ISO 11114-2:2021
(Main)Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2: Non-metallic materials
Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2: Non-metallic materials
This document gives guidance on the selection and evaluation of compatibility between non-metallic materials for gas cylinders and valves and the gas contents. It is also applicable to tubes, pressure drums and bundles of cylinders. This document covers composite and laminated materials used for gas cylinders. It does not include ceramics, glasses and adhesives. This document considers the influence of the gas in changing the material and mechanical properties (e.g. chemical reaction or change in physical state). The basic properties of the materials, such as mechanical properties required for design purposes (normally available from the materials supplier), are not considered. Other aspects, such as quality of delivered gas, are not considered. The compatibility data given are related to single component gases but can be applicable to gas mixtures. This document does not apply to cryogenic fluids (this is covered in ISO 21010).
Bouteilles à gaz — Compatibilité des matériaux des bouteilles et des robinets avec les contenus gazeux — Partie 2: Matériaux non métalliques
Le présent document donne des recommandations pour la sélection et l’évaluation de la compatibilité entre les matériaux non métalliques des bouteilles à gaz/robinets avec le gaz. Il s’applique également aux tubes, aux fûts sous pression et aux cadres de bouteilles. Le présent document couvre les matériaux composites et les matériaux stratifiés utilisés pour les bouteilles à gaz. Il n’inclut pas les céramiques, les verres ni les adhésifs. Le présent document traite de l’influence du gaz sur la transformation du matériau ou sur la modification de ses propriétés mécaniques (par exemple une réaction chimique ou une modification de l’état physique). Les propriétés fondamentales des matériaux, telles que les propriétés mécaniques requises pour la conception d’un produit (en général fournies par le fabricant du matériau), ne sont donc pas abordées. D’autres aspects, tels que la qualité du gaz fourni, ne sont pas pris en compte. Les données de compatibilité indiquées se rapportent à des gaz à un composant unique, mais elles peuvent être applicables aux mélanges gazeux. Le présent document ne s’applique pas aux fluides cryogéniques (qui font l’objet de la norme ISO 21010).
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INTERNATIONAL ISO
STANDARD 11114-2
Third edition
2021-10
Gas cylinders — Compatibility of
cylinder and valve materials with gas
contents —
Part 2:
Non-metallic materials
Bouteilles à gaz — Compatibilité des matériaux des bouteilles et des
robinets avec les contenus gazeux —
Partie 2: Matériaux non métalliques
Reference number
ISO 11114-2:2021(E)
© ISO 2021
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ISO 11114-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
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ISO copyright office
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Email: copyright@iso.org
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Published in Switzerland
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ISO 11114-2:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Materials . 2
4.1 General . 2
4.2 Type of materials . 2
5 General consideration .3
6 Specific considerations . 4
6.1 General . 4
6.2 Non-compatibility risks . 4
6.2.1 Violent reaction (oxidation/burning) (F) . 4
6.2.2 Mass loss (W) . 6
6.2.3 Swelling of material (S) . 6
6.2.4 Change in mechanical properties (M) . 6
6.2.5 Other compatibility considerations . 6
7 Compatibility data . .7
7.1 Table of compatibility . 7
7.2 Symbols and abbreviated terms . 8
7.2.1 Symbols for compatibility . 8
7.2.2 Abbreviated terms for materials . 8
7.2.3 Symbols for compatibility risks . 9
7.2.4 Examples . 9
7.2.5 Tables 1 and 2 . 10
Bibliography .20
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ISO 11114-2:2021(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 of 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
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 23, Transportable gas
cylinders, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This third edition cancels and replaces the second edition (ISO 11114-2:2013), which has been
technically revised. The main changes compared with the previous edition are as follows:
— new materials were added in Table 1;
— Table 2, dedicated to the compatibility for liners, was added.
A list of all parts in the ISO 11114 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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ISO 11114-2:2021(E)
Introduction
This document provides guidance on the compatibility of non-metallic materials used for gas cylinders
and gas cylinder valves with the gas contents of the cylinder. Compatibility of metallic materials is
covered in ISO 11114-1.
Non-metallic materials are very often used for the construction of gas cylinder valves as seals,
e.g. O-ring, gland packing, seats or as lubrication products to avoid friction. They are also commonly
used to ensure sealing of the valve/cylinder connection. For gas cylinders, they are sometimes used as
an internal coating or as a liner for composite materials.
Non-metallic materials not in contact with the gas are not covered by this document.
This document is based on current international experience and knowledge. Some data are derived
from experience involving a mixture of the gas concerned with a dilutant, where no data for single
component gases were available.
[7]
This document has been written so that it is suitable to be referenced in the UN Model Regulations .
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INTERNATIONAL STANDARD ISO 11114-2:2021(E)
Gas cylinders — Compatibility of cylinder and valve
materials with gas contents —
Part 2:
Non-metallic materials
1 Scope
This document gives guidance on the selection and evaluation of compatibility between non-metallic
materials for gas cylinders and valves and the gas contents. It is also applicable to tubes, pressure
drums and bundles of cylinders.
This document covers composite and laminated materials used for gas cylinders. It does not include
ceramics, glasses and adhesives.
This document considers the influence of the gas in changing the material and mechanical properties
(e.g. chemical reaction or change in physical state). The basic properties of the materials, such as
mechanical properties required for design purposes (normally available from the materials supplier),
are not considered. Other aspects, such as quality of delivered gas, are not considered.
The compatibility data given are related to single component gases but can be applicable to gas
mixtures.
This document does not apply to cryogenic fluids (this is covered in ISO 21010).
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 10286, Gas cylinders — Vocabulary
ISO 10297, Gas cylinders — Cylinder valves — Specification and type testing
ISO 11114-3, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 3:
Autogenous ignition test for non-metallic materials in oxygen atmosphere
ISO 15001, Anaesthetic and respiratory equipment — Compatibility with oxygen
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 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
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO 11114-2:2021(E)
3.1
competent person
person who has the necessary technical knowledge, qualification, experience and authority to assess
and approve materials for use with gases and to define any special conditions of use that are necessary
[SOURCE: ISO 11114-1:2020, 3.1, modified — “qualification” has been added to the definition.]
3.2
acceptable
satisfactory material/gas combination, under normal conditions of use, provided that any indicated
non-compatibility risks are taken into account
Note 1 to entry: Normal conditions of use are defined in Clause 5.
Note 2 to entry: Non-compatibility risks are provided in Table 1.
3.3
not acceptable
unsafe material/single gas combination, under normal conditions of use
Note 1 to entry: For gas mixtures, special conditions can apply.
Note 2 to entry: Normal conditions of use are defined in Clause 5.
3.4
dynamic sealing
non-metallic material used, in normal operation, to provide a pressure seal between two surfaces that
have relative motion to each other
4 Materials
4.1 General
Non-metallic materials shall be suitable for the intended service. They are suitable if their compatibility
is stated as acceptable in Table 1, and Table 2 for the cylinder liners, or the necessary properties have
been proved by tests or long and safe experience to the satisfaction of a competent person.
NOTE When plastic liner materials are used, it is necessary to use metallic bosses. For compatibility of
metallic bosses, see ISO 11114-1.
If coated materials are used, the suitability of the combination shall be assessed and approved if all
technical aspects have been considered and validated by a competent person. These technical aspects
include, but are not limited to, compatibility of the coating material with the intended gas, durability of
the coating during all its intended use and gas permeability through it.
