SIST EN ISO 9809-4:2023

Gas cylinders - Design, construction and testing of refillable seamless steel gas cylinders and tubes - Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa (ISO 9809-4:2021)

This document specifies the minimum requirements for the materials, design, construction and workmanship, manufacturing processes, examinations and testing at time of manufacture for refillable, seamless, stainless steel gas cylinders with water capacities up to and including 150 l.
It is applicable to cylinders for compressed, liquefied and dissolved gases with a maximum actual tensile strength, Rma, of less than 1 100 MPa.
NOTE   If so desired, cylinders of water capacity between 150 l and 450 l can be manufactured to be in full conformance to this document.

Gasflaschen - Auslegung, Herstellung und Prüfung von wiederbefüllbaren nahtlosen Gasflaschen aus Stahl - Teil 4: Flaschen aus Edelstahl mit einem Rm-Wert von weniger als 1 100 MPa (ISO 9809-4:2021)

Dieses Dokument legt die Mindestanforderungen an die Werkstoffe, Auslegung, den Bau und die Ausführung, Herstellungsverfahren, Herstellungsuntersuchungen und  prüfungen für wiederbefüllbare nahtlose Gasfla¬schen aus nichtrostendem Stahl mit Fassungsräumen bis einschließlich 150 l (bezogen auf Wasser) fest.
Es ist anzuwenden für Flaschen für verdichtete, verflüssigte und gelöste Gase mit einer tatsächlichen Höchst Zugfestig¬keit Rma von weniger als 1 100 MPa.
ANMERKUNG   Falls gewünscht, können Gasflaschen mit einem Fassungsraum zwischen 150 l und 450 l hergestellt werden, die mit diesem Dokument vollständig übereinstimmen.

Bouteilles à gaz - Conception, construction et essais des bouteilles à gaz et des tubes rechargeables en acier sans soudure - Partie 4: Bouteilles en acier inoxydable avec une valeur Rm inférieure à 1 100 MPa (ISO 9809-4:2021)

Le présent document spécifie les exigences minimales concernant le matériau, la conception, la construction et la mise en œuvre, les procédés de fabrication, les examens et les essais au moment de la fabrication des bouteilles à gaz rechargeables en acier sans soudure d’une contenance en eau inférieure ou égale à 150 l.
Il s’applique aux bouteilles pour les gaz comprimés, liquéfiés et dissous ayant une résistance à la traction réelle, Rma, maximale inférieure à 1 100 MPa.
NOTE            Si cela est souhaité, les bouteilles d’une contenance en eau comprise entre 150 l et 450 l peuvent être fabriquées conformément au présent document.

Plinske jeklenke - Konstruiranje, izdelava in preskušanje ponovno polnljivih plinskih jeklenk in velikih jeklenk iz celega iz jekla - 4. del: Nerjavne jeklenke iz jekla z vrednostjo Rm, manjšo od 1100 MPa (ISO 9809-4:2021)

Ta dokument določa minimalne zahteve za materiale, konstruiranje, izdelavo in izvedbo, postopke izdelave, pregled in preskušanje ob času proizvodnje za ponovno polnljive nevarjene plinske jeklenke s prostornino vode do vključno 150 l.
Uporablja se za jeklenke za stisnjene, utekočinjene in raztopljene pline z največjo dejansko natezno trdnostjo Rma, manjšo od 1100 MPa.
OPOMBA:   Po želji je mogoče izdelati jeklenke s prostornino vode med 150 l in 450 l, ki so popolnoma skladne s tem dokumentom.

