SIST EN ISO 10156:2018

SLOVENSKI STANDARD
SIST EN ISO 10156:2018
01-maj-2018
1DGRPHãþD
SIST EN ISO 10156:2010
SIST EN ISO 10156:2010/AC:2010
3OLQVNHMHNOHQNH3OLQLLQ]PHVLSOLQRY'RORþLWHYVWRSQMHYQHWOMLYRVWLLQ
RNVLGDWLYQRVWL]DL]ELURL]KRGQHJDSULNOMXþNDYHQWLOD]DMHNOHQNR,62
Gas cylinders - Gases and gas mixtures - Determination of fire potential and oxidizing
ability for the selection of cylinder valve outlets (ISO 10156:2017)
Gasflaschen - Gase und Gasgemische - Bestimmung der Brennbarkeit und des
Oxidationsvermögens zur Auswahl von Ventilausgängen (ISO 10156:2017)
Bouteilles à gaz - Gaz et mélanges de gaz - Détermination du potentiel d'inflammabilité
et d'oxydation pour le choix des raccords de sortie de robinets (ISO 10156:2017)
Ta slovenski standard je istoveten z: EN ISO 10156:2017
ICS:
23.020.35 Plinske jeklenke Gas cylinders
71.100.20 Industrijski plini Gases for industrial
application
SIST EN ISO 10156:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 10156:2018

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SIST EN ISO 10156:2018


EN ISO 10156
EUROPEAN STANDARD

NORME EUROPÉENNE

August 2017
EUROPÄISCHE NORM
ICS 23.020.35; 71.100.20 Supersedes EN ISO 10156:2010
English Version

Gas cylinders - Gases and gas mixtures - Determination of
fire potential and oxidizing ability for the selection of
cylinder valve outlets (ISO 10156:2017)
Bouteilles à gaz - Gaz et mélanges de gaz - Gasflaschen - Gase und Gasgemische - Bestimmung der
Détermination du potentiel d'inflammabilité et Brennbarkeit und des Oxidationsvermögens zur
d'oxydation pour le choix des raccords de sortie de Auswahl von Ventilausgängen (ISO 10156:2017)
robinets (ISO 10156:2017)
This European Standard was approved by CEN on 19 August 2017.

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 10156:2017 E
worldwide for CEN national Members.

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SIST EN ISO 10156:2018
EN ISO 10156:2017 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 10156:2018
EN ISO 10156:2017 (E)
European foreword
This document (EN ISO 10156:2017) has been prepared by Technical Committee ISO/TC 58 “Gas
cylinders” in collaboration with Technical Committee CEN/TC 23 “Transportable gas cylinders” the
secretariat of which is held by BSI.
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 2018, and conflicting national standards
shall be withdrawn at the latest by February 2018.
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 10156:2010.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
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 10156:2017 has been approved by CEN as EN ISO 10156:2017 without any modification.
3

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SIST EN ISO 10156:2018

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SIST EN ISO 10156:2018
INTERNATIONAL ISO
STANDARD 10156
Fourth edition
2017-07
Gas cylinders — Gases and gas
mixtures — Determination of fire
potential and oxidizing ability for the
selection of cylinder valve outlets
Bouteilles à gaz — Gaz et mélanges de gaz — Détermination du
potentiel d’inflammabilité et d’oxydation pour le choix des raccords de
sortie de robinets
Reference number
ISO 10156:2017(E)
©
ISO 2017

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SIST EN ISO 10156:2018
ISO 10156:2017(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
ii © ISO 2017 – All rights reserved

