Safety and control devices for gas burners and gas-burning appliances — Particular requirements — Part 4: Valve-proving systems for automatic shut-off valves

ISO 23551-4:2018 specifies safety, constructional and performance requirements of valve-proving systems (VPS), intended for use with gas burners and gas-burning appliances. It also describes the test procedures for checking compliance with these requirements and provides information necessary for the purchaser and user. ISO 23551-4:2018 is applicable to all types of VPS which are used for the automatic detection of leakage in a gas burner section having at least two valves designed in accordance with ISO 23551‑1 and which give a signal if the leakage of one of the valves exceeds the detection limit. ISO 23551-4:2018 is applicable to VPS with a maximum working pressure up to and including 500 kPa for use in systems using fuel gases. ISO 23551-4:2018 is not applicable to VPSs for use in explosive atmospheres. NOTE Provisions for production control are not part of the ISO 23551 series.

Dispositifs de contrôle et de sécurité pour les brûleurs à gaz et pour les appareils utilisant le gaz — Exigences particulières — Partie 4: Systèmes de contrôle d'étanchéité pour robinets automatiques de sectionnement

General Information

Status
Published
Publication Date
24-Apr-2018
Current Stage
6060 - International Standard published
Start Date
25-Apr-2018
Completion Date
25-Apr-2018
Ref Project

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INTERNATIONAL ISO
STANDARD 23551-4
Second edition
2018-04
Safety and control devices for gas
burners and gas-burning appliances —
Particular requirements —
Part 4:
Valve-proving systems for automatic
shut-off valves
Dispositifs de contrôle et de sécurité pour les brûleurs à gaz et pour
les appareils utilisant le gaz — Exigences particulières —
Partie 4: Systèmes de contrôle d'étanchéité pour robinets
automatiques de sectionnement
Reference number
ISO 23551-4:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 23551-4:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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

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below or ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2018 – All rights reserved
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ISO 23551-4:2018(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

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

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

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

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

4 Classification ............................................................................................................................................................................................................ 3

4.1 Classes of control .................................................................................................................................................................................. 3

4.2 Groups of controls ................................................................................................................................................................................ 3

4.3 Types of DC supplied controls ................................................................................................................................................... 3

4.4 Classes of control functions ......................................................................................................................................................... 3

5 Test conditions and tolerances .............................................................................................................................................................. 3

6 Construction .............................................................................................................................................................................................................. 3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Construction requirements .......................................................................................................................................................... 3

6.3 Materials ....................................................................................................................................................................................................... 4

6.4 Gas connections ...................................................................................................................................................................................... 4

6.5 Gas controls employing electrical components in the gas way ..................................................................... 4

6.6 Electronic parts of the control ................................................................................................................................................... 4

6.7 Additional constructional requirements for VPS systems ................................................................................ 4

6.7.1 Signal for indication ...................................................................................................................................................... 4

6.7.2 VPS setting............................................................................................................................................................................. 4

7 Performance .............................................................................................................................................................................................................. 4

7.1 General ........................................................................................................................................................................................................... 4

7.2 Leak tightness .......................................................................................................................................................................................... 4

7.2.1 General...................................................................................................................................................................................... 4

7.2.2 Requirements ..................................................................................................................................................................... 4

7.2.3 Test ............................................................................................................................................................................................... 5

7.3 Torsion and bending .......................................................................................................................................................................... 5

7.4 Rated flow rate ........................................................................................................................................................................................ 5

7.5 Durability ..................................................................................................................................................................................................... 6

7.6 Functional requirements ................................................................................................................................................................ 6

7.6.1 Manufacturer information ....................................................................................................................................... 6

7.6.2 Detection limit ................................................................................................................................................................... 6

7.6.3 Programme sequence .................................................................................................................................................. 6

7.6.4 Timing ....................................................................................................................................................................................... 6

7.6.5 Test of the programme sequence and timing .......................................................................................... 7

7.6.6 Self-checking ....................................................................................................................................................................... 7

7.6.7 Lock-out function ............................................................................................................................................................ 7

7.6.8 Mains power interruption ....................................................................................................................................... 8

7.7 Endurance ................................................................................................................................................................................................... 8

7.7.1 General...................................................................................................................................................................................... 8

7.7.2 Stress test ............................................................................................................................................................................... 8

7.8 Vibration test ............................................................................................................................................................................................ 9

7.9 Performance tests for electronic controls ....................................................................................................................... 9

7.9.1 At ambient temperature .........................................................................................................................................10

7.9.2 At low temperature ........................................................................................................................................... ..........10

7.9.3 At high temperature ...................................................................................................................................................10

8 Electrical equipment .....................................................................................................................................................................................10

8.1 General ........................................................................................................................................................................................................10

8.2 Requirements ........................................................................................................................................................................................10

8.3 Test .................................................................................................................................................................................................................10

© ISO 2018 – All rights reserved iii
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ISO 23551-4:2018(E)