General Information

• Status: Published
• Public Enquiry End Date: 02-Oct-2022
• Publication Date: 12-Mar-2023
• ICS: 23.020.35 - Gas cylinders
• Technical Committee: TLP - Pressure vessels
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 25-Jan-2023
• Due Date: 01-Apr-2023
• Completion Date: 13-Mar-2023
• Directive: 2008/68/EC - Directve 2008/68/EC of the European Parliament and of the council of 24 September 2008 on the inland transport of the dangerous goods
• Mandate: M/TDG - Standards for referencing in the RID-ADR
• Ref Project: EN ISO 9809-4:2022 - Gas cylinders - Design, construction and testing of refillable seamless steel gas cylinders and tubes - Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa (ISO 9809-4:2021)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 9809-4:2023
01-april-2023
Plinske jeklenke - Konstruiranje, izdelava in preskušanje ponovno polnljivih
plinskih jeklenk in velikih jeklenk iz celega iz jekla - 4. del: Nerjavne jeklenke iz
jekla z vrednostjo Rm, manjšo od 1100 MPa (ISO 9809-4:2021)
Gas cylinders - Design, construction and testing of refillable seamless steel gas cylinders
and tubes - Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa
(ISO 9809-4:2021)
Gasflaschen - Auslegung, Herstellung und Prüfung von wiederbefüllbaren nahtlosen
Gasflaschen aus Stahl - Teil 4: Flaschen aus Edelstahl mit einem Rm-Wert von weniger
als 1 100 MPa (ISO 9809-4:2021)
Bouteilles à gaz - Conception, construction et essais des bouteilles à gaz et des tubes
rechargeables en acier sans soudure - Partie 4: Bouteilles en acier inoxydable avec une
valeur Rm inférieure à 1 100 MPa (ISO 9809-4:2021)
Ta slovenski standard je istoveten z: EN ISO 9809-4:2022
ICS:
23.020.35 Plinske jeklenke Gas cylinders
SIST EN ISO 9809-4:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9809-4:2023

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SIST EN ISO 9809-4:2023


EN ISO 9809-4
EUROPEAN STANDARD

NORME EUROPÉENNE

December 2022
EUROPÄISCHE NORM
ICS 23.020.35
English Version

Gas cylinders - Design, construction and testing of
refillable seamless steel gas cylinders and tubes - Part 4:
Stainless steel cylinders with an Rm value of less than 1
100 MPa (ISO 9809-4:2021)
Bouteilles à gaz - Conception, construction et essais des Gasflaschen - Auslegung, Herstellung und Prüfung von
bouteilles à gaz et des tubes rechargeables en acier wiederbefüllbaren nahtlosen Gasflaschen aus Stahl -
sans soudure - Partie 4: Bouteilles en acier inoxydable Teil 4: Flaschen aus Edelstahl mit einem Rm-Wert von
ayant une valeur de Rm inférieure à 1 100 MPa (ISO weniger als 1 100 MPa (ISO 9809-4:2021)
9809-4:2021)
This European Standard was approved by CEN on 11 December 2022.

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, Türkiye 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9809-4:2022 E
worldwide for CEN national Members.

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SIST EN ISO 9809-4:2023
EN ISO 9809-4:2022 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 9809-4:2023
EN ISO 9809-4:2022 (E)
European foreword
The text of ISO 9809-4:2021 has been prepared by Technical Committee ISO/TC 58 "Gas cylinders” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 9809-
4:2022 by 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 June 2023, and conflicting national standards shall be
withdrawn at the latest by June 2023.
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 has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national standards body.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 9809-4:2021 has been approved by CEN as EN ISO 9809-4:2022 without any
modification.

3

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SIST EN ISO 9809-4:2023

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SIST EN ISO 9809-4:2023
INTERNATIONAL ISO
STANDARD 9809-4
Second edition
2021-11
Gas cylinders — Design, construction
and testing of refillable seamless steel
gas cylinders and tubes —
Part 4:
Stainless steel cylinders with an R
m
value of less than 1 100 MPa
Bouteilles à gaz — Conception, construction et essais des bouteilles à
gaz et des tubes rechargeables en acier sans soudure —
Partie 4: Bouteilles en acier inoxydable avec une valeur R
m
inférieure à 1 100 MPa
Reference number
ISO 9809-4:2021(E)
© ISO 2021

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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
 © ISO 2021 – All rights reserved

