Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2: Non-metallic materials (ISO 11114-2:2021)

Gasflaschen - Verträglichkeit von Werkstoffen für Gasflaschen und Ventile mit den in Berührung kommenden Gasen - Teil 2: Nichtmetallische Werkstoffe (ISO 11114-2:2021)

Dieses Dokument enthält eine Anleitung für die Auswahl und Bewertung der Verträglichkeit von nichtmetallischen Werkstoffen für Gasflaschen und Ventile mit den in Berührung kommenden Gasen. Es gilt auch für Bündel, Großflaschen und Druckfässer.
Dieses Dokument kann für Verbund- und Schichtwerkstoffe von Nutzen sein, die für Gasflaschen verwendet werden.
Es behandelt das Thema nicht vollständig und ist nur als Hilfestellung zur Bewertung der Verträglichkeit von Gas/Werkstoffkombinationen vorgesehen.
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 diesem Dokument nicht berücksichtigt.
Die enthaltenen Verträglichkeitsdaten beziehen sich auf Einzelgase, können jedoch in gewissem Umfang auch für Gasgemische verwendet werden. Dieses Dokument gilt nicht für Keramiken, Gläser und Klebstoffe.
Andere Gesichtspunkte, wie z. B. die Qualität des gelieferten Gases, werden nicht berücksichtigt.
Dieses Dokument 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 11114-2:2021)

Plinske jeklenke - Združljivost materialov za ventil in jeklenko s plinom - 2. del: Nekovinski materiali (ISO 11114-2:2021)

General Information

Status
Published
Public Enquiry End Date
28-Feb-2021
Publication Date
12-Dec-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
19-Nov-2021
Due Date
24-Jan-2022
Completion Date
13-Dec-2021

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SLOVENSKI STANDARD
SIST EN ISO 11114-2:2022
01-januar-2022
Nadomešča:
SIST EN ISO 11114-2:2013

Plinske jeklenke - Združljivost materialov za ventil in jeklenko s plinom - 2. del:

Nekovinski materiali (ISO 11114-2:2021)

Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2:

Non-metallic materials (ISO 11114-2:2021)

Gasflaschen - Verträglichkeit von Werkstoffen für Gasflaschen und Ventile mit den in

Berührung kommenden Gasen - Teil 2: Nichtmetallische Werkstoffe (ISO 11114-2:2021)

Bouteilles à gaz - Compatibilité des matériaux des bouteilles et des robinets avec les

contenus gazeux - Partie 2: Matériaux non métalliques (ISO 11114-2:2021)
Ta slovenski standard je istoveten z: EN ISO 11114-2:2021
ICS:
23.020.35 Plinske jeklenke Gas cylinders
SIST EN ISO 11114-2:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 11114-2:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 11114-2:2022
EN ISO 11114-2
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2021
EUROPÄISCHE NORM
ICS 23.020.35 Supersedes EN ISO 11114-2:2013
English Version
Gas cylinders - Compatibility of cylinder and valve
materials with gas contents - Part 2: Non-metallic
materials (ISO 11114-2:2021)

Bouteilles à gaz - Compatibilité des matériaux des Gasflaschen - Verträglichkeit von Werkstoffen für

bouteilles et des robinets avec les contenus gazeux - Gasflaschen und Ventile mit den in Berührung

Partie 2: Matériaux non métalliques (ISO 11114- kommenden Gasen - Teil 2: Nichtmetallische

2:2021) Werkstoffe (ISO 11114-2:2021)
This European Standard was approved by CEN on 24 October 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11114-2:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 11114-2:2022
EN ISO 11114-2:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 11114-2:2022
EN ISO 11114-2:2021 (E)
European foreword

This document (EN ISO 11114-2:2021) 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 May 2022, and conflicting national standards shall be

withdrawn at the latest by May 2022.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 11114-2:2013.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 11114-2:2021 has been approved by CEN as EN ISO 11114-2:2021 without any

modification.
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SIST EN ISO 11114-2:2022
---------------------- Page: 6 ----------------------
SIST EN ISO 11114-2:2022
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
---------------------- Page: 7 ----------------------
SIST EN ISO 11114-2:2022
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

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 11114-2:2022
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

iii
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 11114-2:2022
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.
© ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 11114-2:2022
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 .

© ISO 2021 – All rights reserved
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SIST EN ISO 11114-2:2022
---------------------- Page: 12 ----------------------
SIST EN ISO 11114-2:2022
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/
© ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 11114-2:2022
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 .
© ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 11114-2:2022
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

© ISO 2021 – All rights reserved
---------------------- Page: 15 ----------------------
SIST EN ISO 11114-2:2022
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

© ISO 2021 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 11114-2:2022
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.
© ISO 2021 – All rights reserved
---------------------- Page: 17 ----------------------
SIST EN ISO 11114-2:2022
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, especia
...

