SIST EN 13322-2:2003

SLOVENSKI STANDARD
01-december-2003
3UHPLþQHSOLQVNHMHNOHQNH3RQRYQRSROQOMLYHMHNOHQNH1DþUWRYDQMHLQL]GHODYD
GHO-HNOHQNHL]QHUMDYQHJDMHNOD
Transportable gas cylinders - Reffilable welded steel gas cylinders - Design and
construction - Part 2: Stainless steel
Ortsbewegliche Gasflaschen - Wiederbefüllbare geschweißte Flaschen aus Stahl -
Gestaltung und Konstruktion - Teil 2: Flaschen aus nichtrostendem Stahl
Bouteilles a gaz transportables - Bouteilles a gaz rechargeables soudées en acier -
Conception et construction - Partie 2: Acier inoxydable
Ta slovenski standard je istoveten z: EN 13322-2:2003
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 13322-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2003
ICS 23.020.30
English version
Transportable gas cylinders - Reffilable welded steel gas
cylinders - Design and construction - Part 2: Stainless steel
Bouteilles à gaz transportables - Bouteilles à gaz Ortsbewegliche Gasflaschen - Wiederbefüllbare
rechargeables soudées en acier - Conception et geschweißte Flaschen aus Stahl - Gestaltung und
construction - Partie 2: Acier inoxydable Konstruktion - Teil 2: Flaschen aus nichtrostendem Stahl
This European Standard was approved by CEN on 28 November 2002.
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,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovak Republic, 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
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13322-2:2003 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 Materials and heat treatment .8
5 Design .9
6 Construction and workmanship.13
7 New design tests.16
8 Batch tests.18
9 Tests on every cylinder .27
10 Failure to meet test requirements .28
11 Records.28
12 Marking .28
Annex A (normative)  Radiographic examination of welds .29
Annex B (normative)  Description, evaluation of manufacturing defects and conditions for rejection of
welded stainless steel gas cylinders at time of visual inspection.32
Annex C (informative)  Examples of design and batch testing certificates .35
Annex D (informative)  Guidance on the relationship between conformity assessment modules and
clauses of this standard.42
Bibliography .48
Foreword
This document (EN 13322-2:2003) 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 September 2003, and conflicting national standards shall be withdrawn at the
latest by September 2003.
This European Standard has been submitted for reference into the RID and/or in 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 in the technical annexes of the ADR.
For relationships with EC directives, RID and ADR see informative annex D, which is an integral part of this
document.
This standard is one of a series of two standards concerning refillable welded steel gas cylinders of water
capacities from 0,5 l up to and including 150 l for compressed, liquefied and dissolved gases:
Part 1: Carbon steel
Part 2: Stainless steel
Annexes A and B are normative. Annexes C and D are 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, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovak Republic, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
The purpose of this European Standard is to provide a specification for the design, manufacture, and testing of
refillable, transportable, welded stainless steel gas 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.
This standard is based on the traditional calculation method. It does not cover other methods such as finite element
analysis (F.E.A.) methods or experimental methods.
1 Scope
This European Standard specifies minimum requirements concerning material, design, construction and
workmanship, manufacturing processes and testing of refillable transportable welded stainless steel gas cylinders
of water capacities from 0,5 l up to and including 150 l for compressed, liquefied and dissolved gases. This
standard is only applicable to cylinders manufactured from stainless steels having a maximum tensile strength of
less than 1 100 MPa.
For acetylene service, additional requirements for the cylinder and the basic requirements for the porous mass are
given in EN 1800.
This standard is primarily for industrial gases other than LPG but may also be applied for LPG.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text, and 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 287-1, Approval testing of welders - Fusion welding - Part 1: Steels.
EN 288-1, Specification and qualification of welding procedures for metallic materials - Part 1: General rules for fusion
welding.
EN 288-3, Specification and approval of welding procedures for metallic materials - Part 3: Welding procedure tests for
the arc welding of steels.
EN 473, Non destructive testing - Qualification and certification of NDT personnel - General principles.
EN 962, Transportable gas cylinders - Valve protection caps and valve guards for industrial and medical gas cylinders -
Design, construction and tests.
EN 970, Non-destructive examination of fusion welds - Visual examination.
