Gas cylinders — Refillable welded steel cylinders containing materials for sub-atmospheric gas packaging (excluding acetylene) — Design, construction, testing, use and periodic inspection
ISO 11513:2011 specifies minimum requirements for the material, design, construction, workmanship, examination and testing at manufacture of refillable welded steel cylinders for the sub-atmospheric pressure storage of liquefied and compressed gases. It only applies to the cylinders themselves, irrespective of the materials contained therein (e.g. adsorbents, media, materials, and/or gases) and other related applications.
Bouteilles à gaz — Bouteilles en acier soudées rechargeables contenant des matériaux pour le stockage des gaz à une pression sub-atmosphérique (à l'exclusion de l'acétylène) — Conception, fabrication, essais, utilisation et contrôle périodique
Standards Content (Sample)
Gas cylinders — Refillable welded steel
cylinders containing materials for sub-
atmospheric gas packaging (excluding
acetylene) — Design, construction,
testing, use and periodic inspection
Bouteilles à gaz — Bouteilles en acier soudées rechargeables
contenant des matériaux pour le stockage des gaz à une pression sub-
atmosphérique (à l’exclusion de l’acétylène) — Conception, fabrication,
essais, utilisation et contrôle périodique
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ii © ISO 2011 – All rights reserved
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Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms and definitions . 2
3.2 Symbols . 2
4 Inspection and testing . 3
5 Materials and stress relieving . 3
6 Design . 4
6.1 General . 4
6.2 Calculation of cylindrical wall thickness . 5
6.3 Design of cylinder ends . 5
6.4 Minimum wall thickness . 6
6.5 Pressure relief device . 7
7 Construction and workmanship . 7
7.1 General . 7
7.2 Welding qualification . 8
7.3 Welding seams of pressure containing parts . 8
7.4 Valve protection . 8
7.5 Boss threads . 8
7.6 Visual examination . 8
8 Technical requirements for type approval testing (new design tests) . 11
8.1 General . 11
8.2 Verifications and tests . 11
8.3 Description of verification tests .12
9 Batch tests .13
9.1 General .13
9.2 Information .13
9.3 Checks and verifications .13
9.4 Tensile test .14
9.5 Bend test .15
9.6 Macroscopic examination of weld cross-sections .16
9.7 Radiographic examination of welds .16
10 Tests on every cylinder .16
11 Failure to meet verification and test requirements .17
12 Marking .17
13 Certification .17
Annex A (normative) Inspection at time of fill.18
Annex B (normative) Periodic inspection and test .20
Annex C (informative) Gases currently being transported.21
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ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11513 was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3, Cylinder design.
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This International Standard provides a specification for the design, manufacture, use and periodic inspection and
testing of a welded steel cylinder necessary to facilitate sub-atmospheric pressure gas packaging technology
on a worldwide basis. The specifications given are based on knowledge of, and experience with, materials,
design requirements, manufacturing processes and control at manufacture of cylinders in common use in
the countries of the ISO member bodies. With respect to those aspects concerning construction materials,
approval of design rules and inspection during manufacture which are subject to national or international
regulations, it is necessary for interested parties to ensure that, in the practical application of this International
Standard, the requirements of the relevant authority are also satisfied.
The pressure shell of the cylinder is fabricated by manufacturing a cylindrical shape with a base and welding
a machined plug (boss) or semi-ellipsoidal or torispherical shape onto the open end of the shell to form the
cylinder. This method of fabrication allows for insertion of material prior to sealing the cylinder.
A further objective of this International Standard is to balance design and economic efficiency against
international acceptance and universal utility. It aims to eliminate the concerns about climate, duplicate
inspections and restrictions currently existing because of lack of definitive International Standards. It should
not be construed as reflecting on the suitability of the practices of any nation or region.
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INTERNATIONAL STANDARD ISO 11513:2011(E)
Gas cylinders — Refillable welded steel cylinders containing
materials for sub-atmospheric gas packaging (excluding
acetylene) — Design, construction, testing, use and periodic
WARNING — This International Standard requires the use of substances and procedures that may
be injurious to health if adequate precautions are not taken. It refers only to technical suitability and
does not absolve the user from legal obligations relating to health and safety at any stage. It has been
assumed in the drafting of this International Standard that the execution of its provisions is entrusted
to appropriately qualified and experienced people.
