SIST EN ISO 22435:2024

SLOVENSKI STANDARD
01-oktober-2024
Nadomešča:
SIST EN ISO 22435:2009
SIST EN ISO 22435:2009/A1:2013
Plinske jeklenke - Ventili za jeklenke z vgrajenim regulatorjem tlaka - Specifikacija
in preskus tipa (ISO 22435:2024)
Gas cylinders - Cylinder valves with integrated pressure regulators - Specification and
type testing (ISO 22435:2024)
Gasflaschen - Flaschenventile mit integriertem Druckminderer - Spezifikation und
Baumusterprüfungen (ISO 22435:2024)
Bouteilles à gaz - Robinets de bouteilles avec détendeur intégré - Spécifications et
essais de type (ISO 22435:2024)
Ta slovenski standard je istoveten z: EN ISO 22435:2024
ICS:
23.020.35 Plinske jeklenke Gas cylinders
23.060.40 Tlačni regulatorji Pressure regulators
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22435
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2024
EUROPÄISCHE NORM
ICS 23.060.40; 23.020.35 Supersedes EN ISO 22435:2007, EN ISO
22435:2007/A1:2012
English Version
Gas cylinders - Cylinder valves with integrated pressure
regulators - Specification and type testing (ISO
22435:2024)
Bouteilles à gaz - Robinets de bouteilles avec Gasflaschen - Flaschenventile mit integriertem
détendeur intégré - Spécifications et essais de type Druckminderer - Spezifikation und
(ISO 22435:2024) Baumusterprüfungen (ISO 22435:2024)
This European Standard was approved by CEN on 8 March 2024.

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

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22435:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22435:2024) has been prepared by Technical Committee ISO/TC 58 "Gas
cylinders" in collaboration with 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 October 2024, and conflicting national standards shall
be withdrawn at the latest by October 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 22435:2007.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 22435:2024 has been approved by CEN as EN ISO 22435:2024 without any modification.

International
Standard
ISO 22435
Second edition
Gas cylinders — Cylinder valves
2024-03
with integrated pressure regulators
— Specification and type testing
Bouteilles à gaz — Robinets de bouteilles avec détendeur intégré
— Spécifications et essais de type
Reference number
ISO 22435:2024(en) © ISO 2024
ISO 22435:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 22435:2024(en)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and descriptions . 5
5 Design requirements and considerations . . 6
5.1 General .6
5.2 Description .7
5.3 Materials .7
5.4 Pressure and flow indicating devices .7
5.4.1 General .7
5.4.2 Flowmeters .7
5.4.3 Pressure indicators and flow gauges .8
5.5 Outlet connection .8
5.6 Outlet pressure for acetylene .8
5.7 Flow control valve (flow controller) .8
5.8 Pressure adjusting device .8
5.9 Filtration .8
5.10 Endurance of the VIPR pressure regulating system .9
5.11 Flow and pressure performance for a VIPR with a pressure outlet .9
5.11.1 Flow performance and characteristics .9
5.11.2 Coefficient of pressure increase upon closure R .9
5.11.3 Irregularity coefficient i .9
5.12 Flow performance for a VIPR with a flow metering device.9
5.13 Pressure relief valve .9
5.14 Leakage .10
5.15 Mechanical strength .10
5.16 Pressure resistance .10
5.17 Resilience to ignition .10
5.18 Design requirements for manufacture .11
5.19 Resistance to vibration .11
5.20 Resistance to shock .11
5.21 Over torque of the pressure adjusting device .11
6 Type testing .11
6.1 General .11
6.2 Documentation . 12
6.3 Test samples . 12
6.4 Test report . 13
6.5 Test temperatures . 13
6.6 Test gas . 13
6.6.1 Gas quality . 13
6.6.2 Reference conditions . 13
6.6.3 Leak tightness tests . 13
6.6.4 Endurance of a VIPR pressure regulating system . 13
6.7 Test schedule . 13
6.8 Mechanical strength test of the low-pressure chamber . 15
6.9 Pressure resistance test of the low-pressure chamber . 15
6.10 Mechanical strength test of flowmeters . 15
6.11 Overpressure and leak tightness test for pressure indicators and flow gauges . 15
6.12 Flow and pressure performance test for a VIPR with a pressure outlet . 15
6.12.1 General . 15

