SIST EN ISO 16664:2017

SLOVENSKI STANDARD
SIST EN ISO 16664:2017
01-september-2017
1DGRPHãþD
SIST EN ISO 16664:2008
Analiza plinov - Ravnanje s kalibracijskimi plini in plinskimi zmesmi - Smernice
(ISO 16664:2017)
Gas analysis - Handling of calibration gases and gas mixtures - Guidelines (ISO
16664:2017)
Gasanalyse - Handhabung von Kalibriergasen und Gasgemischen - Richtlinien (ISO
16664:2017)
Analyse des gaz - Mise en oeuvre des gaz et des mélanges de gaz pour étalonnage -
Lignes directrices (ISO 16664:2017)
Ta slovenski standard je istoveten z: EN ISO 16664:2017
ICS:
71.040.40 Kemijska analiza Chemical analysis
SIST EN ISO 16664:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 16664:2017

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SIST EN ISO 16664:2017


EN ISO 16664
EUROPEAN STANDARD

NORME EUROPÉENNE

June 2017
EUROPÄISCHE NORM
ICS 71.040.40 Supersedes EN ISO 16664:2008
English Version

Gas analysis - Handling of calibration gases and gas
mixtures - Guidelines (ISO 16664:2017)
Analyse des gaz - Mise en oeuvre des gaz et des Gasanalyse - Handhabung von Kalibriergasen und
mélanges de gaz pour étalonnage - Lignes directrices Gasgemischen - Richtlinien (ISO 16664:2017)
(ISO 16664:2017)
This European Standard was approved by CEN on 19 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 16664:2017 E
worldwide for CEN national Members.

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SIST EN ISO 16664:2017
EN ISO 16664:2017 (E)
Contents Page
European foreword . 3
2

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SIST EN ISO 16664:2017
EN ISO 16664:2017 (E)
European foreword
This document (EN ISO 16664:2017) has been prepared by Technical Committee ISO/TC 158 "Analysis
of gases".
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 December 2017, and conflicting national standards
shall be withdrawn at the latest by December 2017.
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 16664:2008.
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, 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 16664:2017 has been approved by CEN as EN ISO 16664:2017 without any modification.

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SIST EN ISO 16664:2017
INTERNATIONAL ISO
STANDARD 16664
Second edition
2017-05
Gas analysis — Handling of calibration
gases and gas mixtures — Guidelines
Analyse des gaz — Mise en oeuvre des gaz et des mélanges de gaz
pour étalonnage — Lignes directrices
Reference number
ISO 16664:2017(E)
©
ISO 2017

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SIST EN ISO 16664:2017
ISO 16664:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
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SIST EN ISO 16664:2017
ISO 16664:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Transport and storage . 3
4.1 General remarks . 3
4.2 Low temperature. 3
4.3 High temperature. 4
4.4 Water . 4
4.5 Storage and handling . 4
5 Mode of withdrawal . 4
5.1 General . 4
5.2 Minimum utilization pressure . 4
5.3 Temperature . 5
5.4 Pressure reduction and flow . 5
5.5 Replacement, change of cylinder positions . 5
6 Transfer system . 5
6.1 Purging procedure . 5
6.2 Considerations when designing and constructing gas transfer lines . 6
6.2.1 Modes of gas sampling . 6
6.2.2 Pressure- and flow-reducing equipment . 7
6.2.3 Material for the construction of transfer lines . 7
6.2.4 General methods and examples of sampling systems .10
7 Stability .13
Annex A (informative) Check on the stability of calibration gas mixtures by end-users .14
Bibliography .16
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ISO 16664:2017(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: w w w . i s o .org/ iso/ foreword .html
This document was prepared by Technical Committee ISO/TC 158, Analysis of gases.
This second edition cancels and replaces the first edition (ISO 16664:2004), which has been technically
revised. The major changes are the following:
— Figures 1 and 5 have been revised to more clearly depict the arrangements;
— several references and terminological entries have been updated.
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SIST EN ISO 16664:2017
ISO 16664:2017(E)

