EN ISO 15995:2021

SLOVENSKI STANDARD
01-september-2021
Nadomešča:
SIST EN ISO 15995:2019
Plinske jeklenke - Specifikacija in preskušanje ventilov za jeklenke za utekočinjeni
naftni plin (UNP) - Ročno upravljanje (ISO 15995:2021)
Gas cylinders - Specifications and testing of LPG cylinder valves - Manually operated
(ISO 15995:2021)
Gasflaschen - Spezifikation und Prüfung von Flaschenventilen für Flüssiggas (LPG) -
Handbetätigt (ISO 15995:2021)
Bouteilles à gaz - Spécifications et essais pour valves de bouteilles de GPL - Fermeture
manuelle (ISO 15995:2021)
Ta slovenski standard je istoveten z: EN ISO 15995:2021
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 15995
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2021
EUROPÄISCHE NORM
ICS 23.020.35 Supersedes EN ISO 15995:2019
English Version
Gas cylinders - Specifications and testing of LPG cylinder
valves - Manually operated (ISO 15995:2021)
Bouteilles à gaz - Spécifications et essais pour valves de Gasflaschen - Spezifikation und Prüfung von
bouteilles de GPL - Fermeture manuelle (ISO Flaschenventilen für Flüssiggas (LPG) - Handbetätigt
15995:2021) (ISO 15995:2021)
This European Standard was approved by CEN on 6 June 2021.

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, Turkey 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15995:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 15995:2021) has been prepared by Technical Committee ISO/TC 58 "Gas
cylinders" in collaboration with Technical Committee CEN/TC 286 “Liquefied petroleum gas equipment
and accessories” the secretariat of which is held by NSAI.
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 December 2021, and conflicting national standards
shall be withdrawn at the latest by December 2021.
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 15995:2019.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 15995:2021 has been approved by CEN as EN ISO 15995:2021 without any modification.

INTERNATIONAL ISO
STANDARD 15995
Third edition
2021-06
Gas cylinders — Specifications and
testing of LPG cylinder valves —
Manually operated
Bouteilles à gaz — Spécifications et essais pour valves de bouteilles de
GPL — Fermeture manuelle
Reference number
ISO 15995:2021(E)
©
ISO 2021
ISO 15995:2021(E)
© ISO 2021
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 2021 – All rights reserved

ISO 15995:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design and specification. 4
4.1 General . 4
4.2 Materials . 5
4.2.1 General. 5
4.2.2 Operating temperatures . 5
4.2.3 Copper alloys . 5
4.2.4 Non-metallic materials . 5
4.3 Essential components . 6
4.3.1 Valve operating mechanism . 6
4.3.2 Valve body . 6
4.3.3 Valve stem . 6
4.3.4 Valve outlet . 6
4.3.5 Excess flow valve . 7
4.4 Optional components . 7
4.4.1 General. 7
4.4.2 Pressure relief valve . 7
4.4.3 Eduction tube . 7
4.4.4 Fixed liquid level gauge . 7
4.4.5 Excess flow valve . 7
4.4.6 Non-return valve . 8
4.4.7 Liquid level indicator . 8
4.4.8 Sealing cap and sealing plug . 8
4.4.9 Sediment tube . 8
4.5 Leak tightness . 8
4.6 Operating torque . 8
4.7 Closing torque . 8
4.8 Opening torque . 8
5 Valve type test . 9
5.1 General . 9
5.2 Test samples . 9
5.3 Test procedure and test requirements .10
5.4 Inspection .11
5.5 Hydraulic pressure test .11
5.5.1 Procedure .11
5.5.2 Requirement .11
5.6 External and internal leak tightness tests .11
5.6.1 Procedure .11
5.6.2 Requirement .12
5.7 Valve stem test .12
5.7.1 Procedure .12
5.7.2 Requirement .13
5.8 Hand wheel fire exposure test .13
5.8.1 Procedure .13
5.8.2 Requirement .13
5.9 Impact test .13
5.9.1 General.13
5.9.2 Procedure .13
ISO 15995:2021(E)
5.9.3 Requirement .15
5.10 Excessive closing torque test .15
5.10.1 Procedure .15
5.10.2 Requirement .15
5.11 Excessive opening torque test.15
5.11.1 Procedure .15
5.11.2 Requirement .15
5.12 Endurance test .16
5.12.1 Procedure .16
5.12.2 Requirement .16
5.13 Examination of dismantled valves .16
5.13.1 Procedure .16
5.13.2 Requirement .17
5.14 Excess flow valve test .17
5.14.1 General.17
5.14.2 Excess flow valve test with air .17
5.14.3 Excess flow valve test with water .17
5.14.4 Excess flow strength test .18
5.15 Non-return valve test .18
5.15.1 Procedure .18
5.15.2 Requirement .18
5.16 Vibration test .19
5.16.1 Procedure .19
5.16.2 Requirement .19
6 Documentation and test report.19
6.1 Documentation .19
6.2 Test report .19
7 Production testing .19
8 Markings .19
Annex A (normative) Special valves .21
Annex B (normative) Production testing and inspection .22
Annex C (normative) Special low temperature requirements .23
Annex D (normative) Vibration testing .24
Bibliography .25
iv © ISO 2021 – All rights reserved

ISO 15995:2021(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.
