ISO 11119-2:2020

INTERNATIONAL ISO
STANDARD 11119-2
Third edition
2020-11
Gas cylinders — Design, construction
and testing of refillable composite gas
cylinders and tubes —
Part 2:
Fully wrapped fibre reinforced
composite gas cylinders and tubes up
to 450 l with load-sharing metal liners
Bouteilles à gaz — Conception, construction et essais des tubes et
bouteilles à gaz rechargeables en matériau composite —
Partie 2: Tubes et bouteilles à gaz entièrement bobinés en matériau
composite renforcés de fibres et d'une contenance allant jusqu'à 450 l
avec liners métalliques structuraux
Reference number
ISO 11119-2:2020(E)
©
ISO 2020

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ISO 11119-2:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 11119-2:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 4
5 Inspection and testing . 4
6 Materials . 4
6.1 Liner materials . 4
6.2 Composite materials . 5
7 Design and manufacture . 5
7.1 General . 5
7.2 Design submission . 6
7.3 Manufacturing . 7
8 Type approval procedure . 8
8.1 General requirements . 8
8.2 Prototype tests . 8
8.3 New design . 9
8.4 Design variants .10
8.5 Type approval test procedures and criteria .13
8.5.1 Proof pressure test .13
8.5.2 Hydraulic volumetric expansion test .13
8.5.3 Liner burst test .14
8.5.4 Cylinder burst test .14
8.5.5 Ambient cycle test .15
8.5.6 Environmental cycle test.17
8.5.7 Flaw test .18
8.5.8 Drop/impact test .19
8.5.9 High velocity impact (gunfire) test .23
8.5.10 Fire resistance test .24
8.5.11 Salt water immersion test .26
8.5.12 Torque test .27
8.5.13 Environmentally assisted stress rupture test .27
8.5.14 Resin shear strength .27
8.5.15 Glass transition temperature .28
8.6 Failure of type approval tests .28
9 Batch inspection and testing .28
9.1 Liner .28
9.2 Failure of liner batch tests .29
9.3 Overwrap materials .29
9.4 Composite cylinder.29
9.5 Cylinder failure during type approval or batch testing .30
10 Cylinder marking .31
10.1 General .31
10.2 Additional marking .31
Annex A (informative) Examples of design approval certificate .32
Annex B (informative) Specimen test reports .33
Annex C (informative) Test report for equivalency .36
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ISO 11119-2:2020(E)

Annex D (informative) Standardized test requirements for thermally activated pressure
relief devices .38
Bibliography .43
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ISO 11119-2:2020(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, Subcommittee SC 3,
Cylinder design.
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.
This third edition cancels and replaces the second edition (ISO 11119-2:2012), which has been
technically revised. It also incorporates the Amendment ISO 11119-2:2012/Amd.1:2014.
The main changes compared to the previous edition are as follows:
— References updated.
— 7.1.3 Minimum fibre stress ratios added.
— 8.5.8 Drop Test. Addition of new alternative test for cylinders up to and including 50 l water capacity
with dedicated compressed gas service. Addition of alternative impact test for tubes 150 l and above.
— 8.5.10 Fire resistance test. Changes to the procedure to make the test more consistent. Adding a
criteria for tubes above 150 l to be tested for 5 min.
— 8.5.12 Torque Test is now only required for taper threads.
A list of all parts in the ISO 11119 series can be found on the ISO website.
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ISO 11119-2:2020(E)

Introduction
The purpose of this document is to provide a specification for the design, manufacture, inspection and
testing of cylinders for worldwide usage. The objective is to balance design and economic efficiency
against international acceptance and universal utility.
This document aims to eliminate the concern about climate, duplicate inspection and restrictions
currently existing because of lack of definitive International Standards and is not to be construed as
reflecting on the suitability of the practice of any nation or region.
[1]
This document has been written so that it is suitable to be referenced in the UN Model Regulations .
This document addresses the general requirements on design, construction and initial inspection and
testing of pressure receptacles of the Recommendations on the transport of dangerous goods: Model
[15]
regulations developed by the United Nations .
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INTERNATIONAL STANDARD ISO 11119-2:2020(E)
Gas cylinders — Design, construction and testing of
refillable composite gas cylinders and tubes —
Part 2:
Fully wrapped fibre reinforced composite gas cylinders
and tubes up to 450 l with load-sharing metal liners
1 Scope
This document specifies minimum requirements for the material, design, construction and
workmanship, manufacturing processes, examination and testing at time of manufacture for:
— type 3 fully wrapped cylinders or tubes with a load-sharing metal liner and composite reinforcement
on both the cylindrical portion and the dome ends;
— water capacities up to 450 l;
— storage and conveyance of compressed or liquefied gases;
— cylinders and tubes with composite reinforcement of carbon fibre, aramid fibre or glass fibre (or a
mixture thereof) within a matrix;
— a minimum design life of 15 years.
This document does not address the design, fitting, and performance of removable protective sleeves.
This document does not apply to cylinders with welded liners.
NOTE 1 References to cylinders in this document include composite tubes if appropriate.
NOTE 2 ISO 11439 applies to cylinders intended for use as fuel containers on natural gas vehicles and
ISO 11623 covers periodic inspection and re-testing of composite cylinders.
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 3341, Textile glass — Yarns — Determination of breaking force and breaking elongation
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 7225, Gas cylinders — Precautionary labels
ISO 7866, Gas cylinders — Refillable seamless aluminium alloy gas cylinders — Design, construction
and testing
ISO 9809-1, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and
tubes — Part 1: Quenched and tempered steel cylinders and tubes with tensile strength less than 1 100 MPa
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ISO 11119-2:2020(E)