4.2 Type of materials
The most commonly used non-metallic materials for gas cylinders and cylinder valves can be grouped
as follows:
— plastics;
— elastomers;
— fluid lubricants.
NOTE 1 Solid lubricants are sometimes used, e.g. MoS .
2
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ISO 11114-2:2021(E)
Materials considered in this document are as follows:
a) plastics:
— polytetrafluoroethylene (PTFE);
— polychlorotrifluoroethylene (PCTFE);
— polyvinylidenefluoride (PVDF);
— polyamide (PA);
— polypropylene (PP);
— polyethylene (PE);
NOTE 2 PE covers grades such as HDPE (high density polyethylene), MDPE (medium density
polyethylene), LDPE (low density polyethylene), PEX (cross-linked), etc.
— polyethylene terephthalate (PET);
— polyetheretherketone (PEEK);
— polypropylene sulfide (PPS);
— polyvinyl chloride (PVC);
— polyimide (PI);
— polyoxymethylene (POM);
b) elastomers (rubber):
— butyl rubber (IIR);
— nitrile butadiene rubber (NBR);
— chloroprene rubber (CR);
— fluorocarbon rubber (FKM);
— methyl-vinyl-silicone rubber (VMQ);
— ethylene propylene diene rubber (EPDM);
— polyacrylate rubber (ACM);
— polyurethane rubber (PUR);
— epichlorohydrin rubber (ECO);
— methyl-fluoro-silicone rubber (FVMQ);
c) fluid lubricants:
— hydrocarbon (HC);
— fluorocarbon (FC).
5 General consideration
It is important to note that these materials are generic types. Within each material type there are
variations in the properties of the materials due to polymer differences and formulations used by
manufacturers to modify physical and chemical properties of the material. The user of the material
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ISO 11114-2:2021(E)
should therefore consult the manufacturer and, if necessary, carry out tests before using the material
(e.g. for critical services such as oxygen and other oxidizing gases).
Lubricants are often used in valves to reduce friction and wear in the moving parts. For valves used for
oxidizing gases or for gases supporting combustion, if lubrication is required, it shall be ensured that
the lubricant is compatible for the intended application when the lubricated components are in contact
with the oxidizing gas or the gas supporting combustion.
Where the lubricant is listed as “not acceptable” in Table 1 for reasons other than violent reaction
(oxidation/burning) (F), it may be used safely and usually satisfactorily in applications which do not
involve contact in normal operation with the gas. An example of such an application is the lubrication of
the valve actuating mechanism not in contact with the gas.
Where the lubricant is listed as “not acceptable” for the reason of violent reaction (oxidation/burning)
(F), it should not be used in any part of the system that can be contacted by the gas, even under abnormal
conditions such as in the event of a failure of the gas sealing system. If there is a risk of violent reaction,
appropriate safety and suitability tests shall be carried out for the lubricant application before it is used
either on the lubricant itself, as specified in ISO 11114-3, or on the lubricated equipment in which it is
intended to be used, as specified in ISO 10297.
The properties of plastics and elastomers including compatibility are dependent on temperature. Low
temperature can cause hardening and the possibility of embrittlement, whereas high temperature
can cause softening and the possibility of material flow. Users of such materials shall check to ensure
their suitability over the entire operating temperature range specified by the cylinder and valve
manufacturing standards.
Some materials become brittle at low temperatures, especially at temperatures at the lower end of
the normal operating range (e.g. fluorocarbon rubber). Temperatures in the refrigerant or cryogenic
ranges affect many materials and caution shall be exercised at temperatures below −50 ° C. This risk
shall be considered in particular when transfilling by thermal siphoning at low temperature or similar
procedures, or for cylinders regularly filled at low temperatures (e.g. carbon dioxide).
6 Specific considerations
6.1 General
The compatibility of gases with non-metallic materials is affected by chemical reactions and physical
influences, which can be classified as defined in 6.2.
6.2 Non-compatibility risks
6.2.1 Violent reaction (oxidation/burning) (F)
6.2.1.1 Principle
Historically the majority of serious accidents from rapid oxidation or violent combustion have occurred
with oxidizing gas supporting combustion at high pressure. Thorough investigation of all materials and
factors should be conducted with great care and all data should be considered before designing or using
equipment to handle oxidizing gases or gases supporting combustion.
Compatibility depends mainly on the operating conditions (pressure, temperature, gas velocity,
particles, equipment design and application). The risk shall particularly be considered with gases such
as oxygen, fluorine, chlorine and nitrogen trifluoride. Most of the non-metallic materials can be ignited
relatively easily when in contact with oxidizing gases (see ISO 10156) and even when in contact with
gases not classified as oxidizing but still supporting combustion.
The selection of a material for use with oxygen or an oxygen enriched atmosphere, or both, is primarily
a matter of understanding the circumstances that cause the material to react with oxygen. Most
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ISO 11114-2:2021(E)
materials in contact with oxygen will not ignite without a source of ignition energy (friction, heat of
compression, particle impacts, etc.). When an energy input rate, as converted to heat, is greater than
the rate of heat dissipation, and the resulting heat increase is continued for sufficient time, ignition and
combustion will occur.
Thus, two general factors shall be considered:
a) the materials compatibility properties (ease of ignition and energy of combustion);
b) the different energy sources that will produce a sufficient increase in the temperature of the
material.
These general factors should be viewed in the context of the entire system design so that the following
specific factors will assume the proper relative significance:
— the properties of the materials, which include the factors affecting ease of ignition and the conditions
affecting potential resulting damage (heat of reaction);
— the operating conditions [e.g. pressure, temperature, oxygen or oxidizing gas concentrations in a
gas mixture, or both, influence of dilutant (e.g. helium), surface contamination];
— the potential sources of ignition (e.g. friction, heat of compression, heat from mass impact, heat from
particle impact, static electricity, electrical arc, resonance, internal flexing);
— the possible consequence (e.g. effects on the surroundings such as propagation of fire);
— the additional factors (e.g. performance requirements, prior experience, availability).
In conclusion, the evaluation of compatibility of non-metallic materials is more critical than that of
metallic materials, which generally perform well when in contact with oxygen.
6.2.1.2 Specifications for oxidizing gases
In accordance with 6.2.1.1, it is not possible to make a simple statement concerning the compatibility
of non-metallic materials with oxidizing gases such as oxygen, chlorine, nitric oxide, nitrous oxide,
nitrogen dioxide, nitrogen trifluoride, etc. (see ISO 10156).
For fluorine, which is the most oxidizing gas, all non-metallic materials would historically fall into the
classification “not acceptable”.
For fluorine mixtures, the gases industry now has evidence of successful testing and safe history of use
of PTFE and PCTFE under controlled conditions (e.g. low concentration and low pressure). Therefore,
following an assessment and authorization by a competent person, these materials are acceptable in
similar conditions.
Oxygen and other oxidizing gases can react violently when tested with all non-metallic materials listed
in 4.2 a), 4.2 b) and 4.2 c). Some materials such as PTFE and FKM are more resistant to ignition than
other plastics and elastomers. HC lubricants are normally not acceptable. Under certain conditions
other plastics and elastomers listed can be safely used in oxidizing service without presenting some
of the disadvantages of PTFE, i.e. poor mechanical properties and risk of release of toxic products for
breathing gas applications (see ISO 15001), or FKM, i.e. swelling, poor mechanical properties at low
temperature, risk of release of toxic products in breathing gas applications, etc.