iii
ISO 22435:2024(en)
6.12.2 Standard discharge, Q , nominal outlet pressure, p , and maximum discharge
1 2
Q test . 15
max
6.12.3 Flow characteristic test.16
6.12.4 Coefficient of pressure increase upon closure R test .18
6.12.5 Irregularity coefficient i test .18
6.13 Accuracy and flow stability of a VIPR with a flow metering device test .21
6.14 Pressure relief valve test .21
6.15 Operating and loosening torques test .21
6.16 Endurance of the VIPR pressure regulating system .21
6.17 Leak tightness test . 22
6.17.1 Number of samples . 22
6.17.2 Internal leakage across the regulating valve seat . 22
6.17.3 External leakage . 22
6.18 Visual examination . 23
7 Marking . .23
8 Instructions .23
Annex A (informative) Vibration test .25
Annex B (informative) Shock test .26
Annex C (informative) Over torque test for the pressure adjusting device .27
Annex D (informative) Promoted ignition test .28
Bibliography .29

iv
ISO 22435:2024(en)
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 2, Cylinder
fittings, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
TC 23, Transportable gas cylinders, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 22435:2007), which has been technically
revised. It also incorporates the Amendment ISO 22435:2007/Amd. 1:2012.
The main changes are as follows:
— Introduction: clarification that this document gives additional requirements to those specified in
ISO 10297, ISO 17871, ISO 17879 and ISO 23826, unless specifically mentioned.
— Scope:
— requirements in this document are in addition to those specified in ISO 10297, ISO 17871, ISO 17879
and ISO 23826, unless specifically mentioned;
— clarification of different VIPR types with different positions of primary operating mechanism within
the valve;
— exclusion of VIPRs for liquefied petroleum gas (LPG) and cryogenic applications.
— Terms and definitions: definition of a primary valve operating mechanism.
— Introduction of VIPR types A, B and C for easy referencing of different design types.
— Symbols and descriptions:
— clarification of inlet pressure to the regulating function p and valve test pressure for different gas types;
v
ISO 22435:2024(en)
— additional characteristic column in table with link to test method, if relevant.
— Design requirements and considerations:
— general: VIPRs to comply with the relevant closure standards;
— materials: lubricant requirements given in relevant closure standard;
— pressure and flow indicating devices: relevant pressure indicator requirements in this document;
— cylinder connection: subclause removed;
— main shut-off valve: subclause removed because requirements already given in relevant closure
standard;
— pressure adjusting device: addition of a new subclause;
— leakage: total external and internal leakage shall not exceed 12 cm /h;
— mechanical strength: mechanical strength of inlet side moved to relevant closure standard;
— resistance to ignition: moved to ISO 10297;
— resilience to ignition: addition of a new subclause;
— resistance to vibration and resistance to shock: addition of two new subclauses.
— Type testing:
— general: clarification of changes to the VIPR design that require repetition of type tests;
— test schedule: table reformatted for relevant tests;
— test method for accuracy of VIPR with flowmeter: reference standard changed to ISO 2503;
— test methods for leakage: test for regulating device only;
— test method for the endurance test of the VIPR with the pressure regulator valve acting as primary
valve operating mechanism: moved to ISO 10297;
— test method for endurance of the filling connection closing device: moved to ISO 10297;
— test method for VIPR pressure regulator endurance test: addition of new test.
— Removal of previous Annex A "Valve impact test" and Annex B "Endurance test", because both are already
given in relevant closure standards.
— Addition of new Annexes A, B, C and D.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

vi
ISO 22435:2024(en)
Introduction
Valves with integrated pressure regulators (VIPRs) are used to reduce the pressure receptacle pressure to a
lower pressure suitable for end use processes.
VIPRs incorporate the basic functionality of a primary valve operating mechanism, with the additional
ability to regulate the pressure and/or flow at the valve outlet. They remove the need for end users to make
and break a high-pressure gas connection.
These valves operate over a wide range of inlet and outlet pressures and flows which require specific design
characteristics. It is important that the operating characteristics of these valves be specified and tested in a
defined manner.
Such valves are more complicated than conventional cylinder valves yet subject to the same environmental
and transport conditions. These conditions should be kept in mind at the design and development stage.
This document gives additional requirements for VIPRs to those given for cylinder valves in general in
ISO 10297, for quick-release cylinder valves in ISO 17871, for self-closing cylinder valves in ISO 17879 or for
ball valves in ISO 23826.
This document focusses on:
a) suitability of materials;
b) safety (mechanical strength, safe relief of excess pressure, etc.);
c) gas-specificity;
d) cleanliness;
e) testing;
f) identification;
g) information supplied.
When a VIPR has been tested according to the previous version of this document, the organisation
responsible for testing the same VIPR to this document should consider which tests need to be performed.
In this document, the unit bar is used, due to its universal use in the field of technical gases. Bar is not an SI
5 5 2
unit and the corresponding SI unit for pressure is Pa (1 bar = 10 Pa = 10 N/m ).
Pressure values given in this document are given as gauge pressure (pressure exceeding atmospheric
pressure) unless noted otherwise.
Tests and examinations performed to demonstrate compliance with this document are conducted using
instruments calibrated before being put into service and thereafter according to an established programme.
Any tolerances given in this document include measurement uncertainties.

