EN ISO 11623:2023

SLOVENSKI STANDARD
01-november-2023
Nadomešča:
SIST EN ISO 11623:2016
Plinske jeklenke - Jeklenke in velike jeklenke iz kompozitnih materialov -
Periodični pregledi in preskusi (ISO 11623:2023)
Gas cylinders - Composite cylinders and tubes - Periodic inspection and testing (ISO
11623:2023)
Gasflaschen - Verbundbauweise (Composite- Bauweise) - Wiederkehrende Inspektion
und Prüfung (ISO 11623:2023)
Bouteilles à gaz - Bouteilles et tubes composites - Contrôles et essais périodiques (ISO
11623:2023)
Ta slovenski standard je istoveten z: EN ISO 11623:2023
ICS:
23.020.35 Plinske jeklenke Gas cylinders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 11623
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2023
EUROPÄISCHE NORM
ICS 23.020.35 Supersedes EN ISO 11623:2015
English Version
Gas cylinders - Composite cylinders and tubes - Periodic
inspection and testing (ISO 11623:2023)
Bouteilles à gaz - Bouteilles et tubes composites - Gasflaschen - Verbundbauweise (Composite-
Contrôles et essais périodiques (ISO 11623:2023) Bauweise) - Wiederkehrende Inspektion und Prüfung
(ISO 11623:2023)
This European Standard was approved by CEN on 27 June 2023.

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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11623:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 11623:2023) has been prepared by Technical Committee ISO/TC 58 "Gas
cylinders" in collaboration with Technical Committee CEN/TC 23 “Transportable gas cylinders” the
secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2024, and conflicting national standards shall
be withdrawn at the latest by March 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11623:2015.
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/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11623:2023 has been approved by CEN as EN ISO 11623:2023 without any modification.

INTERNATIONAL ISO
STANDARD 11623
Third edition
2023-07
Gas cylinders — Composite cylinders
and tubes — Periodic inspection and
testing
Bouteilles à gaz — Bouteilles et tubes composites — Contrôles et
essais périodiques
Reference number
ISO 11623:2023(E)
ISO 11623:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11623:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Due dates for periodic inspection and testing . 4
5 Procedures for periodic inspection and testing . 4
5.1 List of procedures . 4
5.2 Heat exposure. 5
6 Identification of cylinder and preparation for periodic inspection and testing .5
7 External visual inspection . 6
7.1 Preparation . 6
7.1.1 General . 6
7.1.2 Permanent protective attachments. 6
7.1.3 Sleeves . 6
7.1.4 Cleaning . 6
7.2 Inspection procedures . 7
7.3 Damage . 7
7.3.1 General . 7
7.3.2 Damage levels . . 7
7.3.3 Types of external damage . 8
7.4 Repairs . 11
8 Internal visual inspection .11
8.1 Translucent cylinders . 11
8.2 Safe removal of valve . 11
8.3 Internal visual inspection and cleaning. 11
8.3.1 General . 11
8.3.2 Metallic liners . .12
8.3.3 Linerless and non-metallic liners .12
8.4 Types of internal damage .12
8.4.1 Type 2 and Type 3 cylinders .12
8.4.2 Type 4 cylinders .13
8.4.3 Type 5 cylinders .13
8.4.4 Excess resin droplets . 14
8.5 Inspection of cylinder neck . 14
8.6 Inspection criteria . 14
9 Pressure test .15
10 Leak test .16
11 Inspection of valve .17
12 Final operations .17
12.1 Drying and cleaning . 17
12.2 Painting . 17
12.3 Cylinder re-valving . 17
12.4 Check of cylinder tare . 17
12.5 Retest marking . 18
12.6 Reference to next periodic inspection and test date . 18
12.7 Identification of contents . 18
12.8 Records . 18
13 Rejection and rendering cylinders unserviceable .19
iii
ISO 11623:2023(E)
Annex A (informative) Intervals between periodic inspection and testing .31
Annex B (normative) Damage criteria for steel wire wound, aluminium-alloy cylinders .34
Annex C (normative) Internal visual inspection of translucent cylinders .35
Annex D (informative) List of gases corrosive to steel liners and steel bosses .36
Annex E (informative) Cleaning of seamless aluminium-alloy liners or aluminium-alloy
components .37
Annex F (informative) Periodic inspection date rings for cylinders .38
Bibliography .39
iv
ISO 11623:2023(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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
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 4, Operational requirements for gas cylinders, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 23, Transportable gas cylinders, in accordance
with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 11623:2015), which has been technically
revised.
