EN 12245:2022

SLOVENSKI STANDARD
01-september-2022
Nadomešča:
SIST EN 12245:2009+A1:2012
Premične plinske jeklenke - Popolnoma obvite jeklenke iz kompozitnih materialov
Transportable gas cylinders - Fully wrapped composite cylinders
Ortsbewegliche Gasflaschen - Vollumwickelte Flaschen aus Verbundwerkstoffen
Bouteilles à gaz transportables - Bouteilles entièrement bobinées en matériaux
composites
Ta slovenski standard je istoveten z: EN 12245:2022
ICS:
23.020.35 Plinske jeklenke Gas cylinders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 12245
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2022
EUROPÄISCHE NORM
ICS 23.020.35 Supersedes EN 12245:2009+A1:2011
English Version
Transportable gas cylinders - Fully wrapped composite
cylinders
Bouteilles à gaz transportables - Bouteilles Ortsbewegliche Gasflaschen - Vollumwickelte Flaschen
entièrement bobinées en matériaux composites aus Verbundwerkstoffen
This European Standard was approved by CEN on 17 January 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12245:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and symbols . 9
3.1 Terms and definitions . 9
3.2 Symbols . 11
4 Design and manufacture . 12
4.1 General. 12
4.2 Liner . 12
4.2.1 Metallic liners . 12
4.2.2 Non-metallic liners . 12
4.2.3 Design drawing . 13
4.2.4 Design of ends . 14
4.2.5 Neck ring . 14
4.3 Composite overwrap. 14
4.3.1 Materials . 14
4.3.2 Winding . 14
4.4 Finished cylinder . 15
4.4.1 Design drawings . 15
4.4.2 Cylinders without liner . 15
4.4.3 Autofrettage . 15
4.4.4 Manufacturing requirements for the finished cylinder . 16
5 Cylinder and material tests . 16
5.1 General. 16
5.2 Requirements and test methods . 16
5.2.1 Test 1 – Composite material tests, including adhesives (where applicable) . 16
5.2.2 Test 2 – Liner material tests . 17
5.2.3 Test 3 – Liner test (for metallic liners only) . 18
5.2.4 Test 4 – Pressure test of finished cylinders at ambient temperature . 20
5.2.5 Test 5 – Cylinder burst test . 20
5.2.6 Test 6 – Resistance to pressure cycles at test pressure (p ) and ambient temperature
h
................................................................................................................................................................... 21
5.2.7 Test 7 – Immersion in salt water . 23
5.2.8 Test 8 - Exposure to elevated temperature at test pressure . 24
5.2.9 Test 9 – Drop/Impact test . 24
5.2.10 Test 10 – Flawed cylinder test . 27
5.2.11 Test 11 – Extreme temperature cycle test . 29
5.2.12 Test 12 – Fire resistance test . 30
5.2.13 Test 13 – Permeability test of cylinders with non-metallic or without liners . 32
5.2.14 Test 14 – Liner collapse and blistering test (only for cylinders with non-metallic liners
for compressed gases) . 33
5.2.15 Test 15 – Test of compatibility of thermoplastic liners and matrix for type 5 cylinders
with air or oxidising gases . 33
5.2.16 Test 16 - Torque test (for taper threads only) . 34
5.2.17 Test 17 – Neck strength . 34
5.2.18 Test 18 – Cylinder stability . 35
5.2.19 Test 19 – Neck ring . 35
5.2.20 Test 20 – Shear stress calculation for parallel threads for steel liners and steel bosses
................................................................................................................................................................... 35
5.3 Failure to meet test requirements . 35
5.3.1 Metallic liners . 35
5.3.2 Finished cylinder . 35
6 Conformity evaluation . 36
7 Marking . 36
8 Operating instructions for cylinders with non-metallic liners . 37
Annex A (normative) Prototype, design variant and production testing . 38
A.1 General . 38
A.2 Prototype testing . 38
A.2.1 General . 38
A.2.2 Definition of new design . 38
A.2.3 Prototype testing requirements . 39
A.2.4 Prototype testing certificate . 39
A.3 Design variant testing . 43
A.3.1 General . 43
A.3.2 Definition of a design variant . 43
A.3.2.1 Conditions to be satisfied . 43
A.3.2.2 Equivalent fibre . 44
A.3.2.3 Equivalent matrix . 44
A.3.2.4 Equivalent liner . 44
A.3.2.5 Cylinder variant . 45
A.3.3 Design variant test requirements . 46
A.3.4 Design variant testing certificate . 46
A.4 Production testing . 49
A.4.1 General . 49