vii
International Standard ISO 22435:2024(en)
Gas cylinders — Cylinder valves with integrated pressure
regulators — Specification and type testing
1 Scope
This document specifies design, type test methods, marking and instruction requirements for cylinder
valves with integrated pressure regulators (VIPRs) intended to be fitted to gas cylinders, pressure drums or
tubes or used as a main valve for bundles of cylinders that convey compressed, liquefied or dissolved gases.
These are requirements for VIPRs that are in addition to those given in the relevant closure standard, for
example, in ISO 10297 for cylinder valves, in ISO 17871 for quick-release cylinder valves, in ISO 17879 for
self-closing cylinder valves or in ISO 23826 for ball valves. For ISO 17871, these requirements are only
applicable to quick-release cylinder valves types B, C, D and E.
NOTE 1 If the pressure regulating system of a VIPR is acting as the primary valve operating mechanism, it is covered by
the relevant closure standard, e.g. ISO 10297, ISO 17871, ISO 17879 and ISO 23826. This also includes designs where closure
of the primary valve operating mechanism of a VIPR is obtained by closing the seat of the pressure regulating system.
NOTE 2 If the primary valve operating mechanism of a VIPR is located at the low-pressure side of the pressure
regulating system, it is covered by the relevant closure standard, e.g. ISO 10297, ISO 17871, ISO 17879 and ISO 23826.
NOTE 3 The term “pressure receptacle” is used within this document to cover instances where no differentiation is
necessary between gas cylinders, bundles of cylinders, pressure drums and tubes.
This document does not apply to VIPRs for
a) medical applications (see ISO 10524-3);
b) liquefied petroleum gas (LPG);
c) cryogenic applications.
NOTE 4 Additional requirements for a VIPR with a residual pressure device (RPD) are specified in ISO 15996.
NOTE 5 Additional requirements for pressure relief valves can exist in international/regional regulations/
standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 5171:2019, Gas welding equipment — Pressure gauges used in welding, cutting and allied processes
ISO 2503:2009, Gas welding equipment — Pressure regulators and pressure regulators with flow-metering
devices for gas cylinders used in welding, cutting and allied processes up to 300 bar (30 MPa)
ISO 7289, Gas welding equipment — Quick-action couplings with shut-off valves for welding, cutting and allied
processes
ISO 9090, Gas tightness of equipment for gas welding and allied processes
ISO 10156, Gas cylinders — Gases and gas mixtures — Determination of fire potential and oxidizing ability for
the selection of cylinder valve outlets

ISO 22435:2024(en)
ISO 10225, Gas welding equipment — Marking for equipment used for gas welding, cutting and allied processes
ISO 10286, Gas cylinders — Vocabulary
ISO 10297, Gas cylinders — Cylinder valves — Specification and type testing
ISO 17871, Gas cylinders — Quick-release cylinder valves — Specification and type testing
ISO 17879, Gas cylinders — Self-closing cylinder valves — Specification and type testing
ISO 23826, Gas cylinders — Ball valves — Specification and testing
ISO/TR 28821, Gas welding equipment — Hose connections for equipment for welding, cutting and allied
processes — Listing of connections which are either standardised or in common use
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286, ISO 10297, ISO 2503 and
the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
valve with integrated pressure regulator
VIPR
device intended to be permanently fitted to a pressure receptacle which comprises of at least a shut-off
function and pressure regulating system
3.2
VIPR type A
VIPR (3.1) design where the primary valve operating mechanism (3.5) is located upstream of the pressure
regulating system (3.7)
Note 1 to entry: For typical designs, see Figure 1. The filling connection can also be located between the primary valve
operating mechanism and the pressure regulating system.
a) Filling connection upstream of the primary b) Filling connection between the primary valve
valve operating mechanism operating mechanism and the pressure regulat-
ing system
ISO 22435:2024(en)
Key
1 valve inlet connection 4 filling connection closing device
2 primary valve operating mechanism 5 pressure regulating system
3 valve filling connection 6 valve outlet connection
Figure 1 — General structure of a VIPR type A design
3.3
VIPR type B
VIPR design where the pressure regulating system (3.7) is also acting as the primary valve operating
mechanism (3.5)
Note 1 to entry: See Figure 2.
Key
1 valve inlet connection 4 filling connection closing device
2 pressure regulating system including primary 5 valve outlet connection
valve operating mechanism
3 valve filling connection
Figure 2 — General structure of a VIPR type B design
3.4
VIPR type C
VIPR design where the primary valve operating mechanism (3.5) is located downstream of the pressure
regulating system (3.7)
Note 1 to entry: The primary valve operating mechanism can be a flow selector.
Note 2 to entry: See Figure 3.

