EN 12257:2002

SLOVENSKI STANDARD
01-november-2002
3UHPLþQHSOLQVNHMHNOHQNH-HNOHQNHL]FHOHJDREURþDVWRREYLWHVNRPSR]LWQR
PDVR
Transportable gas cylinders - Seamless, hoop-wrapped composite cylinders
Ortsbewegliche Gasflaschen - Nahtlose umfangsgewickelte Flaschen aus
Verbundwerkstoffen
Bouteilles a gaz transportables - Bouteilles sans soudure, frettées composites
Ta slovenski standard je istoveten z: EN 12257:2002
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 12257
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2002
ICS 23.020.30
English version
Transportable gas cylinders - Seamless, hoop-wrapped
composite cylinders
Bouteilles à gaz transportables - Bouteilles sans soudure, Ortsbewegliche Gasflaschen - Nahtlose umfangsgewickelte
frettées composites Flaschen aus Verbundwerkstoffen
This European Standard was approved by CEN on 9 November 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12257:2002 E
worldwide for CEN national Members.

Contents
page
Foreword .3
Introduction .4
1 Scope.5
2 Normative references.5
3 Terms, definitions and symbols .6
4 Design and manufacture .7
5 Cylinder and material tests .10
6 Conformity evaluation .21
7 Marking.21
Annex A (normative)  Prototype testing, design variant testing and production testing .22
Annex B (informative)  Examples of type approval and production testing certificates .33
Bibliography .37
Foreword
This document EN 12257:2002 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 August 2002, and conflicting national standards shall
be withdrawn at the latest by August 2002.
This European Standard has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association, and supports the objectives of the framework
Directives on Transport of Dangerous Goods.
This European Standard has been submitted for reference into the RID and/or the technical annexes
of the ADR. Therefore in this context the standards listed in the normative references and covering
basic requirements of the RID/ADR not addressed within the present standard are normative only
when the standards themselves are referred to in the RID and/or the technical annexes of the ADR.
Annex A is normative and annex B is informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
The purpose of this standard is to provide a specification for the design, manufacture, inspection and
testing of refillable transportable seamless, hoop wrapped composite cylinders.
The specifications given are based on knowledge of, and experience with, materials, design
requirements, manufacturing processes and control during manufacture of cylinders in common use in
the countries of the CEN members.
1 Scope
This European Standard specifies minimum requirements for the materials, design, construction,
prototype testing and routine manufacturing inspections of composite gas cylinders with a water
capacity up to and including 450 litres for compressed, liquefied and dissolved gases.
NOTE For the purposes of this standard, the word “cylinder” includes tubes up to 450 litres water capacity.
This standard is applicable to cylinders that comprise a seamless metal liner reinforced over a
substantial part of the parallel length by wound composite fibres of glass, carbon, aramid, or wire.
This standard is not applicable to gas cylinders which are almost totally covered with fibres and
commonly called "fully-wrapped" cylinders. For fully-wrapped composite cylinders see EN 12245.
NOTE The specification does not address the design, fitting and performance of removable protective
sleeves. Where these are fitted they should be considered separately.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate place in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references the latest edition of the publication referred to applies (including amendments).
EN 1089-1, Transportable gas cylinders— Gas cylinder identification (excluding LPG) –
Part 1: Stampmarking.
EN 1964-1, Transportable gas cylinders — Specification for the design and construction of refillable
transportable seamless steel gas cylinders of water capacities from 0,5 litre up to and including 150
litres — Part 1: Cylinders made of seamless steel with an R value of less than 1 100 MPa.
m
prEN 1964-2, Transportable gas cylinders — Specification for the design and construction of refillable
transportable seamless steel gas cylinders from 0,5 litres up to and including 150 litres — Part 2:
Tensile strength (R max)
1 100 MPa.
m
EN 1964-3, Transportable gas cylinders — Specification for the design and construction of refillable
transportable seamless steel gas cylinders of capacity from 0,5 litres up to 150 litres — Part 3:
Stainless steel cylinders.
EN 1975, Transportable gas cylinders — Specification for the design and construction of refillable