The main changes are as follows:
— revision of the Scope to include cylinders and tubes with a water capacity up to 3 000 l;
— modification of Table 1 to separate abrasion damage based on water capacity of the cylinder;
— clarification that a transparent sleeve may be left in place during inspection (7.1.3);
— clarification on the use of tare during inspection.
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 11623:2023(E)
Introduction
The principal aim of periodic inspection and testing is that at the completion of the test, the cylinders
can be reintroduced into service. It is not possible to identify all considerations for periodic inspection
and testing of composite cylinders in this document. In such cases or where there is doubt, questions
regarding specific cylinders should be directed to the manufacturer or owner.
This document is intended to be used under a variety of national regulatory regimes but has been
[1]
written so that it is suitable for the application of the UN Model Regulations.
This document also gives other requirements concerning preparation, finishing and maintenance of
composite cylinders and tubes as well as the safety precautions for the personnel performing this work.
These requirements can be mandatory under other regulations.
vi
INTERNATIONAL STANDARD ISO 11623:2023(E)
Gas cylinders — Composite cylinders and tubes — Periodic
inspection and testing
1 Scope
This document specifies the requirements for periodic inspection and testing to verify the integrity for
further service of hoop-wrapped and fully-wrapped composite transportable gas cylinders and tubes,
with aluminium-alloy, steel or non-metallic liners or of linerless construction (Types 2, 3, 4, and 5),
intended for compressed, liquefied or dissolved gases under pressure, of water capacity from 0,5 l up to
3 000 l.
This document addresses the periodic inspection and testing of composite cylinders and tubes
constructed according to ISO 11119-1, ISO 11119-2, ISO 11119-3, ISO 11119-4 or ISO 11515. It can be
applied to other composite cylinders and tubes designed to comparable standards when authorized by
the competent authority.
As far as practicable, this document can also be applied to cylinders of less than 0,5 l water capacity
when authorized by the manufacturer.
NOTE Unless noted by exception, the use of the word “cylinder” in this document refers to both cylinders
and tubes.
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 7225, Gas cylinders — Precautionary labels
ISO 10286, Gas cylinders — Vocabulary
ISO 10460, Gas cylinders — Welded aluminium-alloy, carbon and stainless steel gas cylinders — Periodic
inspection and testing
ISO 11114-2, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2:
Non-metallic materials
ISO 11119 (all parts), Gas cylinders — Design, construction and testing of refillable composite gas cylinders
and tubes
ISO 11515, Gas cylinders — Refillable composite reinforced tubes of water capacity between 450 l and 3000
l — Design, construction and testing
ISO 11621, Gas cylinders — Procedures for change of gas service
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 13769, Gas cylinders — Stamp marking
ISO 18119, Gas cylinders — Seamless steel and seamless aluminium-alloy gas cylinders and tubes — Periodic
inspection and testing
ISO 22434, Gas cylinders — Inspection and maintenance of valves
ISO 25760, Gas cylinders — Operational procedures for the safe removal of valves from gas cylinders
ISO 11623:2023(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
composite overwrap
combination of fibres (3.3) (including steel wire) and matrix (3.15)
3.2
external coating
layer of material applied to the cylinder as a protective coating not intended to be removed or for
cosmetic purposes
EXAMPLE Gel coat and paint.
Note 1 to entry: Not all composite cylinders have a special external coating.
3.3
fibre
load-carrying part of the composite overwrap (3.1)
EXAMPLE Glass, aramid or carbon.
