Gas cylinders - Residual pressure valves - Specification and type testing of cylinder valves incorporating residual pressure devices (ISO 15996:2017)

ISO 15996:2017 specifies design, type testing and marking requirements for cylinder valves incorporating residual pressure devices, hereinafter referred to as residual pressure valves (RPVs). This document applies to the following types of RPVs:
a)    cylinder valves intended to be fitted to refillable transportable gas cylinders;
b)    main valves (excluding ball valves) for cylinder bundles;
c)    cylinder valves or main valves with integrated pressure regulator (VIPR);
d)    valves for pressure drums and tubes;
which convey compressed or liquefied gases.
NOTE          Where there is no risk of ambiguity, cylinders, pressure drums, tubes and cylinder bundles are addressed with the collective term "cylinder" within this document.
These requirements are in addition to those in ISO 10297.
For RPD stand-alone devices this document can also be applied.
ISO 15996:2017 does not apply to RPVs for portable fire extinguishers, cryogenic equipment, low pressure refrigerant gases (cylinder test pressure less than 50 bar), dissolved gases or liquefied petroleum gas (LPG).

Gasflaschen - Restdruckventile - Spezifikation und Baumusterprüfungen von Flaschenventilen mit integrierten Restdruckeinrichtungen (ISO 15996:2017)

Diese Internationale Norm legt Anforderungen an die Auslegung, Baumusterprüfung und Kennzeichnung von Ventilen mit integrierten Restdruckeinrichtungen fest, die im Folgenden Restdruckventile (RPV) genannt werden. Diese Internationale Norm gilt für folgende RPV Typen:
a)   Flaschenventile zur Anbringung an wiederbefüllbare ortsbewegliche Gasflaschen;
b)   Hauptabsperrventile (ausgenommen Kugelhähne) für Flaschenbündel;
c)   Flaschen  oder Hauptabsperrventile mit integriertem Druckregler (VIPR, en: valves with integrated pressure regulator);
d)   Ventile für Druckfässer und Großflaschen;
die verdichtete oder verflüssigte Gase befördern.
Diese Internationale Norm gilt nicht für Restdruckventile (RPV) für tragbare Feuerlöscher, Kryo Zubehör, Niedrigdruck-Kältemittelgase (Prüfdruck des Druckgefäßes niedriger als 50 bar) oder Flüssiggas (LPG).

Bouteilles à gaz - Robinets à pression résiduelle - Spécifications et essais de type de robinets de bouteille intégrant des dispositifs de pression résiduelle (ISO 15996:2017)

ISO 15996:2017 spécifie les exigences applicables à la conception, aux essais de type et au marquage des robinets de bouteille comportant des dispositifs de pression résiduelle, désignés dans le présent document par le terme «robinets à pression résiduelle» (RPV). Le présent document s'applique aux types de RPV suivants:
a)    les robinets de bouteille destinés à être montés sur des bouteilles à gaz transportables rechargeables;
b)    les vannes principales (à l'exception des robinets à boisseau sphérique) pour cadres de bouteilles;
c)    les robinets de bouteille ou robinets de bouteille à détendeur intégré (VIPR);
d)    les robinets pour les fûts à pression et les tubes;
utilisés pour transporter des gaz comprimés ou liquéfiés.
NOTE          Lorsqu'il n'existe aucun risque d'ambiguïté, les bouteilles, fûts à pression, tubes et cadres de bouteilles sont désignés par le terme générique «bouteille» dans le présent document.
Ces exigences s'ajoutent à celles de l'ISO 10297.
ISO 15996:2017 peut également être appliqué aux dispositifs RPD autonomes.
Le présent document ne s'applique pas aux RPV destinés aux extincteurs d'incendie portables, aux équipements cryogéniques, aux gaz réfrigérants à basse pression (pression d'épreuve de la bouteille inférieure à 50 bar), aux gaz dissous ou aux gaz de pétrole liquéfié (GPL).