Introduction
This document uses the terms “calibration gas” for both gas mixtures and pure gases as the limiting
case of gas mixtures.
The quality of calibration gases in cylinders as certified by producers is defined by
a) the correct analyte content;
b) a known uncertainty which is appropriate for its intended use;
c) the stability;
d) the homogeneity.
During its utilization period, the quality of calibration gases is influenced by
— storage conditions at the manufacturer’s and user’s sites;
— transport conditions;
— modes of calibration gas withdrawal and transfer;
— the transfer system employed.
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SIST EN ISO 16664:2017
INTERNATIONAL STANDARD ISO 16664:2017(E)
Gas analysis — Handling of calibration gases and gas
mixtures — Guidelines
SAFETY PRECAUTIONS — National and international safety regulations concerning storage,
use and transportation of pure gases and gas mixtures are to be followed in addition to this
document.
1 Scope
This document describes factors that may influence the composition of pure gases and homogeneous
gas mixtures used for calibration purposes. This document only applies to gases or gas mixtures that
are within the “utilization period”. It provides the following guidelines for the handling and use of
calibration gas mixtures:
— storage of calibration gas cylinders;
— calibration gas withdrawal from cylinders;
— transfer of calibration gas from cylinders to the point of calibration.
It also outlines a method of assessing the stability of a gas mixture, taking into account the gas
composition uncertainty given on the certificate and the user’s measurement uncertainty.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www.e lectropedia. org/
— ISO Online browsing platform: available at http:// www. iso. org/o bp
3.1
calibration gas
pure gas or gas mixture used for calibration
3.2
calibration gas mixture
gas mixture of known stability (3.9) and homogeneity (3.4) whose composition is well established for
use in the calibration or verification of a measuring instrument or for the validation of a measurement
Note 1 to entry: Calibration gas mixtures are measurement standards (Annex A) as defined in
ISO/IEC Guide 99:2007.
[SOURCE: ISO 7504:2015, 5.1]
3.3
component
chemical entity at a defined physical state present in a material or in a mixture
[SOURCE: ISO 7504:2015, 3.3]
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3.4
homogeneity
state of a gas mixture wherein all of its components are distributed uniformly throughout the volume
occupied by the gas mixture
[SOURCE: ISO 7504:2015, 3.1]
3.5
impurity
undesired minor component present in a parent gas (and thus detectable in a gas mixture made of this
parent gas
[SOURCE: ISO 7504:2015, 5.5]
3.6
leak rate
volume of fluid leaking from the system per unit of time due to incomplete sealing of materials
3.7
leak tightness
conformity to a specified leak rate
3.8
step response time
duration between the instant when an input quantity value of a measuring instrument or measuring
system is subjected to an abrupt change between two specified constant quantity values and the instant
when a corresponding indication settles within specified limits around its final steady value
[SOURCE: ISO/IEC Guide 99:2007]
3.9
stability
attribute of a gas mixture, under specified conditions, to maintain its composition within specified
uncertainty limits for a specified period of time (maximum storage life)
[SOURCE: ISO 7504:2015, 3.2]
3.10
maximum storage life
period after which the properties stated for a gas mixture cannot be warranted to lie within their limits
Note 1 to entry: This period is usually identified as that for which the producer ensures that the gas mixture
maintains its composition within the specified limits when it is stored in accordance with the requirements
based upon the concepts defined in ISO 7504:2015, 7.1 to 7.4.
Note 2 to entry: The end of this period may be indicated by an “expiry date” (see also ISO 6142-1).
[SOURCE: ISO 7504:2015, 7.5]
3.11
transfer system
gas-conducting system which begins at the cylinder valve and ends at the gas sample inlet to the
measuring instrument and includes all structural elements
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3.12
measurement uncertainty
non-negative parameter characterizing the dispersion of the quantity values being attributed to a
measurand, based on the information used
Note 1 to entry: Measurement uncertainty includes components arising from systematic effects, such as
components associated with corrections and the assigned quantity values of measurement standards, as well
as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead,
associated measurement uncertainty components are incorporated.
Note 2 to entry: The parameter may be, for example, a standard deviation called standard measurement
uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability.
Note 3 to entry: Measurement uncertainty comprises, in general, many components. Some of these may be
evaluated by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity
values from series of measurements and can be characterized by standard deviations. The other components,
which may be evaluated by Type B evaluation of measurement uncertainty, can also be characterized by standard
deviations, evaluated from probability density functions based on experience or other information.
Note 4 to entry: In general, for a given set of information, it is understood that the measurement uncertainty is
associated with a stated quantity value attributed to the measurand. A modification of this value results in a
modification of the associated uncertainty.
[SOURCE: ISO/IEC Guide 99:2007, 2.26]
3.13
utilization period
time between the date of certification and the expiry date
3.14
permeability
property of a material of transmitting gases and liquids by passage through one surface and out at
another surface by diffusion and sorption processes
Note 1 to entry: Not to be confused with porosity.
[SOURCE: ISO 472:2013, 2.690]
4 Transport and storage
4.1 General remarks
After preparation of the calibration gas, the gas cylinder is transported to the user. The environment
in which the cylinders are transported is not normally regulated in terms of temperature and
humidity. Low temperatures may have a detrimental impact on the mixture composition, especially
when condensable components are present in the mixture. As a consequence of this, environmental
conditions during transport and storage should never exceed those recommended by the manufacturer.
Gas cylinders and especially cylinder valves shall be free of grease and other lubricants. During storage
and transportation, cylinder valves shall be closed, sealing nuts or plugs shall be tightened and suitable
protection devices shall be attached, e.g. caps or valve guards.
The gas cylinders are transported in several ways, e.g. by air, railway, road and on water. In some specific
cases, the temperature restrictions may be such that not every means of transport is acceptable.
4.2 Low temperature
The gas cylinder may be exposed to low temperatures during storage and transportation. For gas
mixtures containing condensable components, it is important that the cylinder is not stored or
transported at temperatures below those recommended by the manufacturer. If the mixture is exposed
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to temperatures below the stated range, some components may condense and this will change the
composition of the mixture.
If the mixture has been exposed to temperatures lower than those recommended by the manufacturer,
the certificate from the manufacturer is no longer valid. In this case, it is very important that the mixture
shall not be used before the manufacturer is asked for further advice. He may advise homogenizing the
mixture before usage.
4.3 High temperature
Avoid high temperatures (heating) close to the cylinder, e.g. from welding flames, blowlamps, ovens or
other intensive heat sources. High temperatures will result in higher pressures leading to potentially
hazardous situations. In addition, elevated temperatures may result in decomposition of thermally
unstable species.
4.4 Water
Gas cylinders shall be protected from excessive humidity during transport. Transportation by boat may
result in the cylinder being sprayed with water; this and/or excessive humidity may cause corrosion of
the cylinder valve. Always protect the cylinder from precipitation to prevent corrosion. If the cylinders
are stored outdoors protected by a roof, the cylinder base should also be protected from water
accumulating on the floor by raising it above the ground.
4.5 Storage and handling
The best way to store calibration gas mixtures for a longer period is by laying the cylinders in a
horizontal position, well protected against rolling and falling. For safety reasons, it is necessary to
separate cylinders containing flammable gases from cylinders containing oxidizing components.
WARNING — For general safety reasons, never heat cylinders above the maximum temperature
specified by the manufacturer.
Mixtures containing condensable components may require rehomogenization if stored for longer
periods of time and if exposure to temperatures below the condensation point cannot be excluded. This
may be done by bringing up the cylinders to ambient temperature and rotating them into a horizontal
position for an appropriate period of time, which may depend on the matrix gas and the components
(see 5.2).
After rehomogenization, it is necessary to contact the manufacturer in order to verify the validity of the
calibration gas.
5 Mode of withdrawal
5.1 General
In the withdrawal of the gas from the cylinder through the transfer system, a number of aspects shall
be considered.
5.2 Minimum utilization pressure
The information attached to the cylinder indicates, if applicable, a pressure value below which the gas
should not be used. It has been reported that in some cases under a certain pressure, gas molecules
that were attached to the cylinder wall come off this cylinder wall when the cylinder pressure drops,