EN 1089-1, Transportable gas cylinders - Gas cylinder identification (excluding LPG) - Part 1: Stampmarking.
EN 1435, Non-destructive examination of welds - Radiographic examination of welded joints.
EN 1800, Transportable gas cylinders - Acetylene cylinders - Basic requirements and definitions.
EN 1968, Transportable gas cylinders - Periodic inspection and testing of seamless steel gas cylinders.
EN 10002-1, Metallic materials - Tensile testing - Part 1: Method of test at ambient temperature.
EN 10028-7, Flat products made of steels for pressure purposes - Part 7: Stainless steels.
EN 10045-1, Metallic materials - Charpy impact test - Part 1: Test method.
EN 10088-1, Stainless steels - Part 1: List of stainless steels.
EN 10088-2, Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip for general purposes.
EN 12517, Non-destructive examination of welds - Radiographic examination of welded joints - Acceptance levels.
EN 13445-2, Unfired pressure vessels - Part 2: Materials.
EN 25817, Arc-welded joints in steel - Guidance on quality levels for imperfections (ISO 5817:1992).
EN ISO 3651-2, Determination of resistance to intergranular corrosion of stainless steels - Part 2: Ferritic, austenitic
and ferritic-austenitic (duplex) stainless steels - Corrosion test in media containing sulfuric acid (ISO 3651-2:1998).
EN ISO 6506-1, Metallic materials - Brinell hardness test - Part 1: Test method (ISO 6506-1:1999).
EN ISO 11114-1, Transportable gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 1:
Metallic materials (ISO 11114-1:1997).
3 Terms, definitions and symbols
For the purpose of this standard, the following terms, definitions and symbols apply:
3.1 Terms and definitions
3.1.1
yield stress
value corresponding to the 0,2 % proof stress (R ), or, for austenitic steels in the solution annealed condition,
p0,2
1 % proof stress (R )
p1,0
3.1.2
solution annealing
softening heat treatment for austenitic steels in which a cylinder is heated to a uniform temperature above the
upper critical point (AC , as defined in EN 10052) of the steel followed by rapid cooling
3.1.3
cryoforming
process where the cylinder is subjected to a controlled low temperature deformation treatment that results in a
permanent increase in strength
3.1.4
cold working
plastic deformation treatment given to sheet material at ambient temperature, with the aim of permanently
increasing the material strength
3.1.5
coldforming
final deformation treatment at ambient temperature given to the prefabricated cylinder, known as the preform,
which results in a permanent increase in the material strength
3.1.6
batch
quantity of finished cylinders made consecutively during the same or consecutive days to the same design, size
and material specifications and from the same material supplier for each pressure containing part on the same
automatic welding machines and, if applicable, heat-treated under the same conditions of temperature and duration
NOTE This definition allows different suppliers to be used for the different pressure containing parts within a batch, e.g.
one supplier for heads, another for bases.
3.1.7
design stress factor (F)
ratio of equivalent wall stress at test pressure (p ) to guaranteed minimum yield stress (R )
h e
3.2 Symbols
a Calculated minimum thickness, in millimetres, of the cylindrical shell
a' Guaranteed minimum thickness, in millimetres, of the cylindrical shell (including any corrosion allowance,
see 7.1)
a Calculated value of a used in the calculation of b (see 5.3.2)
a Mean wall thickness, in millimetres, of the cylindrical shell of the cylinder preform
m
A Percentage elongation after fracture
b Calculated minimum thickness, in millimetres, of the cylinder end
b' Guaranteed minimum thickness, in millimetres, of the cylinder end (including corrosion allowance, see 7.1)
C Shape factor of dished ends
D Outside diameter, in millimetres, of the cylinder (see Figure 1)
D Diameter of former in millimetres (see Figure 10),
f
D Mean diameter of the cylindrical shell of a cylinder preform, in millimetres
m,
F Design stress factor (see 3.1.7)
f Cryoforming factor established by the manufacturer for each batch of cylinders
c
h Height, in millimetres, of the cylindrical part of the end (see Figure 1)
H Outside height, in millimetres, of the domed part of the end (see Figure 1)
J Stress reduction factor (see annex A)
L Length, in millimetres, of the cylinder
n Ratio of diameter of bend test former (D ) to the thickness of the test piece (t)
f
p Measured burst pressure, in bar , above atmospheric pressure, in the burst test