Consequently, non-metallic materials may only be used if it has been proven by tests (or long and safe
service experience), taking into account all the operating conditions and especially the design of the
equipment, that their use is safe. ISO 11114-3 and ISO 21010 give test methods for polymeric materials
and fluid lubricants that result in conservative value. Some non-metallic materials can be safely used
at higher pressure if they are satisfactorily tested in the final design configuration, e.g. in gas cylinder
valves and regulators. Cylinder valves intended to be used for oxidizing gas service shall be tested in
accordance with ISO 10297.
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ISO 11114-2:2021(E)
6.2.2 Mass loss (W)
6.2.2.1 Extraction
Solvent extraction of plasticizers from elastomers can cause shrinkage, especially in highly plasticized
products.
Some solvents, e.g. acetone or DMF (dimethylformamide) used for dissolved gases such as acetylene,
can damage non-metallic materials.
Liquefied gases can act as solvents.
6.2.2.2 Chemical attack
Some non-metallic materials can be chemically attacked by gases, e.g. the chemical attack of silicone
elastomers by ammonia.
NOTE This attack can sometimes lead to the complete destruction of the material.
6.2.3 Swelling of material (S)
Elastomers and plastics can be subject to swelling due to gas (or liquid) absorption. This can lead to an
unacceptable increase of dimensions (especially for O-rings) or the cracking due to sudden out-gassing
when the partial pressure is decreased, e.g. carbon dioxide with fluorocarbon.
Initial swelling can be masked by subsequent extraction of plasticizers and fillers while in service. Other
important effects such as changes in mechanical strength and hardness should also be considered.
Differences in the compounding, formulation and curing of a given elastomer can cause significant
differences in the swelling of the material in service.
Regardless of the above compatibility evaluation, the design configuration (e.g. static or dynamic
sealing) shall be taken into account before deciding to use elastomers or plastics. In this document, a
swelling of more than approximately 15 % in normal service conditions is marked N (in particular not
acceptable for dynamic sealing); a swelling less than this is marked A (acceptable) provided other risks
are also acceptable.
NOTE There is also a risk of cross bonding between sulfur vulcanised rubbers and copper alloys.
6.2.4 Change in mechanical properties (M)
Gases can lead to an unacceptable change of mechanical properties in some non-metallic materials.
This can result, for example, in an increase in hardness or a decrease in elasticity (i.e. an increase in
compression set). ISO 1817 gives testing methods to check the influence of the gas on the mechanical
properties.
6.2.5 Other compatibility considerations
6.2.5.1 Impurities in the gas (I)
Some gases contain typical impurities which it is possible will not be compatible with the intended
materials (e.g. acetone in acetylene, hydrogen sulfide in methane).
6.2.5.2 Contamination of the material (C)
Some materials become contaminated in toxic gas use by the toxic gas and become hazardous
themselves (e.g. during maintenance of equipment).
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ISO 11114-2:2021(E)
6.2.5.3 Release of dangerous products (D)
Many materials when subjected to extreme conditions (such as elevated temperature) can release
dangerous products (e.g. toxic products). This risk shall be considered in particular for breathing gases
as specified in ISO 15001.
6.2.5.4 Ageing (G)
Ageing is a gradual change in the mechanical and physical properties of the material due to the
environment in which it is used or stored (e.g. exposure to UV light). Many elastomer and plastic
materials are particularly subject to ageing; some gases like oxygen and in general exposure to high
temperatures can accelerate the ageing process, leading to degradation such as cracking, brittleness, etc.
6.2.5.5 Permeation (P)
Permeation is a slow process by which gas passes through materials.
The permeation of some gases (e.g. helium, hydrogen, carbon dioxide) through non-metallic materials
can be significant. For a given material, the permeation rate mainly depends on the temperature,
pressure, thickness and surface area of the material in contact with the gas. The molecular radius
of the gas and the specific formulation of plasticizers and other additives can cause a wide range of
permeation rates for a particular type of plastic or elastomer.
This risk shall be considered for effects to the surroundings (e.g. toxicity, fire potential).
Permeation through the liner can lead to gas pressure between the liner and the composite, thus
potentially causing liner collapse and/or blistering.
7 Compatibility data
7.1 Table of compatibility
Table 1 lists the gases in alphabetic order with their UN number. The compatibility data are given using
the symbols and abbreviated terms defined in 7.2.1 and 7.2.2. When a gas/material combination is not
acceptable, the main reason is given, using the appropriate abbreviation for the non-compatibility risk
(see 6.2). The abbreviated terms are also sometimes used for acceptable combinations to show a limited
risk.
If no UN number is listed in Table 1 for a gas (or a liquid), this means that this gas has no official UN
number but it can be transported using a generic NOS (not otherwise specified) number (e.g. compressed
gas, flammable, NOS, UN 1954).
Compatibility evaluations are based on the following documents:
— literature data;
— operational experiences;
— laboratory tests.
The material resistance to gases can be estimated by simple immersion tests in the respective gas with
approximately the same or intensified exposure conditions (increase of temperature, pressure or flow
rate). Time- and equipment-consuming test methods to evaluate the permeation and the absorption as
well as the resistance to stress cracking are required in many cases.
Apart from the visual evaluation of detectable changes, changes in mass and dimension as well as the
course of mechanical and other physical characteristics, depending on the immersion time, are the
parameters of immersion tests. They are consulted as classification characteristics.
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ISO 11114-2:2021(E)
Testing procedures described
...
NORME ISO
INTERNATIONALE 11114-2
Troisième édition
2021-10
Bouteilles à gaz — Compatibilité
des matériaux des bouteilles et des
robinets avec les contenus gazeux —
Partie 2:
Matériaux non métalliques
Gas cylinders — Compatibility of cylinder and valve materials with
gas contents —
Part 2: Non-metallic materials
Numéro de référence
ISO 11114-2:2021(F)
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ISO 11114-2:2021(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
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être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
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Publié en Suisse
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ISO 11114-2:2021(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Références normatives .1
3 Termes et définitions . 1
4 Matériaux . 2
4.1 Généralités . 2
4.2 Type de matériaux . 2
5 Critères généraux . 3
6 Critères spécifiques .4
6.1 Généralités . 4
6.2 Risques liés à la non-compatibilité . 4
6.2.1 Réaction violente (oxydation/combustion) (F) . 4
6.2.2 Perte de masse (W). 6
6.2.3 Gonflement des matériaux (S) . 6
6.2.4 Modification des propriétés mécaniques (M) . 7
6.2.5 Autres critères de compatibilité . 7
7 Données de compatibilité .8
7.1 Tableau de compatibilité . 8
7.2 Symboles et abréviations . 8
7.2.1 Symboles de compatibilité . 8
7.2.2 Abréviations des matériaux . 8
7.2.3 Symboles pour les risques liés à la compatibilité . 9
7.2.4 Exemples . 10
7.2.5 Tableaux 1 et 2 . 10
Bibliographie .19
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ISO 11114-2:2021(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document
a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de
brevets reçues par l’ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion
de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant: www.iso.org/iso/fr/avant-propos.
Le présent document a été élaboré par le comité ISO/TC 58, Bouteilles à gaz, en collaboration avec le
comité technique CEN/TC 23, Bouteilles à gaz transportables, du Comité européen de normalisation
(CEN), conformément à l’Accord de coopération technique entre l’ISO et le CEN (Accord de Vienne).