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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
5 Inspection and testing .4
6 Materials . 4
6.1 General requirements . 4
6.2 Controls on chemical composition . 5
6.3 Heat treatment. 5
6.4 Cold working or cryoforming . 5
6.5 Failure to meet test requirements . 6
7 Design . 6
7.1 General requirements . 6
7.2 Design of cylindrical shell thickness . 6
7.3 Design of convex ends (heads and bases) . 7
7.4 Design of the concave base ends . 8
7.5 Neck design . 9
7.6 Foot rings . . 9
7.7 Neck rings . 9
7.8 Design drawing . 10
8 Construction and workmanship .10
8.1 General . 10
8.2 Wall thickness . 10
8.3 Surface imperfections . 10
8.4 Ultrasonic examination . 10
8.5 Out-of-roundness . 11
8.6 Mean diameter . 11
8.7 Straightness . 11
8.8 Verticality and stability . 11
8.9 Neck threads .12
9 Type approval procedure .12
9.1 General requirements . 12
9.2 Prototype test . 13
9.2.1 General requirements . 13
9.2.2 Pressure cycling test . 14
9.2.3 Base check . 14
9.2.4 Torque test for taper thread only . 15
9.2.5 Shear stress calculation for parallel threads . 15
9.3 Type approval certificate .15
9.4 Specific type approval/production tests for cylinders ordered in small quantities . 16
10 Batch tests . .16
10.1 General requirements . 16
10.2 Tensile test . 18
10.3 Bend test and flattening test . 19
10.3.1 Bend test . 19
10.3.2 Flattening test . . 20
10.3.3 Ring flattening test. 20
10.4 Impact test . 20
iii
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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(E)
10.5 Hydraulic burst test . 22
10.5.1 Test installation . .22
10.5.2 Test conditions . 23
10.5.3 Interpretation of test results . 24
10.6 Intergranular corrosion test .25
11 Tests/examinations on every cylinder .25
11.1 General . 25
11.2 Hydraulic test . 26
11.2.1 Proof pressure test .26
11.2.2 Volumetric expansion test . 26
11.3 Hardness test . 26
11.4 Leak test . 26
11.5 Capacity check . 27
12 Certification .27
13 Marking . .27
Annex A (normative) Description and evaluation of manufacturing imperfections and
conditions for rejection of seamless steel gas cylinders at the time of final
inspection by the manufacturer.28
Annex B (normative) Ultrasonic examination .43
Annex C (informative) Example of type approval certificate .49
Annex D (informative) Example of acceptance certificate .50
Annex E (informative) Example of shear strength calculation for parallel threads .52
Bibliography .54
iv
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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(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, Subcommittee SC 3,
Cylinder design.
This second edition cancels and replaces the first edition (ISO 9809-4:2014), which has been technically
revised. The main changes compared with the previous edition are as follows:
— update of Clause 5;
— clarification of Figure 3;
— clarification of 8.9;
— modification of 9.1, 9.2, 9.2.4 and Annex A;
— new subclause 9.2.5 for parallel threads;
— new subclause 9.4 for cylinders ordered in small quantities.
A list of all parts in the ISO 9809 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.
v
© ISO 2021 – All rights reserved