Plinske jeklenke - Ventili za zagotavljanje ostanka tlaka - Specifikacija in preskus tipa ventilov za jeklenke z elementom za zagotavljanje ostanka tlaka (ISO 15996:2017)

ISO 15996:2005 določa zahteve za preostale tlačne ventile s funkcijo vračanja ali brez nje za plinske jeklenke in načine preskušanja takšnih ventilov za tipsko odobritev.
ISO 15996:2005 se uporablja pri ventilih, ki bodo nameščeni na plinske jeklenke s kapaciteto do 150 l, ki so predvidene za stisnjene, utekočinjene ali raztopljene pline.
ISO 15996:2005 ne obsega ventilov za gasilnike, kriogensko opremo ali utekočinjeni naftni plin.

General Information

Status
Published
Publication Date
05-Sep-2017
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Sep-2017
Completion Date
06-Sep-2017

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SLOVENSKI STANDARD
SIST EN ISO 15996:2018
01-maj-2018
1DGRPHãþD
SIST EN ISO 15996:2005
SIST EN ISO 15996:2005/A1:2008

Plinske jeklenke - Ventili za zagotavljanje ostanka tlaka - Specifikacija in preskus

tipa ventilov za jeklenke z elementom za zagotavljanje ostanka tlaka (ISO
15996:2017)

Gas cylinders - Residual pressure valves - Specification and type testing of cylinder

valves incorporating residual pressure devices (ISO 15996:2017)
Gasflaschen - Restdruckventile - Spezifikation und Baumusterprüfungen von
Flaschenventilen mit integrierten Restdruckeinrichtungen (ISO 15996:2017)

Bouteilles à gaz - Robinets à pression résiduelle - Spécifications et essais de type de

robinets de bouteille intégrant des dispositifs de pression résiduelle (ISO 15996:2017)

Ta slovenski standard je istoveten z: EN ISO 15996:2017
ICS:
23.020.35 Plinske jeklenke Gas cylinders
23.060.40 7ODþQLUHJXODWRUML Pressure regulators
SIST EN ISO 15996:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 15996:2018
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SIST EN ISO 15996:2018
EN ISO 15996
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2017
EUROPÄISCHE NORM
ICS 23.020.35 Supersedes EN ISO 15996:2005
English Version
Gas cylinders - Residual pressure valves - Specification and
type testing of cylinder valves incorporating residual
pressure devices (ISO 15996:2017)

Bouteilles à gaz - Robinets à pression résiduelle - Gasflaschen - Restdruckventile - Spezifikation und

Spécifications et essais de type de robinets de bouteille Baumusterprüfungen von Flaschenventilen mit

intégrant des dispositifs de pression résiduelle (ISO integrierten Restdruckeinrichtungen (ISO

15996:2017) 15996:2017)
This European Standard was approved by CEN on 11 July 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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: Avenue Marnix 17, B-1000 Brussels

© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15996:2017 E

worldwide for CEN national Members.
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SIST EN ISO 15996:2018
EN ISO 15996:2017 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 15996:2018
EN ISO 15996:2017 (E)
European foreword

This document (EN ISO 15996:2017) 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 March 2018, and conflicting national standards shall

be withdrawn at the latest by March 2018.

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 15996:2005.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Serbia, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 15996:2017 has been approved by CEN as EN ISO 15996:2017 without any modification.

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SIST EN ISO 15996:2018
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SIST EN ISO 15996:2018
INTERNATIONAL ISO
STANDARD 15996
Second edition
2017-07
Gas cylinders — Residual pressure
valves — Specification and type testing
of cylinder valves incorporating
residual pressure devices
Bouteilles à gaz — Robinets à pression résiduelle — Spécifications
et essais de type de robinets de bouteille intégrant des dispositifs de
pression résiduelle
Reference number
ISO 15996:2017(E)
ISO 2017
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SIST EN ISO 15996:2018
ISO 15996:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland

All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
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SIST EN ISO 15996:2018
ISO 15996:2017(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 RPV design considerations and requirements ...................................................................................................................... 3

4.1 Design considerations....................................................................................................................................................................... 3

4.1.1 Resistance against vibration .................................................................................................................................. 3

4.1.2 Integrity under high flow ......................................................................................................................................... 4

4.2 Design requirements ......................................................................................................................................................................... 4

4.2.1 General...................................................................................................................................................................................... 4

4.2.2 Valve outlet connection .............................................................................................................................................. 4

