ISO 11119-3:2013

Gas cylinders - Refillable composite gas cylinders and tubes - Design, construction and testing - Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450L with non-load-sharing metallic or non-metallic liners

ISO 11119-3:2013 specifies requirements for composite gas cylinders up to 150 l water capacity and composite tubes above 150 l water capacity and up to 450 l water capacity, for the storage and conveyance of compressed or liquefied gases. The cylinders and tubes in ISO 11119-3:2013 are Type 4 Fully Wrapped Cylinders or Tubes with a non-load sharing liner and composite reinforcement on both the cylindrical portion and the dome ends, and Type 5 Fully Wrapped Cylinders or Tubes without liners (including cylinders without liners manufactured from two parts joined together) and with a test pressure of less than 60 bar. The cylinders are constructed in the form of a disposable mandrel overwrapped with carbon fibre or aramid fibre or glass fibre (or a mixture thereof) in a resin matrix to provide longitudinal and circumferential reinforcement, and in the form of two filament wound shells joined together. Cylinders and tubes manufactured and tested to ISO 11119-3:2013 are not intended to contain toxic, oxidizing or corrosive gases. ISO 11119-3:2013 is limited to cylinders and tubes with composite reinforcement of carbon fibre or aramid fibre or glass fibre (or a mixture thereof) in a matrix. Cylinders and tubes manufactured and tested to ISO 11119-3:2013 have a minimum design life of 15 years. ISO 11119-3:2013 does not address the design, fitting and performance of removable protective sleeves.

Bouteilles à gaz — Bouteilles à gaz rechargeables en matériau composite et tubes — Conception, construction et essais — Partie 3: Bouteilles à gaz composites entièrement bobinées renforcées par des fibres et tubes d'une contenance allant jusqu'à 450 l avec liners métalliques ou non métalliques ne transmettant pas la charge

General Information

• Status: Withdrawn
• Publication Date: 16-Apr-2013
• Withdrawal Date: 16-Apr-2013
• ICS: 23.020.30 - Pressure vessels, gas cylinders
• ICS: 23.020.35 - Gas cylinders
• Technical Committee: ISO/TC 58/SC 3 - Cylinder design
• Drafting Committee: ISO/TC 58/SC 3/WG 27 - Composite cylinders
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 23-Nov-2020
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 11119-3:2020 - Gas cylinders - Design, construction and testing of refillable composite gas cylinders and tubes - Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450 l with non-load-sharing metallic or non-metallic liners or without liners
• Effective Date: 12-May-2018
• Revises: ISO 11119-3:2002 - Gas cylinders of composite construction - Specification and test methods - Part 3: Fully wrapped fibre reinforced composite gas cylinders with non-load-sharing metallic or non-metallic liners
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11119-3
Second edition
2013-04-15
Gas cylinders — Refillable composite gas
cylinders and tubes
Part 3:
Fully wrapped fibre reinforced composite
gas cylinders and tubes up to 450L with
non-load-sharing metallic or non-metallic
liners
Bouteilles à gaz — Bouteilles à gaz rechargeables en matériau
composite et tubes
Partie 3: Bouteilles à gaz composites entièrement bobinées renforcées
par des fibres et tubes d'une contenance allant jusqu'à 450 l avec liners
métalliques ou non métalliques ne transmettant pas la charge

Reference number
©
ISO 2013
©  ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword . iv
Introduction . v
1  Scope . 1
2  Normative references . 2
3  Terms and definitions . 2
4  Symbols and units . 4
5  Inspection and testing . 4
6  Materials . 5
6.1  Liner materials . 5
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. 7
8.1  General requirements . 7
8.2  Prototype tests . 7
8.3  New design . 9
8.4  Design variants . 10
8.5  Type approval test procedures and criteria. 13
8.6  Failure of type approval tests . 27
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
Bibliography . 39

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11119-3 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 11119-3:2002), which has been technically
revised.
ISO 11119 consists of the following parts, under the general title Gas cylinders — Refillable composite gas
cylinders and tubes — Design, construction and testing:
 Part 1: Hoop wrapped fibre reinforced composite gas cylinders and tubes up to 450 l
 Part 2: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450 l with load-sharing
metal liners
 Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450L with non-load-
sharing metallic or non-metallic liners
The following part is under preparation:

