SIST EN ISO 11114-2:2013
(Main)Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2: Non-metallic materials (ISO 11114-2:2013)
Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2: Non-metallic materials (ISO 11114-2:2013)
This part of ISO 11114 gives guidance in the selection and evaluation of compatibility between non-metallic materials for gas cylinders and valves and the gas contents. It also covers bundles, tubes and pressure drums. This part of ISO 11114 can be helpful for composite and laminated materials used for gas cylinders. It does not cover the subject completely and is intended to give guidance only in evaluating the compatibility of gas/material combinations. Only the influence of the gas in changing the material and mechanical properties is considered (for example chemical reaction or change in physical state). The basic properties of the materials, such as mechanical properties, required for design purposes are normally available from the materials supplier and are not considered in this part of ISO 11114. The compatibility data given are related to single component gases but can be used to some extent for gas mixtures. Ceramics, glasses, and adhesives are not covered by this part of ISO 11114. Other aspects such as quality of delivered gas are not considered. This part of ISO 11114 is not intended to be used for cryogenic fluids (see ISO 21010).
Gasflaschen - Verträglichkeit von Flaschen- und Ventilwerkstoffen mit den in Berührung kommenden Gasen - Teil 2: Nichtmetallische Werkstoffe (ISO 11114-2:2013)
Diese Norm liefert eine Anleitung für die Auswahl und Bewertung der Verträglichkeit von nichtmetallischen Werkstoffen für Gasflaschen und Ventile mit den in Berührung kommenden Gasen. Diese Norm gilt auch für Bündel, Großflaschen und Druckfässer.
Diese Norm kann für Gasflaschen verwendete Verbund- und Schichtwerkstoffe von Nutzen sein.
Es wird ausschließlich die Auswirkung des Gases auf Änderungen der Werkstoff- und mechanischen Eigenschaften (z. B. chemische Reaktion oder Änderungen des physikalischen Zustandes) berücksichtigt. Die für Auslegungszwecke notwendigen grundsätzlichen Werkstoffeigenschaften, wie z. B. mechanische Eigenschaften, werden üblicherweise vom Werkstofflieferanten bereitgestellt und in dieser Norm nicht berücksichtigt.
Die enthaltenen Verträglichkeitsdaten beziehen sich auf Einzelgase, können jedoch in gewissem Umfang auch für Gasgemische verwendet werden. Diese Norm gilt nicht für Keramiken, Gläser und Klebstoffe.
Andere Gesichtspunkte, wie z. B. die Qualität des gelieferten Gases, werden nicht berücksichtigt.
Diese Norm ist nicht zur Verwendung für tiefkalte Fluide (siehe ISO 21010) bestimmt.
Bouteilles à gaz - Compatibilité des matériaux des bouteilles et des robinets avec les contenus gazeux - Partie 2: Matériaux non métalliques (ISO 11114-2:2013)
L'ISO 11114-2:2013 donne des lignes directrices pour la sélection et l'évaluation de la compatibilité entre les matériaux non métalliques des bouteilles à gaz/robinets avec le gaz. Elle couvre également les cadres, tubes et fûts sous pression.
L'ISO 11114-2:2013 peut se révéler utile pour les matériaux composites et les matériaux stratifiés utilisés pour les bouteilles à gaz.
Elle ne couvre pas la totalité du sujet et n'a pour but que de donner une orientation pour l'évaluation de la compatibilité des combinaisons gaz/matériau.
Seule l'influence du gaz sur la transformation du matériau ou sur la modification de ses propriétés mécaniques est considérée (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 sont en général fournies par le fabricant du matériau et ne sont donc pas abordées dans l'ISO 11114-2:2013.
Les données de compatibilité indiquées se rapportent à des gaz à un composant unique, mais elles peuvent être utilisées dans une certaine mesure pour des mélanges gazeux. Les céramiques, les verres et les adhésifs ne sont pas traités dans l'ISO 11114-2:2013.
D'autres aspects, tels que la qualité du gaz fourni, ne sont pas pris en compte.
L'ISO 11114-2:2013. n'est pas destinée à être utilisée pour les fluides cryogéniques (voir l'ISO 21010).