4.3 Performance requirements for RPDs................................................................................................................................... 4

4.3.1 Requirements for type 1 and type 2 RPDs ................................................................................................. 4

4.3.2 Additional requirements for type 1 RPDs .................................................................................................. 5

5 RPV type testing .................................................................................................................................................................................................... 5

5.1 General ........................................................................................................................................................................................................... 5

5.2 Documentation ....................................................................................................................................................................................... 6

5.3 Test samples .............................................................................................................................................................................................. 6

5.4 Test report ................................................................................................................................................................................................... 7

5.5 Test temperatures ................................................................................................................................................................................ 7

5.6 Test pressures .......................................................................................................................................................................................... 7

5.6.1 RPV test pressure ............................................................................................................................................................ 7

5.6.2 Other test pressures ...................................................................................................................................................... 7

5.7 Test gases ..................................................................................................................................................................................................... 7

5.7.1 Gas quality ............................................................................................................................................................................. 7

5.7.2 Verification of opening pressure and closing-off pressure.......................................................... 8

5.7.3 Leak tightness test in the reverse direction for type 1 RPDs ..................................................... 8

5.7.4 Endurance test ................................................................................................................................................................... 8

5.7.5 Oxygen pressure surge test..................................................................................................................................... 8

5.7.6 Vibration test ...................................................................................................................................................................... 8

5.7.7 Integrity under high flow test ............................................................................................................................... 9

5.8 Test schedule ............................................................................................................................................................................................ 9

5.9 RPD performance tests .................................................................................................................................................................10

5.9.1 Strength test of the non-return function in the reverse direction for

type 1 RPDs .......................................................................................................................................................................10

5.9.2 Verification of opening pressure and closing-off pressure.......................................................10

5.9.3 Endurance test ................................................................................................................................................................11

5.9.4 Leak tightness test in the reverse direction for type 1 RPDs ..................................................11

5.9.5 Visual examination ......................................................................................................................................................12

6 Marking .......................................................................................................................................................................................................................12

Annex A (informative) Design considerations .........................................................................................................................................13

Annex B (normative) Oxygen pressure surge test ...............................................................................................................................14

Annex C (informative) Vibration test ................................................................................................................................................................15

Annex D (informative) Integrity under high flow test .....................................................................................................................16

Annex E (informative) Examples of test equipment ..........................................................................................................................18

Bibliography .............................................................................................................................................................................................................................21

© ISO 2017 – All rights reserved iii
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SIST EN ISO 15996:2018
ISO 15996:2017(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 on 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 the following

URL: w w w . i s o .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 2,

Cylinder fittings.

This second edition cancels and replaces the first edition (ISO 15996:2005), which has been technically

revised. It also incorporates the Amendment ISO 15996:2005/Amd 1:2007.
The main changes compared to the previous edition are as follows:

a) Title and scope: extension to cover the complete RPV (valve including the residual pressure device)

and not the RPD (residual pressure device) only; informative reference to ISO 10297 was modified;

b) Scope: inclusion of main valves, valves with integrated pressure regulator (VIPRs) and RPVs for

pressure drums and tubes; exclusion of dissolved gases, possible application for RPD stand-alone

devices;

c) Terms, definitions and symbols: introduction of new definitions and adaptation of existing

definitions; introduction of different types of RPDs to replace the old descriptions and change of

order (type A became type 2 and type B became type 1);

d) Valve design considerations: inclusion of design considerations with addition of informative

Annex A;
e) Performance requirements and considerations:

1) Closing-off pressure and opening pressure: introduction of requirements for opening pressure

and closing-off pressure, especially of a minimum value for the closing-off pressure;

2) Endurance: reduction of number of endurance cycles for type 2 RPDs;

3) Visual examination: introduction of visual examination at the end of the complete test

procedure;
iv © ISO 2017 – All rights reserved
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SIST EN ISO 15996:2018
ISO 15996:2017(E)

4) Resistance of the non-return function against pressure in the reverse direction for type 1

RPDs: exclusion of RPDs in VIPRs and adaptation of pass-fail requirements;

5) Leak tightness in the reverse direction for type 1 RPDs: exclusion of RPDs in VIPRs;