3.4
Type 5 cylinder
fully wrapped cylinder without a liner (3.11) and with composite reinforcement on both the cylindrical
portion and dome ends
3.5
Type 4 cylinder
fully wrapped cylinder with a non-load sharing liner (3.11) and composite reinforcement on both the
cylindrical portion and dome ends
3.6
Type 3 cylinder
fully wrapped cylinder with a load sharing metal liner (3.11) and composite reinforcement on both the
cylindrical portion and the dome ends
3.7
Type 2 cylinder
hoop-wrapped cylinder with a load-sharing metal liner (3.11) and composite reinforcement on the
cylindrical portion only
3.8
translucent cylinder
cylinder that permits the passage of light
3.9
identification label
label containing the permanent markings required by the relevant design specification
3.10
design life
maximum life (in number of years) to which a composite cylinder or tube is designed and approved in
accordance with the applicable standard
ISO 11623:2023(E)
3.11
liner
inner portion of a composite cylinder, comprising a metallic or non-metallic vessel, whose purpose is
both to contain the gas and transmit the gas pressure to the composite overwrap (3.1)
3.12
non-metallic liner
liner (3.11) made from thermoplastic, thermosetting or elastomeric material
3.13
sleeve
transparent or non-transparent cover fitted to the outside surface of the cylinder
3.14
repair
set of activities performed on defective pressure equipment to restore its compliance with the relevant
specification
Note 1 to entry: Repair can include replacing worn or damaged parts meeting the original specification.
3.15
matrix
material that is used to bind and hold the fibres (3.3) in place
Note 1 to entry: The matrix is sometimes called resin.
3.16
rejected cylinder
cylinder not fit for service or which needs to be set aside for further evaluation or testing in its present
condition
3.17
bulge
visible swelling of the wall
Note 1 to entry: A bulge is away from the centre line (convex) and a dent is towards the centre line (concave).
3.18
crack
split or separation in the material, typically appearing as a line on the surface
3.19
crease
off-colour linear or non-linear feature formed as a result of previous localized over-stressing
3.20
protective attachment
component connected to the cylinder that prevents or resists damage to the composite cylinder
EXAMPLE Casing.
Note 1 to entry: Some protective attachments are designed to be removed at the time of periodic inspection and
testing.
3.21
permanent protective attachment
integral part of the cylinder design permanently affixed to composite cylinders (Types 2 to 5) covering
part of or the entire surface of the cylinder, providing additional functions during handling, transport
and use
ISO 11623:2023(E)
3.22
stoving
treat by heating (e.g. in an oven) in order to apply a desired surface coating
4 Due dates for periodic inspection and testing
A cylinder shall be due for periodic inspection and testing on its first receipt by a filler following the
expiry of the interval established in accordance with the requirements of national or international
[1]
regulations or, in the absence of regulations, in accordance with the UN Model Regulations.
NOTE Annex A provides guidance regarding the intervals between periodic inspection and testing.
The expiry date is based on the last test date shown on the cylinder. Other means of indicating the
expiry date are permitted.
Provided the cylinder has not been subjected to abusive and abnormal conditions such as being
involved in an accident, heat exposure or other severe conditions that would render it unsafe, there is
no requirement for the user to return a cylinder before the contents have been used even though the
periodic inspection and testing interval has lapsed.
When the design life has expired, the cylinder shall not be refilled and shall be removed from service
when presented for the next filling (see Clause 13).
In some jurisdictions, it is the responsibility of the owner or user to submit cylinders used for emergency
purposes for periodic inspection and testing within the specified interval.
5 Procedures for periodic inspection and testing
5.1 List of procedures
The inspection, testing and repair of composite cylinders shall be carried out only by competent persons
in suitable facilities for cylinders of the size and type being requalified. Care shall be taken to ensure
that during the retest procedure, cylinders are handled carefully, particularly with respect to loading.
When moving from handling pallets or other transport frames, processes shall be developed to ensure
cylinders are not dropped or impacted during movement. Special handling methods and tooling may be
required to safely handle cylinders.
Handling procedures shall be available at the authorized inspection site.
Tests and examinations performed to demonstrate compliance shall be conducted using instruments
calibrated before being put into service and thereafter according to an established programme.