Plinske jeklenke - Združljivost materialov za ventil in jeklenko s plinom - 2. del: Nekovinski materiali (ISO 11114-2:2013)
Ta del standarda ISO 11114 podaja smernice za izbiro in oceno združljivosti nekovinskih materialov za plinske jeklenke in ventile ter vsebnost plina. Zajema tudi snope, cevi in sode pod tlakom. Ta del standarda ISO 11114 je lahko v pomoč pri sestavljenih in laminiranih materialih, ki se uporabljajo za plinske jeklenke. Tematike ne obravnava v celoti in je namenjen samo svetovanju pri oceni združljivosti kombinacij plina/materiala. Obravnava se samo vpliv plina na spreminjanje materialnih in mehanskih lastnosti (na primer kemijska reakcija ali sprememba fizikalnega stanja). Osnovne lastnosti materialov, kot so mehanske lastnosti, zahtevane za potrebe projektiranja, običajno predloži dobavitelj materialov in niso obravnavane v tem delu standarda ISO 11114. Navedeni podatki o združljivosti se nanašajo na enokomponentne pline, vendar jih je mogoče do določene mere uporabiti za mešanice plinov. Keramika, stekla in lepila niso vključeni v ta del standarda ISO 11114. Drugi vidiki, kot so kakovost dobavljenega plina, niso obravnavani. Ta del standarda ISO 11114 ni namenjen za uporabo za kriogene tekočine (glej standard ISO 21010).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11114-2:2013
01-december-2013
1DGRPHãþD
SIST EN ISO 11114-2:2002
Plinske jeklenke - Združljivost materialov za ventil in jeklenko s plinom - 2. del:
Nekovinski materiali (ISO 11114-2:2013)
Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2:
Non-metallic materials (ISO 11114-2:2013)
Gasflaschen - Verträglichkeit von Flaschen- und Ventilwerkstoffen mit den in Berührung
kommenden Gasen - Teil 2: Nichtmetallische Werkstoffe (ISO 11114-2:2013)
Bouteilles à gaz - Compatibilité des matériaux des bouteilles et des robinets avec les
contenus gazeux - Partie 2: Matériaux non métalliques (ISO 11114-2:2013)
Ta slovenski standard je istoveten z: EN ISO 11114-2:2013
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
SIST EN ISO 11114-2:2013 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11114-2:2013
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SIST EN ISO 11114-2:2013
EUROPEAN STANDARD
EN ISO 11114-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2013
ICS 23.020.30 Supersedes EN ISO 11114-2:2000
English Version
Gas cylinders - Compatibility of cylinder and valve materials with
gas contents - Part 2: Non-metallic materials (ISO 11114-
2:2013)
Bouteilles à gaz - Compatibilité des matériaux des Gasflaschen - Verträglichkeit von Flaschen- und
bouteilles et des robinets avec les contenus gazeux - Partie Ventilwerkstoffen mit den in Berührung kommenden Gasen
2: Matériaux non métalliques (ISO 11114-2:2013) - Teil 2: Nichtmetallische Werkstoffe (ISO 11114-2:2013)
This European Standard was approved by CEN on 9 February 2013.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11114-2:2013: E
worldwide for CEN national Members.
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SIST EN ISO 11114-2:2013
EN ISO 11114-2:2013 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 11114-2:2013
EN ISO 11114-2:2013 (E)
Foreword
This document (EN ISO 11114-2:2013) 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 October 2013, and conflicting national standards shall be withdrawn at
the latest by October 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11114-2:2000.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 11114-2:2013 has been approved by CEN as EN ISO 11114-2:2013 without any modification.
3
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SIST EN ISO 11114-2:2013
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SIST EN ISO 11114-2:2013
INTERNATIONAL ISO
STANDARD 11114-2
Second edition
2013-04-01
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 11114-2:2013(E)
©
ISO 2013
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
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
Case postale 56 CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(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 Types of material . 2
5 General considerations. 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 Weight loss (W) . 5
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 abbreviations . 8
7.2.1 Symbols for compatibility . 8
7.2.2 Abbreviations for materials . 8
7.2.3 Abbreviations for non-compatibility risks . 9
7.2.4 Examples . 9
Bibliography . 14
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11114-2 was prepared by Technical Committee ISO/TC 58, Gas cylinders, in collaboration with
Technical Committee CEN/TC 23, Transportable Gas cylinders in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition, Clauses 4 and 6, and Table 1 of which have been
technically revised. Annex A has been deleted.
ISO 11114 consists of the following parts, under the general title Gas cylinders — Compatibility of cylinder and
valve materials with gas contents:
— Part 1: Metallic materials;
— Part 2: Non-metallic materials;
— Part 3: Autogenous ignition test for non-metallic materials in oxygen atmosphere;
— Part 4: Test methods for selecting metallic materials resistant to hydrogen embrittlement.
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
Introduction
This part of ISO 11114 deals with 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 treated 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 part of ISO 11114.
This part of ISO 11114 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.
This part of ISO 11114 has been written to be in conformity with the UN Recommendations on the Transport
of Dangerous Goods: Model Regulations. When published it will be submitted to the UN Sub Committee of
Experts on the Transport of Dangerous Goods with a request that it be included in the Model Regulations.
Where there is any conflict between this part of ISO 11114 and any applicable regulation, the regulation
always takes precedence.
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SIST EN ISO 11114-2:2013
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SIST EN ISO 11114-2:2013
INTERNATIONAL STANDARD ISO 11114-2:2013(E)
Gas cylinders — Compatibility of cylinder and valve materials
with gas contents —
Part 2:
Non-metallic materials
1 Scope
This part of ISO 11114 gives guidance in the selection and evaluation of compatibility between non-metallic
materials for gas cylinders and valves and the gas contents. It also covers bundles, tubes and pressure
drums.
