ISO 23551-2:2018

INTERNATIONAL ISO
STANDARD 23551-2
Second edition
2018-09
Safety and control devices for gas
burners and gas-burning appliances —
Particular requirements —
Part 2:
Pressure regulators
Dispositifs de commande et de sécurité pour brûleurs à gaz et
appareils à gaz — Exigences particulières —
Partie 2: Régulateurs de pression
Reference number
©
ISO 2018
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Pressure regulators . 2
3.2 Pressures . 2
3.3 Flow rates . 4
3.4 Component parts . 4
3.5 Performance . 5
4 Classification . 6
4.1 Classes of control . 6
4.2 Groups of controls . 6
4.3 Types of DC supplied controls . 6
5 Test conditions . 7
6 Construction . 7
6.1 General . 7
6.2 Construction requirements . 7
6.2.1 Appearance . 7
6.2.2 Holes . 7
6.2.3 Breather holes . 7
6.2.4 Vent limiters . 7
6.2.5 Screwed fastenings . 7
6.2.6 Moving parts . 7
6.2.7 Sealing caps . 7
6.2.8 Disassembling and assembling for servicing and/or adjustment . 7
6.2.9 Auxiliary channels and orifices . 7
6.2.10 Pre-setting device . 7
6.2.11 Adjustments . 8
6.2.12 Resistance to pressure . 8
6.2.13 Blockage of canals and orifices . 8
6.2.14 Signal tube connections . 8
6.3 Materials . 8
6.3.1 General material requirements . 8
6.3.2 Housing . 8
6.3.3 Springs providing closing force and sealing force . 9
6.3.4 Resistance to corrosion and surface protection . 9
6.3.5 Impregnation . 9
6.3.6 Seals for glands for moving parts . 9
6.3.7 Jointing . 9
6.4 Connections . 9
6.4.1 General. 9
6.4.2 Connection sizes . 9
6.4.3 Connection types . 9
6.4.4 Threads . 9
6.4.5 Union joints . 9
6.4.6 Flanges . 9
6.4.7 Compression fittings . . . 9
6.4.8 Flare connections . 9
6.4.9 Nipples for pressure test . 9
6.4.10 Strainers .10
6.4.11 Gas connections by GQC .10
6.5 Gas controls employing electrical components in the gas way .10
7 Performance .10
7.1 General .10
7.2 Leak-tightness.10
7.2.1 General.10
7.2.2 Requirements .10
7.2.3 Test .10
7.3 Torsion and bending .11
7.4 Rated flow rate .11
7.4.1 General.11
7.4.2 Requirements .11
7.4.3 Test .11
7.5 Durability .11
7.6 Functional requirements .11
7.7 Endurance .11
7.8 Vibration test .12
7.9 Putting the regulator out of action.12
7.9.1 Requirement .12
7.9.2 Test putting the regulator out of action .
...