ISO 24431:2006

INTERNATIONAL ISO
STANDARD 24431
First edition
2006-09-15

Gas cylinders — Cylinders for
compressed and liquefied gases
(excluding acetylene) — Inspection at
time of filling
Bouteilles à gaz — Bouteilles à gaz comprimés et liquéfiés (à
l'exception de l'acétylène) — Contrôle au moment du remplissage




Reference number
ISO 24431:2006(E)
©
ISO 2006

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ISO 24431:2006(E)
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ISO 24431:2006(E)
Contents
Foreword. iv
Introduction . v
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Filling inspection .3
5 Description of inspection items .3
5.1 Verification of serviceable condition.3
5.2 Identification of cylinder owner.4
5.3 Verification of tare and calculation of weight of gas to be charged.4
5.4 Verification of internal cylinder condition.5
5.5 Verification of the integrity of permanent attachments.5
5.6 Verification of valve integrity and suitability .5
5.7 Check for correct filling pressure .6
5.8 Check for correct filling weight.6
5.9 Check of the valve protection.6
Annex A (informative) Example of a procedure to establish a correct tare .7
Annex B (informative) Procedures to be adopted when de-valving and/or when it is suspected
that a cylinder valve is obstructed.8
B.1 Check for obstructed valve.8
B.2 Valve unobstructed.8
B.3 Valve obstructed.8
Bibliography .11

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ISO 24431:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
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 24431 was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 4,
Operational requirements for gas cylinders.
This first edition of ISO 24431 cancels and replaces ISO 10463:1993 and ISO 11113:1995, of which it
constitutes a technical revision.

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ISO 24431:2006(E)
Introduction
This International Standard covers requirements that reflect current practice and experience.
Each transportable gas cylinder is inspected at the time of filling in order to establish that:
⎯ it has no defects which render it unsafe for filling or continued use;
⎯ it can be identified and complies with the relevant requirements with regard to marking, labelling, colour
coding and completeness of its accessories;
⎯ its valve functions satisfactorily.
The cylinder filling inspection is carried out exclusively by persons who have the appropriate training and
competences, so as to ensure that each cylinder is safe for continued use.
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INTERNATIONAL STANDARD ISO 24431:2006(E)

Gas cylinders — Cylinders for compressed and liquefied gases
(excluding acetylene) — Inspection at time of filling
1 Scope
This International Standard specifies the inspection requirements at the time of filling, and applies to seamless
or welded transportable gas cylinders made of steel or aluminium alloy for liquefied or compressed gases
(excluding acetylene) of a water capacity of between 0,5 l and 150 l. It also applies to cylinders of less than
0,5 l water capacity, as far as practicable.
This International Standard does not apply to cylinders manifolded in bundles or trailers.
This International Standard applies primarily to industrial gases other than liquefied petroleum gas (LPG), but
may also be applied to LPG. For specific LPG applications, refer to ISO 10691.
For cylinders manifolded in bundles, refer to ISO 11755.
NOTE In International Standards, weight is equivalent to a force, expressed in newtons, However, in common
parlance (as used in terms defined in this International Standard), the word “weight” continues to be used to mean “mass”,
although this practice is deprecated (see ISO 80000-4).
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 6406, Gas cylinders — Seamless steel gas cylinders — Periodic inspection and testing
ISO 10460, Gas cylinders — Welded carbon-steel gas cylinders — Periodic inspection and testing
ISO 10461, Gas cylinders — Seamless aluminium-alloy gas cylinders — Periodic inspection and testing
ISO 11114-1, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 1: Metallic materials
ISO 11114-2, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 2: Non-metallic materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
compressed gas
gas which when packaged under pressure for transport is entirely gaseous at −50 °C
NOTE This category includes all gases with a critical temperature less than or equal to −50 °C.
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ISO 24431:2006(E)
3.2
empty weight
empty mass
mass of the cylinder including all integral parts (e.g. neck ring, foot ring), but excluding the mass of valve,
valve cap or valve guard and any coating
3.3
filler
person (or persons) responsible for inspection prior to, during and immediately after filling, who has received an
appropriate level of training for the work involved and who has access to all necessary data for the cylinder, valve
and all other fittings used
3.4
filling pressure
pressure to which a cylinder is filled at the time of filling
NOTE Filling pressure varies according to the gas temperature in the cylinder, which is dependent on the charging
parameters and ambient conditions.
3.5
filling ratio
ratio of the mass of gas to the mass of water at 15 °C that would fill completely a pressure receptacle fitted
ready for use
3.6
liquefied gas
gas which, when packaged under pressure for transport, is partially liquid at temperatures above −50 °C
NOTE A distinction is made between:
⎯ high pressure liquefied gas, a gas with a critical temperature between −50 °C and +65 °C, and
⎯ low pressure liquefied gas, a gas with a critical temperature above +65 °C.
3.7
maximum permissible filling weight
maximum permissible filling mass
product of the water capacity of the cylinder and the filling ratio (3.5) of the gas
3.8
pallet
device for handling several cylinders at the same time
3.9
pressure relief device
device fitted to the cylinder or its valve, which is designed to open to prevent a rise of pressure in excess of a
specified value, due to excess temperature and/or pressure
3.10
tare
sum of the empty weight (3.2) plus the mass of the valve, including dip tube where fitted, any fixed valve guard
and all other parts that are permanently attached (e.g. by clamping or bolted fixing) to the cylinder when presented
for filling
3.11
total weight
total mass
tare (3.10) of the cylinder plus the maximum permissible filling weight (3.7)
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ISO 24431:2006(E)
3.12
working pressure
settled pressure of a compressed gas (3.1) at a reference temperature of 15 °C in a pressure receptacle
4 Filling inspection
Each cylinder shall be subjected to an inspection prior to, during and immediately after filling. The following items
shall be covered by a filling inspection:
a) verification of serviceable condition (see 5.1),
b) identification of cylinder owner, if required (see 5.2),
c) for cylinders filled by weight, verification of tare and calculation of weight of gas to be charged (see 5.3),
d) verification of internal cylinder condition (see 5.4),
e) verification of integrity of neck ring/threaded boss (see 5.5),
f) verification of valve integrity and suitability (see 5.6),
g) verification of correct filling pressure as applicable (see 5.7),
h) verification of correct filling weight as applicable (see 5.8), and
i) verification of the valve protection (see 5.9).
Cylinders which do not satisfy the criteria listed above shall be handled in accordance with the relevant
procedures of the filling company before any further action is taken.
5 Description of inspection items
5.1 Verification of serviceable condition
5.1.1 General criteria
Before filling a cylinder, it shall be established that:
a) the cylinder has not exceeded its due date for periodic inspection and testing,
b) the cylinder is compatible with the intended gas content and filling pressure,
c) the cylinder is permitted for filling in the country of the filling station,
d) the intended gas contents correspond to any identification label and shoulder or body colour on the
cylinder (e.g. through verification of the cylinder's markings or by questioning the owner of the cylinder),
and
e) each cylinder, whether individual or palletized, is in a serviceable condition.
Cylinders judged to be unserviceable shall be clearly marked and separated for further treatment, in accordance
with the written procedures of the filling company.
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ISO 24431:2006(E)
5.1.2 Individual cylinder
Before a cylinder is filled it shall be established that the external surface of the cylinder is clean and free of
foreign material (i.e. such that the cylinder can be assessed for mechanical damage that would prevent it from
being filled safely) and that it does not exhibit any abnormalities that could render it unsafe, such as
...