— Part 4: Fully wrapped fibre reinforced composite gas cylinders with load-sharing welded metal liners
iv © ISO 2013 – All rights reserved

Introduction
The purpose of ISO 11119 is to provide a specification for the design, manufacture, inspection and testing of
cylinders for world-wide usage. The objective is to balance design and economic efficiency against
international acceptance and universal utility.
ISO 11119 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.
This part of ISO 11119 addresses the general requirements on design, construction and initial inspection and
testing of pressure receptacles of the United Nations “Recommendations on the Transport of Dangerous
Goods Model Regulations.”
INTERNATIONAL STANDARD ISO 11119-3:2013(E)

Gas cylinders — Refillable composite gas cylinders and
tubes —
Part 3:
Fully wrapped fibre reinforced composite gas cylinders and
tubes up to 450L with non-load-sharing metallic or non-metallic
liners
1 Scope
This part of ISO 11119 specifies requirements for composite gas cylinders up to 150 l water capacity and
composite tubes above 150 l water capacity and up to 450 l water capacity, for the storage and conveyance of
compressed or liquefied gases.
The cylinders and tubes in this part of ISO 11119 are
a) Type 4 Fully Wrapped Cylinders or Tubes with a non-load sharing liner and composite reinforcement on
both the cylindrical portion and the dome ends, and
b) Type 5 Fully Wrapped Cylinders or Tubes without liners (including cylinders without liners manufactured
from two parts joined together) and with a test pressure of less than 60 bar.
The cylinders are constructed:
1) in the form of a disposable mandrel overwrapped with carbon fibre or aramid fibre or glass fibre (or a
mixture thereof) in a resin matrix to provide longitudinal and circumferential reinforcement;
2) in the form of two filament wound shells joined together.
Cylinders and tubes manufactured and tested to this part of ISO 11119 are not intended to contain toxic,
oxidizing or corrosive gases.
This part of ISO 11119 is limited to cylinders and tubes with composite reinforcement of carbon fibre or aramid
fibre or glass fibre (or a mixture thereof) in a matrix.
Cylinders and tubes manufactured and tested to this part of ISO 11119 have a minimum design life of 15
years.
This part of ISO 11119 does not address the design, fitting and performance of removable protective sleeves.
NOTE 1 References to cylinders in this International Standard 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, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 527-1, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics
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 (scales A, B, C, D, E, F, G, H,
K, N, T)
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7225, Gas cylinders — Precautionary labels
ISO 10618, Carbon fibre — Determination of tensile properties of resin-impregnated yarn
ISO 14130, Fibre-reinforced plastic composites — Determination of apparent interlaminar shear strength by
short-beam method
ISO 11114-1, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 1:
Metallic materials
ISO 11114-2, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2: Non-
metallic materials
ISO 13769, Gas cylinders — Stamp marking
ASTM D7269, Standard Test Methods for Tensile Testing of Aramid Yarns
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE References to cylinders include composite tubes if appropriate.
3.1
aramid fibre
continuous filaments of aramid laid up in tow form
3.2
batch
set of homogeneous items or material
NOTE The number of items in a batch can vary according to the context in which the term is used.
3.3
batch of metallic liners
quantity of liners of the same nominal diameter, length, thickness and design, made successively from the
same batch of materials, subjected to the same manufacturing process and heat treated to the same
conditions of temperature and time
2 © ISO 2013 – All rights reserved