Each cylinder shall be submitted to periodic inspection and testing. The following procedures form the
requirements for this periodic inspection and testing and are explained more fully in this document in
the noted clauses:
— identification of cylinder and preparation for periodic inspection and testing (see Clause 6);
— external visual inspection (see Clause 7);
— safe removal of valve (see 8.2);
— internal visual inspection and cleaning (see 8.3);
— pressure test (see Clause 9);
— leak test (see Clause 10);
— inspection of valve (see Clause 11);
ISO 11623:2023(E)
— final operations (see Clause 12);
— rejection and rendering cylinders unserviceable (see Clause 13).
The external and internal visual examination (see Clauses 7 and 8) shall be carried out prior to the
pressure test (see Clause 9). It is recommended that the other tests are performed in the sequence listed
in 5.1; for the safe removal of a valve, the requirements in ISO 25760 shall be met.
Cylinders that fail inspection or testing shall be rejected (see Clause 13). When a cylinder passes
the procedures listed in 5.1, but the condition of the cylinder remains in doubt, additional testing
shall be performed to confirm its suitability for continued service or the cylinder shall be rendered
unserviceable. Depending on the reason for the rejection, cylinders may be recovered and/or repaired
(see 7.4).
5.2 Heat exposure
When cylinders are refurbished during periodic inspection, it can be necessary to expose them to heat,
for example, during initial cleaning, or as part of a stoving operation when painting or powder coating
the cylinder. This heat exposure can affect the mechanical properties of the liners and/or the finished
composite cylinder.
It is therefore essential that information on precise heat-effect temperatures from the cylinder
manufacturer be available; in the absence of this information, cylinders shall not be exposed to a
temperature exceeding 70 °C during refurbishment. If the cylinder manufacturer confirms (i.e. either
on a cylinder label or through documentation) that the allowable temperature is greater than 70 °C,
then the manufacturer’s recommendations shall be followed during refurbishment.
6 Identification of cylinder and preparation for periodic inspection and testing
Before any work is carried out, the relevant cylinder marks (as defined in ISO 13769) and the gas
contents (as defined in ISO 7225) shall be identified. The marking shall be checked to ensure that
the cylinder in question is within its design life. When composite cylinders have been designed and
manufactured for a limited design life, this is indicated on the cylinder marking.
The cylinder shall be depressurized and emptied in a safe, controlled manner before proceeding. For
Type 4 and Type 5 cylinders, take necessary precautions and/or consult the cylinder manufacturer for
depressurization procedures to avoid damaging the cylinder.
WARNING — The uncontrolled opening and/or removal of valves from cylinders can lead to
injury, death and/or property damage.
Prior to valve removal, the user shall follow the procedures described in ISO 25760 to verify that the
cylinder is empty of gas. Provided that the requirements in ISO 25760 have been complied with, the
cylinder shall be considered safely depressurized, and the valve shall be removed.
Cylinders with unknown gas contents shall be emptied as if the gas is dangerous (i.e. toxic, flammable
or oxidizing) as described in ISO 25760.
When the valve is non-functional, cylinders shall be emptied safely as described in ISO 25760.
Access shall be provided to the entire external surface of the cylinder for visual inspection and
measurement.
ISO 11623:2023(E)
7 External visual inspection
7.1 Preparation
7.1.1 General
The composite material including any external coating applied for protection shall not be removed for
the visual inspection.
Composite cylinders differ from their metal counterparts in that a competent person may repair them
when only limited damage has taken place (see 7.4). (This repair is not allowed for metal cylinders.)
These limits are specified in Table 1. Following this repair, cylinders shall be subjected to a pressure
test before being returned to service.
If the cylinder identification label is illegible, the manufacturer shall be contacted, or the cylinder shall
be rejected in accordance with Clause 13.
The manufacturer can provide a supplementary identification label to the cylinder if, as a minimum, the
original label’s serial number is still clearly legible.
When the cylinder manufacturer provides acceptance/rejection criteria for external damage, it takes
precedence over the criteria specified in Table 1.
7.1.2 Permanent protective attachments
Permanent protective attachments of the composite cylinder shall not be removed prior to inspection,
provided that these attachments are part of the original design. The manufacturer shall provide
acceptance/rejection criteria to be applied during the visual inspection for any damage to the
permanent protective attachments.