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 286, Liquefied petroleum gas equipment and accessories, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 15995:2019) of which it constitutes a
minor revision. The changes compared to the previous edition are as follows:
— correction of Clause 8, list item c).
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.
ISO 15995:2021(E)
Introduction
This document covers the function of a LPG cylinder valve as a closure (defined by the UN Model
[15]
Regulations ).
This document has been written so that it is suitable to be referenced in the UN Model Regulations.
Cylinder valves complying with this document can be expected to perform satisfactorily under normal
service conditions.
When an LPG cylinder valve has been approved according to a previous version of this document, the
body responsible for approving the same LPG cylinder valve to this new edition 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. It should,
however, be noted that bar is not an SI unit, and that the corresponding SI unit for pressure is Pa
5 5 2
(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.
vi © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 15995:2021(E)
Gas cylinders — Specifications and testing of LPG cylinder
valves — Manually operated
1 Scope
This document specifies the requirements for design, specification, type testing and production testing
and inspection of dedicated LPG manually operated cylinder valves for use with and directly connected
to transportable refillable LPG cylinders.
It also includes requirements for associated equipment for vapour and liquid service. Bursting discs
and/or fusible plugs are not covered in this document.
Annex B identifies requirements for production testing and inspection.
This document excludes other LPG cylinder devices which are not an integral part of the dedicated
manually operated cylinder valve.
This document does not apply to cylinder valves for fixed automotive installations and ball valves.
NOTE For self-closing LPG cylinder valves see ISO 14245. For cylinder valves for compressed, dissolved and
[2] [6] [7]
other liquefied gases see ISO 10297, ISO 17871 or ISO 17879 .
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 11114-1, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 1:
Metallic materials
ISO 11114-2, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2:
Non-metallic materials
ISO 2859-1:1999, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by
acceptance quality limit (AQL) for lot-by-lot inspection
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 10286, Gas cylinders — Terminology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10286 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
ISO 15995:2021(E)
3.1
liquefied petroleum gas
LPG
low pressure liquefied gas composed of one or more light hydrocarbons which are assigned to UN 1011,
UN 1075, UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane,
butane isomers, butene with traces of other hydrocarbon gases
[SOURCE: ISO 10286:2015, 723, modified.]
3.2
cylinder valve
valve
primary shutoff device fitted to LPG cylinders, intended for liquid or vapour filling and withdrawal
Note 1 to entry: The valve includes the valve body (3.8), valve stem (3.14), valve outlet (3.15) and valve operating
mechanism (3.22).
Note 2 to entry: The valve can also include additional devices, e.g. eduction tube (3.5), liquid level indicator (3.7),
fixed liquid level gauge (3.6), excess flow valve (3.9), non-return valve (3.10), sediment tube (3.19), and pressure
relief valve (3.30).