3.4
batch of non-metallic liners
quantity of liners of the same nominal diameter, length, thickness and design, made successively from the
same batch of materials and subjected to the same manufacturing process
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 liner or 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 manufactured from the same nominal raw materials, using the same process of manufacture and having
the same physical structure and the same nominal physical properties, and where the average tensile strength
and modulus is within  5 % of the fibre properties in an approved cylinder design
3.11
equivalent liner
liner that are manufactured from the same nominal raw materials, using the same process of manufacture and
having the same physical structure and the same nominal physical properties as in an approved cylinder
design
3.12
exterior coating
layers of material applied to the cylinder as protection or for cosmetic purposes
NOTE The coating can be clear or pigmented.
3.13
glass fibre
continuous filaments of glass laid up in tow form
3.14
liner
inner portion of the composite cylinder, comprising a metallic or non-metallic vessel, whose purpose is both to
contain the gas and transmit the gas pressure to the fibres
3.15
matrix
material that is used to bind and hold the fibres in place
3.16
non-load-sharing liner
liner that has a burst pressure less than 5 % of the nominal burst pressure of the finished composite cylinder
3.17
thermoplastic material
plastics capable of being repeatedly softened by increase of temperature and hardened by decrease of
temperature
3.18
thermosetting material
plastics that, when cured by the application of heat or chemical means, harden permanently into a
substantially infusible and insoluble product
3.19
nominal outside diameter
diameter of the cylinder specified by the manufacturer for the type approval including tolerances (e.g. +/- 1 %)
3.20
Type 4 cylinder
fully wrapped cylinder with a non-load sharing liner and composite reinforcement on both the cylindrical
portion and the dome ends
3.21
Type 5 cylinder
fully wrapped cylinder without a liner and with composite reinforcement on both the cylindrical portion and
dome ends
3.22
working pressure
settled pressure of a compressed gas at a reference temperature of 15 °C in a full gas cylinder
4 Symbols and units
Symbols and their designations
Symbol Designation Unit
p Burst pressure of 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
p Working pressure bar
w
5 Inspection and testing
ISO 11119-3 is intended to be used under a variety of national regulatory regimes but has been written so that
it is suitable for use with the conformity assessment system of the UN Model Regulations for the
Transportation of Dangerous Goods. Attention is drawn to requirements in specified relevant national
regulations of the country (countries) where the cylinders are intended to be used that might override the
requirements given in this International Standard.
4 © ISO 2013 – All rights reserved

To ensure that the cylinders conform to this part of ISO 11119, 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 (including metal boss) shall be manufactured from a material suitable for the gas to be
contained, as specified in ISO 11114-1 and ISO 11114-2. Metal bosses attached to a non-metallic liner shall
fulfil the performance requirements of this document.
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, and
maintain records from which the batch of materials used for the manufacture of each cylinder can be identified.
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 and, for cylinders manufactured from two halves, the adhesive, shall be a polymer suited
to the application, environment and intended life of the product.
6.2.3 The suppliers of the filament material, the matrix component materials and, if applicable, the
adhesive component material 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 conformance from the material manufacturer is considered acceptable for the purposes of
verification.
6.2.5 Batches of materials shall be identified and documented to the satisfaction of the inspector.
7 Design and manufacture
7.1 General
7.1.1 A Type 4 fully-wrapped composite gas cylinder with non-load-sharing metallic or non-metallic liner
shall comprise of:
a) an internal metal or non-metallic liner which carries no significant load;
b) metallic boss(es) for thread connections, where these are part of the design;
c) a composite overwrap formed by layers of continuous fibres in a matrix and
d) 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 A Type 5 fully-wrapped cylinder with a test pressure of less than 60 bar can be manufactured either:
a) in the form of a disposable mandrel overwrapped with carbon fibre or aramid fibre or glass fibre (or a
mixture thereof) in a matrix to provide longitudinal and circumferential reinforcement or;
b) in the form of two filament wound shells overwrapped with carbon fibre or aramid fibre or glass fibre (or a
mixture thereof) in a matrix to provide longitudinal and circumferential reinforcement joined together.
7.1.3 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.
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 and metal boss(es) shall include (but not be limited to):
a) material(s), 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;
g) dimensional details of valve threads and any other permanent features;
h) method of sealing boss to liner for bonded bosses.
7.2.3 Documentation for 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;
d) thermoplastic matrix system – main component materials, specifications and process temperatures;
e) overwrap construction including the number of strands used, number of layers and layer orientation and
tensioning of the fibre at wrapping (where applicable);
f) curing process, temperatures, duration and tolerances;
g) adhesive system, main components and specifications where applicable;
h) adhesive system, curing agent, materials and specifications where applicable;
i) adhesive system, accelerator, materials and specifications where applicable;
j) for cylinders without liners where comprised of two wound shells, dimensions of adhesive bond (length,
angle of bond, thickness of adhesive).
6 © ISO 2013 – All rights reserved