transportable seamless aluminium and aluminium alloy gas cylinders of capacity from 0,5 l up to 150 l.
EN 10002-1, Metallic materials — Tensile testing — Part 1: Method of test (at ambient temperature)
EN ISO 11114-1, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 1: Metallic Materials (ISO 11114-1:1997).
EN ISO 11120, Gas Cylinders — Refillable seamless steel tubes of water capacity between 150 l
and 3000 l — Design, construction and testing (ISO 11120:1999).
EN ISO 13341, Transportable gas cylinders — Fitting of valves to gas cylinders (ISO 13341:1997).
ASTM D 2290-92, Test method for apparent tensile strength of ring or tubular plastics and reinforced
plastics by split disk method.
ASTM D 2291-83, Fabrication of ring test specimens for glass-resin composites.
ASTM D 2343-95, Test method for tensile properties of glass fibre strands, yarns and rovings used in
reinforced plastics.
ASTM D 4018-93, Test methods for tensile properties of continuous filament carbon and graphite fiber
tows.
3 Terms, definitions and symbols
For the purposes of this European Standard, the following terms, definitions and symbols apply.
3.1 Terms and definitions
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 internally when at zero internal gauge pressure
3.1.3
batch, (of fibres, wires or components of the resin system)
homogeneous quantity of material, identified and certified as such by the supplier
3.1.4
batch, (of metallic liners)
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, (of finished cylinders with liners)
quantity of up to 200 finished cylinders plus finished cylinders required for destructive testing, of the
same nominal diameter, thickness, length and design. The batch may contain different batches of
liners (providing the batches are nominally the same and have had the same treatments), fibres and
matrix materials
3.1.6
burst pressure
highest pressure reached in a cylinder or liner during the relevant burst test
3.1.7
composite overwrap
fibres and matrix taken together as a combined unit, or wire reinforcement
3.1.8
exterior coating
layer of clear or pigmented material applied to the cylinder for protection or for cosmetic purposes
3.1.9
fibre or strand
load-carrying part of the composite overwrap e.g. glass, aramid or carbon
3.1.10
hoop-wrapped cylinder
cylinder with composite overwrap along the cylindrical portion of the liner which carries part of the
circumferential stress
3.1.11
liner
metallic cylinder that contains the gas and provides a substantial structural strength to the composite
cylinder
3.1.12
matrix
material which is used to bind and hold the fibres in place
3.1.13
rejected cylinder
cylinder which in its present condition has not passed the test requirements
3.1.14
wire reinforcement
load carrying overwrap, using a metallic wire (e.g. steel), that does not require a matrix
3.2 Symbols
1)
p actual burst pressure of composite cylinder, in bar above atmospheric pressure
b
1)
p burst pressure of liner, in bar above atmospheric pressure
bL
1)
p minimum burst pressure of composite cylinder obtained during design variant testing, in bar
bmin
above atmospheric pressure
1)
p hydraulic test pressure of composite cylinder, in bar above atmospheric pressure
h
4 Design and manufacture
4.1 General
A hoop-wrapped composite gas cylinder shall comprise the following parts:
4.1.1

An internal metal liner, which carries the total longitudinal load and a substantial circumferential
load; and either

a composite overwrap formed by layers of continuous fibres in a matrix; or

wire reinforcement.

An optional exterior coating to provide external protection. When this is an integral part of the
design it shall be permanent.
1) 1 bar = 10 Pa = 0,1 MPa.
The cylinder can also include additional parts such as rings, bases, etc.
4.1.2 Cylinders shall be designed with one or two openings along the central axis only.
4.2 Liner
4.2.1 Liner materials
The liners shall be manufactured in accordance with the relevant sections of the following European
standards:
a) seamless steel liners: EN 1964-1 or prEN 1964-2 as appropriate;
b) seamless stainless steel liners: EN 1964-3;
c) seamless aluminium alloy liners: EN 1975;
d) steel tubes (i.e. >150 l): EN ISO 11120.
The relevant sections are: materials, thermal treatments, neck design, construction and workmanship,
mechanical tests.
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 or aluminium
alloy the relevant sections of the appropriate standard also apply.
The liner material shall be compatible with the gases intended to be used as determined by
EN ISO 11114-1.
4.2.2 Design drawing
A fully dimensioned drawing of the liner shall be supplied which includes the specification of the
material and material properties. The following material properties shall be specified:

minimum yield stress;

minimum tensile strength;

minimum elongation;

minimum burst pressure;

compatibility with the contained gas as determined by EN ISO 11114-1.
4.2.3 Design of ends (heads and bases)
The design of the ends shall be in accordance with the general requirements of the relevant cylinder
standard (as identified in 4.2.1). In order to achieve satisfactory stress distribution, the liner wall
thickness shall increase progressively in the transition zone between the cylindrical shell and the
ends, particularly the base.
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 No 12
(see 5.2.12) and Test No 13 (see 5.2.13).
4.2.4 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 material.
4.3 Composite overwrap
4.3.1 Materials
Material requirements for the fibre and the matrix, and for the wire where appropriate, shall be as
specified by the cylinder manufacturer.
4.3.2 Winding
Appropriate procedures shall be defined for the winding and curing process to ensure good
repeatability and traceability.
The following parameters shall be defined and monitored:

percentages of the components of the matrix system and their batch numbers;

the batch numbers of the fibres or wire used;

the number of strands used;

the winding tension per strand or wire, (if applicable);

the winding speed(s);

the winding angle and/or pitch for each layer;

resin bath temperature range, (if applicable);

the number of layers;

the procedure used to obtain correct impregnation (e.g. wet winding or pre-impregnation);

the polymerisation cycle;

the polymerisation process (e.g., thermal cycle, 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 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 also include tolerances on all dimensions, including out-of-roundness,
straightness, weight and water capacity.
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 test pressure, autofrettage pressure (if applicable) and minimum burst pressure for the design
shall be specified. The minimum burst pressure shall be at least 1,67  test pressure (p ).
h
Any special characteristics or special limitations (e.g. design life, underwater suitability and/or
maximum fitting torque restrictions) shall also be stated.
4.4.2 Autofrettage
Internal pressurisation 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.
During the autofrettage operation, the following parameters shall be recorded:

autofrettage pressure;

length of application of this pressure.
If autofrettage is performed, a check shall be made that the procedure has been effectively performed on
all cylinders (e.g. through measurement of autofrettage expansions or other equivalent methods).
4.4.3 Manufacturing requirements for the finished cylinder
The internal and external surfaces of the finished cylinder shall be free of defects which could
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).
5 Cylinder and material tests
5.1 General
This clause describes tests to be conducted on seamless, hoop-wrapped composite cylinders,
cylinder liners and the materials used in manufacture of cylinders for prototype testing of new cylinder
designs, design variant testing and batch acceptance tests. The tests listed may be required or
optional, as identified in the schedule of testing and inspections in annex A.
No tests shall be performed with a removable protective sleeve fitted to the cylinder.
5.2 Test procedures and test requirements
5.2.1 Test No 1 - Composite material tests
Procedure:
Tests on the composite materials to establish their mechanical properties shall be carried out
in accordance with the following procedures:
a) Tensile properties of fibres:
For glass, aramid: - ASTM D 2290-92 and ASTM 2291-83;
- ASTM D 2343-95;
For carbon: - ASTM D 4018-93.
b) Tensile properties of wires: - EN 10002-1
Equivalent tests in accordance with alternative standards or test specifications acceptable to
the inspection body may be applied.
Criteria:
The mechanical properties shall meet the minimum requirements for the design as specified by
the manufacturer.
5.2.2 Test No 2 - Liner material tests
Procedure:
Tests on the liner material shall be carried out following the test procedures of the appropriate
standards as follows:
a) Seamless steel - as described in EN 1964-1, prEN 1964-2, or EN ISO 11120, as appropriate;
b) Seamless stainless steel - as described in EN 1964-3;
c) Seamless aluminium - as described in EN 1975.
Criteria:
The material properties shall meet the minimum requirements for the design as specified by the
manufacturer.
5.2.3 Test No 3 - Liner burst test at ambient temperature
Procedure:
The hydraulic burst test shall be carried out using a test rig, which allows pressure to be
increased at a controlled rate.
The test shall be carried out in ambient conditions and the temperature on the external
surface of the liner shall be maintained at less than 50 °C. The rate of pressurization shall not
exceed 10 bar/s and the duration of the test shall be at least 40 s.
The cylinder shall be pressurized at a controlled rate until failure. The pressure against time
curve or pressure against volume curve shall be plotted.
The maximum pressure achieved during the test shall be recorded as the burst pressure.
Criteria:

burst pressure of the liner (p ) shall be greater than or equal to 0,85 times test pressure (p ) and
bl h
to the minimum specified in 4.2.2;

burst initiation shall be in the cylindrical part and the liner shall remain in one piece.
Parameters to monitor and record:

burst pressure;

the number of pieces;

description of failure;

pressure/time curve or pressure/volume curve.
5.2.4 Test No 4 - Hydraulic (proof) test of finished cylinders at ambient temperature
Procedure:
Where cylinders are subjected to autofrettage the hydraulic proof pressure test may
immediately follow or be part of the autofrettage operation.
The water pressure in the cylinder shall increase at a controlled rate until the test pressure
(p ) is reached. The cylinder shall remain at the test pressure (p ) for at least 30 s.
h h
3%
The limit deviation on attaining test pressure shall be test pressure (p ).
h
Criteria:

pressure shall remain steady;

there shall be no leaks;

after the test the cylinder shall show no visible permanent deformation.
Parameters to monitor during the test:

pressure.
5.2.5 Test No 5 – Cylinder burst test at ambient temperature
Procedure:
The hydraulic pressure burst test shall be carried out using a test rig, which allows pressure to
be increased at a controlled rate.
The test shall be carried out in ambient conditions and the temperature on the external
surface of the cylinder shall be maintained at less than 50 °C. The rate of pressurisation shall
not exceed 10 bar /s and the duration of the test shall be at least 40 s.
The cylinder shall be pressurised at a controlled rate until failure. The pressure against time
curve or pressure against volume curve shall be plotted.
The maximum pressure achieved during the test shall be recorded as the burst pressure.
Criteria:

burst pressure shall be greater than or equal to the manufacturer's minimum specified design
burst pressure and 1,67  test pressure (p  1,67 p );
b h

burst initiation shall be by longitudinal failure in the cylindrical part and the liner shall remain in
one piece.
Parameters to monitor and record:

burst pressure;

the number of pieces;

description of failure;

pressure/time curve or pressure/volume curve.
5.2.6 Test No 6 - Resistance to pressure cycles at test pressure (p ) and ambient temperature
h
a) For non-limited life
Procedure:
The cycle test shall be carried out using a test rig, which allows pressure to be increased and
decreased at a controlled rate and automatically suspend the test when the cylinder has
failed, either by leakage or rupture.
The test shall be carried out with a non-corrosive liquid subjecting the cylinder to successive
reversals at an upper cyclic pressure equal to the hydraulic test pressure (p ). The value of
h
the lower cyclic pressure shall not exceed 10 % of the upper cyclic pressure and shall have
an absolute maximum of 30 bar.
The cylinder shall actually experience the maximum and minimum cyclic pressures during this
test.
The cycle tests shall be carried out in ambient conditions and the temperature on the outside
surface of the cylinder shall not exceed 50 °C during the test. The frequency of reversals of
pressure shall not exceed 0,25 Hz (15 cycles per minute).
The temperature of the external surface of the cylinder shall be monitored at least twice a
day.
The number of cycles achieved during the test shall be recorded.
After completion of this test the cylinder shall then be destroyed (e.g. by bursting), or made
incapable of holding pressure.
Criteria:

the cylinder shall withstand 12 000 cycles to test pressure (p ) without failure by burst or leakage.
h
Parameters to monitor and record:

the temperature of the cylinder;

number of cycles achieving upper cyclic pressure;

minimum and maximum cyclic pressures;