A.4.2 Production test requirements . 49
A.4.3 Liner batch tests and inspections . 49
A.4.3.1 Metallic liner . 49
A.4.3.2 Non-metallic liner . 50
A.4.4 Composite materials batch tests and inspections. 50
A.4.5 Tests and inspections of the finished cylinder . 50
A.4.5.1 Tests . 50
A.4.5.2 Inspections . 51
A.4.6 Batch acceptance certificate . 51
Annex B (informative) Examples of prototype approval and production testing certificates
................................................................................................................................................................... 52
B.1 Type approval certificate – composite cylinders with metallic liners . 52
B.2 Type approval certificate – composite cylinders with non-metallic liners . 53
B.3 Type approval certificate – composite cylinders without liners . 54
B.4 Design variant approval certificate – composite cylinders with metallic liners . 55
B.5 Production test certificate . 56
Annex C (informative) Example of high velocity impact (bullet) test . 58
C.1 Procedure . 58
C.2 Criteria . 58
C.3 Parameters to monitor and record . 58
Annex D (informative) Standardized test requirements for thermally activated pressure
relief devices . 59
D.1 General. 59
D.2 Cylinder test . 59
D.2.1 Cylinder set up . 59
D.2.2 Fire source . 59
D.2.3 Temperature and pressure measurements . 59
D.2.4 General test requirements . 60
D.2.5 Tests options . 60
D.2.5.1 Option A – Controlled release of pressure . 60
D.2.5.2 Option B – Fire until rupture . 60
D.3 PRD test . 60
D.4 Vent test . 60
D.5 System assessment . 61
D.5.1 Qualification limit envelope. 61
D.5.2 Service limit envelope . 61
D.5.3 Acceptable results . 61
Bibliography . 64

European foreword
This document (EN 12245:2022) has been prepared by Technical Committee CEN/TC 23 “Transportable
gas cylinders”, the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2022, and conflicting national standards shall
be withdrawn at the latest by November 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12245:2009+A1:2011.
This document has been submitted for reference in:
— the RID; and
— the technical annexes of the ADR.
NOTE These regulations take precedence over any clause of this standard. It is emphasized that RID/ADR are
being revised regularly at intervals of two years which may lead to temporary non-compliances with the clauses of
this standard.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
The purpose of this document is to provide a specification for the design, manufacture, inspection and
testing of refillable, transportable fully wrapped composite cylinders and tubes.
The specifications given are based on knowledge of, and experience with, materials, design requirements,
manufacturing processes and control during manufacture of cylinders and tubes in common use in the
countries of the CEN members.
1 Scope
This document specifies minimum requirements for the materials, design, construction, prototype testing
and routine manufacturing inspections of fully wrapped composite gas cylinders for compressed,
liquefied and dissolved gases.
NOTE 1 For the purposes of this document, the word “cylinder” includes tubes (seamless transportable pressure
receptacles of a water capacity exceeding 150 l and of not more than 3 000 l).
This document is applicable to cylinders that comprise a liner of metallic material (welded or seamless)
or non-metallic material (or a mixture thereof), reinforced by a wound composite consisting of fibres of
glass, carbon or aramid (or a mixture thereof) embedded in a matrix.
This document is also applicable to composite cylinders without liners.
This document is not applicable to gas cylinders which are partially covered with fibres and commonly
called “hoop wrapped” cylinders. For hoop wrapped composite cylinders, see EN 12257.
NOTE 2 This document does not address the design, fitting and performance of removable protective sleeves.
Where these are fitted, they are considered separately.
This document is primarily for compressed, liquefied and dissolved gases other than LPG.
NOTE 3 For dedicated LPG cylinders, see EN 14427.
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.