ISO 9809-2, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and
tubes — Part 2: Quenched and tempered steel cylinders and tubes with tensile strength greater than or
equal to 1 100 MPa
ISO 9809-3, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and
tubes — Part 3: Normalized steel cylinders and tubes
ISO 9809-4, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and testing —
Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa
ISO 10286, Gas cylinders — Terminology
ISO 10618, Carbon fibre — Determination of tensile properties of resin-impregnated yarn
ISO 11114-1, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 1:
Metallic materials
ISO 11114-4, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 4: Test methods for selecting steels resistant to hydrogen embrittlement
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 13769, Gas cylinders — Stamp marking
ISO 14130, Fibre-reinforced plastic composites — Determination of apparent interlaminar shear strength
by short-beam method
ASTM D7269, Standard test methods for tensile testing of aramid yarns
ASTM E1356–08, Standard Test Method for Assignment of the Glass Transition Temperatures by Differential
Scanning Calorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions 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/
3.1
aramid fibre
continuous filaments of aramid laid up in tow form
3.2
autofrettage
pressure application procedure which strains the metal liner past its yield point sufficient to cause
permanent plastic deformation, and results in the liner having compressive stresses and the fibres
having tensile stresses when at zero internal gauge pressure
3.3
batch
set of homogeneous items or material
Note 1 to entry: The number of items in a batch can vary according to the context in which the term is used.
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ISO 11119-2:2020(E)

3.4
batch of liners
production quantity of up to 200 finished liners successively produced (plus units required for
destructive testing) of the same nominal diameter, length, thickness and design, from the same material
cast and heat treated to the same conditions of temperature and time
3.5
batch of finished cylinders
production quantity of up to 200 finished cylinders successively produced by the same manufacturing
process plus finished cylinders required for destructive testing, of the same nominal diameter, length,
thickness and design
3.6
burst pressure
highest pressure reached in a cylinder during a burst test
3.7
carbon fibre
continuous filaments of carbon laid up in tow form
3.8
composite overwrap
combination of fibres and matrix
3.9
dedicated gas service
service in which a cylinder is to be used only with a specified gas or gases
3.10
equivalent fibre
fibre from the same material family and similar properties to a fibre used in a previously prototype
tested cylinder
3.11
equivalent liner
liner of the same alloy family, and that has certified properties and performance so as to be a directly
comparable to a liner used in an already approved cylinder
3.12
equivalent matrix
resin matrix from the same chemical family and similar properties to the resin matrix used in a
previously prototype tested cylinder
3.14
glass fibre
continuous filaments of glass laid up in tow form
3.15
liner
inner portion of the composite cylinder, comprising a metallic vessel, whose purpose is both to contain
the gas and transmit the gas pressure to the fibres
3.16
matrix
material used to bind and hold the fibres in place
3.17
load-sharing liner
liner which has a burst pressure greater than or equal to 5 % of the nominal burst pressure of the
finished composite cylinder
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ISO 11119-2:2020(E)

3.18
thermoplastic
plastics capable of being repeatedly softened by increase of temperature and hardened by decrease of
temperature
3.19
thermosetting
plastics that, when cured by the application of heat or chemical means, harden permanently into a
substantially infusible and insoluble product
3.20
working pressure
p
w
settled pressure, in bar, of a compressed gas at a reference temperature of 15 °C in a full gas cylinder
3.21
nominal outside diameter
diameter of the cylinder specified by the manufacturer for the type approval including tolerances
(e.g. ±1 %)
3.22
glass transition temperature
Tg
the temperature where a polymer substrate changes from a rigid glassy material to a soft (not melted)
material, and is usually measured in terms of the stiffness, or modulus.
4 Symbols
p burst pressure of finished liner bar
bl
p burst pressure of finished cylinder bar
b
p test pressure bar
h
p maximum developed pressure at 65 °C bar
max
5 Inspection and testing
To ensure that the cylinders conform to this document, they shall be subject to inspection and testing in
accordance with Clauses 6, 7, 8, and 9 by an inspection body (hereafter referred to as “the inspector”)
authorized to do so. Example forms of certificates that can be used are shown in Annexes A and B.
Equipment used for measurement, testing, and examination during production shall be maintained and
calibrated within a documented quality management system.
6 Materials
6.1 Liner materials
6.1.1 The liner materials shall conform in all relevant respects to the appropriate standard:
a) seamless steel liners: ISO 9809-1, ISO 9809-2 or ISO 9809-3, as appropriate;
b) seamless stainless steel liners: ISO 9809-4;
c) seamless aluminium alloy liners: ISO 7866.
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ISO 11119-2:2020(E)