This International Standard specifies minimum requirements for the material, design, construction, workmanship,
examination and testing at manufacture of refillable welded steel cylinders for the sub-atmospheric pressure
storage of liquefied and compressed gases. It only applies to the cylinders themselves, irrespective of the
materials contained therein (e.g. adsorbents, media, materials and/or gases) and other related applications.
The cylinders have a test pressure not greater than 42 bar and a water capacity from 0,5 l up to and including
12 l exposed to ambient temperatures for the purpose of facilitating the sub-atmospheric pressure storage of
liquefied and compressed gases. Inspection at the time of fill is specified in Annex A and periodic inspection
and testing is specified in Annex B.
High-pressure and low-pressure liquefied gases as specified in Annex C can be suitably filled into these
cylinders. The filling pressure will be less than one bar gauge at 21 °C.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 2504:1973, Radiography of welds and viewing conditions for films — Utilization of the recommended
patterns of image quality indications (I.Q.I.)
ISO 4978, Flat rolled steel products for welded gas cylinders
ISO 6892-1:2009, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7438, Metallic materials — Bend test
ISO 9809-3:2010, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and
testing — Part 3: Normalised steel cylinders
ISO 11117, Gas cylinders — Valve protection caps and valve guards — Design, construction and tests
ISO 13769, Gas cylinders — Stamp marking
ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints
ISO 17639, Destructive tests on welds in metallic materials — Macroscopic and microscopic examination of welds
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UN Recommendations on the Transport of Dangerous Goods — Model Regulations, sixteenth edition,
Packaging Note P200
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
3.1 Terms and definitions
value corresponding to the lower yield strength, R , or 0,92 × the upper yield strength, R , or for steels that
do not exhibit a defined yield, the 0,2 % proof strength, R 0,2
heat treatment given to the drawn pressure shell by heating to a uniform temperature below the lower critical
point, AC , of the steel and cooling in a still atmosphere
NOTE The object is to reduce the residual stresses without altering the metallurgical structure of the steel.
quantity of finished cylinders made consecutively during the same or consecutive days to the same design, size
and material specifications and cast for each pressure-containing part on the same equipment and subjected
to the same heat-treatment conditions
NOTE Different suppliers can be used for the different pressure-containing parts within a batch, e.g. one supplier for
shells, another for plugs.
design stress factor
ratio of equivalent wall stress at test pressure, p , to guaranteed minimum yield strength, R
sub-atmospheric gas packaging
gas source package that stores and delivers gas at sub-atmospheric pressure, which includes a container
(e.g. gas cylinder and outlet valve) that stores and delivers gas at a pressure of less than 1 bar at normal
conditions of temperature and pressure
NOTE The container can incorporate a medium in order to reduce the pressure of the gas to sub-atmospheric levels.
a Calculated minimum thickness, in millimetres, of the cylindrical shell
a′ Guaranteed minimum thickness, in millimetres, of the cylindrical shell (including any corrosion allowance,
a Guaranteed minimum thickness, in millimeters, of a concave base at the knuckle. See Figure 1 a).
a Guaranteed minimum thickness, in millimetres, at the centre of a concave base. See Figure 1 a).
Calculated minimum thickness, in millimetres, of the cylinder end
Percentage elongation after fracture
Outside diameter of the cylinder, in millimetres
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d Internal diameter of the cylinder, in millimetres
F Design stress factor
h Outside height, in millimetres, of domed part (convex base end). See Figure 1 a).
L Length of the cylinder, in millimetres
P Measured burst pressure, in bars, above atmospheric pressure, in the burst test
p Test pressure above atmospheric pressure, in bars
P The observed pressure when cylinder starts yielding during hydraulic bursting tests, in bars, above
r Inside knuckle radius, in millimetres. See Figures 1 and 2.
R Guaranteed minimum yield strength in megapascals (yield strength as defined in 3.1.1), for the finished
cylinder and used for design calculation
R Value of the actual yield strength in megapascals (yield strength as defined in 3.1.1), determined by the
tensile test. See 188.8.131.52.
R Value of the actual tensile strength in megapascals as determined by the tensile test. See 184.108.40.206.
R Guaranteed minimum tensile strength in megapascals, for the finished cylinder and used for design
4 Inspection and testing
Evaluation of conformity shall be performed in accordance with the relevant regulations of the country or
countries where the cylinders are used.
To ensure that the cylinders conform to this International Standard, they should be subject to inspection and
testing by an authorized inspection body recognized in the country or countries of manufacture.
