SIST EN ISO 6145-1:2019

SLOVENSKI STANDARD
SIST EN ISO 6145-1:2019
01-december-2019
Nadomešča:
SIST EN ISO 6145-1:2008
Analiza plinov - Priprava kalibracijskih plinskih zmesi z uporabo dinamičnih metod
- 1. del: Splošni vidiki (ISO 6145-1:2019)
Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 1:
General aspects (ISO 6145-1:2019)
Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamische
Verfahren - Teil 1: Kalibrierverfahren (ISO 6145-1:2019)
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage à l'aide de
méthodes dynamiques - Partie 1 : Aspects généraux (ISO 6145-1:2019)
Ta slovenski standard je istoveten z: EN ISO 6145-1:2019
ICS:
71.040.40 Kemijska analiza Chemical analysis
SIST EN ISO 6145-1:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 6145-1:2019

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SIST EN ISO 6145-1:2019


EN ISO 6145-1
EUROPEAN STANDARD

NORME EUROPÉENNE

October 2019
EUROPÄISCHE NORM
ICS 71.040.40 Supersedes EN ISO 6145-1:2008
English Version

Gas analysis - Preparation of calibration gas mixtures
using dynamic methods - Part 1: General aspects (ISO
6145-1:2019)
Analyse des gaz - Préparation des mélanges de gaz Gasanalyse - Herstellung von Kalibriergasgemischen
pour étalonnage à l'aide de méthodes dynamiques - mit Hilfe von dynamische Verfahren - Teil 1:
Partie 1 : Aspects généraux (ISO 6145-1:2019) Kalibrierverfahren (ISO 6145-1:2019)
This European Standard was approved by CEN on 1 September 2019.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6145-1:2019 E
worldwide for CEN national Members.

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SIST EN ISO 6145-1:2019
EN ISO 6145-1:2019 (E)
Contents Page
European foreword . 3

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SIST EN ISO 6145-1:2019
EN ISO 6145-1:2019 (E)
European foreword
This document (EN ISO 6145-1:2019) has been prepared by Technical Committee ISO/TC 158 "Analysis
of gases" in collaboration with Technical Committee CEN/SS N21 “Gaseous fuels and combustible gas”
the secretariat of which is held by CCMC.
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 April 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 6145-1:2008.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 6145-1:2019 has been approved by CEN as EN ISO 6145-1:2019 without any
modification.

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SIST EN ISO 6145-1:2019

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SIST EN ISO 6145-1:2019
INTERNATIONAL ISO
STANDARD 6145-1
Third edition
2019-09
Gas analysis — Preparation of
calibration gas mixtures using
dynamic methods —
Part 1:
General aspects
Analyse des gaz — Préparation des mélanges de gaz pour étalonnage
à l'aide de méthodes dynamiques —
Partie 1: Aspects généraux
Reference number
ISO 6145-1:2019(E)
©
ISO 2019

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SIST EN ISO 6145-1:2019
ISO 6145-1:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