3.3
external leak tightness
leak tightness to atmosphere (leakage in and/or leakage out), when the valve is open
3.4
internal leak tightness
leak tightness across the valve seat (leakage in and/or leakage out), when the valve is closed
3.5
eduction tube
tube fitted to the valve to allow withdrawal of liquid LPG with the cylinder in its normal operating
position
3.6
fixed liquid level gauge
device such as a dip tube in combination with a vent valve to verify that the predetermined maximum
liquid level in a cylinder has been reached or surpassed
3.7
liquid level indicator
device such as a float gauge, permitting the gauging of the liquid level in the cylinder
3.8
valve body
major valve component including valve stem (3.14) and valve outlet (3.15) and, where applicable, the
provision for other optional components
3.9
excess flow valve
valve comprising two or more components designed to close or partially close when the flow of liquid or
vapour passing through it exceeds a predetermined value and to re-open when the pressure differential
across the valve has been restored below a certain value
3.10
non-return valve
automatic valve which allows gas/liquid to flow only in one direction
[SOURCE: ISO 10286:2015, 349, amended — liquid added.]
2 © ISO 2021 – All rights reserved

ISO 15995:2021(E)
3.11
dual valve
valve designed to allow separate vapour and liquid withdrawal from a cylinder in its normal operating
position each port having its own valve operating mechanism
3.12
sealing element
element used to obtain internal leak tightness (3.4)
3.13
special valve
valve which is only used for cylinders up to and including 7,5 l water capacity, having a hand wheel
diameter less than 30 mm and where the maximum section of gas passage is not more than 4 mm
diameter
3.14
valve stem
section of the valve body (3.8), which connects to the cylinder
3.15
valve outlet
section of the valve body (3.8) to which a regulator or connector can be fitted for vapour or liquid
withdrawal
Note 1 to entry: The valve outlet is also normally used for filling the cylinder.
3.16
type test
test or series of tests conducted to prove that the design meets the requirements of this document
3.17
cylinder opening
part of the cylinder to which the valve stem (3.14) connects
3.18
test pressure
pressure at which the valve or component is tested
3.19
sediment tube
device designed to reduce the risk of foreign matter, which can be in the cylinder, entering the valve
3.20
sealing cap
device which is intended to seal the external outlet connection of a valve
[SOURCE: ISO 10286:2015, 368]
3.21
sealing plug
device which is intended to seal the internal outlet connection of a valve
[SOURCE: ISO 10286:2015, 369]
3.22
valve operating mechanism
mechanism which closes and opens the valve orifice and which includes the internal and external
sealing systems
[SOURCE: ISO 10286:2015, 328, modified — EXAMPLE deleted.]
Note 1 to entry: Normally the valve operating mechanism includes the hand wheel.
ISO 15995:2021(E)
3.23
operating torque
torque during opening or closing the valve, after the first half rotation of the hand wheel in opening the
valve and before the last half rotation of the hand wheel in closing the valve
3.24
opening torque
initial torque required to open the valve from the closed position
3.25
closing torque
torque required to close the valve and obtain internal leak tightness (3.4)
3.26
valve protection cap
device securely fixed over the valve during handling, transport and storage and which is removed for
access to the valve
[SOURCE: ISO 10286:2015, 360]
3.27
valve shroud
integral part of a cylinder which is permanently attached for valve protection during transportation,
handling and storage
[SOURCE: ISO 10286:2015, 362]
3.28
valve guard
device securely fixed over the valve during handling transport and storage and which does not need to
be removed for access to the valve
3.29
gross mass
total package mass of the heaviest cylinder on which the valve is intended to be fitted, including any
permanently attached accessories and the maximum mass of the LPG content
3.30
pressure relief valve
pressure actuated valve held shut by a spring or other means and designed to relieve excessive pressure
automatically by starting to open at the set pressure and reclosing after the pressure has fallen below
the set pressure
3.31
nominal set pressure
predetermined pressure of the pressure relief valve (3.30) at which the valve is set to start to discharge
4 Design and specification
4.1 General
The valve shall be capable of withstanding:
a) operating pressures and test pressures;
b) operating temperatures and test temperature;
c) mechanical stresses during operation;
d) vibration during transport.