SLOVENSKI STANDARD
oSIST prEN ISO 11114-2:2021
01-februar-2021

Plinske jeklenke - Združljivost materialov za ventil in jeklenko s plinom - 2. del:

Nekovinski materiali (ISO/DIS 11114-2:2020)

Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2:

Non-metallic materials (ISO/DIS 11114-2:2020)

Gasflaschen - Verträglichkeit von Flaschen- und Ventilwerkstoffen mit den in Berührung

kommenden Gasen - Teil 2: Nichtmetallische Werkstoffe (ISO/DIS 11114-2:2020)

Bouteilles à gaz - Compatibilité des matériaux des bouteilles et des robinets avec les

contenus gazeux - Partie 2: Matériaux non métalliques (ISO/DIS 11114-2:2020)
Ta slovenski standard je istoveten z: prEN ISO 11114-2
ICS:
23.020.35 Plinske jeklenke Gas cylinders
oSIST prEN ISO 11114-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 11114-2:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 11114-2:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11114-2
ISO/TC 58 Secretariat: BSI
Voting begins on: Voting terminates on:
2020-12-09 2021-03-03
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
ICS: 23.020.35
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
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oSIST prEN ISO 11114-2:2021
ISO/DIS 11114-2:2020(E)
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oSIST prEN ISO 11114-2:2021
ISO 11114-2:2020(E)
Contents

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 ......................................................................................................................................... 4

6 Specific considerations ........................................................................................................................................ 4

6.1 General ...................................................................................................................................................................... 4

6.2 Non-compatibility risks ....................................................................................................................................... 4

7 Compatibility data ................................................................................................................................................. 7

7.1 Table of compatibility .......................................................................................................................................... 7

7.2 Symbols and abbreviations ................................................................................................................................ 8

Bibliography .................................................................................................................................................................... 0

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oSIST prEN ISO 11114-2:2021
ISO 11114-2:2020(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.

This third edition cancels and replaces the second edition (ISO 11114-2:2013), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— new materials were integrated in Table 1;
— a table dedicated to the compatibility for liner was introduced.
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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oSIST prEN ISO 11114-2:2021
ISO 11114-2:2020(E)
Introduction

This document 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 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.
[1]

This document has been written so that it is suitable to be referenced in the UN Model Regulations .

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oSIST prEN ISO 11114-2:2021
ISO 11114-2:2020(E)
Gas cylinders – Compatibility of cylinder and valve materials with
gas contents – Part 2: Non-metallic materials
1 Scope

This document 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 document 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 document.

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 document.
Other aspects such as quality of delivered gas are not considered.
This document is not intended to be used for cryogenic fluids (see 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 - Terminology

ISO 10297, Gas cylinders — Refillable gas cylinder valves — Specification and type testing

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 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 11114-2:2020(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 1 to entry: 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
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.

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 Solid lubricants are sometimes used, e.g. MoS2.
Materials considered in this document are as follows:
a) Plastics:

When plastic liner materials are used, it is necessary to use metallic bosses. For compatibility of metallic bosses, see ISO 11114-

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oSIST prEN ISO 11114-2:2021
ISO 11114-2:2020(E)
 Polytetrafluoroethylene (PTFE);
 Polychlorotrifluoroethylene (PCTFE);
 Polyvinylidenefluoride (PVDF);
 Polyamide (PA);
 Polypropylene (PP);
 Polyethylene (PE);

NOTE 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 sulphide (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).
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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 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.

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 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. CO ).
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.
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ISO 11114-2:2020(E)

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.

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),

 the possible consequence (e.g. effects on the surroundings such as propagation of fire), and

 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 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

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ISO 11114-2:2020(E)

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.

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. 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 document, 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.
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ISO 11114-2:2020(E)
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 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).
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. Many elastomer and plastic materials are particularly subject

to ageing; some gases like oxygen and in general exposure to high temperatures may accelerate the ageing

process, leading to degradation such as cracking, brittleness, etc.
6.2.5.5 Permeation (P) and liner collapse
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 material can

be significant. For a given material, the permeation rate mainly depends on 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 creating liner collapse.
7 Compatibility data
7.1 Table of compatibility

Table 1 lists the gases in alphabetic order with the UN number in bracket. In this table, the compatibility

data is given using the symbols and abbreviations 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 abbreviations are also sometimes used for acceptable combinations to

show a limited risk.

If no UN number is listed in the table for a gas (or a liquid), this means that this gas has no official UN

number but it may be transported using a generic NOS (Not Otherwise Specified) number (e.g.

compressed gas, flammable, NOS, UN 1954).
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ISO 11114-2:2020(E)
Compatibility evaluations are based on the following documents:
 literature data;
 operational experiences; and
 laboratory tests.

The 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, 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 weight 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.

In literature and company leaflets frequently used classifications are “resistant”, "conditionally resistant"

and "not resistant".
Test procedures are described in ISO 1817 and in ISO 9539.
7.2 Symbols and abbrevi
...

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