EN 12862, Transportable gas cylinders - Specification for the design and construction of refillable
transportable welded aluminium alloy gas cylinders
EN 13322-1, Transportable gas cylinders - Refillable welded steel gas cylinders - Design and construction -
Part 1: Carbon steel
EN 13322-2, Transportable gas cylinders - Reffilable welded steel gas cylinders - Design and construction -
Part 2: Stainless steel
EN 14638-1, Transportable gas cylinders - Refillable welded receptacles of a capacity not exceeding 150
litres - Part 1: Welded austenitic stainless steel cylinders made to a design justified by experimental methods
EN 14638-3, Transportable gas cylinders - Refillable welded receptacles of a capacity not exceeding 150
litres - Part 3: Welded carbon steel cylinders made to a design justified by experimental methods
EN ISO 75-1, Plastics - Determination of temperature of deflection under load - Part 1: General test method
(ISO 75-1)
EN ISO 75-3, Plastics - Determination of temperature of deflection under load - Part 3: High-strength
thermosetting laminates (ISO 75-3)
EN ISO 527-1, Plastics - Determination of tensile properties - Part 1: General principles (ISO 527-1)
EN ISO 527-2, Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and
extrusion plastics (ISO 527-2)
EN ISO 1183 (all parts), Plastics — Methods of determining the density and relative density of non-cellular
plastics (ISO 1183)
EN ISO 1628-3, Plastics - Determination of the viscosity of polymers in dilute solution using capillary
viscometers - Part 3: Polyethylenes and polypropylenes (ISO 1628-3)
EN ISO 2884-1, Paints and varnishes - Determination of viscosity using rotary viscometers - Part 1: Cone-
and-plate viscometer operated at a high rate of shear (ISO 2884-1)
EN ISO 3146, Plastics - Determination of melting behaviour (melting temperature or melting range) of semi-
crystalline polymers by capillary tube and polarizing-microscope methods (ISO 3146)
EN ISO 7866, Gas cylinders - Refillable seamless aluminium alloy gas cylinders - Design, construction and
testing (ISO 7866)
EN 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
(ISO 9809-1)
EN 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 9809-2)
EN ISO 10156, Gas cylinders - Gases and gas mixtures - Determination of fire potential and oxidizing ability
for the selection of cylinder valve outlets (ISO 10156)
EN ISO 10618, Carbon fibre - Determination of tensile properties of resin-impregnated yarn (ISO 10618)
EN ISO 11114-1, Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 1:
Metallic materials (ISO 11114-1)
EN ISO 11114-2, Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2:
Non-metallic materials (ISO 11114-2)
EN ISO 11114-3, Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 3:
Autogenous ignition test for non-metallic materials in oxygen atmosphere (ISO 11114-3)
EN 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 11114-4)
EN ISO 11114-5:2022, Gas cylinders — Compatibility of cylinder and valve materials with gas contents —
Part 5: Test methods for evaluating plastic liners (ISO 11114-5:2022)
EN ISO 11120, Gas cylinders - Refillable seamless steel tubes of water capacity between 150 l and 3000 l -
Design, construction and testing (ISO 11120)
EN ISO 11357-2, Plastics - Differential scanning calorimetry (DSC) - Part 2: Determination of glass
transition temperature and step height (ISO 11357-2)
EN ISO 13341, Gas cylinders - Fitting of valves to gas cylinders (ISO 13341)
EN ISO 14130, Fibre-reinforced plastic composites - Determination of apparent interlaminar shear strength
by short-beam method (ISO 14130)
ISO 3341, Textile glass — Yarns — Determination of breaking force and breaking elongation
ISO 6721-11, Plastics — Determination of dynamic mechanical properties — Part 11: Glass transition
temperature
ISO 9809-4, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and
tubes — Part 4: Stainless steel cylinders with an Rm value of less than 1 100 MPa
ASTM D 2196-18e1, Standard test method for rheological properties of non-Newtonian materials by
rotational (Brookfield) viscosimeter
ASTM D 2290-19a, Standard test method for apparent hoop tensile strength of plastic or reinforced plastic
pipe
ASTM D 2291/D 2291M-16, Standard practice for fabrication of ring test specimens for glass-resin
composites
ASTM D 2344/D 2344M-16, Standard test method for short-beam strength of polymer matrix composite
materials and their laminates
ASTM D 4018-17, Standard test methods for properties of continuous filament carbon and graphite fiber
tows
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms, definitions and symbols 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 https://www.electropedia.org/
3.1.1
ambient temperature
temperature of surroundings varying between 10 °C and 35 °C (for test purposes only)
3.1.2
autofrettage
pressure application procedure which strains the metal liner past its yield point sufficiently 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
[SOURCE: EN ISO 10286:2021, 3.3.4 – “yield strength” has been replaced with “yield point”]
3.1.3
batch
homogeneous quantity of material,
identified and certified as such by the supplier
3.1.4
batch
quantity of liners of the same nominal diameter, thickness, length and design, made
successively from the same material cast and subjected to the same heat treatment for the same length
of time
3.1.5
batch
quantity of liners of the same nominal diameter, thickness, length and design, made
successively from the same batch of materials and subjected to the same manufacturing process
3.1.6
batch
quantity of up to 200 finished cylinders, plus cylinders for destructive
testing, of the same nominal diameter, thickness, length and design which may contain different batches
of liners (providing the batches are nominally the same and have had the same treatments), fibres and
matrix materials
3.1.7
batch
production quantity of up to 200 finished cylinders, plus cylinders for
destructive testing, of the same nominal diameter, thickness, length and design
3.1.8
burst pressure
highest pressure reached in a cylinder or liner during the relevant burst test
[SOURCE: EN ISO 10286:2021, definition 732, modified — “or liner” and “relevant” have been added.]