b
1)
p Cryoforming or coldforming pressure in bar , above atmospheric pressure
c
p Hydraulic test pressure, in bar , above atmospheric pressure
h
p Observed yield pressure, in bar , above atmospheric pressure
y
r Inside radius of the knuckle end, in millimetres (see Figure 1)
R Inside radius of the dished end, in millimetres (see Figure 1)
R Yield stress, in megapascals, as defined in 3.1.1 and used for design calculation
e
R Value of the actual yield stress in megapascals determined by the tensile test
ea
1 bar = 10 Pa = 0,1 MPa
R Minimum value of 0,2 % proof stress in megapascals, guaranteed by the cylinder manufacturer for the
p0,2
finished cylinder, in accordance with EN 10002-1. (See Note)
R Minimum value of 1,0 % proof stress in megapascals, guaranteed by the cylinder manufacturer for the
p1,0
finished cylinder, in accordance with EN 10002-1. (See Note)
R Minimum value of tensile strength, in megapascals, guaranteed by the cylinder manufacturer for the finished
g
cylinder
R Actual value of tensile strength, in megapascals, determined by tensile test (see 8.4)
m
t Actual thickness of the test specimen, in millimetres (see Figure 7)
NOTE For cryoformed and coldformed cylinders the minimum value guaranteed by the manufacturer refers only to the
cylindrical part of the finished cylinder.
4 Materials and heat treatment
4.1 General
4.1.1 Materials of shells and end pressings shall be stainless steels in a condition suitable for pressing or
drawing and welding and shall conform to EN 10088-1 or EN 10028-7.
4.1.2 Grades of steel used for the cylinder manufacture shall be compatible with the intended gas service (e.g.
corrosive gases, embrittling gases) in accordance with EN ISO 11114-1.
4.1.3 There is a risk of sensitisation to intergranular corrosion resulting from the hot processing of austenitic and
duplex stainless steels. An intergranular corrosion test in accordance with 7.3.3 shall be carried out on such
stainless steels when intended to be used for corrosive applications. Corrosive gases are listed in EN 1968, and
cylinders for such gases shall be stamp marked "HG" as specified in EN 1089-1.
4.1.4 The manufacturer shall be able to guarantee cylinder steel casting traceability for each cylinder.
4.1.5 All parts welded to the cylinder shall be made of compatible material with respect to the weldability.
4.1.6 The cylinder manufacturer shall obtain and provide certificates of the ladle analysis of the steel supplied for
the construction of the pressure retaining parts of the cylinder and for the welding consumables.
4.1.7 Some grades of stainless steel may be susceptible to environmental stress corrosion cracking. Special
precautions shall be taken in such cases.
4.1.8 The welding consumables shall be such that they are capable of giving consistent welds with minimum
tensile strengths at least equal to that specified for the parent materials (R ) in the finished cylinder.
g
4.1.9 Cylinders for acetylene service shall be manufactured with materials compatible with the manufacturing
process of the porous mass, or an internal coating shall be applied.
4.2 Categories
The following four broad categories of stainless steels are recognised:
ferritic;
martensitic;
austenitic;
ferritic/austenitic (duplex).
The steels used shall be in accordance with EN 10088-1 or EN 10028-7.
4.3 Heat treatment
4.3.1 For cylinders subjected to coldforming or cryoforming processes, heat treatment of the pre-form component
part is not required. Cold-formed or cryoformed cylinders shall not be subjected to any subsequent heat treatment
or to additional heat application, such as welding.
4.3.2 For other types of stainless steel cylinders, components used for the manufacture of pressure retaining
parts of the cylinders shall be annealed for martensitic and ferritic steels, or solution annealed for austenitic and
duplex steels.
4.3.3 The cylinder manufacturer shall obtain and provide certificates for the heat treatment of all pressure
retaining parts used for the construction of the gas cylinders.
4.4 Test requirements
The material of the finished cylinders shall satisfy the requirements of clause 7.
5 Design
5.1 General requirements
5.1.1 The calculation of the wall thickness of the pressure containing parts shall be related to the yield stress of
the parent material.
5.1.2 For calculation purposes, the value of the yield stress R is limited to a maximum of 0,85 R .
e g
5.1.3 The internal pressure upon which the calculation of gas cylinders is based shall be the test pressure p
h.