Cette troisième édition annule et remplace la deuxième édition (ISO 11114-2:2013), qui a fait l’objet d’une
révision technique. Les principales modifications par rapport à l’édition précédente sont les suivantes:
— de nouveaux matériaux ont été ajoutés dans le Tableau 1;
— le Tableau 2, consacré à la compatibilité pour les liners a été ajouté.
Une liste de toutes les parties de la série ISO 11114 se trouve sur le site web de l’ISO.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www.iso.org/fr/members.html.
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ISO 11114-2:2021(F)
Introduction
Le présent document fournit des recommandations relatives à la compatibilité des matériaux non
métalliques utilisés pour les bouteilles à gaz et les robinets de bouteilles à gaz avec le gaz de la bouteille.
La compatibilité des matériaux métalliques fait l’objet de la norme ISO 11114-1.
Des matériaux non métalliques sont souvent utilisés pour la construction des robinets des bouteilles
à gaz comme joints d’étanchéité, par exemple joints toriques, presse-étoupes, sièges, ou comme
lubrifiants pour éviter les frottements. Ils sont aussi fréquemment utilisés pour assurer l’étanchéité
de la connexion robinet/bouteille. Pour les bouteilles à gaz, ils sont parfois utilisés comme revêtement
interne ou comme liner pour des matériaux composites.
Les matériaux non métalliques qui ne sont pas en contact avec le gaz ne sont pas couverts par le présent
document.
Le présent document repose sur l’expérience et les connaissances internationales actuelles. En l’absence
d’informations concernant les gaz à un composant unique, certaines données sont déduites de
l’expérience acquise sur un mélange du gaz concerné avec un diluant.
Le présent document a été rédigé de manière à pouvoir être cité en référence dans le Règlement type de
[7]
l’ONU .
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NORME INTERNATIONALE ISO 11114-2:2021(F)
Bouteilles à gaz — Compatibilité des matériaux des
bouteilles et des robinets avec les contenus gazeux —
Partie 2:
Matériaux non métalliques
1 Domaine d’application
Le présent document donne des recommandations pour la sélection et l’évaluation de la compatibilité
entre les matériaux non métalliques des bouteilles à gaz/robinets avec le gaz. Il s’applique également
aux tubes, aux fûts sous pression et aux cadres de bouteilles.
Le présent document couvre les matériaux composites et les matériaux stratifiés utilisés pour les
bouteilles à gaz. Il n’inclut pas les céramiques, les verres ni les adhésifs.
Le présent document traite de l’influence du gaz sur la transformation du matériau ou sur la
modification de ses propriétés mécaniques (par exemple une réaction chimique ou une modification
de l’état physique). Les propriétés fondamentales des matériaux, telles que les propriétés mécaniques
requises pour la conception d’un produit (en général fournies par le fabricant du matériau), ne sont
donc pas abordées. D’autres aspects, tels que la qualité du gaz fourni, ne sont pas pris en compte.
Les données de compatibilité indiquées se rapportent à des gaz à un composant unique, mais elles
peuvent être applicables aux mélanges gazeux.
Le présent document ne s’applique pas aux fluides cryogéniques (qui font l’objet de la norme ISO 21010).
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 10286, Bouteilles à gaz — Vocabulaire
ISO 10297, Bouteilles à gaz — Robinets de bouteilles — Spécifications et essais de type
ISO 11114-3, Bouteilles à gaz — Compatibilité des matériaux de bouteilles et de robinets avec les contenus
gazeux — Partie 3: Essai d’auto-inflammation des matériaux non métalliques sous atmosphère d’oxygène
ISO 15001, Matériel d’anesthésie et de réanimation respiratoire — Compatibilité avec l’oxygène
3 Termes et définitions
Pour les besoins du présent document, les termes et les définitions de l’ISO 10286 ainsi que les suivants
s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
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ISO 11114-2:2021(F)
3.1
personne compétente
personne possédant les connaissances techniques, les qualifications, l’expérience et l’autorité
nécessaires pour évaluer et autoriser l’utilisation de certains matériaux avec certains gaz, ainsi que
pour définir les conditions d’utilisation particulières éventuellement nécessaires
[SOURCE: ISO 11114‑1:2020, 3.1, modifié — «qualifications» a été ajouté à la définition.]
3.2
acceptable
combinaison satisfaisante de matériau et de gaz, dans les conditions normales d’utilisation, pourvu que
les risques de non-compatibilité indiqués soient pris en considération
Note 1 à l'article: Les conditions normales d’utilisation sont définies à l’Article 5.
Note 2 à l'article: Les risques de non-compatibilité sont exposés dans le Tableau 1.
3.3
inacceptable
combinaison de matériau et d’un gaz pur jugée non sûre, dans les conditions normales d’utilisation
Note 1 à l'article: Pour les mélanges de gaz, des conditions particulières peuvent s’appliquer.
Note 2 à l'article: Les conditions normales d’utilisation sont définies à l’Article 5.
3.4
étanchéité dynamique
matériau non métallique utilisé, en fonctionnement normal, en vue de fournir un joint d’étanchéité
entre deux surfaces en mouvement relatif l’une par rapport à l’autre
4 Matériaux
4.1 Généralités
Les matériaux non métalliques doivent être adaptés au service prévu. Ils sont adaptés si leur comptabilité
est indiquée comme acceptable dans le Tableau 1 et le Tableau 2 pour les liners de bouteilles, ou si
des essais ou une expérience sur le long terme et en toute sécurité ont prouvé qu’ils possédaient les
propriétés requises selon l’avis d’une personne compétente.
NOTE Lorsque des matières plastiques sont utilisées pour les liners, il est nécessaire d’utiliser des embases
métalliques. Pour la compatibilité des embases métalliques, voir l’ISO 11114-1.
Si des matériaux avec un revêtement sont utilisés, l’adéquation de la combinaison doit être évaluée et
autorisée si tous les aspects techniques ont été pris en compte et validés par une personne compétente.
Ces aspects techniques peuvent comprendre, sans s’y limiter, la compatibilité du matériau revêtu avec
le gaz prévu, la durabilité du revêtement pendant son usage prévu et la perméabilité au gaz à travers le
revêtement.
4.2 Type de matériaux
Les matériaux non métalliques les plus communément utilisés pour les bouteilles à gaz et les robinets
peuvent être classés dans les différents groupes suivants:
— les plastiques;
— les élastomères;
— les lubrifiants.
NOTE 1 Des lubrifiants solides sont parfois utilisés, par exemple MoS .
2
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ISO 11114-2:2021(F)
Les matériaux considérés dans le présent document sont les suivants:
a) les plastiques:
— polytétrafluoroéthylène (PTFE);
— polychlorotrifluoroéthylène (PCTFE);
— polyfluorure de vinylidène (PVDF);
— polyamide (PA);
— polypropylène (PP);
— polyéthylène (PE);
NOTE 2 Le PE couvre des types tels que le PEHD (polyéthylène haute densité), le PEMD
(polyéthylène moyenne densité), le PEBD (polyéthylène basse densité), le PER (polyéthylène réticulé),
etc.
— polyéthylène téréphtalate (PET);
— polyétheréthercétone (PEEK);
— polysulfure de propylène (PPS);
— polychlorure de vinyle (PVC);
— polyimide (PI);
— polyoxyméthylène (POM);
b) les élastomères (caoutchouc):
— caoutchouc isobutène - isoprène butyl (IIR);
— caoutchouc nitrile butadiène (NBR);
— caoutchouc chloroprène (CR);
— caoutchouc fluorocarbone (FKM);
— caoutchouc silicone méthyle vinyle (VMQ);
— caoutchouc éthylène-propylène-diène (EPDM);
— caoutchouc polyacrylique (ACM);
— caoutchouc polyuréthane (PUR);
— caoutchouc épichlorhydrine (ECO);
— caoutchouc fluorosilicone (FVMQ);
c) les lubrifiants:
— hydrocarbure (HC);
— fluorocarbone (FC).