3.1.9
composite overwrap
fibres and matrix taken together as a combined unit
3.1.10
cylinder without liner
cylinder having no liner and consisting wholly of the composite winding
3.1.11
elastomer
material which at ambient temperature can be stretched repeatedly to at least twice its original length
and will return with force to approximately its original length immediately upon release of the stress
3.1.12
exterior coating
layer of clear or pigmented material applied to the cylinder as protection or for cosmetic purposes
3.1.13
fibre or strand
load-carrying part of the composite overwrap e.g. glass, aramid or carbon
3.1.14
fully wrapped cylinder
cylinder reinforced by wrapping to take both circumferential and longitudinal stress
3.1.15
liner
metallic or non-metallic vessel that contains the gas but can also contribute to the mechanical behaviour
of the cylinder
[SOURCE: EN ISO 10286:2021, 3.1.3.3 modified]
3.1.16
non-load sharing liner
liner that has a burst pressure less than 5 % of the nominal burst pressure of the finished composite
cylinder
3.1.17
non-metallic liner
liner made from thermoplastic, thermosetting or elastomer material, or a combination thereof
3.1.18
matrix
material that is used to bind and hold the fibres in place
[SOURCE: EN ISO 10286:2021, 3.1.3.2]
3.1.19
neck ring
ring securely attached externally to the cylinder or boss, with external thread or other means for
attaching valve cap or guard
Note 1 to entry: Neck rings are not common on type 4 composite gas cylinders.
3.1.20
permanent protective attachment
integral part of the cylinder design affixed to composite cylinders, covering part of or the entire surface
of the cylinder, providing functions during handling, transport and use
3.1.21
thermoplastic
plastics capable of being repeatedly softened by increase of temperature and hardened by decrease of
temperature
3.1.22
thermosetting material
plastics which, when cured by the application of heat or chemical means, change into a substantially
infusible and insoluble product
3.1.23
test pressure
required pressure applied during a pressure test
[SOURCE: EN ISO 10286:2021, 3.5.24]
3.2 Symbols
p
actual burst pressure of composite cylinder, in bar above atmospheric pressure (1 bar = 10
b
Pa = 0,1 MPa)
p
burst pressure of liner, in bar above atmospheric pressure (1 bar = 10 Pa = 0,1 MPa)
bL
p minimum burst pressure of composite cylinder obtained during design variant approval
bmin
testing, in bar above atmospheric pressure (1 bar = 10 Pa = 0,1 MPa)
p hydraulic test pressure of composite cylinder, in bar above atmospheric pressure (1
h
bar = 10 Pa = 0,1 MPa)
p
maximum developed pressure at 65 °C, in bar above atmospheric pressure (1 bar = 10
max
Pa = 0,1 MPa)
4 Design and manufacture
4.1 General
A fully wrapped composite gas cylinder may be manufactured with a metallic or non-metallic liner or
without a liner. The composite overwrap shall not be manufactured from two or more parts joined
together regardless of the joining methods (e.g. using adhesive).
An optional exterior coating or additional fibre layers may be used to provide external protection. When
this is an integral part of the design, it shall not be removed.
The cylinder may also include additional parts (e.g. neck rings and foot rings).