7.2.4 Documentation for the composite cylinder shall include (but not be limited to):
a) nominal water capacity in litres at ambient conditions;
b) list of intended contents if intended for dedicated gas service;
c) working pressure, p (if applicable) that shall not exceed 2/3 times test pressure;
w
d) test pressure, p ;
h
e) maximum developed pressure at 65 °C for specific dedicated gas(es), p ;
max
f) minimum design burst pressure;
g) design life in years; cylinders with a test pressure of less than 60 bar shall have a non-limited design life;
h) nominal weight of the finished composite cylinder, including tolerances;
i) for cylinders without liners, the method of sealing the boss to cylinder (if applicable);
j) details of components which are permanently attached and form part of the qualified design (e.g. neck
rings, protective boots etc).
7.3 Manufacturing
7.3.1 The liner and metal bosses, where incorporated, shall be manufactured in accordance with the
manufacturer's design (see 7.2.2).
7.3.2 The composite cylinder shall be fabricated from a non-load-sharing liner, or fabricated on a
disposable mandrel, fully over-wrapped with layers of continuous fibres in a matrix applied under controlled
tension to develop the design composite thickness as specified in 7.2.3.
Liners can be stripped and re-wound provided that the overwrap has not been cured. The liner shall not be
over-wrapped if it has been damaged or scored by the stripping process.
For cylinders without liners, manufactured from two parts joined together, the individual parts shall be wound
to develop the required composite thickness before being joined with appropriate adhesive.
7.3.3 After wrapping is completed the composite shall be cured (if appropriate) using a controlled
temperature profile as specified in the documentation in 7.2.3. The maximum temperature shall be such that
the mechanical properties of the liner material, if fitted, and composite overwrap are not adversely affected.
NOTE If cylinders are subjected to fibre tensioning during wrapping, the tensioning shall be recorded or monitored.
8 Type approval procedure
8.1 General requirements
Each new cylinder design shall be submitted by the manufacturer to the inspector. The type approval tests
detailed in 8.2 shall be performed, under the supervision of the inspector, on each new cylinder design or
design variant.
8.2 Prototype tests
8.2.1 A minimum of 30 cylinders that are representative of the new design shall be made available for
prototype testing. Upon successful completion of all prototype tests, the remaining untested cylinders from the
prototype qualification batch can be used for service.
8.2.2 If, for special applications, the total number of cylinders required is less than 30, enough cylinders
shall be made to complete the prototype tests required, in addition to the production quantity. Then the
approval validity shall be limited to this batch only.
For a limited design change (design variant), in accordance with Table 1, a reduced number of cylinders shall
be selected by the inspector.
8.2.3 The batch of liners, prior to being wrapped, shall conform to the design requirements and shall be
inspected and tested in accordance with 9.1.
8.2.4 The composite material(s), prior to the cylinders being wrapped, shall conform to the design
requirements and shall be tested in accordance with 9.3.
8.2.5 Tests for a new cylinder design shall be supervised by an inspector and shall consist of:
a) hydraulic proof pressure test, in accordance with 8.5.1, or hydraulic volumetric expansion test, in
accordance with 8.5.2;
b) cylinder burst test in accordance with 8.5.3;
c) ambient temperature cycle test, in accordance with 8.5.4;
d) environmental cycle test, in accordance with 8.5.6;
e) flaw test, in accordance with 8.5.8;
f) drop test, in accordance with 8.5.9;
g) high velocity impact (gunfire) test, in accordance with 8.5.10;
h) fire resistance test in accordance with 8.5.11;
i) torque test on cylinder neck boss in accordance with 8.5.13;
j) leak test in accordance with 8.5.15;
k) pneumatic cycle test in accordance with 8.5.16;
l) liner burst test in accordance with 8.5.18.
8.2.6 Tests that are optional depending upon the design and intended use of the cylinder are:
a) vacuum test in accordance with 8.5.5;
b) environmentally assisted stress rupture test in accordance with 8.5.7;
c) permeability test in accordance with 8.5.12 if cylinders are manufactured with non-metallic liners or
without liners;
d) salt water immersion test in accordance with 8.5.14;
e) for linerless cylinders comprised of two halves joined together, the water boil test in accordance with
8.5.17.
8.2.7 For approval of a design variant as specified in 8.4, it is only necessary to carry out the tests as
prescribed in Table 1. Under supervision of the inspector A cylinder, approval by a reduced series of tests
shall not be used as a basis for a second design variant approval with a reduced set of tests (i.e. multiple
changes from an approved design are not permitted) although individual test results can be used as
applicable (see 8.4.2).
8 © ISO 2013 – All rights reserved