5 Critères généraux
Il est important de noter que ces matériaux désignent des groupes génériques. Il existe à l’intérieur
de chacun de ces groupes des différences dans les caractéristiques des matériaux, dues aux différents
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ISO 11114-2:2021(F)
polymères et aux formules particulières utilisés par les fabricants pour modifier les propriétés
physiques et chimiques des matériaux. Il est donc recommandé à l’utilisateur de se renseigner auprès
du fabricant et, si nécessaire, de procéder à des essais avant d’utiliser le matériau (par exemple pour
des applications critiques telles qu’avec l’oxygène ou autres gaz oxydants).
Les lubrifiants sont souvent utilisés dans les robinets pour diminuer les frottements et l’usure des
parties mobiles. En ce qui concerne les robinets associés à des gaz oxydants ou des gaz supportant
la combustion, s’il doit y avoir lubrification, il doit être garanti que ce lubrifiant est compatible avec
l’oxygène pour l’application prévue, lorsque les composants lubrifiés sont en contact avec un gaz
oxydant ou un gaz supportant la combustion.
Lorsque les lubrifiants sont indiqués comme «inacceptables» dans le Tableau 1 pour des raisons
autres que «réaction violente (oxydation/combustion)» (F), ils peuvent être utilisés en toute sécurité
et en général d’une manière satisfaisante, pour des applications qui n’impliquent pas de contact avec
le gaz dans le cadre d’une utilisation normale. Un exemple de cette application est la lubrification du
mécanisme de commande sans contact avec le gaz.
Lorsque les lubrifiants sont indiqués comme «inacceptables» pour cause de «réaction violente
(oxydation/combustion)» (F), il convient de ne pas les utiliser dans toute partie du système susceptible
d’être en contact avec le gaz, même dans des conditions anormales comme dans le cas de détérioration
du système d’étanchéité du gaz. S’il existe un risque de réaction violente, des essais de sécurité et de
compatibilité appropriés doivent être réalisés avant d’appliquer le procédé de lubrification, soit sur le
lubrifiant lui‑même, comme spécifié dans l’ISO 11114‑3, soit sur l’équipement lubrifié dans lequel il est
destiné à être utilisé, comme spécifié dans l’ISO 10297.
Les propriétés des plastiques et des élastomères, y compris la comptabilité, dépendent de la température.
Des températures basses peuvent provoquer un durcissement et une possibilité de fragilisation, alors
que des températures élevées peuvent donner lieu à un ramollissement du matériau avec possibilité
de fluage. Les utilisateurs de ces matériaux doivent vérifier leur adéquation sur toute la plage des
températures de fonctionnement spécifiées par les normes de fabrication des bouteilles et des robinets.
Certains matériaux se fragilisent à basse température, en particulier à des valeurs situées
dans l’extrémité inférieure de la plage de fonctionnement normal (par exemple les caoutchoucs
fluorocarbones). Les températures engendrées par les fluides frigorigènes ou les gaz cryogéniques
altèrent les propriétés de nombreux matériaux et il est donc recommandé d’agir avec grande prudence
lorsque la valeur des températures devient inférieure à −50 °C. Ce risque doit être pris en considération,
en particulier lors des transvasements par thermo-siphonage à basse température ou d’autres
opérations similaires ainsi que pour des bouteilles remplies régulièrement à basse température
(par exemple le dioxyde de carbone).
6 Critères spécifiques
6.1 Généralités
La compatibilité entre des gaz et des matériaux non métalliques est affectée par des réactions chimiques
et des influences physiques, qui peuvent être classées comme défini en 6.2.
6.2 Risques liés à la non-compatibilité
6.2.1 Réaction violente (oxydation/combustion) (F)
6.2.1.1 Principe
L’expérience prouve que la majorité des accidents graves dus à une oxydation rapide ou à une
combustion violente se sont produits avec des gaz oxydants supportant la combustion à haute pression.
Il est recommandé de procéder à des recherches approfondies sur tous les matériaux et tous les
facteurs pouvant influer sur leur comportement et il convient d’étudier toutes les données avant de
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ISO 11114-2:2021(F)
concevoir ou d’utiliser des équipements destinés à transporter des gaz oxydants ou des gaz supportant
la combustion.
La compatibilité dépend principalement des conditions d’utilisation (pression, température, vitesse
des gaz, particules, conception de l’équipement et application). Le risque doit en particulier être pris
en compte avec les gaz tels que l’oxygène, le fluor, le chlore et le trifluorure d’azote. La plupart des
matériaux non métalliques sont facilement inflammables au contact de gaz oxydants (voir l’ISO 10156)
et même au contact de gaz non classés comme oxydants mais néanmoins supportant la combustion.
La sélection d’un matériau pour une utilisation dans une atmosphère d’oxygène, ou enrichie en oxygène,
ou les deux, repose essentiellement sur la connaissance des causes qui provoquent la réaction de ce
matériau avec l’oxygène. La plupart des matériaux en contact avec l’oxygène ne s’enflamme pas en
l’absence d’une source d’inflammation (frottement, chaleur dégagée par la compression, impacts de
particules, etc.). Lorsque l’apport d’énergie, converti en chaleur, est supérieur au pouvoir de dissipation
thermique, et que l’augmentation de chaleur est poursuivie pendant une durée suffisante, il se produit
alors le phénomène d’inflammation et de combustion.
En conséquence, deux facteurs généraux doivent être pris en considération:
a) les propriétés de compatibilité des matériaux (facilité d’inflammation et énergie de combustion);
b) les différentes sources d’énergie qui vont provoquer l’élévation suffisante de température du
matériau.
Il convient de considérer ces facteurs généraux dans le contexte de l’intégralité du système afin que les
facteurs spécifiques suivants prennent leur propre influence relative:
— les propriétés des matériaux qui incluent les facteurs agissant sur l’inflammabilité et les conditions
agissant sur les dommages potentiels (chaleur de réaction);
— les conditions de fonctionnement [par exemple pression, température, concentration d’oxygène ou
de gaz oxydants dans un mélange de gaz, ou les deux, influence du diluant (par exemple hélium),
contamination de surface];
— les sources potentielles d’inflammation (par exemple frottement, chaleur de compression, chaleur
d’impact de masse ou de particules, électricité statique, arc électrique, phénomène de résonance,
flexion interne);
— les conséquences possibles (par exemple effets sur le milieu environnant, tels que la propagation
d’un incendie);
— les facteurs supplémentaires (par exemple exigences de performance, expérience antérieure,
disponibilité).
En conclusion, l’évaluation de la compatibilité des matériaux non métalliques est une démarche plus
critique que celle appliquée aux matériaux métalliques qui ont généralement un meilleur comportement
au contact de l’oxygène.
6.2.1.2 Spécifications relatives aux gaz oxydants
Conformément à 6.2.1.1, il est impossible de formuler une déclaration simple concernant la compatibilité
des matériaux non métalliques avec des gaz oxydants comme l’oxygène, le chlore, le monoxyde d’azote,
le protoxyde d’azote, le dioxyde d’azote, etc. (voir l’ISO 10156).