Equipment used for measurement, testing and examination during production shall be maintained and calibrated
within a documented quality management system.
5 Materials and stress relieving
5.1 Materials for shells and end pressings shall conform to either ISO 4978 or ISO 9809-3.
NOTE “Materials” refers to materials in the state before transformation with regard to the manufacturing process.
To conform to the state of the art for modern steel manufacturing and steel grades used for pressure purposes,
the same limits on sulphur and phosphorous contents as noted in 5.9.1 of ISO 4706:2008 for refillable welded steel
cylinders and Table 3 of ISO 9809-3:2010 shall apply in this International Standard. The following limits are noted:
— carbon: 0,25 % max.;
— silicon: 0,45 % max.;
— manganese: 1,60 % max.;
— phosphorous: 0,040 % max.;
— sulphur: 0,040 % max.
5.2 All parts welded to the cylinder shall be made of compatible materials with respect to their weldability.
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5.3 The welding consumables selected by the manufacturer shall be compatible with the base materials and
shall produce welds which meet the minimum strength values used in the design of the cylinder and guaranteed
by the manufacturer of the finished cylinder.
5.4 The cylinder manufacturer shall have certificates of the ladle analysis and mechanical properties of the
steel supplied for the construction of the pressure-retaining parts of the cylinder.
5.5 The manufacturer shall maintain a system of identification for the materials used in fabrication so that all
materials for pressure parts in the completed cylinder are traceable to their origin.
5.6 Grades of steel used for cylinder manufacture shall be compatible with the intended gas service,
e.g. corrosive gases, embrittling gases. See ISO 11114-1.
5.7 The drawn pressure shell and plug shall be delivered in the stress-relieved condition. Localized stress
relief of the drawn pressure shell and plug shall not be undertaken.
The quality of the welds shall be checked by non-destructive examination (NDE) or other equivalent means to
demonstrate that the cylinder is fit for the intended service. See 9.7.4.
The actual temperature of stress relief to which a type of steel is subjected for a given tensile strength shall not
deviate by more than 30 °C from the temperature specified by the manufacturer for the cylinder type.
5.8 The material properties of the finished cylinders shall be suitable to meet the requirements of Clause 8
and Clause 9.
Only steel pressure receptacles resistant to hydrogen embrittlement can be used for gases assigned the
special packing provision “d” as per Table 2 of P200 of the UN Model Regulations. See Annex C.
6.1.1 The calculation of the wall thickness of the pressure-containing parts shall be related to the guaranteed
minimum yield strength, R , for the parent material in the finished cylinder.
For certain gases, additional corrosion allowances may be applicable.
6.1.2 For calculation purposes, the value of the yield strength, R , shall be limited to a maximum of 0,85 R .
6.1.3 The internal pressure upon which the minimum sidewall thickness calculation of gas cylinders is based
shall be the test pressure, p .
6.1.4 A fully dimensioned drawing including the specification of the material shall be produced.
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6.2 Calculation of cylindrical wall thickness
The guaranteed minimum thickness of the cylindrical shell shall be not less than that calculated using the
10×F ×R − 3 × p
a = × 1−
2 10×F ×R
where F is the lesser of or 0,77.
shall not exceed 0,85.
The guaranteed minimum thickness of the cylinder shell shall also conform to 6.4.
6.3 Design of cylinder ends
NOTE Examples of typical cylinder ends are shown in Figure 1. Figure 1 a) is a typical base end concave to pressure
and Figure 1 b) is a typical end plug used to seal the top of the cylinder.
The thickness in the base of a cylinder with a convex base end shall not be less than the guaranteed minimum
wall thickness of the cylindrical shell specified in 6.2.
6.3.2 Design of base concave to pressure
When concave base ends [see Figure 1 a)] are used, the following design values are recommended:
a ≥ 2a
a ≥ 2a
h ≥ 0,12 D
r ≥ 0,075 D
The design drawing shall at least show values for a , a , h and r.
The cylinder manufacturer shall in all cases prove by the pressure cycling test given in 8.3.2 that the design is
NOTE 1 An example of a typical end is shown in Figure 1 a).
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a) Illustration of cylinder base end concave to pressure
b) Boss style end plug with inlet threads
Figure 1 — Typical cylinder ends
6.4 Minimum wall thickness
6.4.1 The minimum wall thickness of the cylindrical shell including the base, a, shall be not less than the value
derived from the appropriate formula listed hereafter:
for D ≤ 100 mm, a = 1,1 mm;
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for 100 mm < D ≤ 150 mm, a = 1,1 + 0,008(D−100) mm;
for D > 150 mm, a = +0,7 mm, with an absolute minimum of 1,5 mm.