8.2.8 Tests can be combined such that one cylinder can be used for more than one test. For example the
cylinder burst test in 8.5.9 Drop test can be used to satisfy the requirement of 8.5.3 Burst test.
8.2.9 If the results of the above prototype tests are satisfactory, the inspector shall issue a design approval
certificate a typical example of which is given in Annex A.
8.2.10 After completion of the tests the cylinders shall be destroyed or made incapable of holding pressure.
8.3 New design
8.3.1 After approval, no alteration shall be made to the design or the method of manufacture without
requalification.
8.3.2 A new cylinder design requires full type approval testing. A cylinder shall be considered to be of a new
design compared with an existing approved design when:
a) It is manufactured in a different factory. A relocation of a factory does not require a new cylinder design
approval provided all equipment and procedures remain the same as for the original design approval.
b) It is manufactured by a process that is significantly different from the process used in the design type
approval. A significant change is regarded as a change that would give rise to a measurable change in
the performance of the liner and/or finished cylinder. The inspector determines when a change in process
or design or manufacture is significantly different from the original qualified design.
c) The nominal outside diameter has changed more than 50 % from the qualified design.
d) A fibre of the same specification classification and mechanical properties but with a different linear density
shall not be considered a new fibre type. Minor changes in the wrapping pattern shall not be considered
to be a new design.
e) The cylinder is manufactured with a new fibre type. A fibre shall be considered to be of a new fibre type
when:
1) The fibre is of a different classification (e.g. glass, aramid or carbon);
2) The fibre is produced from a different precursor [e.g. Polyacrylonitrile (PAN) or pitch for carbon];
3) The fibre is not equivalent [see 8.4.1 (i)] to the fibre in the original design.
f) The matrix materials (i.e. resin, curing agent, accelerator) are different and not chemically equivalent to
the original design (e.g. a change from an epoxy to a polyester);
g) The test pressure has increased more than 60 % from the qualified design.
8.3.3 A cylinder shall also be considered to be of a new design compared with an existing approved design
if the method of liner manufacture or liner design has changed and when
a) It is manufactured from a material of different composition or composition limits from that used in the
original type tests.
b) The material properties are outside the original design limits.
c) It is manufactured by a different process.
8.4 Design variants
8.4.1 For cylinders that are variants of another design, a reduced type approval testing programme is
required as specified in Table 1. A cylinder shall be considered to be a design variant if changes are limited to:
a) the nominal length of the cylinder has changed by more than 5 %;
b) the nominal outside diameter has changed by 50 % or less;
c) there is a change in the design test pressure up to and including 60 %. Where a cylinder is to be used
and marked for a lower test pressure than that for which design approval has been given, it is not deemed
to be of a new design or design variant;
d) there have been changes to the composite thickness or wrap pattern other than the changes necessary
to accommodate the changes of diameter and/or length;
e) the minimum wall thickness of the liner has changed by more than 10 %;
f) matrix materials (i.e. resin, curing agent, accelerator) are chemically equivalent to the original design;
g) the design or method of joining the neck boss to the liner has changed;
h) when equivalent overwrapping fibres are used:
1) Equivalent fibres are manufactured from the same nominal raw materials, using the same process of
manufacture and having the same physical structure and the same nominal physical properties, and
where the average tensile strength and modulus is within  5 % of the fibre properties in an approved
cylinder design. Carbon fibres made from the same precursor can be equivalent, Aramid, carbon and
glass fibres are not equivalent.
2) Where a new equivalent fibre has been prototype tested for an existing design, then all the
manufacturer's existing prototype tested designs are regarded as prototype tested with the new fibre
without the need for any additional prototype testing;
i) when an equivalent liner is used:
1) Equivalent liners are manufactured from the same nominal raw materials, using the same process of
manufacture and having the same physical structure and the same nominal physical properties as in
an approved cylinder design.
2) The equivalent liner material shall be subjected to the material tests specified in 9.1.2 for metal liners
and 9.1.3 for polymer liners and the liner burst test specified in 8.5.18 and shall meet the minimum
requirements specified in 7.2.2 and the criteria of 8.5.18.
3) Where a new equivalent liner has been prototype tested for an existing design, all the manufacturer's
existing prototype tested designs are regarded as prototype tested with the new liner without the need
for any additional prototype testing.
j) when the cylinder thread has changed;
1) When a cylinder design has only a different thread compared to an approved design only the torque
test, in accordance with 8.5.13, shall be performed.
8.4.2 A cylinder approval by a reduced series of tests (a design variant) shall not be used as a basis for a
second design variant approval with a reduced set of tests, i.e. multiple changes from an approved design are
not permitted. If a test has been conducted on a design variant (A) that falls within the testing requirements for
a second variant (B) then the result for (A) can be applied to the new design variant (B) test programme.
However design variant (A) shall not be used as the reference for determining the testing required for any new
design variant.
10 © ISO 2013 – All rights reserved