Pour le fluor, qui est le gaz le plus oxydant, l’expérience montre que tous les matériaux non métalliques
seraient classés «inacceptables».
Pour les mélanges de fluor, l’industrie gazière dispose désormais de preuves avec des essais réussis et des
antécédents d’utilisation en toute sécurité du PTFE et du PCTFE en situations contrôlées (par exemple
faible concentration et basse pression). Par conséquent, après évaluation et autorisation par une
personne compétente, ces matériaux sont acceptables dans des conditions similaires. L’oxygène et les
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ISO 11114-2:2021(F)
autres gaz oxydants peuvent réagir violemment lors des essais avec tous les matériaux non métalliques
énumérés en 4.2 a), 4.2 b) et 4.2 c). Des matériaux tels que le PTFE et le FKM sont davantage résistants à
l’inflammation que les autres plastiques et élastomères. Les lubrifiants HC ne sont pas acceptables. Dans
certaines conditions, tous les autres plastiques et élastomères énumérés peuvent être utilisés en toute
sécurité en service oxydant sans présenter certains des inconvénients du PTFE [mauvaises propriétés
mécaniques et risque de libération de produits toxiques pour les applications avec des gaz respiratoires
(voir l’ISO 15001)] ou du FKM (gonflement, mauvaises propriétés mécaniques à basse température,
risque de libération de produits toxiques pour les applications avec gaz respiratoires, etc.).
Par conséquent, les matériaux non métalliques ne peuvent être utilisés que si des essais (ou une
expérience en service sur le long terme et en toute sécurité) ont prouvé que leur utilisation est sûre,
en tenant compte de toutes les conditions de fonctionnement et en particulier de la conception de
l’équipement. L’ISO 11114-3 et l’ISO 21010 indiquent des méthodes d’essai pour les polymères et les
lubrifiants qui fournissent une valeur prudente. Certains matériaux non métalliques peuvent être
utilisés en toute sécurité à une pression plus élevée s’ils sont soumis à essai de manière satisfaisante
dans la configuration de conception finale, par exemple dans les régulateurs et les robinets de bouteilles
à gaz. Les robinets des bouteilles destinées à être utilisées pour le service de gaz oxydants doivent être
soumis à essai conformément à l’ISO 10297.
6.2.2 Perte de masse (W)
6.2.2.1 Extraction
Dans les élastomères, l’extraction du solvant des plastifiants peut provoquer un retrait, en particulier
pour les produits hautement plastifiés.
Certains solvants, par exemple l’acétone ou le DMF (diméthylformamide), utilisés pour des gaz dissous
comme l’acétylène, peuvent endommager les matériaux non métalliques.
Les gaz liquéfiés peuvent agir comme des solvants.
6.2.2.2 Attaque chimique
Certains matériaux non métalliques peuvent être attaqués chimiquement par des gaz, par exemple
l’attaque chimique des élastomères au silicone par l’ammoniac.
NOTE Cette attaque peut parfois conduire à la destruction totale du matériau.
6.2.3 Gonflement des matériaux (S)
De par leur pouvoir d’absorption des gaz (ou des liquides), les élastomères et les plastiques peuvent
être sujets au gonflement. Cela peut provoquer une augmentation inacceptable des dimensions
(en particulier pour les joints toriques) ou des fissures dues à la soudaine libération du produit gazeux
lors d’une diminution de la pression partielle, par exemple le dioxyde de carbone avec le fluorocarbone.
Un gonflement initial peut être masqué par l’extraction des plastifiants et des matériaux de charge
en service. Il convient de prendre en compte d’autres effets importants, tels que la modification de la
résistance mécanique et de la dureté.
Des variations de la composition, de la formule et de la cure d’un élastomère donné peuvent provoquer
des différences significatives des capacités de gonflement du matériau en service.
Indépendamment de l’évaluation de la compatibilité ci‑dessus, la configuration de conception
(par exemple étanchéité statique ou dynamique) doit être prise en compte avant de décider d’utiliser
des élastomères ou des plastiques. Dans le présent document, un gonflement supérieur à environ
15 % en utilisation normale est indiqué par la lettre N (inacceptable en particulier pour l’étanchéité
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ISO 11114-2:2021(F)
dynamique); un gonflement inférieur à cette valeur est indiqué par la lettre A (acceptable), à condition
que les autres risques soient eux aussi acceptables.
NOTE Il existe également un risque de réticulation entre les caoutchoucs vulcanisés au soufre et les alliages
de cuivre.
6.2.4 Modification des prop
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 11114-2
ISO/TC 58
Gas cylinders — Compatibility of
Secretariat: BSI
cylinder and valve materials with gas
Voting begins on:
2021-07-29 contents —
Voting terminates on:
Part 2:
2021-09-23
Non-metallic materials
Bouteilles à gaz — Compatibilité des matériaux des bouteilles et des
robinets avec les contenus gazeux —
Partie 2: Matériaux non métalliques
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 11114-2:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
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NATIONAL REGULATIONS. ISO 2021
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ISO/FDIS 11114-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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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
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ISO/FDIS 11114-2:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Materials . 2
4.1 General . 2
4.2 Type of materials. 2
5 General consideration . 3
6 Specific considerations . 4
6.1 General . 4
6.2 Non-compatibility risks . 4
6.2.1 Violent reaction (oxidation/burning) (F). 4
6.2.2 Mass loss (W) . 6
6.2.3 Swelling of material (S) . 6
6.2.4 Change in mechanical properties (M) . 6
6.2.5 Other compatibility considerations . 6
7 Compatibility data . 7
7.1 Table of compatibility . 7
7.2 Symbols and abbreviated terms. 8
7.2.1 Symbols for compatibility . 8
7.2.2 Abbreviated terms for materials . 8
7.2.3 Symbols for compatibility risks . 9
7.2.4 Examples . 9
7.2.5 Tables 1 and 2 .10
Bibliography .19
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ISO/FDIS 11114-2:2021(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 of 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 www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 23, Transportable gas
cylinders, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This third edition cancels and replaces the second edition (ISO 11114-2:2013), which has been
technically revised. The main changes compared with the previous edition are as follows:
— new materials were added in Table 1;
— Table 2, dedicated to the compatibility for liners, was added.
A list of all parts in the ISO 11114 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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ISO/FDIS 11114-2:2021(E)
Introduction
This document provides guidance on the compatibility of non-metallic materials used for gas cylinders
and gas cylinder valves with the gas contents of the cylinder. Compatibility of metallic materials is
covered in ISO 11114-1.
Non-metallic materials are very often used for the construction of gas cylinder valves as seals,
e.g. O-ring, gland packing, seats or as lubrication products to avoid friction. They are also commonly
used to ensure sealing of the valve/cylinder connection. For gas cylinders, they are sometimes used as
an internal coating or as a liner for composite materials.
Non-metallic materials not in contact with the gas are not covered by this document.
This document is based on current international experience and knowledge. Some data are derived
from experience involving a mixture of the gas concerned with a dilutant, where no data for single
component gases were available.
[7]
This document has been written so that it is suitable to be referenced in the UN Model Regulations .
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 11114-2:2021(E)
Gas cylinders — Compatibility of cylinder and valve
materials with gas contents —
Part 2:
Non-metallic materials
1 Scope
This document gives guidance on the selection and evaluation of compatibility between non-metallic
materials for gas cylinders and valves and the gas contents. It is also applicable to tubes, pressure
drums and bundles of cylinders.