Cylinders shall be designed with one or two openings along the central axis only.
A permanent protective attachment (PPA) is always an integral part of the cylinder design. It shall be
permanently fixed to the cylinder such that they cannot be removed during service without destroying
them, or by use of special tools. Under certain conditions, such PPA can be replaced following the
manufacturer’s instructions.
4.2 Liner
4.2.1 Metallic liners
Metallic liners shall be manufactured in accordance with the relevant sections of:
a) seamless steel liners: EN ISO 9809-1, EN ISO 9809-2, EN ISO 11120, as appropriate;
b) seamless stainless steel liners: ISO 9809-4;
c) seamless aluminium alloy liners: EN ISO 7866;
d) welded steel liners: EN 13322-1 or EN 14638-3, as appropriate;
e) welded stainless steel liners: EN 13322-2 or EN 14638-1, as appropriate;
f) welded aluminium liners: EN 12862.
The relevant sections are those covering materials, thermal treatments, neck design, construction and
workmanship and mechanical tests.
The liner material shall be compatible with the gases intended to be used as determined by
EN ISO 11114-1.
Steel liners with a tensile strength above 950 MPa shall be qualified according to EN ISO 11114-4 for
embrittling gases.
NOTE This excludes the design requirements, since these are specified by the manufacturer for the design of
the composite cylinder. For liners with water capacity above 150 l manufactured of stainless steel, aluminium or
welded steel, the relevant sections of the appropriate standard also apply.
4.2.2 Non-metallic liners
A cylinder with a non-metallic liner shall be designed as if the liner will be non-load sharing. The liner
material shall be compatible with the gases intended for use as recommended in EN ISO 11114-2 or it
can be demonstrated by suitable testing.
NOTE EN ISO 11114-5:2022 specifies some gas compatibility test methods (on samples and/or cylinders) to
evaluate plastic materials suitable for use in the manufacture of liners.
Where a metal end boss is used in a non-metallic liner, it shall be considered part of the liner material
and shall fulfil the material requirements specified in the relevant standard, as listed in 4.2.1. Other
materials are acceptable if compatibility is demonstrated by testing according to EN ISO 11114-4 or if it
is accepted by design standards (e.g. EN ISO 7866). When the metal end boss is made of brass, the
material shall fulfil the requirements in relevant sections of EN ISO 11114-1 and EN 12165.
The drawing of the liner shall include the specification of the material and material properties of the boss.
Important material properties shall be specified in the design and are those such as:
a) minimum yield stress;
b) minimum tensile strength;
c) minimum elongation of the boss material;
d) compatibility with the contained gas as determined by EN ISO 11114-1.
The metal end boss bearing the cylinder thread shall be designed to withstand the torque applied in fitting
the valve to the cylinder and the tests specified in Test 16 (for taper threads only see 5.2.16) and Test 17
(see 5.2.17).
4.2.3 Design drawing
A fully dimensioned drawing of the liner shall be supplied which includes the specification of the material
and material properties. Material and liner properties to be specified on the drawing are:
a) for metallic liners:
1) minimum yield stress;
2) minimum tensile strength;
3) minimum elongation;
4) liner proof pressure defined by the manufacturer for the leak test (for welded liners);
5) minimum burst pressure;
6) weld profile (see ISO 11119-4:2016, 7.3.1) and procedure specification, if applicable;
7) compatibility with the contained gas as determined by EN ISO 11114-1;
b) for non-metallic liners:
1) density;
2) melting point for thermoplastics as determined by EN ISO 3146 (or EN ISO 11357-3);
3) heat distortion temperature for thermosetting materials as determined by EN ISO 75-1,
(EN ISO 75-2);
4) auto-ignition temperature in oxygen as determined by EN ISO 11114-3 (for cylinders intended
for air and oxidising gases (see EN ISO 10156 for definition of oxidising gases));
5) glass transition temperature as determined by ISO 6721-11 (or EN ISO 11357-2) (differential
scanning calorimetry);
6) composition (e.g. datasheet); additive systems constituting more than 10 % of the total
composition shall be defined individually as components of the liner;
7) compatibility with the contained gas as recommended by EN ISO 11114-2 or demonstrated by
suitable testing;
8) end boss design in accordance with 4.2.2.