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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(E)
Introduction
This document provides a specification for the design, manufacture, inspection and testing of a
seamless stainless steel cylinder. The objective is to balance the design and economic efficiency against
international acceptance and universal utility.
ISO 9809 (all parts) aims to eliminate the concern about climate, duplicate inspections and restrictions
because of the lack of definitive International Standards.
[1]
This document has been written so that it is suitable to be referenced in the UN Model Regulations .
vi
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SIST EN ISO 9809-4:2023
INTERNATIONAL STANDARD ISO 9809-4:2021(E)
Gas cylinders — Design, construction and testing of
refillable seamless steel gas cylinders and tubes —
Part 4:
Stainless steel cylinders with an R value of less than 1 100
m
MPa
1 Scope
This document specifies the minimum requirements for the materials, design, construction and
workmanship, manufacturing processes, examinations and testing at time of manufacture for refillable,
seamless, stainless steel gas cylinders with water capacities up to and including 150 l.
It is applicable to cylinders for compressed, liquefied and dissolved gases with a maximum actual
tensile strength, R , of less than 1 100 MPa.
ma
NOTE If so desired, cylinders of water capacity between 150 l and 450 l can be manufactured to be in full
conformance to this document.
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 3651-2, Determination of resistance to intergranular corrosion of stainless steels — Part 2:
Ferritic,austenitic and ferritic-austenitic (duplex) stainless steels — Corrosion test in media containing
sulfuric acid
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 9328-1, Steel flat products for pressure purposes — Technical delivery conditions — Part 1: General
requirements
ISO 9329-4, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 4: Austenitic
stainless steels
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 10286, Gas cylinders — Vocabulary
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 13769, Gas cylinders — Stamp marking
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 and the following apply.
1
© ISO 2021 – All rights reserved

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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(E)
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/
3.1
batch
quantity of up to 200 cylinders, plus cylinders for destructive testing of the same nominal diameter,
thickness, length and design made successively on the same equipment, from the same cast of steel, and
subjected to the same heat treatment for the same duration of time
3.2
burst pressure
p
b
highest pressure reached in a cylinder during a burst test
3.3
cold working
process in which a cylinder is subjected to a pressure higher than the cylinder test pressure (3.11) to
increase the yield strength (3.12) of the steel
3.4
cryoforming
process where the cylinder is subjected to a controlled low-temperature deformation treatment that
results in a permanent increase in strength
3.5
design stress factor
F
ratio of the equivalent wall stress at test pressure, p , (3.11) to guaranteed minimum yield strength, R
h eg
3.6
quenching
hardening heat treatment in which a cylinder, which has been heated to a uniform temperature above
the upper critical point, Ac , of the steel, is cooled rapidly on a suitable medium
3
3.7
reject
action to set aside a cylinder (Level 2 or Level 3) that is not allowed to go into service
3.8
rendered unserviceable
cylinder that has been treated in such a way as to render it impossible for use
Note 1 to entry: Examples for acceptable methods to render cylinders unserviceable can be found in ISO 18119.
Any actions on cylinders rendered unserviceable are outside the scope of this document.
3.9
repair
action to return a rejected cylinder to a Level 1 condition
3.10
tempering
toughening heat treatment which follows quenching (3.6), in which the cylinder is heated to a uniform
temperature below the critical point, Ac , of the steel
1
2
  © ISO 2021 – All rights reserved

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SIST EN ISO 9809-4:2023
ISO 9809-4:2021(E)
3.11
test pressure
p
h
required pressure applied during a pressure test
Note 1 to entry: Test pressure is used for the cylinder wall thickness calculation.
3.12
yield strength
stress value corresponding to the 0,2 % proof stress or for austenitic steels in the solution-annealed
condition, 1 % proof stress
3.13
working pressure
settled pressure of a compressed gas at a uniform reference temperature of 15 °C in a full gas cylinder
4 Symbols
A percentage elongation a
...

SLOVENSKI STANDARD
oSIST prEN ISO 9809-4:2022
01-september-2022
Plinske jeklenke - Konstruiranje, izdelava in preskušanje ponovno polnljivih
plinskih jeklenk in velikih jeklenk iz celega iz jekla - 4. del: Nerjavne jeklenke iz
jekla z vrednostjo Rm, manjšo od 1100 MPa (ISO 9809-4:2021)
Gas cylinders - Design, construction and testing of refillable seamless steel gas cylinders
and tubes - Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa
(ISO 9809-4:2021)
Bouteilles à gaz - Conception, construction et essais des bouteilles à gaz et des tubes
rechargeables en acier sans soudure - Partie 4: Bouteilles en acier inoxydable avec une
valeur Rm inférieure à 1 100 MPa (ISO 9809-4:2021)
Ta slovenski standard je istoveten z: prEN ISO 9809-4
ICS:
23.020.35 Plinske jeklenke Gas cylinders
oSIST prEN ISO 9809-4:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 9809-4:2022