resulting in a higher mole fraction.
In addition to this effect on the stability of the gas mixture, it is important from the point of view of the
manufacturer that a cylinder is not completely emptied, as the cylinder could then be contaminated
with environmental air. This especially applies to specially treated cylinders where stability is an issue.
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5.3 Temperature
Gas mixtures containing condensable components are often limited to a certain temperature range by
the manufacturer. In calculating such a mixture, the manufacturer will assume a certain temperature
of usage to calculate the vapour pressure at that specific temperature. Normally, a safety tolerance is
included to allow use of the mixture within a certain temperature range; however, outside this range
the condensable component may condensate, resulting in a change of gas mixture composition. In
analysing gas mixtures, it is recommended to allow all cylinders to reach temperature equilibrium.
Differences in temperature of different gas mixtures will influence the response of the gas analyser to
these mixtures, according to the gas law (Boyle, Gay-Lussac).
5.4 Pressure reduction and flow
Normally, the withdrawal of gas from a cylinder is regulated by a pressure reducer and/or flow
controller (needle valve, mass-flow controller, capillary, etc.). Due to the reversible adiabatic expansion
of the gas when withdrawing the gas from the cylinder, cooling of the gas in the cylinder will occur.
Furthermore, Joule Thomson cooling and/or heating will change the temperature of the transported
gas itself. Again, especially with mixtures containing condensable components, condensation might
occur due to these temperature effects. It is important that the pressure drop across flow controllers
is minimized. Flow characteristics of flow controllers are normally specified by the manufacturer and
give sufficient information to judge whether the requested flow can be controlled by the chosen flow
controllers. In calculating the pressure drop, tube sizing (inside diameter and length) shall also be
considered.
External heating of the gas at or before the reducer and using more than one reducer to drop the
pressure in stages could help to minimize the danger of condensation.
5.5 Replacement, change of cylinder positions
Re-connecting cylinders may result in leaking connections. This shall be avoided by completing leak
testing. In an optimum set-up, the reducer should remain on the cylinder and the cylinder is preferably
left with some gas inside. This will help to reduce the number of purge cycles to flush the reducer prior
to analysis. Even in this optimum set-up, some environmental air diffusion into the reducer over time
may occur, even if this is pressurized.
NOTE In the long run, there will usually be some diffusion from O and H O from the environment into the
2 2
reducing valve, even if this is pressurized.
6 Transfer system
6.1 Purging procedure
The transfer-line integrity, including the leak tightness and cleanliness of all the components (pressure
regulator, valves, transfer line, connections, etc.) shall be guaranteed. In order to guarantee this, an
appropriate purging procedure shall be used. There are several simple methods that may be used to
purge the transfer system; the most effective method uses a vacuum pump. In any case, it is important
to open the cylinder valve only partially and only for a very short time (i.e. 0,5 s), both for safety reasons
and in order to avoid back contamination.
If a vacuum pump is available, then the purging procedure should be as follows (see also Figure 1).
Sequentially evacuate and pressurize the entire transfer line with the gas mixture to be used. This
procedure should be repeated several times; typically, three cycles are sufficient. Make sure that
pressure regulators are suited for evacuation and that the purging cycle starts with evacuation.
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Key
1 pressure regulator with purge valve
2 dose valve
3 shut-off valve
4 transfer line
5 three-way valve
6 excess-flow line with flow indicator (applicable only for extractive monitors)
7 motor with sample pump
8 vacuum pump
9 gas mixture
Figure 1 — Arrangement for a periodic purging procedure for monitor systems
If a vacuum pump is not available, the following procedure is recommended.
Sequentially pressurize and vent the transfer system with the gas mixture to be used. This method
is not as effective as the vacuum method, hence more cycles, typically five to eight, are required. The
number of cycles depends on the concentration of the measurand; low-concentration mixtures require
more steps. However, this method is prone to back contamination and should not be used for oxygen-
sensitive mixtures; for these mixtures, the evacuation method is strongly recommended.
For both methods, the insertion of a stop valve after the pressure regulator is recommended for safety
reasons.
6.2 Considerations when designing and constructing gas transfer lines
6.2.1 Modes of ga
...