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SIST EN ISO 6145-1:2019
ISO 6145-1:2019(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
5.1 General . 2
5.2 Suitability of the method to the application . 3
5.3 Piston pumps . 3
5.4 Continuous (syringe) injection . 4
5.5 Capillary . 4
5.6 Critical flow orifices . 4
5.7 Thermal mass flow controller . 5
5.8 Diffusion . 5
5.9 Saturation . 5
5.10 Permeation method . 6
5.11 Electrochemical generation . 6
5.12 Summary . 6
6 Recommendations for handling the dynamic system . 7
6.1 Safety considerations . 7
6.1.1 Reactions between mixture components . 7
6.1.2 Reactions with dynamic system materials . 8
6.2 Quality considerations . 8
6.2.1 Purity of parent gas standards or "zero" gas . 8
6.2.2 Gas handling . 8
7 Calibration methods of a dynamic system . 8
7.1 Generalities on the calibration . 8
7.2 Calibration of each element . 9
7.2.1 General. 9
7.2.2 Calibration devices for flow rate: Principle and uncertainty .10
7.3 Single point calibration of a dynamic system by comparison with reference gas
mixtures .13
7.4 Calibration certificate .13
8 Calculation of the composition and its uncertainty .13
8.1 General .13
8.2 Calculations for volumetric methods . .14
8.2.1 General.14
8.2.2 Formulae .14
8.3 Calculations for gravimetric methods .15
8.3.1 General.15
8.3.2 Formula .15
9 Sources of uncertainty and uncertainty of the final mixture .15
10 Verification .16
10.1 Principle .16
10.2 Verification criteria .16
10.3 Recalibration criteria .16
Annex A (normative) Calculation details .17
Annex B (informative) Atomic weights and molar masses .21
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Bibliography .23
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SIST EN ISO 6145-1:2019
ISO 6145-1:2019(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.
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 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 158, Gas analysis.
This third edition cancels and replaces the second edition (ISO 6145-1:2003), which has been technically
revised. The main changes compared to the previous edition are as follows.
— The techniques for the preparation of gas mixtures are described in an abbreviated manner since
there is no need to repeat the text and formulae from each of the different parts of the ISO 6145
series. However, a summary table (Table 1) presenting the advantages and limitations of each
method has been introduced.
— Recommendations regarding the handling of the dynamic mixing systems and quality considerations
have been added.
— The methods and instruments to calibrate a dynamic system have changed and are better described.
— The calculations to obtain composition and uncertainties are more detailed, and the different ways
of mixing gases (volume flow rates or mass flow rates) have been taken into account.
— Clauses on certificates (7.4) and verification (Clause 10) have been added.
A list of all parts in the ISO 6145 series can be found on the ISO website.
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.
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Introduction
This document is one of a series of standards which describes the various dynamic methods for the
preparation of calibration gas mixtures.
Several techniques are available and the choice between them is decided based on the desired gas
composition range, the consistency of equipment with the application and the required level of
uncertainty. This document aids with making an informed choice by listing all the advantages and
limitations of the methods.
The main techniques used for the preparation of gas mixtures are:
a) piston pumps;
b) continuous injection;
c) capillary;
d) critical orifices;
e) thermal mass-flow controllers;
f) diffusion;
g) saturation;
h) permeation;
i) electrochemical generation.
In dynamic methods, a gas A is introduced at a known constant volume or mass flow rate into a known
constant flow rate of a complementary gas B. Gases A and B can be either pure gases or gas mixtures.
The preparation process can be continuous (such as mass flow controllers, permeation tube) or pseudo-
continuous (such as piston pump).
The dynamic preparation techniques produce a continuous flow of calibration gas mixtures into the
analyser but do not generally allow the build-up of a reserve by storage under pressure.
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SIST EN ISO 6145-1:2019
INTERNATIONAL STANDARD ISO 6145-1:2019(E)
Gas analysis — Preparation of calibration gas mixtures
using dynamic methods —
Part 1:
General aspects
1 Scope
This document gives a brief overview of each of the dynamic techniques which are described in detail
in the subsequent parts of ISO 6145. This document provides basic information to support an informed
choice for one or another method for the preparation of calibration gas mixtures. It also describes how
these methods can be linked to national measurement standards to establish metrological traceability
for the composition of the prepared gas mixtures.
Since all techniques are dynamic and rely on flow rates, this document describes the calibration process
by measurement of each individual flow rate generated by the device.
Methods are also provided for assessing the composition of the generated gas mixtures by comparison
with an already validated calibration gas mixture.
This document provides general requirements for the use and operation of dynamic methods for gas
mixture preparation. It also includes the necessary expressions for calculating the calibration gas
composition and its associated uncertainty.
Gas mixtures obtained by these dynamic methods can be used to calibrate or control gas analysers.
The storage of dynamically prepared gas mixtures into bags or cylinders is beyond the scope of this
document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 6143, Gas analysis — Comparison methods for determining and checking the composition of calibration
gas mixtures
ISO 7504, Gas analysis — Vocabulary
ISO 12963, Gas analysis — Comparison methods for the determination of the composition of gas mixtures
based on one- and two-point calibration
ISO 14912, Gas analysis — Conversion of gas mixture composition data
ISO 19229, Gas analysis — Purity analysis and the treatment of purity data
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7504 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
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ISO 6145-1:2019(E)