cycle frequency;

test medium used;

mode of failure, if appropriate.
b) For limited life:
Procedure:
This test shall be conducted in accordance with the procedure as described in a) above and
shall consist of two parts run sequentially and continuously. Different criteria apply to the two
parts, as shown in Figure 1.
After completion of this test the cylinder shall then be destroyed (e.g. by bursting), or made
incapable of holding pressure.
Criteria:

the cylinder shall first withstand N cycles to test pressure (p ) without failure by burst or leakage,
h
where:
N = y  250
where
y is the number of years of design service life, and shall be a whole
number greater than 10;
N cycles, or until failure by leakage whichever is the sooner. In

the test shall continue for a further
either case the cylinder shall be deemed to have passed the test. However should failure during
this second half of the test be by burst, then the cylinder shall have failed Test No. 6.
st nd
1 part 2 part
Number of cycles 0 ‹---------------------------›NN ‹-------------------------›2N
Criteria No leakage/burst = Pass
No leakage or burst Leakage = Pass
st
Pass 1 part Burst = Fail
Figure 1 — Criteria for Test No 6
Parameters to monitor and record:

the temperature of the cylinder;

number of cycles, achieving upper cyclic pressure;

minimum and maximum cyclic pressures;

cycle frequency;

test medium used;

mode of failure, if appropriate.
5.2.7 Test No 7 - Immersion in salt water
This test is required for all cylinder designs intended for diving and is optional for other applications.
Procedure:
The cylinder shall be finished as for the intended application and without external coating
unless this is an integral part of the design.
Two closed cylinders shall be immersed in an aqueous solution containing 35 g/l of sodium
chloride at (20 ± 5) °C for 90 days continuously.
The cylinders shall be immersed:

for 45 days at not less than 2/3 test pressure (p );
h

for 45 days without pressure.
The pressure shall be recorded at least at the beginning of the test and after 45 days, prior to
de-pressurisation.
Then, following the 90 day immersion:

one of the two cylinders shall be subjected to Test No 5 (see 5.2.5);

the other cylinder shall be subjected to Test No 6 (see 5.2.6);
After completion of Test No.6, the cylinder shall then be destroyed (e.g. by bursting), or made
incapable of holding pressure.
Criteria:

for the first cylinder, burst pressure shall be greater than or equal to 1,67  test pressure (p  1,67
b
p ), burst initiation shall be by longitudinal failure in the cylindrical part and the liner shall remain
h
in one piece;

for the second cylinder, criteria shall be as for Test No. 6 (see 5.2.6), as appropriate for the
design life.
Parameters to monitor and record:

the temperature of the solution, at least twice a day;

filling pressure;

duration of immersion;

parameters specified in Test No 5 (see 5.2.5);

parameters specified in Test No 6 (see 5.2.6).
5.2.8 Test No 8 - Exposure to elevated temperature at test pressure
This test is not required for cylinders wound with wire.
Procedure:
For a design service life of up to 20 years, one cylinder shall be hydraulically pressurised to
test pressure (p ), and shall be maintained at this pressure for 1 000 h.
h
For a design service life of greater than 20 years, including non-limited life, the test shall run for
2 000 h.
The test shall be conducted at (70 ± 5) C and a relative humidity of less than 50 %. After this
test, the cylinder shall be subjected to Test No 5 (see 5.2.5).
Criteria:

burst pressure shall be greater than or equal to 1,67  test pressure (p  1,67 p ), burst initiation
b h
shall be by longitudinal failure in the cylindrical part and the liner shall remain in one piece;
Parameters to monitor and record:

measurement of the water capacity before and after test;

temperature and relative humidity, at least twice a day;

cylinder pressure at least twice a day;