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SIST EN ISO 10156:2018
ISO 10156:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 1
4 Flammability of gases and gas mixtures in air . 3
4.1 General . 3
4.2 Test method . 3
4.2.1 Key points concerning safety . 3
4.2.2 Principle . 4
4.2.3 Test apparatus and materials . 4
4.2.4 Procedure for determination of flammability . 5
4.2.5 Procedure for determination of flammability limits . . 5
4.2.6 Results for pure gases . . 5
4.3 Calculation method for flammability of gas mixtures containing n flammable gases
and p inert gases . 8
4.4 Examples .11
4.5 Calculation method for lower flammability limit of gas mixtures .12
4.5.1 General.12
4.5.2 Mixtures of flammable gases and mixtures of flammable gases with
nitrogen and/or air .13
4.5.3 Mixtures of flammable gases with inert gases other than nitrogen and air .13
4.6 Examples .13
4.7 Classification according to the Globally Harmonized System (GHS) .15
5 Oxidizing power of gases and gas mixtures .15
5.1 General .15
5.2 Test method .15
5.2.1 Key points concerning safety .15
5.2.2 Principle .15
5.2.3 Test apparatus .16
5.2.4 Procedure .19
5.2.5 Results .19
5.3 Calculation method .19
5.3.1 Principle .19
5.3.2 C coefficients .20
i
6 Mixtures containing oxygen and flammable gases .21
6.1 General .21
6.2 Basis of flammability classification .22
6.3 Examples .24
Annex A (informative) Classification according to the Globally Harmonized System (GHS) .26
Bibliography .27
© ISO 2017 – All rights reserved iii

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SIST EN ISO 10156:2018
ISO 10156:2017(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 58, Gas cylinders, Subcommittee SC 2,
Cylinder fittings.
This fourth edition cancels and replaces the third edition (ISO 10156:2010), which has been technically
revised. It also incorporates ISO 10156:2010/Cor 1:2010.
The main changes compared to the previous edition are as follows:
— 4.1, 4.2.5 and 4.4 have been technically revised;
— 4.5 and 4.6 have been added.
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SIST EN ISO 10156:2018
ISO 10156:2017(E)

Introduction
ISO 5145 specifies the dimensions of different cylinder valve outlets for different compatible gas groups.
These compatible gas groups are determined according to practical criteria defined in ISO 14456.
These criteria are based on certain physical, chemical, toxic and corrosive properties of the gases. In
particular, the flammability in air and the oxidizing ability are considered in this document.
One of the potential complications that prompted the development of this document is that while there
are abundant data in the literature relating to pure gases, differences can be found, depending upon the
test methods employed. In the case of gas mixtures, data in the literature are often incomplete or even
non-existent.
The initial aim of this document was to eliminate the ambiguities in the case of differences in the
literature, and above all, to supplement existing data (mainly in the case of gas mixtures).
Subsequently, this document was used for other purposes than the selection of cylinder valve outlets,
such as establishing flammability and oxidizing potential data for the classification and labelling of
gases and gas mixtures.
This document is intended to be used under a variety of national regulatory regimes, but has been
[9]
written so that it is suitable for the application of the UN Model Regulations and the UN-GHS .
© ISO 2017 – All rights reserved v

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SIST EN ISO 10156:2018

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SIST EN ISO 10156:2018
INTERNATIONAL STANDARD ISO 10156:2017(E)
Gas cylinders — Gases and gas mixtures — Determination
of fire potential and oxidizing ability for the selection of
cylinder valve outlets
1 Scope
This document specifies methods for determining whether or not a gas or gas mixture is flammable in
air and whether a gas or gas mixture is more or less oxidizing than air under atmospheric conditions.
This document is intended to be used for the classification of gases and gas mixtures including the
selection of gas cylinder valve outlets.
This document does not cover the safe preparation of these mixtures under pressure and at
temperatures other than ambient.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, symbols and units
3.1 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 .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1.1
gas or gas mixture flammable in air
gas or gas mixture that is ignitable in air at atmospheric pressure and a temperature of 20 °C
3.1.2
lower flammability limit in air
minimum content of a gas or gas mixture in a homogeneous mixture with air at which a flame just
starts to propagate
Note 1 to entry: The lower flammability limit is determined at atmospheric conditions.
Note 2 to entry: The term “flammability limit”, as used in this document, is sometimes called “explosion limit”.
3.1.3
upper flammability limit in air
maximum content of a gas or gas mixture in a homogeneous mixture with air at which a flame just
starts to propagate
Note 1 to entry: The upper flammability limit is determined at atmospheric conditions.
Note 2 to entry: The term “flammability limit”, as used in this document, is sometimes called “explosion limit”.
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SIST EN ISO 10156:2018
ISO 10156:2017(E)