— IEC Electropedia: available at http: //www .electropedia .org/
3.1
mass flow rate
q
m
mass of gas per unit of time
3.2
volume flow rate
q
v
volume of gas per unit of time
4 Symbols
Symbol Definition
i, k Indices for components in a gas or gas mixture
j Index for a parent gas
K Conversion factor between two gases
m Mass of a component
M Molar mass of a component
p Pressure
q Number of components in the gas mixture
q Mass flow rate
m
q Amount-of-substance flow rate
n
R Ideal gas constant
r Number of parent gases
T Temperature
V Volume
q Volume flow rate
v
u(x) Standard uncertainty of a quantity x
v Mass fraction of a component in a parent gas
w Mass fraction of a component in a gas mixture
x Amount-of-substance fraction of a component in a parent gas
y Amount-of-substance fraction of a component in a gas mixture
Z Compressibility factor
φ Volume fraction of a component in a parent gas
ϕ Volume fraction of a component in a gas mixture
5 Principle
5.1 General
All preparation techniques described in ISO 6145 (all parts) are based on the combination of gas flows.
These flow rates can be measured on a volume or mass basis. The composition is calculated from the
flow rate data and the composition of the parent gases.
It is applicable only to
— pure gases,
— gas mixtures, or
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— totally vaporized components at ambient pressure,
which do not react with each other or with any surfaces of the mixing device.
For the calculation of the composition, it is essential to appreciate the composition of the parent gases
used for preparing the calibration gas mixture. Even if such gases are considered “pure”, their purity
shall be verified in accordance with ISO 19229. The corresponding compositional data of these parent
gases shall be used in the calculation of the composition, as described in Clause 7.
Practically, all preparation systems are furthermore sensitive to changes or fluctuations in the
conditions under which the calibration gas mixture is prepared. These conditions typically include
the pressure and temperature of the gases, as well as the dynamic effects of combining flows and
homogenization of the calibration gas mixture, among others. In the subsequent parts of ISO 6145,
attention is drawn to these effects, and care shall be taken to follow these instructions.
Several techniques are available and the choice between them should be decided based on the desired
composition range, the availability of equipment and the required uncertainty.
The principles of gas mixing systems are described in each part of ISO 6145.
Depending on its principle, each dynamic method will generate gas mixtures of composition based
on either volume fraction, mass fraction, amount-of-substance fraction or mass concentration. The
calibration procedure will also affect the expression of gas mixture composition (mass, volume or
amount-of-substance fraction). The final fraction and its associated uncertainty depend both on the
calibration method and on the preparation technique.
5.2 Suitability of the method to the application
Before preparing a gas mixture, it is necessary to consider the suitability of the dynamic system to
the application. Pressure and flow rates should be consistent with the analyser to which the dynamic
system will be linked.
Users shall comply with the manufacturers' recommendations. Check if the dynamic method is sensitive
to external parameters, such as temperature or atmospheric pressure, and follow the recommendations
given in each part of ISO 6145.
Depending on the principle used by the dynamic system, the achievable range of concentration in
the final mixture will differ. In order to compare the capabilities of each method, a dilution ratio is
estimated as follows:
— use of pure components as parent components (for example: in cylinders, or permeation tubes or by
syringe injection);
— only one step dilution is considered.
This dilution ratio could be extended for some dynamic systems by two step dilution.
When choosing the type of the dynamic method, the user shall take into consideration the advantages
and limitations of each method.
5.3 Piston pumps
ISO 6145-2 specifies a volumetric method for the dynamic preparation of calibration gas mixture using
piston pumps. Two or more piston pumps, combined in a gas-mixing pump, are driven with a defined
ratio of strokes. The stroke volume of each piston pump is individually determined by the geometry
(cross-section) of the cylinder and the height of stroke of the piston. The composition is rapidly
changed by the mechanical changing of the ratio of strokes. Suitable peripherals for gas feeding and
homogenization of the final mixture are recommended.
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ISO 6145-1:2019(E)

The calibration of the stroke volume is made by dimensional measurements in the SI base unit of length.
Uncertainty evaluation of the gas mixture composition and an assessment of potential sources with
quantification of significant sources of uncertainty are out lined in detail in ISO 6145-2.
The merits of the method are that the composition and the associated uncertainty of the calibration gas
mixture are calculated from the geometric stroke volume and the ratio of strokes of the piston pumps.
The content of each component is directly expressed in volume fractions and in amount-of-substance
fractions.
Final mixture flow rates from 5 l/h to 500 l/h can be prepared depending on the equipment used.
4
Using this method, dilution ratios from 1:1 up to 1:10 can be prepared from initial amount-of-substance
fraction. Higher dilution ratios can be prepared by a two-stage dilution.
5.4 Continuous (syringe) injection
ISO 6145-4 specifies a method for preparation of calibration gas mixtures using continuous injection.
The calibration component, either in the gaseous or liquid phase, is displaced from a reservoir through
a capillary into a complementary inert gas stream. The system may contain a syringe, whose plunger
is continuously driven by a suitable variable-speed motor. Alternatively, the component may be forced
through the capillary by controlled pressurization of the reservoir.
This method applies also to multi-component mixtures of known composition. In the case of l
...