This document covers composite and laminated materials used for gas cylinders. It does not include
ceramics, glasses and adhesives.
This document considers the influence of the gas in changing the material and mechanical properties
(e.g. chemical reaction or change in physical state). The basic properties of the materials, such as
mechanical properties required for design purposes (normally available from the materials supplier),
are not considered. Other aspects, such as quality of delivered gas, are not considered.
The compatibility data given are related to single component gases but can be applicable to gas
mixtures.
This document does not apply to cryogenic fluids (this is covered in ISO 21010).
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 10286, Gas cylinders — Vocabulary
ISO 10297, Gas cylinders — Cylinder valves — Specification and type testing
ISO 11114-3, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 3:
Autogenous ignition test for non-metallic materials in oxygen atmosphere
ISO 15001, Anaesthetic and respiratory equipment — Compatibility with oxygen
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 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
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO/FDIS 11114-2:2021(E)
3.1
competent person
person who has the necessary technical knowledge, qualification, experience and authority to assess
and approve materials for use with gases and to define any special conditions of use that are necessary
[SOURCE: ISO 11114-1:2020, 3.1, modified — "qualification" has been added to the definition.]
3.2
acceptable
satisfactory material/gas combination, under normal conditions of use, provided that any indicated
non-compatibility risks are taken into account
Note 1 to entry: Normal conditions of use are defined in Clause 5.
Note 2 to entry: Non-compatibility risks are provided in Table 1.
3.3
not acceptable
unsafe material/single gas combination, under normal conditions of use
Note 1 to entry: For gas mixtures, special conditions can apply.
Note 2 to entry: Normal conditions of use are defined in Clause 5.
3.4
dynamic sealing
non-metallic material used, in normal operation, to provide a pressure seal between two surfaces that
have relative motion to each other
4 Materials
4.1 General
Non-metallic materials shall be suitable for the intended service. They are suitable if their compatibility
is stated as acceptable in Table 1, and Table 2 for the cylinder liners, or the necessary properties have
been proved by tests or long and safe experience to the satisfaction of a competent person.
NOTE When plastic liner materials are used, it is necessary to use metallic bosses. For compatibility of
metallic bosses, see ISO 11114-1.
If coated materials are used, the suitability of the combination shall be assessed and approved if all
technical aspects have been considered and validated by a competent person. These technical aspects
include, but are not limited to, compatibility of the coating material with the intended gas, durability of
the coating during all its intended use and gas permeability through it.
4.2 Type of materials
The most commonly used non-metallic materials for gas cylinders and cylinder valves can be grouped
as follows:
— plastics;
— elastomers;
— fluid lubricants.
NOTE 1 Solid lubricants are sometimes used, e.g. MoS .
2
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ISO/FDIS 11114-2:2021(E)
Materials considered in this document are as follows:
a) plastics:
— polytetrafluoroethylene (PTFE);
— polychlorotrifluoroethylene (PCTFE);
— polyvinylidenefluoride (PVDF);
— polyamide (PA);
— polypropylene (PP);
— polyethylene (PE);
NOTE 2 PE covers grades such as HDPE (high density polyethylene), MDPE (medium density
polyethylene), LDPE (low density polyethylene), PEX (cross-linked), etc.
— polyethylene terephthalate (PET);
— polyetheretherketone (PEEK);
— polypropylene sulfide (PPS);
— polyvinyl chloride (PVC);
— polyimide (PI);
— polyoxymethylene (POM);
b) elastomers (rubber):
— butyl rubber (IIR);
— nitrile butadiene rubber (NBR);
— chloroprene rubber (CR);
— fluorocarbon rubber (FKM);
— methyl-vinyl-silicone rubber (VMQ);
— ethylene propylene diene rubber (EPDM);
— polyacrylate rubber (ACM);
— polyurethane rubber (PUR);
— epichlorohydrin rubber (ECO);
— methyl-fluoro-silicone rubber (FVMQ);
c) fluid lubricants:
— hydrocarbon (HC);
— fluorocarbon (FC).
5 General consideration
It is important to note that these materials are generic types. Within each material type there are
variations in the properties of the materials due to polymer differences and formulations used by
manufacturers to modify physical and chemical properties of the material. The user of the material
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ISO/FDIS 11114-2:2021(E)
should therefore consult the manufacturer and, if necessary, carry out tests before using the material
(e.g. for critical services such as oxygen and other oxidizing gases).
Lubricants are often used in valves to reduce friction and wear in the moving parts. For valves used for
oxidizing gases or for gases supporting combustion, if lubrication is required, it shall be ensured that
the lubricant is compatible for the intended application when the lubricated components are in contact
with the oxidizing gas or the gas supporting combustion.
Where the lubricant is listed as “not acceptable” in Table 1 for reasons other than violent reaction
(oxidation/burning) (F), it may be used safely and usually satisfactorily in applications which do not
involve contact in normal operation with the gas. An example of such an application is the lubrication of
the valve actuating mechanism not in contact with the gas.
Where the lubricant is listed as “not acceptable” for the reason of violent reaction (oxidation/burning)
(F), it should not be used in any part of the system that can be contacted by the gas, even under abnormal
conditions such as in the event of a failure of the gas sealing system. If there is a risk of violent reaction,
appropriate safety and suitability tests shall be carried out for the lubricant application before it is used
either on the lubricant itself, as specified in ISO 11114-3, or on the lubricated equipment in which it is
intended to be used, as specified in ISO 10297.
The properties of plastics and elastomers including compatibility are dependent on temperature. Low
temperature can cause hardening and the possibility of embrittlement, whereas high temperature
can cause softening and the possibility of material flow. Users of such materials shall check to ensure
their suitability over the entire operating temperature range specified by the cylinder and valve
manufacturing standards.
Some materials become brittle at low temperatures, especially at temperatures at the lower end of
the normal operating range (e.g. fluorocarbon rubber). Temperatures in the refrigerant or cryogenic
ranges affect many materials and caution shall be exercised at temperatures below −50 ° C. This risk
shall be considered in particular when transfilling by thermal siphoning at low temperature or similar
procedures, or for cylinders regularly filled at low temperatures (e.g. carbon dioxide).
6 Specific considerations
6.1 General
The compatibility of gases with non-metallic materials is affected by chemical reactions and physical
influences, which can be classified as defined in 6.2.
6.2 Non-compatibility risks
6.2.1 Violent reaction (oxidation/burning) (F)
6.2.1.1 Principle
Historically the majority of serious accidents from rapid oxidation or violent combustion have occurred
with oxidizing gas supporting combustion at high pressure. Thorough investigation of all materials and
factors should be conducted with great care and all data should be considered before designing or using
equipment to handle oxidizing gases or gases supporting combustion.
Compatibility depends mainly on the operating conditions (pressure, temperature, gas velocity,
particles, equipment design and application). The risk shall particularly be considered with gases such
as oxygen, fluorine, chlorine and nitrogen trifluoride. Most of the non-metallic materials can be ignited
relatively easily when in contact with oxidizing gases (see ISO 10156) and even when in contact with
gases not classified as oxidizing but still supporting combustion.
The selection of a material for use with oxygen or an oxygen enriched atmosphere, or both, is primarily
a matter of understanding the circumstances that cause the material to react with oxygen. Most
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ISO/FDIS 11114-2:2021(E)
materials in contact with oxygen will not ignite without a source of ignition energy (friction, heat of
compression, particle impacts, etc.). When an energy input rate, as converted to heat, is greater than
the rate of heat dissipation, and the resulting heat increase is continued for sufficient time, ignition and
combustion will occur.