4.2.4 Design of ends
The external diameter and thickness of the formed neck end of the liner shall be designed to withstand
the torque applied in fitting the valve to the cylinder and the tests specified in Test 16 (for taper threads
only see 5.2.16) and Test 17 (see 5.2.17).
4.2.5 Neck ring
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, cylinder or boss material.
4.3 Composite overwrap
4.3.1 Materials
Material requirements for the fibre and matrix or the pre-impregnated material shall be as specified by
the manufacturer. If glass fibre is used as the structural reinforcement of the cylinder, then only boron
free glass fibre shall be used.
4.3.2 Winding
Appropriate procedures shall be defined for the winding and curing process to ensure good repeatability
and traceability.
Parameters to be specified and monitored are:
a) composite overwrap component percentages;
b) batch numbers of the material used as defined in 3.1.3 to 3.1.6;
c) number of strands used;
d) winding tension per strand (if applicable);
e) control winding speed(s);
f) winding angle and/or pitch for each layer;
g) resin bath temperature range (if applicable);
h) temperature of the strand before consolidation (if applicable);
i) number and order of layers;
j) procedure used to obtain correct impregnation (e.g. wet winding or pre-impregnation);
k) polymerisation cycle (if applicable);
l) polymerisation process (e.g. thermal cycling, ultrasonic, ultraviolet or radiation).
For thermal polymerisation, the temperature and the length of the polymerisation cycle of the resin
system shall be such that they do not adversely affect the mechanical characteristics of the liner. In
addition, tolerances for holding time and temperature at each stage shall be defined.
4.4 Finished cylinder
4.4.1 Design drawings
A fully dimensioned drawing of all parts that constitute the finished cylinder shall be supplied. The design
drawing shall include tolerances on all dimensions, including out-of-roundness and straightness.
The drawing shall include the specification of the material(s), the material properties and the
reinforcement pattern. The specifications and the reinforcement patterns may be given in a technical
specification enclosed with the drawing.
The details of a permanently applied exterior coating, if it is an integral part of the design, shall be defined.
The test pressure, autofrettage pressure (if applicable) and minimum burst pressure for the design shall
be specified.
Any special characteristics or special limitations (e.g. design life, underwater suitability, vacuum
suitability and/or maximum fitting torque restrictions) shall be stated.
4.4.2 Cylinders without liner
The requirements for the composite materials and their properties to be specified are:
a) tensile strength;
b) tensile modulus;
c) elongation at break;
d) heat distortion temperature;
e) viscosity.
The composite materials shall be compatible with the contained gas as determined by EN ISO 11114-2 or
demonstrated by suitable testing. The auto-ignition temperature in oxygen gas shall be determined in
accordance with EN ISO 11114-3 for cylinders intended for air, oxygen and oxidising gases.
NOTE EN ISO 11114-5:2022 specifies some gas compatibility test methods (on samples and/or cylinders) to
evaluate plastic matrix materials used for cylinders without liner (Type 5 cylinders).
Where a metal end boss is used in a cylinder without liner, the drawing of the cylinder shall include the
specification of the material and material properties of the boss in accordance with 4.2.2.
4.4.3 Autofrettage
Internal pressurization to autofrettage pressure of cylinders with metallic liners can be part of the
manufacturing process; if so this operation shall be executed after polymerisation of the composite for
thermosetting resins or after the consolidation process for thermoplastics.
During the autofrettage operation, the parameters to be recorded are:
a) autofrettage pressure;
b) length of application of the autofrettage pressure;
c) expansion at autofrettage pressure;
d) permanent expansion after autofrettage.
If autofrettage is used, a check shall be made on all cylinders that the procedure has been effectively
performed.
4.4.4 Manufacturing requirements for the finished cylinder
The internal and external surfaces of the finished cylinder shall be free of defects which can adversely
affect the safe working of the cylinder. In addition, there shall be no visible foreign matter present inside
the cylinder (e.g. resin, swarf or other debris).
NOTE EN ISO 9809-1, EN ISO 9809-2, EN ISO 7866, EN 13322-1 and EN 14638-3 provide guidelines on
possible defects in metallic liners. For composite cylinders, EN ISO 11623 contains information on possible defects.
5 Cylinder and material tests
5.1 General
This clause describes tests to be conducted on fully wrapped composite cylinders, cylinder liners and the
materials used i
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