8.4.3 Where a design variant involves more than one parameter change all the tests required by those
parameter changes shall be performed once only.
8.4.4 The inspector shall determine the level of reduced testing if not defined in Table 1, but a fully
approved design shall always be used as a reference for the new design variant (i.e. new design variants shall
not be approved by reference only to a previous design variant).
12 © ISO 2013 – All rights reserved
Table 1 — Type approval tests
Design variant changes
Length Diameter Test pressure Composite
New
Liner Equi- Equi-
Test No. Test
design thickness Neck
thickness valent valent Thread
> 5%
 50 %  20 %  20 %  20 %
 20 %
or pattern or boss
>10% fibre matrix
 50 %  50 %
 60 %
Liner base form
9.1 Liner material test 
8.5.19 Resin shear test x      x
9.3 Composite material tests       
8.5.1/2 Hydraulic pressure            
8.5.3 Cylinder burst            
8.5.4 Ambient cycle            
8.5.5 Vacuum (c)(e)    (d)   
8.5.6 Environmental cycle       
8.5.7 Stress rupture test (c)       
8.5.8 Flaw   
8.5.9 Drop      
8.5.10 High velocity impact    (a)
8.5.11 Fire resistance       (b)
8.5.12 Permeability (c)(e)       
8.5.13 Torque (f)       
8.5.14 Salt water (c)       
8.5.15 Leak        
8.5.16 Pneumatic cycle    
8.5.17 Water boil test (c)       
8.5.18 Liner Burst test x x x x
a
Test to be conducted for reduction in diameter only or if an increase in diameter requires a larger calibre bullet.
b
Only if cylinder in previous fire test leaked at the neck boss.
c
Optional test required according to the design and intended use of the cylinder.
d
For liner thickness decrease only.
e
For non-metallic liners only.
f
When a cylinder design has only a different thread compared to an approved design only the torque test, in accordance with 8.5.13, shall be performed.