3.1.4
flammability range
range of concentration between the lower and upper flammability limits
Note 1 to entry: The term “flammability range”, as used in this document, is sometimes also called “explosion range”.
3.1.5
gas or gas mixture more oxidizing than air
gas or gas mixture that is able, at atmospheric pressure, to support the combustion more than a
reference mixture consisting of 23,5 % oxygen in nitrogen
3.1.6
oxidizing power
OP
dimensionless number that compares the oxidizing capability of a gas or gas mixture to that of oxygen
Note 1 to entry: OP is calculated as the sum of the products of the mole fraction(s) of each oxidizing component
times its coefficient of oxygen equivalency, C .
i
3.1.7
atmospheric conditions
standard pressure of 101,3 kPa at 20 °C
3.2 Symbols
th
A molar fraction of the i flammable gas in a gas mixture, in %
i
th
B molar fraction of the k inert gas in a gas mixture, in %
k
C coefficient of oxygen equivalency
i
th
F i flammable gas in a gas mixture
i
th
I k inert gas in a gas mixture
k
n number of flammable gases in a gas mixture
p number of inert gases in a gas mixture
K coefficient of equivalency of an inert gas relative to nitrogen (see Table 1)
k
equivalent content of a flammable gas
′
A
i
L lower flammability limit in air of a flammable gas
i
T maximum content of flammable gas which, when mixed with nitrogen, is not flammable in
ci
air, in %
x molar fraction of the oxidizing component, in %
i
He helium
Ar argon
Ne neon
Kr krypton
Xe xenon
N nitrogen
2
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SIST EN ISO 10156:2018
ISO 10156:2017(E)

H hydrogen
2
O oxygen
2
CO carbon dioxide
2
SO sulfur dioxide
2
N O nitrous oxide
2
SF sulfur hexafluoride
6
CF carbon tetrafluoride
4
C F octafluoropropane
3 8
C HF pentafluoroethane
2 5
CH methane
4
3.3 Units
For the purposes of this document, all gas percentages (%) are given as molar fractions (mol. %) which
are equivalent to volume fractions (vol. %) under normal atmospheric conditions.
4 Flammability of gases and gas mixtures in air
4.1 General
4.2 and 4.3 give a test method and a calculation method for determining whether a gas or gas mixture is
flammable in air. This is used to determine a valve outlet for transportation or GHS classification.
The test method (given in 4.2) may be used in all cases but shall be used when T (or L ) values are not
ci i
available.
The calculation method (given in 4.3) may only be used if reliable T (or L ) values are available.
ci i
4.5 gives a calculation method to determine the lower flammability limit of the flammable mixture
determined in 4.3 and may be used for the GHS flammable gas categories.
In cases where the test result is different from that obtained by calculation, the test result shall take
precedence.
The non-flammable mixtures defined by UN number shall overrule any classification done by
calculation.
4.2 Test method
4.2.1 Key points concerning safety
Tests shall be carried out by trained and competent personnel working in accordance with authorized
procedures (see also 4.2.4). The reaction tube and flowmeter shall be adequately screened to protect
personnel in the event of an explosion. Personnel shall wear personal protective equipment including
safety glasses. During the ignition sequence, the reaction tube shall be open to the atmosphere and
isolated from the gas supply. Care shall also be taken during the analysis of the test gas or mixture.
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SIST EN ISO 10156:2018
ISO 10156:2017(E)

