EN ISO 6144:2006

SLOVENSKI STANDARD
01-november-2006
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Gas analysis - Preparation of calibration gas mixtures - Static volumetric method (ISO
6144:2003)
Gasanalyse - Herstellung von Prüfgasen - Volumetrisch - statisches Verfahren (ISO
6144:2003)
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage - Méthode
volumétrique statique (ISO 6144:2003)
Ta slovenski standard je istoveten z: EN ISO 6144:2006
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 6144
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2006
ICS 71.040.40
English Version
Gas analysis - Preparation of calibration gas mixtures - Static
volumetric method (ISO 6144:2003)
Analyse des gaz - Préparation des mélanges de gaz pour Gasanalyse - Herstellung von Prüfgasen - Volumetrisch -
étalonnage - Méthode volumétrique statique (ISO statisches Verfahren (ISO 6144:2003)
6144:2003)
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
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.
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© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6144:2006: E
worldwide for CEN national Members.

Foreword
The text of ISO 6144:2003 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 6144:2006 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 6144:2003 has been approved by CEN as EN ISO 6144:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 6144
Second edition
2003-02-01
Gas analysis — Preparation of calibration
gas mixtures — Static volumetric method
Analyse des gaz — Préparation des mélanges de gaz pour
étalonnage — Méthode volumétrique statique

Reference number
ISO 6144:2003(E)
©
ISO 2003
ISO 6144:2003(E)
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ii © ISO 2003 — All rights reserved

ISO 6144:2003(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Principle .2
5 Apparatus.2
6 Procedure for preparing the calibration gas mixture .4
7 Calculation of the volume fraction of the calibration component in the gas mixture.7
8 Determination of the uncertainty in the concentration of the calibration component in the
gas mixture .9
Annex A (informative) Example of an apparatus suitable for the preparation of calibration gas
mixtures by the static volumetric method.12
Annex B (informative) Example of determination of the volume of metering syringes .15
Annex C (informative) Example of the determination of the uncertainty in the concentration of a
calibration gas mixture prepared by the static volumetric method.17
Annex D (informative) Example of the determination of the stability, as a function of time, of
prepared calibration gas mixtures .22
Bibliography.29

ISO 6144:2003(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 6144 was prepared by Technical Committee ISO/TC 158, Analysis of gases.
This second edition cancels and replaces the first edition (ISO 6144:1981), which has been technically
revised.
iv © ISO 2003 — All rights reserved

INTERNATIONAL STANDARD ISO 6144:2003(E)

Gas analysis — Preparation of calibration gas mixtures —
Static volumetric method
1 Scope
This International Standard specifies a method for the preparation of calibration gas mixtures by a static
volumetric method and provides a procedure for calculating the volumetric composition of the mixture. It can
be used either with binary gas mixtures (containing one calibration component in a complementary gas, which
[1, 2]
is usually nitrogen or air ) or with mixtures containing more than one component in the complementary gas.
This International Standard also specifies how the expanded uncertainty in the volume fraction of each
calibration component in the mixture is determined by a rigorous evaluation of all the measurement
uncertainties involved, including those associated with the apparatus used for the preparation of the gas
mixture and those associated with the experimental procedure itself.
NOTE 1 This International Standard is generally applicable to the preparation of calibration gas mixtures containing
−9 −6
calibration components in the concentration range 10 × 10 (10 ppb — parts per billion) to 50 × 10 (50 ppm — parts per
million) by volume. However, gas mixtures may be prepared at larger or smaller volume fractions, provided that the
components used in the static dilution process are selected appropriately.
NOTE 2 A relative expanded uncertainty of not greater than ± 1 % at a level of confidence of 95 % may be achievable
at these concentrations, provided that:
 the purities of the parent gases have been determined by analysis and any significant impurities and the uncertainties
in their measured concentrations have been taken into account;
 no significant adsorption effects or chemical reactions occur between the gaseous constituents and the internal
surfaces of the apparatus, and there are no reactions between any of the gaseous components, i.e. between the
calibration component and complementary gas or between the calibration components themselves;
 all the relevant apparatus used in the preparation of a calibration gas mixture have been calibrated with assigned
measurement uncertainties which are appropriate to calculating the final expanded uncertainty for the calibration gas
mixture prepared.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7504, Gas analysis — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7504 apply.
ISO 6144:2003(E)
4 Principle
A calibration gas mixture consists of one of more calibration components in a complementary (diluent) gas,
mixed in a suitable gas-mixing chamber. These calibration components are generally pure gases taken from
cylinders, or from pure, volatile liquids that are allowed to evaporate into the gas-mixing chamber. The gas
mixture is prepared using syringes to inject:
 either known volumes of gaseous calibration components (each at a pressure of about 1 × 10 Pa);
 or known masses or volumes of liquid calibration components;
These are injected into a volume of complementary gas contained in the mixing chamber (which is also at a
pressure of about 1 × 10 Pa). Further complementary gas is then added to increase the overall pressure of
the gas mixture to an accurately measured value above ambient atmospheric pressure. This final (above-
atmospheric) pressure is required so that the calibration gas mixture will subsequently flow out of the mixing
chamber and can be used to calibrate a gas analyser, which is usually operated at ambient pressure.
At each stage in the preparation procedure, the mixture is homogenized, usually by means of a suitable
stirring device, and then left to equilibrate to ambient atmospheric temperature.
The volume fraction of each calibration component in the calibration gas mixture is determined by calculation
of the ratio of the volume of the calibration component to the total volume of the mixture.
5 Apparatus
5.1 Gas-mixing chamber, consisting of the components specified in 5.1.1 to 5.1.8.
NOTE An example of a suitable gas-mixing chamber is described in Annex A.
5.1.1 Vessel, comprising the gas-mixing chamber itself, of sufficient internal volume to deliver the amount
of calibration gas mixture required for any subsequent instrumental calibrations, manufactured of a suitable
material that is inert to all the component gases, and designed both to be evacuable and to withstand the
required above-atmospheric operating pressures. It shall also have vacuum/high-pressure fl
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