Markings specific to permanent attachments on the cylinder shall indicate if the attachments shall
remain in place at the time of the periodic inspection and testing. If such markings are not present, the
cylinder manufacturer shall be consulted to establish whether the permanent attachments need to be
removed.
7.1.3 Sleeves
When a transparent sleeve is used, it may be left in place as long as the composite wrapping can be
inspected effectively without its removal.
When a non-transparent sleeve is used that is not part of the cylinder design, it shall be removed prior
to inspection.
When the cylinder is suspected to be damaged, or if there are concerns regarding the operating
environment of the cylinder, e.g. saline atmosphere, the transparent sleeve shall be removed, and an
inspection of the composite material undertaken.
7.1.4 Cleaning
Care shall be taken not to remove any evidence of in-service damage (e.g. heat and fire damage), which
can affect the outcome of this inspection (see Table 1).
Each cylinder shall be cleaned and have all loose foreign matter removed from its external surface by a
suitable method (e.g. washing, light brushing, controlled water jet cleaning, plastic bead blasting).
Grit and shot blasting are not suitable. Chemical cleaning agents, paint strippers and solvents shall not
be used unless it has been established that they would not have an adverse effect on the cylinder or its
materials.
ISO 11623:2023(E)
Care shall be taken to ensure the legibility of the identification marks when undertaking a cleaning
operation.
7.2 Inspection procedures
The cylinder manufacturer should determine the acceptance/rejection criteria for external damage
and make the criteria available to the inspector. The manufacturer’s guidance takes precedence over
the criteria outlined in Table 1.
The acceptance/rejection criteria given in Table 1 are to be followed in the absence of specific
instructions from the manufacturer of the cylinder being examined. The external metallic surface
of hoop-wrapped cylinders shall be visually inspected in accordance with the applicable clauses of
ISO 18119. Particular attention shall be paid to the interface with the composite overwrap to check for
crevice corrosion.
The external surface shall be inspected for damage to the composite overwrap. There are three levels
of damage that shall be considered (see 7.3.2); of these, only Level 2 can be repaired (see Table 1).
7.3 Damage
7.3.1 General
Damage to the composite overwrap can appear in many forms, and examples of these are described in
7.3.3. The acceptance/rejection criteria are specified in Table 1, which refers to specified damage levels
and the types of damage. Care shall be taken to establish the total extent of damage from impact (see
7.3.3.3) and delamination (see 7.3.3.4) as surface appearance will possibly not indicate the full extent of
the damage.
Annex B specifies additional damage criteria for steel wire wound, aluminium-alloy cylinders that shall
be taken into account.
When damage is caused by installation (e.g. trailer or bundle), severity or conditions of service, or by
improper cylinder use, the inspector should advise the cylinder owner of the need to take corrective
action to prevent or reduce further cylinder damage, or to prevent damage to a replacement cylinder.
Such actions should be developed with the manufacturer of the cylinder and the original installer.
7.3.2 Damage levels
7.3.2.1 General
The surface of the cylinder shall be inspected for evidence of damage. Damage shall be evaluated
in accordance with Table 1. For damage not specified in this document, the manufacturer shall be
consulted for guidance.
7.3.2.2 Level 1 damage
Cylinders with minor or superficial damage are categorized as having Level 1 damage. Such damage has
no adverse effects on the safety of the cylinder and its continued use. These cylinders may be returned
to service with no repair.
Scratched paint or nicks that have no appreciable depth in metal, or similar damage in the composite
cylinder paint or resin where there are no visible frayed fibres, are considered to be of this level of
damage.
ISO 11623:2023(E)
7.3.2.3 Level 2 damage
Level 2 damage is rejectable damage that requires repair, testing or rendering the cylinder
unserviceable. Level 2 damage is also reserved for conditions specified by the manufacturer, which can
differ from Level 1 or Level 3 damage outlined in Table 1.
7.3.2.4 Level 3 damage
Level 3 damage is sufficiently severe that the cylinder shall not be repaired but shall be rejected and
subsequently rendered unserviceable. See Tables 1 and 2.