5.1.4 A fully dimensioned drawing including the specification of the material shall be produced.
5.1.5 Cylinders for acetylene service shall be designed to allow for a test pressure of at least 60 bar.
5.1.6 Cylinders for acetylene service shall be designed and manufactured to ensure that conditions are safe for
the eventual filling of the porous mass, e.g. preventing sharp edges and voids.
5.2 Calculation of cylindrical wall thickness
The wall thickness of the cylindrical shell shall not be less than that calculated using the formula:

10.F.J.R - 3.p
D
e h
a = 1-
2 10.F.J.R
e
Ł ł
0,65
where the value of F is the lesser of or 0,77.
(R / R )
e g
R /R shall not exceed 0,85.
e g
The value of J shall be selected in accordance with annex A.
The minimum wall thickness shall also satisfy the requirements of 5.4.
5.3 Design of convex ends (see Figure 1)
5.3.1 The shape of ends of gas cylinders shall be such that the following conditions are fulfilled:
for torispherical ends (see Figure 1a): R
D; r D; h b (see Figure 1a)
for ellipsoidal ends (see Figure 1b): H  D; h b (see Figure 1b)
5.3.2 The wall thickness of the ends of gas cylinders shall be not less than that calculated using the formula:
b = a · C
where
a is the value of a calculated in accordance with 5.2 using J = 1,0;
C is a shape factor, whose value shall be obtained from the graph given in Figure 2 or Figure 3.
5.3.3 For cryoformed cylinders, convex ends shall be hemispherically shaped. The shape factor C shall be
equal to 1.
The minimum 1,0 % proof stress to be achieved in the hemispherical ends shall be equal to:
R = R · (a ‚ 2b )
p p0,1 b b
a) Torispherical b) Ellipsoidal
Figure 1 — Illustration of cylinder ends
Figure 2 — Values of shape factor C for H/D between 0,2 and 0,25
Figure 3 — Values of shape factor C for H/D between 0,25 and 0,5
5.4 Minimum wall thickness
5.4.1 The minimum wall thickness of the cylindrical shell a and of the end b shall be not less than the value
derived from the appropriate one of the following formulae:
for D £ 100 mm, a = b = 1,1 mm;
for 100 mm < D £ 150 mm, a = b = 1,1 + 0,008 (D-100) mm;
for D > 150 mm,
D
a = b = + 0,7 mm, with an absolute minimum of 1,5 mm.
These formulae apply to cylindrical shells and ends irrespective of whether they are designed by calculation under
5.2 and 5.3 or by the pressure cycling test in 7.3.2.
5.4.2 Apart from the requirements of 5.3, 5.4 and 5.5 any cylindrical part integral with an end shall, except as
qualified by 5.4.3, also satisfy the requirements given in 5.2 for the cylindrical shell.
5.4.3 Where the length of the cylindrical portion of the gas cylinder, measured between the beginning of the
domed parts of the two ends, is not more than 2bD the wall thickness shall be not less than that of the domed part
(see 5.3.2).
5.5 Ends of other shapes
Ends of shapes other than those covered by 5.3 may be used provided that the adequacy of their design is
demonstrated by a pressure cycling test in accordance with 7.3.2 or by stress analysis.
5.6 Design of openings
5.6.1 The location of all openings shall be restricted to the end(s) of cylinder.
5.6.2 Each opening in the cylinder shall be reinforced, either by a valve boss or pad, of weldable and compatible
steel, securely attached by welding and so designed as to be of adequate strength and to result in no harmful
stress concentrations. This shall be confirmed by design calculations or a pressure cycling test in accordance with
7.3.2.
5.6.3 The welds of the openings shall be separated from longitudinal and circumferential joints by a distance not
less than 3a.
6 Construction and workmanship
6.1 General
The cylinder or cylinder preform shall be produced either by:
using seamless or longitudinally welded tube with forged ends being circumferentially welded; or
using longitudinally welded tube with spun ends; or
using a seamless tube, followed by hot forming where the base is sealed with added weld metal; or
using coldworked tube or plate; or
using welded deep drawn parts; or
using coldforming or cryoforming of welded cylinder pre-forms.