4 © ISO 2021 – All rights reserved

ISO 15995:2021(E)
The valve shall be externally and internally leak tight for the full range of pressure and temperature
conditions.
The valve and its optional components shall be secured to prevent unintentional disassembly during
normal operation and their function shall not be affected as a result of vibration during transport.
4.2 Materials
4.2.1 General
Materials in contact with LPG shall be physically and chemically compatible with LPG under all
operating conditions for which the valve is designed in accordance with ISO 11114-1 and ISO 11114-2.
In selecting an appropriate material for valve components, it is important to select not only for
adequate strength in service, but also to give consideration to other modes of failure due to atmospheric
corrosion, brass dezincification, stress corrosion, shock loads, and material failure.
4.2.2 Operating temperatures
Materials used shall be suitable for the temperatures for which the valve is designed.
The minimum operating temperature to which the valve is expected to be exposed during normal use
is −20 °C. For some countries and for certain applications, lower minimum operating temperatures
are used. When valves are designed for an operating temperature of −40 °C, they shall also meet the
requirements of Annex C.
The maximum operating temperature to which the valve is expected to be exposed during normal
operation is +65 °C.
4.2.3 Copper alloys
Valve bodies made from copper alloys shall be manufactured from materials in accordance with
[9] [10]
recognized international, regional (e.g. EN 12164 and EN 12165 ) or national standards or from
alloys of equivalent properties and standards.
4.2.4 Non-metallic materials
Non-metallic materials in contact with LPG shall be compatible with LPG and shall not fail during the
valve service life. They shall not distort, harden, swell or adhere to the body or seat face to such an
extent as to impair the function of the valve.
[8]
In accordance with recognized international, regional (e.g. EN 549 ) or national standards, rubber
materials in contact with LPG, for temperatures of –20 °C (–40 °C for low temperature applications) to
+65 °C, shall meet the requirements for resistance to:
a) gas (n-pentane test);
b) lubricants;
c) ageing;
d) compression;
e) ozone (where the material is exposed to the atmosphere); and
f) condensate/liquid phase of combustible gases (liquid B test).
ISO 15995:2021(E)
4.3 Essential components
4.3.1 Valve operating mechanism
The valve operating mechanism shall be designed in such a way that it remains captive and achieves
direct contact with the valve body in the absence of the sealing element, in order to limit the leakage
rate of gas and shall satisfy the requirements of 5.4. There shall be sufficient travel distance for the
valve operating mechanism so that the seal housing makes contact with the seat.
The valve shall operate without difficulty, even after prolonged use, and shall satisfy the requirements
of 5.13.
When a torque is applied in excess of that given in 5.10 and 5.11 the valve operating mechanism shall not
disassemble from the valve body and the valve shall not leak. However, the valve operating mechanism
may break or become inoperable.
The material of the hand wheel shall withstand fire engulfment such that the valve can still be closed
by hand or using a simple tool after cooling, during the early stage of an incident, and shall satisfy the
requirements of 5.8.
The sealing element shall be attached or otherwise assembled and shall not become dislocated under
service conditions to ensure internal leak tightness. The means to secure the sealing element shall not
rely only on adhesive.
All valves shall close when turned clockwise and open when turned anti-clockwise. The hand wheel
shall be visibly marked with a portion of circle terminating by two arrows. One arrow shall be marked
with “–” (closure) and the other arrow with “+” (opening) to indicate the result of the rotation.
4.3.2 Valve body
If the valve body is made of more than one part, precautions shall be taken to ensure that there can be
no unintentional disassembly.
4.3.3 Valve stem
Valve inlet connections shall conform to an international, regional or national standard.
[3] [5]
NOTE Valve inlet connection standards are for example ISO 11363-1 and ISO 15245-1 .
The design of the valve stem shall prevent leakage, loosening in service, and meet the requirements of
5.7.
Tapered valve stems shall withstand the torque identified in Table 3, without causing such damage as
to affect performance, valve operating mechanism, internal leak tightness and external leak tightness.
However, such torque values shall not be used for normal operational applications, see ISO 13341.