7.3.3 Types of external damage
7.3.3.1 Abrasion damage
Abrasion damage is caused by wearing, grinding or rubbing away by friction of the overwrap material.
Minor abrasion damage to the protective coating or paint is shown in Figure 1 a) and b). “Flat spots”
evident on the surface can indicate excessive loss of composite overwrap thickness [see Figure 1 c)].
7.3.3.2 Damage from cuts
Cuts or gouges are caused by contact with sharp objects in such a way as to cut into the composite
overwrap, reducing its thickness at that point, see Figure 2 a), b) and c).
7.3.3.3 Impact damage
Impact damage can appear as hairline cracks in the resin, or delamination or cuts of the composite
overwrap, see Figure 3 a) and b). The resin can have a frosted, crazed or opaque appearance.
7.3.3.4 Delamination
Delamination is a separation of layers of strands, or of the strands themselves, of the composite
overwrap, see Figure 4 a) and b). It also can appear as a whitish patch, like a blister, or an air space
beneath the surface.
7.3.3.5 Heat or fire damage [see Figure 5 a) and b)]
7.3.3.6 Structural damage
Structural damage is any evidence of:
— external bulges, distorted neck thread connections or depressions not originally designed;
— bulging of the liner of Type 2 or Type 3 cylinders;
— internal bulging of Type 4 or Type 5 cylinders.
7.3.3.7 Chemical attack
Chemical attack would appear as the dissolution of the matrix surrounding the fibres, see Figure 6 a)
and b). The resulting cylinder surface can be pitted, feel soft/sticky, discoloured, etc.
7.3.3.8 Loose permanent attachments
For example, signs of a collar, neck ring or permanent protective attachment that is part of the design
becoming loose are causes for rejecting the cylinder.
ISO 11623:2023(E)
7.3.3.9 Damaged permanent attachments
Damage to permanent attachments, e.g. cage, outer casing, permanent protective attachment, etc.,
excluding transparent sleeves (see 7.1.3), that are part of the original cylinder design is Level 3 damage
unless the manufacturer provides an inspection manual of damage criteria based on experimental data.
7.3.3.10 Improper repairs
Signs of damage in the repaired area in excess of Level 1 are causes for rejecting the cylinder.
Table 1 — Acceptance/rejection criteria for external damage
Level of damage
Type of damage Level 1 Level 2 Level 3
Acceptable damage Rejectable damage Condemned damage
(requiring additional (not repairable)
inspections or repairs)
Abrasion damage Damage to the following Damage greater than Level 1 but Without further refer-
for cylinders with depth is acceptable: less than Level 3 shall be referred ence to manufacturer’s
a water capacity of to the manufacturer for repair instructions, damage
Less than or equal to 10 % of
less than 80 l procedures. Otherwise, the dam- greater than 10 % of
the thickness of the compos-
age shall be considered Level 3. the thickness of the
ite overwrap with a maxi-
composite overwrap
mum length in any direction If the manufacturer does not pro-
or with a maximum
of 25 % of the cylinder vide repair instructions, the dam-
length in any direction
diameter. age shall be considered Level 3.
more than 25 % of the
cylinder diameter shall
be considered Level 3.
Abrasion damage Damage to the following Damage greater than Level 1 but Without further refer-
for cylinders with depth is acceptable: less than Level 3 shall be referred ence to manufacturer’s
a water capacity of to the manufacturer for repair instructions, damage
Less than or equal to 15 % of
80 l or more procedures. Otherwise, the dam- greater than 15 % of
the thickness of the compos-
age shall be considered Level 3. the thickness of the
ite overwrap with a maxi-
composite overwrap
mum length in any direction If the manufacturer does not pro-
or with a maximum
of 15 % of the cylinder vide repair instructions, the dam-
length in any direction
diameter. age shall be considered Level 3.
more than 15 % of the
cylinder diameter shall
be considered Level 3.
Damage from cuts Damage to the following Damage greater than Level 1 but Without further refer-
for cylinders with depth is acceptable: less than Level 3 shall be referred ence to manufacturer’s
a water capacity of to the manufacturer for repair instructions, damage
Less than o
...