6.2 Welding procedures
Each manufacturer, before proceeding with the production of a given design of cylinder, shall qualify all welding
procedures to EN 288-1 and EN 288-3 and welders to EN 287-1. Records of such qualification shall be kept on file
by the manufacturer.
6.3 Cryoforming procedure
6.3.1 Cryoforming as defined in 3.1.3 is a method to increase the mechanical properties especially of metastable
austenitic steels by applying a high internal pressure to the vessel preform at cryogenic temperatures.
The relevant process parameters are the cryoforming pressure p and the cryoforming temperature.
c
The design of the finished cylinder shall be in accordance with clause 5.
6.3.2 The cryoforming operation shall be carried out at a cryoforming pressure p , which shall be calculated
c
according to:
f · R · 20 · a
c p1,0 m
p =
c
D
m
f depends on the cryoforming temperature, the cast analysis for each batch of cylinders and the yield strength to
c
be achieved and shall be established by the manufacturer so that the finished cylinders satisfy the requirements as
specified in clauses 5 and 7. Between batches of one design of cylinder (as defined in 7.3.1), f shall not vary by
c
more than ± 10 %.
6.3.3 For each cryoformed cylinder, the manufacturer shall record a pressure-time diagram of the cryoforming
process where the rate of pressure increase, the achieved cryoform pressure and the holding time are shown. The
rate of pressure increase shall not be more and the holding time shall not be less than that established during the
design testing for the cylinder.
6.3.4 The maximum permanent deformation of the vessel’s perimeter due to the cryoforming shall be no more
than 15 %.
6.3.5 The cryoforming temperature shall remain constant during the process (e.g. by submerging the cylinder
preform in a suitable cryogenic liquid), and shall be established during the design test.
6.4 Welded joints of pressure containing parts
6.4.1 The longitudinal joint, of which there shall be not more than one, shall be butt-welded.
6.4.2 Circumferential joints of which there shall be no more than two in the cylindrical part, shall be butt-welded
in all cases for cryoformed cylinders and for all cylinders used in corrosive gas applications.
6.4.3 For acetylene service, the joints shall be designed in such a way as to eliminate the risk of damaging the
porous mass.
6.5 Non-pressure-containing attachments
6.5.1 Parts which are not submitted to pressure, such as footrings, handles and neckrings shall be made of steel
compatible with that of the cylinder.
6.5.2 Each attachment shall be designed to permit inspection of the attachment welds, shall be clear of
longitudinal and circumferential joints, and so designed as to avoid trapping water.
6.5.3 A footring or other support shall be fitted to the cylinder when required to provide stability, and attached so
as to permit inspection of the bottom circumferential weld. Permanently attached footrings shall be drained and the
space enclosed by the footring shall be ventilated.
6.5.4 In case of cylinders subjected to a cold-forming or cryoforming process, the non-pressure retaining
attachments shall be welded to the cylinder preform before cold-forming or cryoforming.
6.6 Valve protection
6.6.1 Valves of cylinders of more than 5 litre water capacity shall be protected from damage which could cause
release of gas, either by the design of the cylinder (e.g. protective shroud) or by a valve protection device (in
accordance with EN 962).
6.6.2 When a protective shroud is used, it shall fulfil the requirements of the drop test as described in EN 962.
6.6.3 The requirements of 6.6.1 and 6.6.2 may be waived when the cylinders are intended to be conveyed in
bundles or cradles, or when some other effective valve protection is provided.
6.7 Neck threads
The internal neck threads shall conform to a recognized standard to permit the use of a corresponding valve thus
minimizing neck stresses following the valve torquing operation. Internal neck threads shall be checked using
gauges corresponding to the agreed neck thread, or by an alternative method. Particular care shall be taken to
ensure that neck threads are accurately cut, are of full form and free from any sharp profiles, e.g. burrs.
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.
6.8 Visual examination
6.8.1 Unacceptable defects
Before assembly, the pressure envelope parts of the cylinder shall be examined for uniform quality and freedom
from unacceptable defects, examples of which are given in annex B.
6.8.2 Welds
6.8.2.1 Before the cylinders are closed, longitudinal welds shall be visually examined from both sides.
Permanent backing strips shall not be used with longitudinal welds.