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oSIST prEN ISO 9809-4:2022
INTERNATIONAL ISO
STANDARD 9809-4
Second edition
2021-11
Gas cylinders — Design, construction
and testing of refillable seamless steel
gas cylinders and tubes —
Part 4:
Stainless steel cylinders with an R
m
value of less than 1 100 MPa
Bouteilles à gaz — Conception, construction et essais des bouteilles à
gaz et des tubes rechargeables en acier sans soudure —
Partie 4: Bouteilles en acier inoxydable avec une valeur R
m
inférieure à 1 100 MPa
Reference number
ISO 9809-4:2021(E)
© ISO 2021

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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
 © ISO 2021 – All rights reserved

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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
5 Inspection and testing .4
6 Materials . 4
6.1 General requirements . 4
6.2 Controls on chemical composition . 5
6.3 Heat treatment. 5
6.4 Cold working or cryoforming . 5
6.5 Failure to meet test requirements . 6
7 Design . 6
7.1 General requirements . 6
7.2 Design of cylindrical shell thickness . 6
7.3 Design of convex ends (heads and bases) . 7
7.4 Design of the concave base ends . 8
7.5 Neck design . 9
7.6 Foot rings . . 9
7.7 Neck rings . 9
7.8 Design drawing . 10
8 Construction and workmanship .10
8.1 General . 10
8.2 Wall thickness . 10
8.3 Surface imperfections . 10
8.4 Ultrasonic examination . 10
8.5 Out-of-roundness . 11
8.6 Mean diameter . 11
8.7 Straightness . 11
8.8 Verticality and stability . 11
8.9 Neck threads .12
9 Type approval procedure .12
9.1 General requirements . 12
9.2 Prototype test . 13
9.2.1 General requirements . 13
9.2.2 Pressure cycling test . 14
9.2.3 Base check . 14
9.2.4 Torque test for taper thread only . 15
9.2.5 Shear stress calculation for parallel threads . 15
9.3 Type approval certificate .15
9.4 Specific type approval/production tests for cylinders ordered in small quantities . 16
10 Batch tests . .16
10.1 General requirements . 16
10.2 Tensile test . 18
10.3 Bend test and flattening test . 19
10.3.1 Bend test . 19
10.3.2 Flattening test . . 20
10.3.3 Ring flattening test. 20
10.4 Impact test . 20
iii
© ISO 2021 – All rights reserved

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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
10.5 Hydraulic burst test . 22
10.5.1 Test installation . .22
10.5.2 Test conditions . 23
10.5.3 Interpretation of test results . 24
10.6 Intergranular corrosion test .25
11 Tests/examinations on every cylinder .25
11.1 General . 25
11.2 Hydraulic test . 26
11.2.1 Proof pressure test .26
11.2.2 Volumetric expansion test . 26
11.3 Hardness test . 26
11.4 Leak test . 26
11.5 Capacity check . 27
12 Certification .27
13 Marking . .27
Annex A (normative) Description and evaluation of manufacturing imperfections and
conditions for rejection of seamless steel gas cylinders at the time of final
inspection by the manufacturer.28
Annex B (normative) Ultrasonic examination .43
Annex C (informative) Example of type approval certificate .49
Annex D (informative) Example of acceptance certificate .50
Annex E (informative) Example of shear strength calculation for parallel threads .52
Bibliography .54
iv
 © ISO 2021 – All rights reserved