4.2.2 Principle
The gas or gas mixture is mixed in the desired proportions with air. In the quiescent test mixture, an
ignition is initiated using an electric spark and it is observed whether or not a flame propagates through
the reaction tube.
4.2.3 Test apparatus and materials
4.2.3.1 General
The apparatus (see Figure 1) includes:
— a mixer;
— a tube in which the reaction takes place;
— an ignition system;
— a system of analysis to determine the test gas composition.
NOTE Alternative equivalent apparatus can be used, as described in standard test methods for the
determination of flammability limits, e.g. EN 1839 and ASTM E681.
4.2.3.2 Preparation
4.2.3.2.1 Test gas
The test gas shall be prepared to represent the most flammable composition that can occur in the
normal course of production. The criteria to be used in establishing the composition of the test gas
are manufacturing tolerances, i.e. the test gas shall contain the highest concentration of flammable
gases encountered in the normal manufacturing process and the moisture content shall be less than or
equal to 0,01 %. The test gas shall be thoroughly mixed and carefully analysed to determine the exact
composition.
4.2.3.2.2 Compressed air
The compressed air shall be analysed and the moisture content shall be less than or equal to 0,01 %.
4.2.3.2.3 Test gas/air mixture
The compressed air and the gas to be tested are mixed in a blender, controlling the flowrates. The air-
flammable gas mixture shall be analysed using a chromatograph or a simple oxygen analyser and a
flammable gas detector.
4.2.3.3 Reaction tube
The test vessel is an upright cylinder of thick glass (e.g. 5 mm) having a minimum inner diameter of
50 mm and a minimum height of 300 mm. The ignition electrodes are separated by a distance of 5 mm
and are placed 50 mm to 60 mm above the bottom of the cylinder. The cylinder is fitted with a pressure-
release opening. The apparatus shall be shielded to restrict any explosion damage.
4.2.3.4 Ignition system
A spark generator capable of supplying high voltage sparks (e.g. 15 kV, 30 mA, a.c.) with energy of 10 J
shall be used. The spark gap (distance between the electrodes) shall be 5 mm, the spark duration 0,2 s
to 0,5 s.
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SIST EN ISO 10156:2018
ISO 10156:2017(E)

4.2.4 Procedure for determination of flammability
When carrying out flammability tests, care shall be taken to avoid explosion. This can be done by
commencing the experimental work at a known “safe” concentration of 1 % test gas in air. Subsequently,
the initial gas concentration can be increased in small steps by 1 % until ignition occurs.
Prior to each ignition attempt, the test vessel shall be purged with the test mixture. The purging volume
shall be at least 10 times the volume of the test vessel. Then, an ignition is attempted with the induction
spark when the test mixture is quiescent, and it is observed visually whether or not a flame detaches
from the ignition source and propagates.
If a flame detachment and an upwards propagation of at least 100 mm is observed, the test substance
shall be classified as flammable.
If the chemical structure of the gas indicates that it would be non-flammable and the composition of the
stoichiometric mixture with air can be calculated, only mixtures in the range from 10 % (absolute) less
than the stoichiometric composition to 10 % greater than this composition need to be tested in 1 % steps.
With mixtures containing hydrogen, the flame is almost colourless. In order to confirm the presence of
such flames, the use of temperature-measuring probes is recommended [see Figure 1 a)].
4.2.5 Procedure for determination of flammability limits
Unlike at the determination of flammability in general, it is necessary to apply a different test procedure
for determining flammability limits (FL). Using the same test apparatus, test gas preparation and
criterion of ignition as described in 4.2.3 and 4.2.4, the characterization of flammability limits consists
of determining the amount of test substance in air with which the test mixture no longer ignites. Close
to the flammability limit, the incremental change of test substance content in air is selected such that it
is almost 0,1 % by volume for FL < 10 % and 0,2 % by volume for FL ≥ 10 %.
For safety reasons, the initial ignition tests are carried out using a test mixture with test substance
content which, if possible, lies outside the expected explosion range.
Prior to each ignition attempt, the test vessel is purged with the test mixture. The purging volume shall
be at least 10 times the volume of the test vessel. When purging is complete, the inlet to the test vessel
is sealed. The test mixture then bypasses the test vessel and flows directly into the exhaust system. An
ignition is attempted using the induction spark under quiescent conditions. It is observed whether or
not a flame detaches from the ignition source and propagates at least 100 mm.
If an ignition is observed, the test gas content in the test mixture is iteratively varied until no further
flame detachment follows. The test mixture concentration at which an ignition just fails (just no flame
detachment) shall be confirmed with four additional tests. The determination is terminated when with
all five tests a flame detachment is not observed. If flame detachment does occur, the test gas content
shall be further changed and the test gas content shall be reduced (lower flammability limit) or to be
increased (upper flammability limit) by one increment. Again, the tests are carried out at the new test
substance content.
The flammability limit is the test gas concentration in mixture with air at which an ignition just fails.
4.2.6 Results for pure gases
A list of flammable gases is given in Table 2 together with T values and L values. These values have
ci i
been obta
...