6.8.2.2 All welds shall have a smooth finish without concavity and shall merge into the parent material without
under-cutting or abrupt irregularity.
6.8.2.3 All welds shall have full penetration.
6.8.2.4 Radiographic examination, radioscopic examination, or NDT examination carried out using another
suitable method, shall be as specified in annex A.
6.8.3 Out of roundness
The out-of-roundness of the cylindrical shell shall be limited so that the difference between the maximum and the
minimum outside diameter in the same cross-section is not more than 2 % of the mean of these diameters.
6.8.4 Straightness
Unless otherwise specified on the manufacturing drawing, the maximum deviation of the cylindrical part of the shell
from a straight line shall not exceed 0,3 % of the cylindrical length.
6.8.5 Verticality
When the cylinder is standing on its base, the cylindrical shell and concentric opening shall be vertical to within 1 %
of the cylindrical length.
6.9 Tightness
Tests appropriate to the manufacturing process shall be carried out to ensure that there is no leakage from the
cylinder.
7 New design tests
7.1 General requirements
7.1.1 Testing shall be carried out for each new design of cylinder.
A cylinder shall be considered to be of a new design compared with an existing design when:
it is manufactured in a different factory; or
it is manufactured by a different welding or manufacturing process or a radical change in an existing process,
e.g. change in heat treatment, change in coldworking or cryoforming operation; or
it is manufactured from a steel of different specified chemical composition range; or
it is given a different heat treatment as specified in accordance with 4.3; or
there is a change in base profile, e.g. concave, convex, hemispherical or there is a change in the base
thickness/cylinder diameter ratio (R ); or
e
the guaranteed minimum yield stress and/or the guaranteed minimum tensile strength (R ) has changed; or
g
the overall length of the cylinder has increased by more than 50 % (cylinders with a length/diameter ratio less
than 3 shall not be used as reference cylinders for any design with this ratio greater than 3); or
the nominal outside diameter has changed; or
the guaranteed minimum wall thickness (a') or the guaranteed minimum end thickness (b') has been
decreased; or
the hydraulic test pressure has been changed (where the cylinder is to be used for a lower pressure duty than
that for which the cylinder was approved, it shall not be deemed a new design); or
the cryoforming factor (f ) varies by more than – 10 % for cryoformed cylinders; or
c
a different cryoforming temperature is used.
7.1.2 A technical specification of the cylinder, including design drawing, design calculations, material details,
welding and manufacturing process and heat treatment, shall be prepared by the manufacturer and attached to the
design test certificate (see annex D).
7.1.3 A minimum of 50 cylinders which shall be guaranteed by the manufacturer to be representative of a new
design, shall be made available for design testing. However, if the total production is less than 50 cylinders, enough
cylinders shall be made to complete the tests required, in addition to the production quantity. In this case the
design test certificate is limited to the particular batch.
7.1.4 The testing process shall include the verifications and tests listed in 7.2.1 and 7.2.2 respectively.
7.2 Verifications and tests
7.2.1 Verifications
It shall be verified that:
the requirements of clause 4 (materials) are fulfilled;
the design conforms to the requirements of clause 5;
the thickness of the walls and domed ends of two cylinders meet the requirements of 5.2 to 5.5, the
measurements being taken at least at three transverse sections of the cylindrical part and on a longitudinal
section of the base and head;
the requirements of clause 6 and annex A are fulfilled for all cylinders selected;
the internal and external surfaces of the cylinders are free of any defect which may make them unsafe for use
(see annex B).
7.2.2 List of tests
The following shall be performed on cylinders selected after the welds of the cylinders have been visually
inspected:
the tests specified in 8.4 (tensile test), 8.5 (bend test), 8.6 (impact test) where applicable, and 8.7
(macroscopic examination of weld cross-sections) on two cylinders, the test pieces being identifiable to the
batch;
the tests specified in 7.3.1 (hydraulic burst test) on two cylinders, the cylinders bearing representative stamp
marking;
radiographic examination, radioscopic examination, or NDT examination carried out using another suitable
method, in accordance with annex B;
the tests specified in 7.3.2 (pressure cycling) on one cylinder, the cylinder bearing representative stamp
marking;
the test specified in 7.3.3 (corrosion test) on one cylinder when the cylinders are intended for use in corrosive
gas service and are manufactured from austenitic or duplex stainless steels.