8.4 Protection by enclosure................................................................................................................................................................10

8.5 Protection against internal faults for the purpose of functional safety ..............................................10

8.5.1 Design and construction requirements .....................................................................................................11

8.5.2 Class A ....................................................................................................................................................................................12

8.5.3 Class B ....................................................................................................................................................................................12

8.5.4 Class C.....................................................................................................................................................................................13

8.5.5 Circuit and construction evaluation .............................................................................................................15

9 Electromagnetic compatibility (EMC) .........................................................................................................................................16

9.1 Protection against environmental influences ...........................................................................................................16

9.2 Harmonics and inter harmonics including mains signalling at a.c. power port, low

frequency immunity ........................................................................................................................................................................16

9.3 Voltage dips, voltage interruptions and voltage variations in the power supply network 16

9.3.1 Voltage dips and voltage interruptions .....................................................................................................16

9.3.2 Test ............................................................................................................................................................................................16

9.3.3 Voltage variation ...........................................................................................................................................................16

9.4 Test of influence of voltage unbalance .............................................................................................................................16

9.5 Surge immunity tests ......................................................................................................................................................................16

9.5.1 General...................................................................................................................................................................................16

9.5.2 Requirements ..................................................................................................................................................................17

9.5.3 Test ............................................................................................................................................................................................17

9.6 Electrical fast transient/burst ................................................................................................................................................18

9.6.1 General...................................................................................................................................................................................18

9.6.2 Requirements ..................................................................................................................................................................18

9.6.3 Test ............................................................................................................................................................................................18

9.7 Ring wave immunity .......................................................................................................................................................................18

9.8 Electrostatic discharge ..................................................................................................................................................................18

9.8.1 General...................................................................................................................................................................................18

9.8.2 Requirements ..................................................................................................................................................................18

9.8.3 Test ............................................................................................................................................................................................18

9.9 Radio-frequency electromagnetic field immunity ................................................................................................19

9.10 Test of influence of supply frequency variations ....................................................................................................19

9.11 Power frequency magnetic field immunity .................................................................................................................19

10 Marking, installation and operating instructions ...........................................................................................................19

10.1 Marking ......................................................................................................................................................................................................19

10.2 Installation and operating instructions ..........................................................................................................................19

10.3 Warning notice .....................................................................................................................................................................................20

Annex A (informative) Leak-tightness test — Volumetric method .....................................................................................21

Annex B (informative) Leak-tightness test — Pressure-loss method ..............................................................................22

Annex C (normative) Conversion of pressure loss into leakage rate ...............................................................................23

Annex D (informative) Gas quick connector (GQC) ............................................................................................................................24

Annex E (normative) Elastomers/requirements resistance to lubricants and gas ..........................................25

Annex F (normative) Specific regional requirements in European countries .......................................................26

Annex G (normative) Specific regional requirements in Canada and USA .................................................................27

Annex H (normative) Specific regional requirements in Japan .............................................................................................29

Annex I (informative) Application guide .......................................................................................................................................................30

Bibliography .............................................................................................................................................................................................................................31

iv © ISO 2018 – All rights reserved
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ISO 23551-4:2018(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: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 161, Controls and protective devices for

gas and/or oil.

This second edition cancels and replaces the first edition (ISO 23551-4:2005), which has been

technically revised. The main changes compared to the previous edition are as follows:

— alignment to the structure of ISO 23550:2018;
— inclusion of updated references to IEC 60730-1:2013+AMD1: 2015;
— inclusion of requirements for “faults during lockout or safety shutdown”;
— inclusion of software and hardware design requirements;
— inclusion of requirements for reset devices;
— updated EMC immunity requirements.
© ISO 2018 – All rights reserved v
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ISO 23551-4:2018(E)
Introduction

This document is designed to be used in combination with ISO 23550. Together with ISO 23550, this

document establishes the full requirements for valve-proving systems for automatic shut-off valves.

Where needed, this document adapts ISO 23550 by stating in the corresponding clause:

— “with the following modification”;
— “with the following addition”;
— “is replaced by the following”; or
— “is not applicable”.

In order to identify specific requirements that are particular to this document, that are not already

covered by ISO 23550, this document may contain clauses or subclauses that are additional to the

structure of ISO 23550. These subclauses are indicated by the introductory sentence: “Subclause (or

Annex) specific to this document.”.

To ensure global relevance of this document, the differing requirements resulting from practical

experience and installation practices in various regions of the world have been taken into account. The

variations in basic infrastructure associated with gas and/or oil controls and appliances have also been

recognized, some of which are addressed in Annexes F, G and H. This document intends to provide a

basic framework of requirements that recognize these differences.
vi © ISO 2018 – All rights reserved
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INTERNATIONAL STANDARD ISO 23551-4:2018(E)
Safety and control devices for gas burners and gas-burning
appliances — Particular requirements —
Part 4:
Valve-proving systems for automatic shut-off valves
1 Scope

This document specifies safety, constructional and performance requirements of valve-proving

systems (VPS), intended for use with gas burners and gas-burning appliances. It also describes the test

procedures for checking compliance with these requirements and provides information necessary for

the purchaser and user.

