6142:2006
(Main)Gas analysis - Preparation of calibration gas mixtures - Gravimetric method (ISO 6142:2001)
Gas analysis - Preparation of calibration gas mixtures - Gravimetric method (ISO 6142:2001)
Specifies the gravimetric method for the preparation of reference gas mixtures in cylinders and is intended for the preparation of calibration gas mixtures whose target accuracy is defined a priori. It is applicable only to mixtures of gaseous, or totally vaporized components which do not react with each other or with the cylinder walls. A procedure is given for the preparation strategy that is based upon preset uncertainty levels of the composition of the final mixture. Multi-component gas mixtures and multiple dilution mixtures are included in this standard and are considered to be special cases of single component weighings.
Gasanalyse - Herstellung von Prüfgasen - Wägeverfahren (ISO 6142:2001)
Diese Internationale Norm legt ein gravimetrisches Verfahren für die Herstellung von Kalibriergasgemischen
in Gasflaschen, von denen die Zielgenauigkeit der Zusammensetzung vorgegeben ist. Es ist nur auf
Gemische von gasförmigen oder vollständig verdampften Komponenten anwendbar, die weder miteinander
noch mit den Flaschenwänden reagieren. Es wird ein Herstellungsverfahren angegeben, das den
Anforderungen an die Zusammensetzung des Endgasgemisches innerhalb vorher festgelegter Unsicherheits-niveaus
zu liegen, genügt. Mehrkomponenten-Gasgemische (einschließlich Erdgas) und Mehrfachver-dünnungsgemische
sind in dieser Internationalen Norm ebenfalls enthalten und werden als Spezialfälle der
gravimetrischen Herstellungsmethode für Einzelkomponenten betrachtet.
Diese Internationale Norm beschreibt auch das Verfahren zur Verifizierung der Zusammensetzung von
gravimetrisch hergestellten Kalibriergasen. Unter der Voraussetzung, dass bei der Herstellung und
Validierung dieser gravimetrischen Gasgemische strenge und umfangreiche Qualitätssicherungs- und
Qualitätskontrollverfahren übernommen werden, können für eine große Palette von Gasgemischen
Kalibriergase höchster Genauigkeit im Vergleich zu anderen Herstellungsmethoden für solche Gase erhalten
werden.
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage - Méthode gravimétrique (ISO 6142:2001)
L'ISO 6142:2001 spécifie une méthode gravimétrique de préparation des mélanges de gaz pour étalonnage dans des bouteilles dont l'exactitude de la composition a été prédéfinie. Elle est applicable uniquement aux mélanges de composants gazeux ou totalement vaporisés qui ne réagissent pas entre eux ou au contact des parois de bouteilles. Un mode opératoire pour une méthode de préparation est fourni avec un certain nombre d'exigences à respecter pour que la composition finale des mélanges gazeux se situe dans les niveaux d'incertitude préétablis. Les mélanges gazeux à plusieurs constituants (y compris le gaz naturel) et les mélanges à dilution multiple sont inclus dans l'ISO 6142:2001 et sont considérés comme des cas particuliers de la méthode de préparation gravimétrique à un seul constituant.
L'ISO 6142:2001 décrit également la méthode de vérification de la composition des gaz pour étalonnage préparés par voie gravimétrique. Sous réserve de l'adoption, au cours de la préparation et de la validation de ces mélanges gazeux gravimétriques, de procédures rigoureuses et exhaustives d'assurance et de contrôle de la qualité, des gaz pour étalonnage de haute exactitude peuvent être obtenus pour une large gamme de mélanges gazeux, en comparaison avec d'autres méthodes de préparation pour ces mêmes gaz.
Analiza plinov - Priprava kalibrirnih plinskih zmesi - Gravimetrijska metoda (ISO 6142:2001)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2006
Analiza plinov - Priprava kalibrirnih plinskih zmesi - Gravimetrijska metoda (ISO
6142:2001)
Gas analysis - Preparation of calibration gas mixtures - Gravimetric method (ISO
6142:2001)
Gasanalyse - Herstellung von Prüfgasen - Wägeverfahren (ISO 6142:2001)
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage - Méthode
gravimétrique (ISO 6142:2001)
Ta slovenski standard je istoveten z: EN ISO 6142:2006
ICS:
71.040.40 Kemijska analiza Chemical analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 6142
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2006
ICS 71.040.40
English Version
Gas analysis - Preparation of calibration gas mixtures -
Gravimetric method (ISO 6142:2001)
Analyse des gaz - Préparation des mélanges de gaz pour Gasanalyse - Herstellung von Prüfgasen - Wägeverfahren
étalonnage - Méthode gravimétrique (ISO 6142:2001) (ISO 6142:2001)
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
versions.
CEN members are the national standards bodies of 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
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Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6142:2006: E
worldwide for CEN national Members.