These tests shall be performed with finished cylinders after all manufacturing processes, including cold-forming or
cryoforming steps, have been completed.
7.3 Descriptions of tests
7.3.1 Hydraulic burst test
7.3.1.1 Cylinders subjected to this test shall bear markings in accordance with the complete stamp markings
required for the finished cylinder. The hydraulic burst test shall be carried out with equipment which enables the
pressure to be increased at a controlled rate until the cylinder bursts and the change in pressure with time to be
recorded.
7.3.1.2 For a test pressure (p ) £ 60 bar the burst pressure (p ) shall be at least 9/4 times the test pressure,
h b
and for a test pressure > 60 bar the burst pressure shall be equal to at least 1,6 times the test pressure.
The observed yield pressure (p ) shall be equal to or greater than the value calculated by the following formula:
y
p ‡ p /F
y h
The burst test shall not cause any fragmentation of the cylinder.
The main fracture shall not show any brittleness, i.e. the edges of the fracture shall not be radial but shall be at an
angle to a diametral plane and display a reduction of area throughout their thickness.
7.3.1.3 If the configuration of the fracture does not conform to the requirements, the cylinder shall be
submitted to a further examination to enable a decision to be reached as to the acceptance or rejection of the
batch.
7.3.2 Pressure cycling test
7.3.2.1 The fatigue test shall be carried out on one cylinder bearing the required stamp markings. See
clause 12 for the particular requirements concerning the stamp marking on the dome ends.
7.3.2.2 This test shall be carried out with a non-corrosive liquid, subjecting the cylinder to successive reversals
at an upper cyclic pressure which is equal to the hydraulic test pressure (p ). The value of the lower cyclic pressure
h
shall not exceed 10 % of the upper cyclic pressure. The frequency of reversals of pressure shall not exceed
0,25 Hz (15 cycles/min). The temperature measured on the outside surface of the cylinder shall not exceed 50 °C
during the test.
7.3.2.3 The cylinder shall be subjected to 12 000 cycles without leakage or failure.
7.3.2.4 After the test, the cylinder bases shall be sectioned in order to measure the thickness and to ascertain
that this thickness is no more than 15 % above the minimum base thickness prescribed in the design. The actual
wall and base thickness shall be measured and recorded on the design test certificate.
7.3.3 Corrosion test
An intergranular corrosion test shall be carried out in accordance with EN ISO 3651-2 on one cylinder for design
testing for cylinders, which are intended to be used for corrosive applications and are manufactured from austenitic
or duplex stainless steels. The specimens shall be taken from a part of the cylinder providing a specimen geometry
suitable for bend testing.
The mechanical properties may depend on the location of the samples. Therefore the exact location of the samples
shall be identified and this location shall be as indicated on Figure 4 or Figure 5. Two specimens shall be taken
from the location shown on Figure 4 or 5 as appropriate.
7.4 Design testing certificate
If the results of the checks are satisfactory, a design testing certificate shall be issued, a typical example of which is
given in annex C.
8 Batch tests
8.1 General
For the purpose of carrying out the batch testing, a random sample of cylinders as indicated in Table 1 shall be
taken from each batch, as defined in 3.1.6. A batch shall consist of a maximum of 3 000 cylinders. All batch tests
shall be carried out on finished cylinders.
Table 1 — Batch sampling
Batch size Number of cylinders Number of cylinders to be tested
taken as samples
Mechanical tests Burst tests (as per
7.3.1)
Up to 200 2 1 1
201 to 500 3 1 2
501 to 1 500 9 2 7
1 501 to 3 000 18 3 15
Mechanical tests comprise tensile tests (as per 8.4), bend tests (as per 8.5), impact tests where
applicable (as per 8.6), and macroscopic examination of weld cross-sections (as per 8.7).
8.2 Information
For the purpose of batch testing, the manufacturer shall provide the following:
— the design test certificate;
— the certificates for the material of construction as required in 4.1.6 stating the cast analyses of the steel
supplied for the construction of the cylinders;
— a list of cylinders, stating serial numbers and stamp markings as required;
— a statement of the thread checking method used and the results thereof.