Parallel threaded valve stems shall withstand the torque identified in 5.7 d).
4.3.4 Valve outlet
Valve outlet connections shall conform to an international, regional or national standard.
[1] [12]
NOTE Valve outlet connection standards are, for example, ISO 5145 and EN 15202 .
In the case of a vapour/liquid dual valve, the following requirements shall apply:
a) The valve shall have separate vapour and liquid outlet connections. The wall thickness between the
passageways through the valve body shall not be less than 1 mm.
b) The liquid outlet shall be a different design from that of the vapour outlet. Valves with liquid
and vapour outlets shall have clear identification to distinguish between them, such as different
connection geometry and/or marking the outlet connections.
6 © ISO 2021 – All rights reserved

ISO 15995:2021(E)
c) It shall not be possible to obtain a flow from the liquid outlet before a leak tight connection has
been made. This shall be verified by dimensional check in accordance with 5.4.
4.3.5 Excess flow valve
Valves with passageways of cross-sectional area equivalent to or greater than a 3 mm diameter hole for
liquid, or an 8 mm diameter hole for vapour, shall be protected by an excess flow valve (see 4.4.5).
This requirement is not applicable for hot air balloon applications where a risk assessment identifies
that the fitting of an excess flow valve would constitute a significant hazard.
4.4 Optional components
4.4.1 General
Optional components, if fitted, shall meet the following requirements.
All optional components necessary for the correct function of the valve, shall be secured to prevent
unintentional disassembly during normal operation and/or their function shall not be affected, as a
result of vibration during transportation.
Valves including their intended optional components shall be designed to ensure external and internal
leak tightness.
4.4.2 Pressure relief valve
Pressure relief valves shall be designed to operate in the vapour phase. Pressure relief valves for
[11]
LPG cylinders shall conform to an international, regional (e.g. EN 13953 ) or national standard.
4.4.3 Eduction tube
Eduction tubes shall be securely fitted to the valve to ensure that they do not disassemble during
operation, for example using adhesive, press fitting or any other mechanical means.
4.4.4 Fixed liquid level gauge
Fixed liquid level gauges that operate by means of temporarily venting a limited quantity of LPG shall
meet the following requirements:
a) The cross-section of the passage way through the gauge body shall at some point be limited to an
area equivalent to or less than a 1,5 mm diameter hole.
b) The orifice shall be controlled by a vent screw.
c) The vent screw shall remain captive or be permanently attached to the gauge body.
The length of the dip tube should be sized to match the maximum liquid contents of the cylinder.
4.4.5 Excess flow valve
Excess flow valves shall be designed so that the excess flow valve function does not interfere with the
operation of a pressure relief valve and/or fusible plug.
Excess flow valves shall be designed so that when closed the flow past the seat, to allow for reduction
of differential pressure across the valve, shall not exceed that of an opening of 1,8 mm cross sectional
area.
ISO 15995:2021(E)
Excess flow valves shall operate at a flow-rate of not more than 10 % above, nor less than 20 % below
the rated closing flow capacity specified and it shall close automatically at a pressure differential across
the valve of not more than 1,4 bar.
The connection to the cylinder shall not affect the function of the valve or its rated flow.
4.4.6 Non-return valve
Non-return valves with soft seats shall maintain internal tightness throughout the valve service life.
Non-return valves shall be designed so that, when closed, the reverse flow past the seat meet the
requirements of 5.15.2 at room temperature (typically between 15 °C and 30 °C).
4.4.7 Liquid level indicator
Liquid level indicators shall be designed not to interfere with the performance of the pressure relief
valve or excess flow valve (if fitted).
4.4.8 Sealing cap and sealing plug
The valve may also be fitted with a sealing cap or sealing plug. Sealing caps and sealing plugs shall
[13]
conform to an international, regional (e.g. EN 16119 ) or national standard.
4.4.9 Sediment tube
The sediment tube inlet shall be in the vapour space when the cylinder is in its normal operating
orientation at its maximum fill and operating temperature.
4.5 Leak tightness
The leak rate for external and internal leak tightness shall not exceed the
...