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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(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, Subcommittee SC 3,
Cylinder design.
This second edition cancels and replaces the first edition (ISO 9809-4:2014), which has been technically
revised. The main changes compared with the previous edition are as follows:
— update of Clause 5;
— clarification of Figure 3;
— clarification of 8.9;
— modification of 9.1, 9.2, 9.2.4 and Annex A;
— new subclause 9.2.5 for parallel threads;
— new subclause 9.4 for cylinders ordered in small quantities.
A list of all parts in the ISO 9809 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 9809-4:2022
ISO 9809-4:2021(E)
Introduction
This document provides a specification for the design, manufacture, inspection and testing of a
seamless stainless steel cylinder. The objective is to balance the design and economic efficiency against
international acceptance and universal utility.
ISO 9809 (all parts) aims to eliminate the concern about climate, duplicate inspections and restrictions
because of the lack of definitive International Standards.
[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 9809-4:2022
INTERNATIONAL STANDARD ISO 9809-4:2021(E)
Gas cylinders — Design, construction and testing of
refillable seamless steel gas cylinders and tubes —
Part 4:
Stainless steel cylinders with an R value of less than 1 100
m
MPa
1 Scope
This document specifies the minimum requirements for the materials, design, construction and
workmanship, manufacturing processes, examinations and testing at time of manufacture for refillable,
seamless, stainless steel gas cylinders with water capacities up to and including 150 l.
It is applicable to cylinders for compressed, liquefied and dissolved gases with a maximum actual
tensile strength, R , of less than 1 100 MPa.
ma
NOTE If so desired, cylinders of water capacity between 150 l and 450 l can be manufactured to be in full
conformance to this document.
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 3651-2, Determination of resistance to intergranular corrosion of stainless steels — Part 2:
Ferritic,austenitic and ferritic-austenitic (duplex) stainless steels — Corrosion test in media containing
sulfuric acid
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 9328-1, Steel flat products for pressure purposes — Technical delivery conditions — Part 1: General
requirements
ISO 9329-4, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 4: Austenitic
stainless steels
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 10286, Gas cylinders — Vocabulary
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 13769, Gas cylinders — Stamp marking
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 and the following apply.
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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
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/
3.1
batch
quantity of up to 200 cylinders, plus cylinders for destructive testing of the same nominal diameter,
thickness, length and design made successively on the same equipment, from the same cast of steel, and
subjected to the same heat treatment for the same duration of time
3.2
burst pressure
p
b
highest pressure reached in a cylinder during a burst test
3.3
cold working
process in which a cylinder is subjected to a pressure higher than the cylinder test pressure (3.11) to
increase the yield strength (3.12) of the steel
3.4
cryoforming
process where the cylinder is subjected to a controlled low-temperature deformation treatment that
results in a permanent increase in strength
3.5
design stress factor
F
ratio of the equivalent wall stress at test pressure, p , (3.11) to guaranteed minimum yield strength, R
h eg
3.6
quenching
hardening heat treatment in which a cylinder, which has been heated to a uniform temperature above
the upper critical point, Ac , of the steel, is cooled rapidly on a suitable medium
3
3.7
reject
action to set aside a cylinder (Level 2 or Level 3) that is not allowed to go into service
3.8
rendered unserviceable
cylinder that has been treated in such a way as to render it impossible for use
Note 1 to entry: Examples for acceptable methods to render cylinders unserviceable can be found in ISO 18119.
Any actions on cylinders rendered unserviceable are outside the scope of this document.
3.9
repair
action to return a rejected cylinder to a Level 1 condition
3.10
tempering
toughening heat treatment which follows quenching (3.6), in which the cylinder is heated to a uniform
temperature below the critical point, Ac , of the steel
1
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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
3.11
test pressure
p
h
required pressure applied during a pressure test
Note 1 to entry: Test pressure is used for the cylinder wall thickness calculation.
3.12
yield strength