parameters specified in Test No 5 (see 5.2.5).
5.2.9 Test No 9 - Extreme temperature cycle test
a) Pressure cycling stages
Procedure:
The cylinder and the contained pressurising medium shall be conditioned for 48 h at
atmospheric pressure, at between 60 °C and 70 °C and at a relative humidity greater than or
equal to 95 %.
The hydraulic pressurising medium, located in the circuit external to the cylinder under test,
shall commence the cycle testing at ambient temperature. 5 000 cycles shall be applied from a
pressure approximately equal to atmospheric pressure to two-thirds of the test pressure (p ).
h
The cycle testing procedure shall be in accordance with Test No 6 (see 5.2.6) but with the
exception that the extreme temperature cycle test has temperature and humidity conditions as
specified in this clause. The rate of pressure cycles for this test shall not exceed 0,08 Hz
(5 cycles per minute) to enable the temperature conditions to be maintained.
On completion of these cycles the pressure shall be released and the cylinder stabilised at
ambient conditions.
The temperature shall then be reduced and the cylinder and the contained pressurising
medium stabilised at a temperature between minus 50 °C and minus 60 °C. The environmental
chamber shall be maintained at the specified conditions by regulating the temperature. The
cylinder skin temperature shall be measured and recorded.
The hydraulic pressurising medium, located in the circuit external to the cylinder under test,
shall commence the second stage of cycle testing at ambient temperature. 5 000 cycles shall
be applied from a pressure approximately equal to atmospheric pressure to two-thirds of the
test pressure (p ).
h
On completion of these cycles the pressure shall be released and the cylinder stabilised at
ambient conditions. 30 cycles shall then be applied from a pressure approximately equal to
atmospheric pressure to test pressure (p ).
h
Parameters to monitor and record:

temperatures during each part;
st

humidity during 1 part of test;

test medium used;

number of cycles, achieving upper cyclic pressure, at each stage;

minimum and maximum cyclic pressures;

cycle frequency.
b) Concluding burst test
The cylinder shall be subjected to Test No 5 (see 5.2.5).
Criteria:

burst pressure shall be greater than or equal to 1,4  test pressure (p  1,4 p )
b h
Parameters to monitor and record:

burst pressure;

description of failure.
5.2.10 Test No 10 - Fire resistance test
This test is required for cylinders when a pressure relief device is fitted to prevent failure in a fire
during service and is otherwise optional.
Procedure:
Two cylinders shall undergo this test;

one in a horizontal position;

one in a vertical position.
The cylinders shall be fitted either:
a) with a valve with the type of pressure relief device intended for service (e.g. fusible plug or
bursting disc); or
b) with a valve fitted with a bursting disc set to operate at between test pressure (p ) and 1,15 p
h h.
If the valve in a) is fitted with a fusible plug this shall operate at a minimum temperature of
100 °C.
The cylinders shall be pressurized with either air or nitrogen to 2/3  test pressure (p ).
h
A suitable fire shall be created with either wood or kerosene. Examples of standards that
contain directions to produce a suitable fire test are EN ISO 11439, CGA C14:1992 and
EN 3-1.
One cylinder shall be placed in the horizontal position with the lowest part of the cylinder
approximately 0,1 m from the top of the firewood or 0,1 m from the surface of the liquid. The
fire shall be capable of enveloping the entire length of the cylinder and valve, but in no case
shall the flames be allowed to impinge directly on to the pressure relief device.
The second cylinder shall be placed in an upright position (valve uppermost), with the lowest
part of the cylinder approximately 0,1 m from the top of the firewood or at the surface of the
liquid. The cylinder shall be exposed to total fire engulfment, but in no case shall the flames
be allowed to impinge directly on to the pressure relief device.
If the cylinder is too long to enable the fire to envelop the entire length of the cylinder when in
the vertical position, and the cylinder does not have pressure relief devices at both ends, the
vertical bonfire test may be replaced by a second test in the horizontal position.
The test is considered complete when all the gas inside the cylinder has vented completely or
when a period of two minutes has elapsed.
After completion of this test the cylinders shall then be destroyed (e.g. by bursting), or made
incapable of holding pressure.
Criteria:
The cylinders shall not burst during a period of 2 min from the start of the fire test. They may
vent through the pressure relief device or leak through the cylinder wall or other surfaces.
Parameters to monitor and record:

type and characteristics of pressure relief device;

initial pressure;

time;