Foreword
The text of ISO 6142:2001 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 6142:2006 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 6142:2001 has been approved by CEN as EN ISO 6142:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 6142
Second edition
2001-04-01
Gas analysis — Preparation of calibration
gasmixtures—Gravimetric method
Analyse des gaz — Préparation des mélanges de gaz pour étalonnage —
Méthode gravimétrique
Reference number
ISO 6142:2001(E)
©
ISO 2001
ISO 6142:2001(E)
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ii © ISO 2001 – All rights reserved
ISO 6142:2001(E)
Contents Page
Foreword.iv
1 Scope .1
2 Normative references .1
3 Principle.1
4 Preparation of the mixture .2
5 Calculation of uncertainty.7
6 Verification of calibration gas mixture composition.9
7 Test report .10
Annex A (informative) Practical example.11
Annex B (informative) Guidelines for estimating filling pressures so as to avoid condensation of
condensable components in gas mixtures.22
Annex C (informative) Precautions to be taken when weighing, handling and filling cylinders .25
Annex D (informative) Derivation of the equation for calculating the calibration gas mixture
composition.29
Annex E (informative) Sources of error .31
Annex F (informative) Estimation of corrections and correction uncertainty .33
Annex G (informative) Computer implementation of recommended methods.35
Bibliography.36
ISO 6142:2001(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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 6142 was prepared by Technical Committee ISO/TC 158, Analysis of gases, in
collaboration with ISO/TC 193, Natural gas.
This second edition cancels and replaces the first edition (ISO 6142:1981), which has been revised to update the
methods of preparation, estimation of the uncertainty and of validation of gravimetrically prepared calibration gases.
Annexes A to G of this International Standard are for information only.
iv © ISO 2001 – All rights reserved
INTERNATIONAL STANDARD ISO 6142:2001(E)
Gas analysis — Preparation of calibration gas mixtures —
Gravimetric method
1 Scope
This International Standard specifies a gravimetric method for the preparation of calibration gas mixtures in
cylinders of which the target accuracy of the composition has been pre-defined. It is applicable only to mixtures of
gaseous or totally vaporized components which do not react with each other or with the cylinder walls. A procedure
is given for a method of preparation based on requirements for the final gas mixture composition to be within pre-
set levels of uncertainty. Multi-component gas mixtures (including natural gas) and multiple dilution mixtures are
included in this International Standard and are considered to be special cases of the single component gravimetric
preparation method.
This International Standard also describes the procedure for verifying the composition of gravimetrically prepared
calibration gases. Provided rigorous and comprehensive quality assurance and quality control procedures are
adopted during the preparation and validation of these gravimetric gas mixtures, calibration gases of the highest
accuracy can be obtained for a wide range of gas mixtures, in comparison with other methods of preparing such
gases.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 6141, Gas analysis — Requirements for certificates for calibration gases and gas mixtures.
1)
ISO 6143:— , Gas analysis — Comparison methods for determining and checking the composition of calibration
gas mixtures.
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories.
IUPAC, Commission on atomic weights and isotopic abundances: Atomic Weights of the Elements, biennial review.
3Principle
Calibration gas mixtures are prepared by transferring parent gases (pure gases or gravimetrically prepared
mixtures of known composition) quantitatively from supply cylinders to the cylinder in which the calibration gas
mixture will be contained. The amount of gaseous component added from the parent gas is determined by
weighing after each successive addition.
1) To be published. (Revision of ISO 6143:1981)
ISO 6142:2001(E)
The amount of parent gas added to the cylinder in which the calibration gas mixture will be contained is determined
by weighing either the supply cylinder or, alternatively, the cylinder in which the calibration gas mixture will be
contained, before and after each addition. The difference in these two weighings corresponds to the mass of the
gas added. The choice between these two weighing methods depends on which one represents the most suitable
procedure for preparing the specified mixture. For example, the addition of small amounts of a specified component
may best be performed by weighing a small, low-volume supply cylinder, before and after addition, on a highly
sensitive, low-capacity balance.
A single-step preparation method may be used where the amount of each gaseous component required is large
enough to accurately measure the mass of the cylinder, in which the calibration gas mixture will be contained, at
each addition within the required composition uncertainty of the final calibration gas mixture. Alternatively, a
multiple dilution method may be used to obtain a final mixture with acceptable uncertainty, particularly when low
concentrations of the minor components are required. In this method, “pre-mixtures” are gravimetrically prepared
and used as parent gases in one or more dilution steps.
The mass fraction of each component in the final calibration gas mixture is then given by the quotient of the mass
of that component to the total mass of the mixture.
The gravimetric method scheme for preparing calibration gas mixtures, based on pre-set requirements for
composition and the level of uncertainty, is given as a flow chart in Figure 1. The individual steps are explained in
more detail in clause 4 (reference is given to the subcla
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