ISO 22435:2024(en)
Key
1 valve inlet connection 4 filling connection closing device
2 primary valve operating mechanism 5 pressure regulating system
3 valve filling connection 6 valve outlet connection
Figure 3 — General structure of a VIPR type C design
3.5
primary valve operating mechanism
mechanism which isolates the pressure receptacle contents by closing and opening the shut-off valve orifice
and which includes the internal and external sealing systems
3.6
secondary shut-off mechanism
mechanism which is located downstream of the primary valve operating mechanism (3.5) and which closes
and opens a shut-off valve orifice
3.7
pressure regulating system
device that reduces the inlet pressure to a controlled outlet pressure
Note 1 to entry: A pressure regulating system can comprise of one or more stages of pressure regulation.
3.8
maximum closing pressure
p
4max
maximum value of p that can be achieved by combination of pressure receptacle pressure and various
settings of set pressure and flow rate
3.9
flow characteristic
variation of the outlet pressure in relation to the rate of flow from zero to maximum capacity flow of the
pressure regulator with the inlet pressure remaining constant
3.10
hysteresis
lagging of the outlet pressure (effect) when the flow (cause) is varied so that at a constant inlet
pressure the values of outlet pressure measured with increasing flow do not coincide with the values of
outlet pressure measured with decreasing flow

ISO 22435:2024(en)
3.11
orifice
restriction of known cross-section that delivers a constant flow of gas when supplied with gas at a constant
upstream pressure and temperature
3.12
pressure characteristic
variation of the outlet pressure with variation of the inlet pressure under specific initial flow conditions
3.13
pressure relief valve
valve designed to release excess pressure at a pre-set value
3.14
test inlet pressure
p
inlet pressure at which the standard discharge of the pressure regulator, Q , is measured
3.15
test outlet pressure
p
highest or lowest value of the outlet pressure resulting from a variation in the inlet pressure between p and
p at previously adjusted conditions p , p , Q
3 1 2 1
3.16
nominal discharge
Q
n
discharge specified by the manufacturer
Note 1 to entry: It is measured downstream of the flow-adjusting and measuring devices.
3.17
pressure outlet
outlet intended to deliver gas at a controlled pressure
3.18
filling connection closing device
closing device located in the filling connection
EXAMPLE Non-return valve, isolating valve.
3.19
flow metering device
device that measures and indicates the flow of a specific gas or gas mixture
4 Symbols and descriptions
The symbols used for the physical characteristics are given in Table 1.