6.4.2 The minimum thickness, b, of end plugs (bosses) used to seal the top of the cylinder shall be at least
twice the thickness of the cylinder sidewall, a, i.e. b ≥ 2a.
The adequacy of the end plug design shall be demonstrated by the pressure cycling test in accordance with 8.3.2.
NOTE An example of a typical end plug to seal the top of the cylinder is shown in Figure 2.
1 end plug (boss)
2 butt weld
3 cylinder shell
r knuckle radius
Figure 2 — Example of boss style end plug welded to cylinder shell
6.5 Pressure relief device
No pressure relief devices shall be included in the design.
7 Construction and workmanship
The containers in question are composed of a seamless shell with a boss welded to the open end.
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The cylinder shall be produced by
a) forging or drop forging from a solid ingot or billet, or
b) pressing from a flat plate.
7.2 Welding qualification
Welding procedures shall be in accordance with ISO 15614-1. It is advisable that welders conform to ISO 9606-1
and welding operators to ISO 14732 for all welding associated with the pressure envelope, including the
non-pressure containing parts.
Welds made in production shall be representative of those generated from the welding procedure approval tests.
7.3 Welding seams of pressure containing parts
The circumferential seam shall be butt welded as illustrated in Figure 2.
7.4 Valve protection
7.4.1 Valves 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 ISO 11117.
7.4.2 When a protective shroud is used, it shall fulfil the requirements of the drop test described in ISO 11117.
7.5 Boss 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 threads or by an alternate method of equivalent sensitivity.
Particular care shall be taken to ensure that the neck threads are accurately cut from full form and are free from
any sharp profiles or burrs.
The internal thread shall be tapered and conform to a recognized standard for tapered threads, such as ISO 11116-1.
When required, the external thread shall conform to a recognized standard.
NOTE For example, where the neck thread is specified as being in accordance with ISO 11116-1, the corresponding
gauges are specified in ISO 11116-2.
7.6 Visual examination
Before assembly, the pressure containing parts of the cylinders shall be examined for uniform quality and
freedom from imperfections which may ultimately affect the cylinder integrity.
220.127.116.11 The welding of the circumferential joint (pressure envelope) shall be performed by a fully mechanized,
semi-automatic or automatic process to provide consistent and reproducible weld quality.
18.104.22.168 The fusion of the welded metal with the parent metal (pressure joint) for circumferential seams and
bosses shall be smooth, have a finish without concavity and that is free from lack of fusion, undercutting or
22.214.171.124 Inspection of welds shall be performed in accordance with ISO 17637.
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126.96.36.199 Circumferential joints, of which there shall be no more than one, shall be butt welded or jogglewelded.
See Figure 3.
188.8.131.52 Welds shall have full penetration. This shall be verified by using ISO 17639. The excess thickness shall
be such that the weld integrity is not compromised. Macro etching and etch tests are authorized in ISO 17639.
184.108.40.206 Vee butt welds shall have weld penetration verified by bend testing and tensile testing. If sufficient material
is not available for these tests due to the cylinder geometry, the integrity of the weld shall be verified by macro-
etching as specified in ISO 17639. The pass/fail criteria for the macro-etch test is in accordance with ISO 17639.
220.127.116.11 Radiographic examination, radioscopic examination, or NDE carried out using another suitable method
shall be as specified in 9.7.
18.104.22.168 Non-pressure containing attachments shall not be welded to the cylinder.
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1 cylinder shell
3 end plug
Figure 3 — Weld penetration
The out-of-roundness of the cylindrical part of the 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
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.
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When the cylinder is standing on its base, the cylindrical shell and concentric top opening shall be vertical to
within 1 % of the cylindrical length.
8 Technical requirements for type approval testing (new design tests)
8.1.1 A technical specification of each new design of cylinder, or cylinder family as specified in g), including
design drawing, design calculations, steel details, manufacturing process and heat treatment details, shall be
submitted by the manufacturer to the inspector. The type approval tests detailed in 8.2 shall be carried out on
each new design under the supervision of the inspector.
A cylinder shall be considered to be of a new design, compared with an existing design, when at least one of
the following applies:
a) it is manufactured in a different factory;
b) it is manufactured by a different welding process or a chang