8.5 Type approval test procedures and criteria
8.5.1 Proof pressure test
8.5.1.1 Procedure
When carrying out the pressure test, a suitable fluid (e.g. normally water) shall be used as the test medium.
This test requires that the pressure in the cylinder be increased gradually and regularly until the test pressure,
p , is reached. The cylinder test pressure shall be held for at least 30 s with the cylinder isolated from the
h
pressure source, during which time there shall be no decrease in the recorded pressure or evidence of any
leakage. Adequate safety precautions shall be taken during the test.
If leakage occurs in the piping or fittings, the cylinders shall be re-tested after repairing such leakages.
The limit deviation on attaining test pressure shall be test pressure +3 % / -0 or +10 bar whichever is the lower.
Pressure gauges with the appropriate accuracy shall be used.
All internal surfaces of cylinders shall be dried (to ensure no free water) immediately after testing.
Alternatively a pneumatic pressure test can be used provided that appropriate measures are taken to ensure
safe operation and to contain any energy that can be released, which is considerably more than in the
hydraulic test.
8.5.1.2 Criteria
The cylinder shall be rejected if there are leaks, failure to hold pressure or visible permanent deformation after
the cylinder is depressurised.
NOTE Cracking of resin is not necessarily a sign of permanent deformation.
8.5.2 Hydraulic elastic expansion test
8.5.2.1 Procedure
When carrying out the pressure test, a suitable fluid (e.g. normally water) shall be used as the test medium.
This test requires that the pressure in the cylinder be increased gradually and regularly until the test pressure,
p , is reached. The cylinder test pressure shall be held for at least 30 s with the cylinder isolated from the
h
pressure source, during which time there shall be no decrease in the recorded pressure or evidence of any
leakage. Adequate safety precautions shall be taken during the test.
If leakage occurs in the piping or fittings, the cylinders shall be re-tested after repairing such leakages.
The elastic expansion shall be determined from the difference in volume measured at 10 % test pressure, p ,
h
and at the test pressure, p , and recorded.
h
The limit deviation on attaining test pressure shall be test pressure +3 % / -0 or +10 bar whichever is the lower.
All internal surfaces of cylinders shall be dried (to ensure no free water) immediately after testing.
8.5.2.2 Criteria
The cylinder shall be rejected if either:
a) it shows an elastic expansion in excess of 110 % of the average elastic expansion for the batch at
manufacture, or
b) if there are leaks or failure to hold pressure.
8.5.3 Cylinder burst test
8.5.3.1 Procedure
Three cylinders shall be tested hydraulically, to destruction, by pressurizing at a rate of no more than 10 bar/s.
The test shall be carried out under ambient conditions. Prior to the commencement of the test, it shall be
ensured that no air is trapped within the system.
The parameters that shall be monitored and recorded are:
a) burst pressure;
b) mode of failure for cylinders without liners;
c) pressure/time curve or pressure/volume curve.
8.5.3.2 Criteria
a) The burst pressure shall exceed the minimum design burst pressure specified by the cylinder
manufacturer (see 7.2.4).
b) The burst pressure, pb, for cylinders with carbon fibre reinforcement shall be not less than the test
pressure, ph  2.0.
c) The burst pressure, pb, for cylinders with aramid fibre reinforcement shall be not less than the test
pressure, ph  2.1.
d) The burst pressure, pb, for cylinders with glass fibre reinforcement shall be not less than the test pressure,
ph  2.4.
e) For cylinders without liners manufactured from two parts joined together, the burst shall not result in
failure at the joint below a pressure 1.2  the burst pressure for the appropriate fibre above.
8.5.4 Ambient cycle test
8.5.4.1 For cylinders with test pressure equal to, or greater than, 60 bar
8.5.4.1.1 General
Where a cylinder is intended for use only with one or more specific gases the design can be designated for
dedicated gas use. The gases permitted in the cylinder shall be identified clearly on the cylinder label
(see 10.2).
8.5.4.1.2 Procedure
Two cylinders shall be subjected to a hydraulic pressure cycle test to test pressure, p , for unspecified gas
h
service or maximum developed pressure at 65 °C, p , for the dedicated gas which has the greatest
max
developed pressure.
The test shall be carried out using a non-corrosive fluid under ambient conditions, subjecting the cylinders to
successive reversals at an upper cyclic pressure that is equal to the hydraulic test pressure, p or maximum
h
developed pressure at 65 °C, p , as appropriate.
max
The value of the lower cyclic pressure shall not exceed 10 % of the upper cyclic pressure, but shall have an
absolute maximum of 30 bar. The frequency of reversals shall not exceed 0,25 Hz (15 cycles/min). The
temperature on the outside surface of the cylinder shall not exceed 50 °C during the test.
14 © ISO 2013 – All rights reserved

The parameters that shall be monitored and recorded are:
a) temperature of the cylinder;
b) number of cycles achieving upper cyclic pressure;
c) minimum and maximum cyclic pressures;
d) cycle frequency;
e) test medium used;
f) mode of failure, if appropriate.
8.5.4.1.3 Criteria
Both cylinders shall withstand N pressurization cycles to test pressure, p , or N pressurization cycles to
h d
maximum developed pressure, p , without failure by burst or leakage
max
where
N = y  250 cycles per year of design life;
N = y  500 cycles per year of design life;
d
y is the number of years of design life.
y shall be a whole number which is not less than 15 years.
The test shall continue for a further N, or N , cycles, or until the cylinder fails by leakage, whichever is the
d
sooner. In either case the cylinder shall be deemed to have passed the test. However, if failure during this
second part of the test is by burst, then the cylinder shall have failed the test. See Table 2.
Table 2 — Criteria for ambient cycle test
1st part 2nd part
0 to N N to 2N but 2N no more than 12 000
Number of cycles
0 to N N to 2N but 2N no more than 24 000
d d d d
No leakage/burst = Pass
Criteria No leakage or burst Leakage = Pass
st
Pass 1 part Burst = Fail
If the cylinder is designed to pass 12 000 hydraulic cycles to test pressure or 24 000 cycles to maximum
developed pressure and achieves this level consistently in the te
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