mode of pressure release, if appropriate.
5.2.11 Test No 11 - High velocity impact (bullet) test
This test is optional (e.g. for military applications).
Procedure:
For cylinders with diameter above 120 mm a cylinder pressurized with air or nitrogen to
2/3  test pressure (p ) shall be impacted by a 7,62 mm (0,3 calibre) armour-piercing
h
projectile of nominal length 51 mm and having a velocity of approximately 850 m/s. The
cylinder shall be positioned in such a way that the point of impact of the projectile shall be in
the sidewall (i.e. the area with circumferential winding) and shot at an angle of approximately
45 to the centre line of the cylinder, so that it would exit through the cylinder sidewall. The
distance from firing location to test cylinder shall not exceed 45 m.
For cylinders with a diameter of 120 mm and below, a 5,6 mm (0,22 calibre) projectile of
13,6 mm nominal length may be used.
Criteria:

the tested cylinder shall reveal no evidence of a fragmentation failure, whether or not the bullet
penetrates the cylinder.
Parameters to monitor and record:

type of projectile;

initial pressure;

description of failure;

approximate size of the entrance and exit openings.
5.2.12 Test No 12 - Torque test
Procedure:
The cylinder threads shall show no permanent expansion or deformation when mated with a
corresponding valve or plug and tightened to 110 % of the maximum torque specified and to
the procedure specified in EN ISO 13341, or as recommended in the manufacturer’s
specification where this standard does not apply. The internal neck thread shall be checked
using gauges corresponding to the agreed neck thread to ensure that it is within tolerance.
NOTE For example, where the neck thread is specified to be in accordance with EN 629-1, the
corresponding gauges are specified in EN 629-2.
Criteria:

the threads shall remain within gauge tolerance.
Parameters to monitor and record:

type of valve/plug material;

valving procedure;

applied torque.
Where the torque recommended by the manufacturer differs from that specified in EN ISO 13341, this
shall be recorded on the label (see clause 7).
5.2.13 Test No 13 - Neck strength
Procedure:
The neck of the cylinder shall show no significant deformation and shall remain within the
drawing tolerance when mated with a corresponding valve or plug and tightened to 150 % of
the torque specified and to the procedures specified in EN ISO 13341, or as recommended in
the manufacturer’s specification where this standard does not apply.
Criteria:

the neck shall show no significant deformation.
Parameters to monitor and record:

type of valve/plug material;

valving procedure;

applied torque.
Where the torque recommended by the manufacturer differs from that specified in EN ISO 13341, this
shall be recorded on the label (see clause 7).
5.2.14 Test No 14 - Cylinder stability
For a cylinder designed to stand on its base, the variation from vertical shall be less than 1 % of its
height, and the outer diameter of the surface in contact with the ground shall be greater than 75 % of
the nominal outside diameter.
5.2.15 Test No 15 - Neck ring
When a neck ring is fitted, the manufacturer shall ensure that the axial load required to remove the
neck ring is greater than 10  the weight of the empty cylinder and not less than 1 000 N. The
minimum torque to turn the neck ring shall be greater than 100 Nm.
5.3 Failure to meet test requirements
5.3.1 Liner
Where the mechanical properties of the liner have not met the specification requirements, they may
be treated in accordance with the appropriate clauses of the relevant standard, as listed in 4.2.1.
5.3.2 Complete cylinder
For complete cylinders the following procedure may be used for prototype testing, design variant
testing and production testing.
In the event of failure to meet test requirements, re-testing shall be carried out, as follows:

if there is evidence of a fault in carrying out a test, or an error of measurement, a second test
shall be performed on the same cylinder if possible. If the results of this test are satisfactory, the
first test shall be ignored;

if the test has been carried out in a satisfactory manner, the cause of test failure shall be
identified or the batch(es) shall be rendered unserviceable for the intended purpose. If the cause
of failure is identified the defective cylinders may be reclaimed by an approved method or shall be
rendered unserviceable for the intended purpose. If reclaimed, these acceptable cylinders along
with the original satisfactory cylinders shall be considered a new batch and the prototype testing
and/or batch test shall be performed again. If any test or part of a test is unsatisfactory, all the
cylinders of the batch or batches covered by the test shall be rendered unserviceable for the
intended application.
6 Conformity evaluation
Prototype testing, design variant testing and production testing shall be carried out in accordance with
annex A.
7 Marking
The permanent markings, including the stamping, shall be in accordance with EN 1089-1.
Specific additional information shall be included on the label as follows:

where a cylinder is approved with a specific pressure relief device, intended to prevent failure in
the case of fire (Test No 10, see 5.2.10), this requirement shall be stated and the type of device
shall be identified on the label;

where the fitting torque for the valve does not correspond to the values given in EN ISO 13341,
the manufacturer’s recommendation shall be shown on the label;

where the cylinder has been approved for special applications this shall be shown on the label
e.g. underwater.
Annex A
(normative)
Prototype testing, design variant testing and production testing
A.1 General
This annex describes the schedules of tests to be carried out on hoop wrapped composite cylinders
as required to verify new cylinder designs (prototype testing), to extend prototype testing to permitted
variants (design variant testing) and also to ensure compliance of a production batch of cylinders with
the design specification of the prototype cylinder design (production testing).
Testing shall be carried for each new design or design variant of cylinder (see A.2. and A.3).
A.2 Prototype testing
A.2.1 General
Prototype testing shall be carried out on each new design of cylinder.
Prototype testing shall be carried out on cylinders of identical design (i.e. materials, liner,
manufacturing process) from the same factory, equipment and the same sub-contractor, if applicable.
The tests shall be performed on cylinders having the same nominal dimensions (i.e. same diameter,
length, liner wall thickness and composite thickness).
The prototype testing is valid for cylinders having the same diameter but whose length may vary from
twice the diameter of the prototype tested cylinder to 1,5 times the length of the prototype tested
cylinder.
Shorter cylinders, i.e. those cylinders whose length is less than twice the diameter of the nominated
prototype tested cylinder, shall not be considered part of the family and shall be tested individually as
a design variant (see A.3).
A.2.2 Definition of new design
A cylinder shall be considered to be of a new design, compared with a previously prototype tested
cylinder, when any of the following conditions apply:
a) It is manufactured in a different factory. However, where a factory moves to a different location
with the same equipment, a reduced testing programme may be agreed with the inspection body;
b) It is manufactured by a significantly different process. A significant change is regarded as a
change that would have a measurable change in the performance of the liner and/or finished
cylinder. The inspection body shall determine when a change in process or design or
manufacture is significantly different from the original prototype tested design;
c) The liner is manufactured from a material of different composition or outside the composition
limits of the material used in the original prototype tested design and/or detailed in the relevant
standard, as listed in 4.2.1;
d) It is manufactured with a new fibre type.
A fibre shall be considered to be of a new fibre type when any of the following conditions apply:
1) The fibre is of a different classification, e.g. glass, aramid, carbon;
2) The fibre is produced from a different precursor (starting material) e.g. polyacrylonitrile
(PAN), pitch for carbon;
3) The nominal fibre modulus, specified by the fibre manufacturer, differs by more than ± 5 %
from that defined in the prototype tested design;
4) The nominal fibre strength, specified by the fibre manufacturer, differs by more than ± 5 %
from that defined in the prototype tested design;
e) It is manufactured using different matrix materials e.g. resin, curing agent, accelerator (see Note 1);
f) The hydraulic test pressure has been increased by more than 60 % (see Note 2);
g) The nominal cylinder diameter has changed by more than 50 %;
h) The nominal autofrettage pressure has changed by more than 5 %.
NOTE 1 Where a new matrix material 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 matrix system
without the need for any additional prototype testing.
NOTE 2 A cylinder can be used and marked for a lower test pressure than stated in the original prototype
testing without additional testing.
A.2.3 Prototype testing requirements
The applicant for prototype testing shall, for each new design of cylinder, submit the documentation
necessary for the checks specified below. The applicant shall make available to the inspection body a
batch of at least 50 cylinders from which the number of cylinders required for the tests referred to
below will be ta
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