This document is applicable to all types of VPS which are used for the automatic detection of leakage in

a gas burner section having at least two valves designed in accordance with ISO 23551-1 and which give

a signal if the leakage of one of the valves exceeds the detection limit.

This document is applicable to VPS with a maximum working pressure up to and including 500 kPa for

use in systems using fuel gases.
This document is not applicable to VPSs for use in explosive atmospheres.
NOTE Provisions for production control are not part of the ISO 23551 series.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 23550, Safety and control devices for gas burners and gas-burning appliances — General requirements

IEC 60730-1:2013+AMD1: 2015, Automatic electrical controls — Part 1: General requirements

IEC 61000-4-5, Electromagnetic compatibility (EMC) — Part 4-5: Testing and measurement techniques —

Surge immunity test
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 23550 and the following apply.

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
valve proving system
VPS

system to check the closure of automatic shut-off valves by detecting leakage, that often consists of a

programming unit, a measuring device, valves and other functional assemblies
© ISO 2018 – All rights reserved 1
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ISO 23551-4:2018(E)
3.2
detecting device

device for direct or inferential detection of leakage, i.e. by measuring flow or pressure

3.3
VPS operational time
time taken by the VPS to perform its entire cycle of operation
3.4
detection limit

maximum amount of leakage that can occur before the VPS is required to give a signal

Note 1 to entry: See Figure 1.
3.5
detection setting
actual leakage rate at which the VPS gives a signal
Note 1 to entry: See Figure 1.
Key
X burner heat, gas flow, expressed in m /h
Y detected leakage rate, expressed in dm /h
1 detection limit, 3.4
2 detection setting, see 3.5
Figure 1 — Illustration of detection limit and detection setting
3.6
leakage testing time
time in which the VPS monitors a gas valve for leakage
3.7
safety shut-down

process which is effected immediately following the detection of a leakage exceeding the detection

limit, or detection of an internal fault, disabling energization of the ignition and of the automatic shut-

off valves
2 © ISO 2018 – All rights reserved
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ISO 23551-4:2018(E)
3.8
volatile lock-out

safety shut-down condition of the system where a restart can only be accomplished by either the

manual reset of the system, or an interruption of the main power and its subsequent restoration

3.9
non-volatile lock-out

safety shut-down condition of the system, where a restart can only be accomplished by the manual

reset of the system and by no other means
4 Classification
4.1 Classes of control
Shall be according ISO 23550:2018, 4.1.
4.2 Groups of controls
Shall be according ISO 23550:2018, 4.2.
4.3 Types of DC supplied controls
Shall be according ISO 23550:2018, 4.3.
4.4 Classes of control functions
Shall be according ISO 23550:2018, 4.4 with the following addition:
VPS is a class C control function.
5 Test conditions and tolerances
Shall be according ISO 23550:2018, Clause 5.
6 Construction
6.1 General
Shall be according to ISO 23550:2018, 6.1 with the following addition.

The VPS shall be designed such that changes in critical circuit component values (such as those affecting

timing or sequence) within the component manufacturer's declared worst case tolerances, including the

long-term stability, shall result in the system continuing to function in accordance with this document.

Compliance shall be checked by worst-case analysis.

The construction of any additional functions included in the VPS for which no provisions exist in this

document shall be such that they do not degrade the safe and correct operation.

Where components are used to complete the VPS, these components shall comply with the relevant

component International Standard.
6.2 Construction requirements
Shall be according to ISO 23550:2018, 6.2.
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ISO 23551-4:2018(E)
6.3 Materials
Shall be according to ISO 23550:2018, 6.3.
6.4 Gas connections
Shall be according to ISO 23550:2018, 6.4.
6.5 Gas controls employing electrical components in the gas way
Shall be according to ISO 23550:2018, 6.5.
6.6 Electronic parts of the control
Subclause specific to this document.
Shall be according to IEC 60730-1:2013/AMD1: 2015.
6.7 Additional constructional requirements for VPS systems
Subclause specific to this document.
6.7.1 Signal for indication

A signal for indication, e.g. optical indication, shall be given when the leakage exceeds the detection limit.

6.7.2 VPS setting

The setting of a detecting device shall require the use of tools. If the VPS is adjustable, the installation

and operating instructions shall provide information for this setting, e.g. detection setting.

7 Performance
7.1 General
Shall be according to ISO 23550:2018, 7.1 with the following addition:

Where components are used to complete the VPS, these components shall comply with the relevant

component International Standard.
7.2 Leak tightness
7.2.1 General
Shall be according to ISO 23550:2018, 7.2.1.
7.2.2 Requirements
Shall be
...

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