6) Integrity under high flow: exclusion of RPDs when installed outside the filling path in a VIPR;

f) RPV type testing:

1) General: introduction of information on how to deal with changes within the RPV design;

2) Test samples: addition of requirement to submit the test samples for oxygen pressure surge

testing with the relevant filling connector(s);

3) Test gases: introduction of requirements on the use and quality of the test gases;

4) Test schedule: adaptation to meet the new requirements, addition of test pressure and test

temperature; deletion of information on variants;

5) Strength test of the non-return function in the reverse direction for type 1 RPD tests: decrease

of number of test samples to one;

6) Verification of opening pressure and closing-off pressure: addition of verification at low and

high temperature; addition of detailed test procedure;

7) Leak tightness test in the reverse direction for type 1 RPDs: modification and clarification of

tightness test in the flow direction; addition of test at 0,5 bar in the reverse direction;

8) Visual examination: addition of visual examination to the test sequence;

9) Oxygen pressure surge test: information transferred to normative Annex B; addition of test for

main valves; addition of detailed information on test procedure;
g) Marking: introduction of marking requirements;

h) Annex A (informative): deletion of examples of RPV designs; introduction of design considerations;

i) Annex B (normative): information on test equipment transferred to informative Annex D; new

Annex B giving mandatory requirements on oxygen pressure surge test;
j) Annex C (informative): update of MIL standard reference for vibration test;

k) Annex D (informative): complete modification of integrity under high flow test (reduction of

number of test samples, adaptation of gases for which an additional test with carbon dioxide

should be carried out, change from liquid carbon dioxide to gaseous carbon dioxide as test gas,

modification of test procedure);

l) Annex E: new informative Annex E giving information on test equipment (former Annex B).

© ISO 2017 – All rights reserved v
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SIST EN ISO 15996:2018
ISO 15996:2017(E)
Introduction

Increased requirements to avoid contamination of gases and cylinders have led to the development

of valves incorporating residual pressure devices (RPDs) hereinafter referred to as residual pressure

valves (RPVs).

These devices are designed to maintain a positive pressure relative to atmosphere within the cylinder

by closing off its internal gas passages in the discharging direction. This prevents the cylinder from

being completely emptied in customer use and stops ingress of atmospheric contamination if the valve

operating mechanism (main shut-off) is left open. Many of these devices include a non-return function

that protects the cylinder from backflow from downstream processes.

This document has been written so that it is suitable for the application of the UN Model Regulations.

Considering the changes described in the Foreword, when an RPV has been approved according to the

previous version of this document, the body responsible for approving the same RPV 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 2017 – All rights reserved
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SIST EN ISO 15996:2018
INTERNATIONAL STANDARD ISO 15996:2017(E)
Gas cylinders — Residual pressure valves — Specification
and type testing of cylinder valves incorporating residual
pressure devices
1 Scope

This document specifies design, type testing and marking requirements for cylinder valves

incorporating residual pressure devices, hereinafter referred to as residual pressure valves (RPVs).

This document applies to the following types of RPVs:

a) cylinder valves intended to be fitted to refillable transportable gas cylinders;

b) main valves (excluding ball valves) for cylinder bundles;
c) cylinder valves or main valves with integrated pressure regulator (VIPR);
d) valves for pressure drums and tubes;
which convey compressed or liquefied gases.

NOTE Where there is no risk of ambiguity, cylinders, pressure drums, tubes and cylinder bundles are

addressed with the collective term “cylinder” within this document.
These requirements are in addition to those in ISO 10297.
For RPD stand-alone devices this document can also be applied.

This document does not apply to RPVs for portable fire extinguishers, cryogenic equipment, low

pressure refrigerant gases (cylinder test pressure less than 50 bar), dissolved gases or liquefied

petroleum gas (LPG).
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 10286, Gas cylinders — Terminology
ISO 10297:2014, Gas cylinders — Cylinder valves — Specification and type testing

ISO 10524-3, Pressure regulators for use with medical gases — Part 3: Pressure regulators integrated with

cylinder valves

ISO 22435, Gas cylinders — Cylinder valves with integrated pressure regulators — Specification and

type testing
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 10286, ISO 10297 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
© ISO 2017 – All rights reserved 1
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SIST EN ISO 15996:2018
ISO 15996:2017(E)
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
residual pressure valve
RPV
valve which incorporates a residual pressure device (3.2)

Note 1 to entry: The term “valve” covers the valves listed in Clause 1, a) to d).