8.3 Checks and verifications
The following checks and verifications shall be carried out on each batch of cylinders:
ascertain that a batch test certificate has been obtained and that the cylinders conform to it;
check whether the requirements set out in clauses 4, 5, 6 and 12 have been met, and in particular check by an
external and internal examination of the cylinders whether the construction and checks carried out by the
manufacturer in accordance with clause 6 are satisfactory. The visual examination shall cover at least 10 % of
the cylinders submitted. However, if an unacceptable defect is found, (as described in annex B), 100 % of
cylinders shall be visually inspected;
carry out or witness the tests specified in 8.4 (tensile test), 8.5 (bend test), 8.6 (impact test) where applicable,
8.7 (macroscopic examination of weld cross-sections) and 7.3.1 (hydraulic burst test) on the number of
cylinders specified in 8.1;
check whether the information supplied by the manufacturer is correct; random checks shall be carried out;
assess the results of the hardness testing, if applicable, as referred to in 9.2;
— assess the results of the NDT examination as specified in annex A.
8.4 Tensile test
8.4.1 General
The tensile test on parent material shall be carried out on a test sample taken from a finished cylinder in
accordance with the requirements of EN 10002-1. The two faces of the test sample formed by the inside and the
outside surfaces of the cylinder shall not be machined. The ends only may be flattened, by cold pressing, for
gripping in the test machine. The tensile test on welds shall be carried out according to 8.4.3.
8.4.2 Tensile test samples from parent material
8.4.2.1 The following test samples shall be taken from the parent material (see Figure 4 for two part cylinders
and Figure 5 for three part cylinders):
one tensile test sample from either of the ends (if the ends are of a different supplier of material, a tensile test
sample shall be taken from each end).
one longitudinal tensile test sample (for three part cylinders from the section 180° away from the longitudinal
weld). For cold-formed or cryoformed cylinders, the tensile samples shall be taken from the middle section of
the cylindrical shell.
8.4.2.2 The values obtained for the yield stress (R ) and tensile strength (R ) shall not be less than those
ea m
guaranteed by the cylinder manufacturer and not less than those given in EN 10088-2 or EN 10028-7. Elongation
values not covered by EN 10088-2 or EN 10028-7 shall be in no case less than 14 %.
8.4.3 Tensile test samples taken from welds
8.4.3.1 The following test samples shall be taken from welds:
one tensile test sample from any longitudinal weld;
one tensile test taken from each circumferential weld, if made by a different welding procedure.
8.4.3.2 The tensile test transverse to the weld shall be carried out on a test sample having a reduced section
25 mm wide over a length of 15 mm beyond the edge of the weld. Outside this central part, the width of the test
sample shall increase progressively (see Figure 6).
8.4.3.3 The tensile strength value obtained shall be at least equal to the minimum value specified in 8.4.2.2 for
the parent metal, regardless of the position of the fracture.
Key
1 1 tensile test piece
2 1 tensile test piece, 1 root bend test piece, 1 face bend test piece
3 1 tensile test piece - Required only if insufficient cylindrical length available
4 Notch impact test
5 Corrosion test piece
Figure 4 — Test pieces from two-part cylinders
Key
1 1 tensile test piece
2 1 tensile test piece
1 root bend test piece
1 face bend test piece
3 1 tensile test piece
1 root bend test piece
1 face bend test piece
Required only if welded by a different process from longitudinal weld (see 8.4.2.1 and 8.4.3.1)
4 Impact test piece
5 1 tensile test piece
6 1 corrosion test piece
Figure 5 — Test pieces in three-part cylinders
Dimensions in millimetres
Key
1Weld
Figure 6 — Dimensions of test sample
8.5 Bend test
8.5.1 The bend test shall be carried out in accordance with EURONORM 6-55. Specimens shall be taken in
accordance with Figure 4 or Figure 5 with dimensions as shown in Figure 7.
8.5.2 The following bend tests are required:
one root and one face bend test from any longitudinal weld;
one root and one face bend test from each circumferential weld, if made by a different welding process.
8.5.3 The test piece shall not crack when bent inwards around a former until the inside edges are not further
apart than the diameter of the former (see Figure 10).
8.5.4 The ratio n between the diameter (D) of the former and the thickness (t) of the test sample shall be as
f
shown in Table 2.
Table 2 — Bend test requirements
Actual tensile strength R in MPa Value of n
m
R £
...