Relevant clauses are those covering materials, thermal treatments, neck design, construction and
workmanship, and mechanical tests. This excludes the design requirements since these are specified by
the manufacturer for the design of the composite cylinder (see 7.2.2).
6.1.2 The materials used shall be of uniform and consistent quality. The composite cylinder
manufacturer shall verify that each new batch of materials has the correct properties and is of satisfactory
quality. They shall also maintain records so that the cast of material and the heat treatment batch (where
applicable) used for the manufacture of each cylinder can be identified.
6.1.3 The liner shall be manufactured from a metal or alloy suitable for the gas to be contained in
accordance with ISO 11114-1. For compatibility with hydrogen see ISO 11114-4.
6.1.4 When a neck ring is provided, it shall be of a material compatible with that of the cylinder, and
shall be securely attached by a method appropriate to the liner material.
6.2 Composite materials
6.2.1 The overwrap materials shall be carbon fibre or aramid fibre or glass fibre or any mixture thereof.
6.2.2 The matrix shall be a polymer suited to the application, environment, and intended life of the
product.
6.2.3 The supplier of the filament material and the matrix system component materials shall provide
sufficient documentation for the composite cylinder manufacturer to be able to identify fully the batch of
materials used in the manufacture of each cylinder.
6.2.4 The materials used shall be of uniform and consistent quality. The composite cylinder
manufacturer shall verify that each new batch of materials has the correct properties and is of satisfactory
quality, and maintain records from which the batch of materials used for the manufacture of each cylinder
can be identified. A certificate of conformity from the material manufacturer is considered acceptable for
the purposes of verification.
6.2.5 Batches of materials shall be identified and documented.
7 Design and manufacture
7.1 General
7.1.1 A type 3 fully-wrapped composite gas cylinder with load-sharing liner shall comprise:
a) an internal metal liner, which carries part of the longitudinal and circumferential load;
b) a composite overwrap formed by layers of continuous fibres in a matrix;
c) an optional external protection system.
Where necessary, care shall be taken to ensure that there is no adverse reaction between the liner and
the reinforcing fibre by the application of a suitable protective coating to the liner prior to the wrapping
process.
7.1.2 Cylinders shall be designed with one or two openings along the central axis only. Threads shall
extend completely through the neck or have sufficient threads to allow full engagement of the valve.
The cylinder can also include additional parts (e.g. neck rings, bases).
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ISO 11119-2:2020(E)

7.1.3 The cylinders shall be designed for high reliability under sustained load and cyclic loading.
Therefore, it is necessary to take account of the properties of the individual composite fibres and to
establish their respective minimum fibre stress ratios.
The fibre stress ratio is defined as the fibre stress at calculated design minimum burst pressure divided
by the fibre stress at 2/3 test pressure.
The minimum fibre stress ratios shall be as follows:
— for glass: 3,6;
— for aramid: 3,1;
— for carbon: 2,4.
The strength of the individual types of fibres used in hybrid construction may be verified by testing of
containers reinforced with a single type of fibre. In a hybrid construction, the applicable stress ratio
requirements shall be met in one of the two following ways:
a) if load sharing between the various fibre reinforcing materials is considered a fundamental part of
the design, each fibre shall meet the stated stress ratio requirements.
b) if load sharing between fibres is not considered as a fundamental part of the design, then one of the
reinforcing fibres shall be capable of meeting the stress ratio requirements even if all other fibre
reinforcing materials are removed.
7.1.4 Examples of certificates are shown in Annexes A and B.
7.2 Design submission
7.2.1 The design submission for each new design of cylinder shall include a detailed drawing, along
with documentation of the design including manufacturing and inspection particulars as detailed in
7.2.2, 7.2.3, and 7.2.4.
7.2.2 Documentation for the liner shall include (but not be limited to):
a) material, including limits of chemical analysis;
b) dimensions, minimum thickness, straightness, and out-of-roundness, with tolerances;
c) process and specification of manufacture;
d) heat treatment, temperatures, duration, and tolerances;
e) inspection procedures (minimum requirements);
f) material properties including minimum mechanical properties and hardness ranges, where
applicable;
g) minimum design burst pressure;
h) dimensional details of valve threads and any other permanent features.
7.2.3 Documentation for the composite overwrap shall include (but not be limited to):
a) fibre material, specification, and mechanical properties requirements;
b) minimum composite thickness;
c) thermosetting matrix: specifications (including resin, curing agent and accelerator), and resin bath
temperature where applicable;
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ISO 11119-2:2020(E)

d) thermoplastic matrix system: main component materials, specifications and process temperatures;
e) overwrap construction including the number of strands used, number of layers, layer orientation,
and tensioning of the fibre at wrapping (where applicable);
f) curing process, temperat
...