This part of ISO 11114 can be helpful for composite and laminated materials used for gas cylinders.
It does not cover the subject completely and is intended to give guidance only in evaluating the compatibility of
gas/material combinations.
Only the influence of the gas in changing the material and mechanical properties is considered (for example
chemical reaction or change in physical state). The basic properties of the materials, such as mechanical
properties, required for design purposes are normally available from the materials supplier and are not
considered in this part of ISO 11114.
The compatibility data given are related to single component gases but can be used to some extent for gas
mixtures. Ceramics, glasses, and adhesives are not covered by this part of ISO 11114.
Other aspects such as quality of delivered gas are not considered.
This part of ISO 11114 is not intended to be used for cryogenic fluids (see ISO 21010).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 11114-3, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 3: Autogenous ignition test for non-metallic materials in oxygen atmosphere
ISO 10297, Gas cylinders — Refillable gas cylinder valves — Specification and type testing
ISO 15001, Anaesthetic and respiratory equipment — Compatibility with oxygen
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(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
3.2
acceptable
material/gas combination that is satisfactory under normal conditions of use (as defined in Clause 5), provided
that any indicated non-compatibility risks, as given in Table 1, are taken into account
3.3
not acceptable
material/single gas combination that is not safe under normal conditions of use (as defined in Clause 5)
NOTE For gas mixtures special conditions can apply.
3.4
dynamic sealing
where in normal operation the non-metallic material is used to provide a pressure seal between two surfaces
that have relative motion to each other
3.5
static sealing
where in normal operation the non-metallic material is used to provide a pressure seal between two surfaces
that have not 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, or the necessary properties have been proved by tests or long and safe
experience to the satisfaction of a competent person.
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 Types of material
The most commonly used non-metallic materials for gas cylinders and cylinder valves can be grouped as
follows:
plastics;
elastomers;
— fluid lubricants.
NOTE Solid lubricants are sometimes used, e.g. MoS2.
Materials considered in this part of ISO 11114 are as follows:
a) Plastics:
Polytetrafluoroethylene (PTFE);
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
Polychlorotrifluoroethylene (PCTFE);
Polyvinylidenefluoride (PVDF);
Polyamide (PA);
Polypropylene (PP);
Polyetheretherketone (PEEK);
Polypropylene sulphide (PPS);
Polyvinyl chloride (PVC)
Polyimide (PI);
Polyoxymethylene (POM).
b) Elastomers:
Butyl rubber (IIR);
Nitrile rubber (NBR);
Chloroprene rubber (CR);
Fluorocarbon rubber (FKM);
Methyl-vinyl-silicone rubber (VMQ);
Ethylene propylene diene monomer (EPDM);
Polyacrylate rubber (ACM);
Polyurethane rubber (PUR);
Methyl-fluoro-silicone rubber (FVMQ).
c) Fluid lubricants:
Hydrocarbon (HC);
Fluorocarbon (FC).
5 General considerations
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 should therefore consult the
manufacturer and if necessary carry out tests before using the material (for example 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.
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
Where the lubricant is listed as "not acceptable" in Table 1 for reasons other than violent reaction (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 (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 have been 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 will 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. CO ).
2
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 follows.
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 and/or an oxygen enriched atmosphere is primarily a matter of
understanding the circumstances that cause the material to react with oxygen. Most materials in contact with
oxygen will not ignite without a source of ignition energy (e.g. 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); and
b) the different energy sources that will produce a sufficient increase in the temperature of the material.
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
These general factors should be viewed in the context of the entire system design so that the specific factors
listed below will assume the proper relative significance.
The specific factors to take into consideration are
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 and/or oxidizing gas concentrations in a gas
mixture, 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),
possible consequence (e.g. effects on the surroundings such as propagation of fire), and
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 authorisation 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 testing methods for polymeric materials and fluid lubricants
that will result in conservative value. Some non-metallic material can be safely used at higher pressure when
they are tested in the final design configuration, e.g. in gas cylinder valves and regulator. Cylinder valves shall
be tested according to ISO 10297 for oxygen service.
6.2.2 Weight loss (W)
6.2.2.1 Extraction
Solvent extraction of plasticizers from elastomers can cause shrinkage, especially in highly plasticized
products.
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SIST EN ISO 11114-2:2013
ISO 11114-2:2013(E)
1)
Some solvents, e.g. acetone or DMF 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. This attack can sometimes lead to the
complete destruction of the material, e.g. the chemical attack of silicone elastomer by ammonia.
6.2.3 Swelling of material (S)
Elastomers and plastics may 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 part of ISO 11114, a swelling
of more than approximately 15 % in normal service conditions is marked N (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 sulphur 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. 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 may not be compatible with the intended materials (e.g. acetone
in acetylene, hydrogen sulphide in methane).
6.2.5.2 C
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