ISO 22435:2024(en)
Table 1 — Symbols and descriptions
Symbol Term Characteristic
ip=−pp
()
52 2
i irregularity coefficient
Test method given in 6.12.5.
For compressed gases p = p
1 w
a
For acetylene p = 25 bar
p inlet pressure to the pressure regulating system
For CO p = 200 bar
2 1
For other gases not listed above, p shall be speci-
fied by the manufacturer.
As required by the VIPR application. To be speci-
p nominal outlet pressure
fied by the manufacturer.
P inter-stage pressure To be specified by the manufacturer.
2m
For VIPR without RPD: pp=+()21 bar
For VIPR with RPD: pp=+()26 bar
p test inlet pressure (see also 3.14)
For VIPR with p >20 bar: p to be specified by
2 3
the manufacturer.
closing pressure after stopping the standard dis-
p Test method given in 6.12.3.
charge downstream of the VIPR
p maximum closing pressure (see 3.8) Test method given in 6.12.3.2.
4max
The highest or lowest outlet pressure during a
p test outlet pressure
test for determining i.
As given in the relevant closure standard, e.g. ISO
p valve test pressure
vt
10297, ISO 17871, ISO 17879 and ISO 23826.
As given in the relevant closure standard, e.g. ISO
p valve hydraulic test pressure
vht
10297, ISO 17871, ISO 17879 and ISO 23826.
As given in the relevant closure standard, e.g. ISO
p valve working pressure
w
10297, ISO 17871, ISO 17879 and ISO 23826.
standard discharge of a pressure regulator with a
Q To be specified by the manufacturer.
pressure outlet
Q maximum discharge Test method given in 6.12.3.2.
max
nominal discharge (see 3.16) of a pressure
Q To be specified by the manufacturer.
n
regulator with a flow-metering device
Q discharge of the pressure relief valve Test method given in 6.14.
RV
Rp=−()pp
42 2
R coefficient of pressure increase upon closure
Test method given in 6.12.4.
T overtorque for the pressure adjusting device Test method given in Annex C.
or
a 5 2
1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm .
NOTE  See ISO 2503 for definitions for p , p , p , Q , Q and Q .
1 2 4 1 max rv
5 Design requirements and considerations
5.1 General
Unless otherwise specified, all requirements will apply to all types of valves with integrated pressure
regulator (VIPR), i.e. VIPR type A, VIPR type B and VIPR type C.
A VIPR shall meet the requirements given in the relevant closure standards (e.g. ISO 10297, ISO 17871,
ISO 17879 or ISO 23826).
ISO 22435:2024(en)
5.2 Description
A VIPR typically comprises
— a body,
— an inlet connection to the pressure receptacle,
— a primary valve operating mechanism,
— a valve operating device,
— a filling connection,
— the pressure regulating system,
— a pressure relief valve on the low-pressure side of the regulating system,
— an outlet connection (for the end user).
A VIPR can also be fitted with
— a mechanism to set the outlet flow,
— a pressure relief device, e.g. burst disc, on the high-pressure side to protect the pressure receptacle,
— a dip tube,
— a screwed plug or cap on the outlet and/or the filling connection,
— an excess flow limiting device,
— a means of preventing the ingress of atmospheric air,
— a residual pressure device (see ISO 15996),
— pressure indicator(s) on the high and/or low-pressure sides of devices,
— a flow indicator (e.g. flowmeter or flow gauge),
— contamination prevention measures, e.g. filters, anti-dust tube.
5.3 Materials
The material compatibility and lubricant requirements are given in the relevant closure standard
(e.g. ISO 10297, ISO 17871, ISO 17879 or ISO 23826).
5.4 Pressure and flow indicating devices
5.4.1 General
Pressure and flow indicating devices shall be of the fail-safe type (in case of a failure due to pressure, the
gas shall be released safely and no parts that are able to cause injuries shall be ejected). Examples of these
devices can be found in ISO 2503:2009, Figure A.2.
Pressure and flow indicating devices should be designed to minimize moisture ingress and to prevent
moisture accumulation.
5.4.2 Flowmeters
Such devices shall not rupture when tested in the installed condition in accordance with 6.10.

ISO 22435:2024(en)
5.4.3 Pressure indicators and flow gauges
There is a need to prevent a dangerous discharge of gas if an indicating device is damaged. When bourdon
tube indicators are used, the inlet orifice of such devices shall be limited to a maximum of 0,1 mm and the
orifice shall always be retained within the valve if the indicator is sheared off.
EXAMPLE The orifice can be within the valve body itself or within the part of the indicator that is retained in the
valve body if the rest of the indicator is sheared off.
Such devices shall be tested for overpressure and leakage in the installed condition in accordance with 6.11.
Design and manufacturing requirements from ISO 5171 should be applied, if relevant to the design of VIPR
and indicating devices.
5.5 Outlet connection
The connection shall be either
a) a welding hose connection (e.g. ISO/TR 28821 for a threaded connection or ISO 7289 for a quick
connection or other regional or national standards), or
b) a proprietary fitting; if a quick connection is used, it shall comply with the endurance tests of ISO 7289.
If a device (e.g. check valve) is fitted within the outlet connection, it shall be designed so that it does not
interfere with a gas withdrawal connection made in accordance with the relevant standard.
5.6 Outlet pressure for acetylene
For acetylene, p shall not exceed 1,5 bar.
4max
5.7 Flow control valve (flow controller)
If a flow control valve is fitted, the flow control knob and the valve spindle shall be captive such that they
cannot be dismantled without the use of a tool.
Compliance shall be tested by attempting to remove the knob and spindle without the use of a tool.
5.8 Pressure adjusting device
The pressure adjusting device, if fitted, shall be captive and shall be removable only by the use of a tool.
It shall be demonstrated that the pressure regulator valve cannot be held in the open position as a
consequence of the pressure regulator spring being compressed to its solid length or by being bound by ice,
thereby allowing gas to pass from the high-pressure to the low-pressure side.
It shall also be demonstrated that the bonnet cannot be disassembled without the use of a tool during normal
operation of the pressure adjustment device. For a VIPR designed to allow filling of the pressure receptacle
through the outlet connection, a special tool may be used to hold the pressure regulating system open for
filling only.
Using the pressure adjusting device, it shall not be possible to set a pressure at which the pressure relief
valv
...