stress value corresponding to the 0,2 % proof stress or for austenitic steels in the solution-annealed
condition, 1 % proof stress
3.13
working pressure
settled pressure of a compressed gas at a uniform reference temperature of 15 °C in a full gas cylinder
4 Symbols
A percentage elongation after fracture
a calculated minimum thickness, in millimetres, of the cylindrical shell
a′ guaranteed minimum thickness, in millimetres, of the cylindrical shell
a guaranteed minimum thickness, in millimetres, of a concave base at the knuckle (see Figure 2)
1
a guaranteed minimum thickness, in millimetres, at the centre of a concave base (see Figure 2)
2
b guaranteed minimum thickness, in millimetres, at the centre of a convex base (see Figure 1)
c maximum permissible deviation, in millimetres, of burst profile for quenched and tempered
1
cylinders (see Figure 11)
c maximum permissible deviation, in millimetres, of the burst profile for cryoformed or solution-
2
annealed cylinders with less than 7,5 mm wall thickness (see Figure 12)
D nominal outside diameter of the cylinder, in millimetres (see Figure 1)
D diameter, in millimetres, of former (see Figure 6)
f
F design stress factor (variable)
H outside height, in millimetres, of the domed part (convex head or base end) (see Figure 1)
h outside depth (concave base end), in millimetres (see Figure 2)
L original gauge length, in millimetres, as defined in ISO 6892-1 (see Figure 5)
o
l overall length of the cylinder, in millimetres (see Figure 3)
n ratio of the diameter of the bend test former to the actual thickness of test piece, t
p measured burst pressure, in bar, above atmospheric pressure
b
5
NOTE 1 bar = 10 Pa = 0,1 MPa.
p hydraulic test pressure, in bar, above atmospheric pressure
h
p observed pressure when the cylinder starts yielding during the hydraulic burst test, in bar, above
y
atmospheric pressure
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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
r inside knuckle radius, in millimetres (see Figures 1 and 2)
R actual value of the yield strength, in megapascals, as determined by the tensile test (see 10.2)
ea
R minimum guaranteed value of the yield strength (see 7.1.1), in megapascals, for the finished cylinder
eg
R actual value of the tensile strength, in megapascals, as determined by the tensile test (see 10.2)
ma
R minimum guaranteed value of the tensile strength, in megapascals, for the finished cylinder
mg
S original cross-sectional area of the tensile test piece, in square millimetres, in accordance with
o
ISO 6892-1
t actual thickness of the test specimen, in millimetres
t average cylinder wall thickness at the position of testing during the flattening test, in millimetres
m
u ratio of the distance between the knife edges or platens in the flattening test to the average
cylinder wall thickness at the position of the test
V water capacity of the cylinder, in litres
w width, in millimetres, of the tensile test piece (see Figure 5)
5 Inspection and testing
Assessment of conformity to this document shall take into account the applicable regulations of the
countries of use.
To ensure that cylinders conform to this document, they shall be subject to inspection and testing in
accordance with Clauses 9, 10 and 11.
Tests and examinations performed to demonstrate compliance with this document shall be conducted
using instruments calibrated before being put into service and thereafter according to an established
programme.
6 Materials
6.1 General requirements
6.1.1 Materials for the manufacture of gas cylinders shall fall within one of the following categories:
a) internationally recognized cylinder steels;
b) nationally recognized cylinder steels;
c) new cylinder steels resulting from technical progress.
For all categories, the relevant conditions specified in 6.2 and 6.3 shall be satisfied.
6.1.2 There is a risk of intergranular corrosion in austenitic and duplex stainless steels resulting
from hot processing which can cause sensitization of the steel (e.g. chromium depletion in the grain
boundary). Intergranular corrosion testing shall be carried out for such materials in accordance with
10.6.
6.1.3 The cylinder manufacturer shall establish the means to identify the cylinders with the cast of
steel from which they are made.
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oSIST prEN ISO 9809-4:2022
ISO 9809-4:2021(E)
6.1.4 Grades of steel used for the cylinder manufacture shall be compatible with the intended gas
service, e.g. corrosive gases and embrittling gases (see ISO 11114-1).
6.1.5 Some grades of stainless steel can be susceptible to environmental stress corrosion cracking.
Special precautions shall be taken in such cases, such as appropriate coating.
6.1.6 Some grades of stainless steel can be susceptible to phase transformation at low temperatures
resulting in a brittle alloy. Special precautions shall be taken in such c
...