Thus, two general factors shall be considered:
a) the materials compatibility properties (ease of ignition and energy of combustion);
b) the different energy sources that will produce a sufficient increase in the temperature of the
material.
These general factors should be viewed in the context of the entire system design so that the following
specific factors will assume the proper relative significance:
— the properties of the materials, which include the factors affecting ease of ignition and the conditions
affecting potential resulting damage (heat of reaction);
— the operating conditions [e.g. pressure, temperature, oxygen or oxidizing gas concentrations in a
gas mixture, or both, influence of dilutant (e.g. helium), surface contamination];
— the potential sources of ignition (e.g. friction, heat of compression, heat from mass impact, heat from
particle impact, static electricity, electrical arc, resonance, internal flexing);
— the possible consequence (e.g. effects on the surroundings such as propagation of fire);
— the additional factors (e.g. performance requirements, prior experience, availability).
In conclusion, the evaluation of compatibility of non-metallic materials is more critical than that of
metallic materials, which generally perform well when in contact with oxygen.
6.2.1.2 Specifications for oxidizing gases
In accordance with 6.2.1.1, it is not possible to make a simple statement concerning the compatibility
of non-metallic materials with oxidizing gases such as oxygen, chlorine, nitric oxide, nitrous oxide,
nitrogen dioxide, nitrogen trifluoride, etc. (see ISO 10156).
For fluorine, which is the most oxidizing gas, all non-metallic materials would historically fall into the
classification “not acceptable”.
For fluorine mixtures, the gases industry now has evidence of successful testing and safe history of use
of PTFE and PCTFE under controlled conditions (e.g. low concentration and low pressure). Therefore,
following an assessment and authorization by a competent person, these materials are acceptable in
similar conditions. Oxygen and other oxidizing gases can react violently when tested with all non-
metallic materials listed in 4.2 a), 4.2 b) and 4.2 c). Some materials such as PTFE and FKM are more
resistant to ignition than other plastics and elastomers. HC lubricants are normally not acceptable. Under
certain conditions other plastics and elastomers listed can be safely used in oxidizing service without
presenting some of the disadvantages of PTFE, i.e. poor mechanical properties and risk of release of
toxic products for breathing gas applications (see ISO 15001), or FKM, i.e. swelling, poor mechanical
properties at low temperature, risk of release of toxic products in breathing gas applications, etc.
Consequently, non-metallic materials may only be used if it has been proven by tests (or long and safe
service experience), taking into account all the operating conditions and especially the design of the
equipment, that their use is safe. ISO 11114-3 and ISO 21010 give test methods for polymeric materials
and fluid lubricants that result in conservative value. Some non-metallic materials can be safely used
at higher pressure if they are satisfactorily tested in the final design configuration, e.g. in gas cylinder
valves and regulators. Cylinder valves intended to be used for oxidizing gas service shall be tested in
accordance with ISO 10297.
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ISO/FDIS 11114-2:2021(E)
6.2.2 Mass loss (W)
6.2.2.1 Extraction
Solvent extraction of plasticizers from elastomers can cause shrinkage, especially in highly plasticized
products.
Some solvents, e.g. acetone or DMF (dimethylformamide) used for dissolved gases such as acetylene,
can damage non-metallic materials.
Liquefied gases can act as solvents.
6.2.2.2 Chemical attack
Some non-metallic materials can be chemically attacked by gases, e.g. the chemical attack of silicone
elastomers by ammonia.
NOTE This attack can sometimes lead to the complete destruction of the material.
6.2.3 Swelling of material (S)
Elastomers and plastics can be subject to swelling due to gas (or liquid) absorption. This can lead to an
unacceptable increase of dimensions (especially for O-rings) or the cracking due to sudden out-gassing
when the partial pressure is decreased, e.g. carbon dioxide with fluorocarbon.
Initial swelling can be masked by subsequent extraction of plasticizers and fillers while in service. Other
important effects such as changes in mechanical strength and hardness should also be considered.
Differences in the compounding, formulation and curing of a given elastomer can cause significant
differences in the swelling of the material in service.
Regardless of the above compatibility evaluation, the design configuration (e.g. static or dynamic
sealing) shall be taken into account before deciding to use elastomers or plastics. In this document, a
swelling of more than approximately 15 % in normal service conditions is marked N (in particular not
acceptable for dynamic sealing); a swelling less than this is marked A (acceptable) provided other risks
are also acceptable.
NOTE There is also a risk of cross bonding between sulfur vulcanised rubbers and copper alloys.
6.2.4 Change in mechanical properties (M)
Gases can lead to an unacceptable change of mechanical properties in some non-metallic materials.
This can result, for example, in an increase in hardness or a decrease in elasticity (i.e. an increase in
compression set). ISO 1817 gives testing methods to check the influence of the gas on the mechanical
properties.
6.2.5 Other compatibility considerations
6.2.5.1 Impurities in the gas (I)
Some gases contain typical impurities which it is possible will not be compatible with the intended
materials (e.g. acetone in acetylene, hydrogen sulfide in methane).
6.2.5.2 Contamination of the material (C)
Some materials become contaminated in toxic gas use by the toxic gas and become hazardous
themselves (e.g. during maintenance of equipment).
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ISO/FDIS 11114-2:2021(E)
6.2.5.3 Release of dangerous products (D)
Many materials when subjected to extreme conditions (such as elevated temperature) can release
dangerous products (e.g. toxic products). This risk shall be considered in particular for breathing gases
as specified in ISO 15001.
6.2.5.4 Ageing (G)
Ageing is a gradual change in the mechanical and physical properties of the material due to the
environment in which it is used or stored (e.g. exposure to UV light). Many elastomer and plastic
materials are particularly subject to ageing; some gases like oxygen and in general exposure to high
temperatures can accelerate the ageing process, leading to degradation such as cracking, brittleness, etc.
6.2.5.5 Permeation (P)
Permeation is a slow process by which gas passes through materials.
The permeation of some gases (e.g. helium, hydrogen, carbon dioxide) through non-metallic materials
can be significant. For a given material, the permeation rate mainly depends on the temperature,
pressure, thickness and surface area of the material in contact with the gas. The molecular radius
of the gas and the specific formulation of plasticizers and other additives can cause a wide range of
permeation rates for a particular type of plastic or elastomer.
This risk shall be considered for effects to the surroundings (e.g. toxicity, fire potential).
Permeation through the liner can lead to gas pressure between the liner and the composite, thus
potentially causing liner collapse and/or blistering.
7 Compatibility data
7.1 Table of compatibility
Table 1 lists the gases in alphabetic order with their UN number. The compatibility data are given using
the symbols and abbreviated terms defined in 7.2.1 and 7.2.2. When a gas/material combination is not
acceptable, the main reason is given, using the appropriate abbreviation for the non-compatibility risk
(see 6.2). The abbreviated terms are also sometimes used for acceptable combinations to show a limited
risk.
If no UN number is listed in Table 1 for a gas (or a liquid), this means that this gas has no official UN
number but it can be transported using a generic NOS (not otherwise specified) number (e.g. compressed
gas, flammable, NOS, UN 1954).
Compatibility evaluations are based on the following documents:
— literature data;
— operational experiences;
— laboratory tests.
The material resistance to gases can be estimated by simple immersion tests in the respective gas with
approximately the sam
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