3.2
residual pressure device
RPD

device that is designed to prevent ingress of contaminants by maintaining a positive pressure within

the cylinder relative to atmosphere by closing off its internal gas passages in the discharging direction

Note 1 to entry: This definition might be different to definitions given in applicable transport regulations.

3.3
type 1 RPD

RPD (3.2) that retains a positive pressure in the cylinder above the pressure downstream of the valve

outlet and also incorporates a non-return feature to prevent backflow into the cylinder from a higher

pressure on the valve outlet

Note 1 to entry: Cylinders with RPVs with a type 1 RPD located between the filling port and cylinder cannot be

filled or vacuumed unless the RPD is neutralized or a special fill connector is used to overcome the non-return

feature.
3.4
type 2 RPD

RPD (3.2) that retains a positive pressure in the cylinder above atmospheric pressure but will not

prevent backflow into the cylinder if the pressure on the valve outlet is high enough to overcome the

RPD mechanism and the residual pressure in the cylinder

Note 1 to entry: Cylinders with RPVs with a type 2 RPD can be filled with a conventional fill connector, but,

if located between the filling port and cylinder, cannot be vacuumed or vented below the closing-off pressure

unless the RPD is neutralized or a special fill connector is used.
3.5
discharging direction

path taken by gas through the RPD (3.2) when flowing out of the cylinder through the outlet connection

3.6
reverse direction

path taken by gas towards the RPD (3.2) in the opposite direction to the discharging direction (3.5)

3.7
filling direction
path taken by gas through the RPV (3.1) when filling the cylinder

Note 1 to entry: Depending on the design of the RPV (3.1), filling direction and reverse direction (3.6) might be

the same.
3.8
opening pressure

differential pressure between upstream pressure and downstream pressure of the RPD (3.2) at which

the RPD starts to open to allow gas to flow in the discharging direction (3.5)

Note 1 to entry: Due to the effects of manufacturing tolerances this is normally expressed as a pressure range.

2 © ISO 2017 – All rights reserved
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SIST EN ISO 15996:2018
ISO 15996:2017(E)
3.9
closing-off pressure

cylinder pressure at which leak tight closure of the RPD (3.2) is achieved during gas withdrawal through

the outlet connection

Note 1 to entry: Due to the effects of manufacturing tolerances and different discharge rates this is expressed as

a pressure range.
3.10
RPV working pressure

settled pressure of a compressed gas at a uniform reference temperature of 15 °C in a full cylinder for

which the RPV (3.1) is intended

Note 1 to entry: This definition does not apply to liquefied gases (e.g. carbon dioxide), or dissolved gases (e.g.

acetylene).
Note 2 to entry: The RPV working pressure is expressed in bar.
3.11
RPV test pressure
pressure applied to a RPV (3.1) during testing

Note 1 to entry: The RPV test pressure is a minimum value and is expressed in bar.

3.12
NTP

normal temperature and pressure i.e. 20,0 °C (293,15 K), 1,013 bar absolute (0,101 3 MPa absolute)

3.13
RPV filling connector

device fitted to the filling connection of RPVs (3.1) fitted with type 1 RPDs (3.3) during filling to overcome

the non-return feature and for both type 1 and type 2 RPDs (3.4) during venting and vacuuming

Note 1 to entry: These connectors are design-specific and usually not standardized.

3.14
standard connector

device that is manufactured to an international, regional or national standard which is fitted to the

valve filling connection of a valve with or without RPD (3.2) to allow users to withdraw gas from the

cylinder and which can also be used to fill cylinders having RPVs (3.1) fitted with type 2 RPDs (3.4)

Note 1 to entry: These connectors are usually standardized.
3.15
RPD neutralization device

device fitted to RPVs (3.1) with type 2 RPDs (3.4) to neutralize the RPD (3.2) if so designed and intended

to be neutralized during filling and vacuuming
4 RPV design considerations and requirements
4.1 Design
...

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