ISO 23550:2018

INTERNATIONAL ISO
STANDARD 23550
Third edition
2018-04
Safety and control devices for gas
and/or oil burners and appliances —
General requirements
Dispositifs de commande et de sécurité pour brûleurs à gaz et
appareils à gaz — Exigences générales
Reference number
©
ISO 2018
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification . 5
4.1 Classes of control . 5
4.2 Groups of controls . 5
4.3 Types of DC supplied controls . 5
4.4 Classes of control functions . 5
5 Test conditions and tolerances . 6
5.1 Test conditions . 6
5.2 Tolerances . 6
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 . 8
6.2.4 Vent limiter . 8
6.2.5 Screwed fastenings . 9
6.2.6 Moving parts . 9
6.2.7 Sealing caps . 9
6.2.8 Disassembling and assembling for servicing and/or adjustment for controls .10
6.2.9 Auxiliary channels and orifices .10
6.2.10 Pre-setting device .10
6.3 Materials .11
6.3.1 General material requirements .11
6.3.2 Housing .11
6.3.3 Springs providing closing force and sealing force .12
6.3.4 Resistance to corrosion and surface protection .12
6.3.5 Impregnation .12
6.3.6 Seals for glands for moving parts .13
6.3.7 Jointing .13
6.4 Connections .13
6.4.1 General.13
6.4.2 Connection sizes .13
6.4.3 Connection types .14
6.4.4 Threads .15
6.4.5 Union joints .16
6.4.6 Flanges .16
6.4.7 Compression fittings . . .16
6.4.8 Flare connections .17
6.4.9 Nipples for pressure tests .17
6.4.10 Strainers .17
6.4.11 Gas connections by GQC .18
6.5 Gas controls employing with electrical components in the gas way .18
6.5.1 General.18
6.5.2 Requirements .18
6.5.3 Ignition trial test .18
6.5.4 Test of ignition source .19
7 Performance .20
7.1 General .20
7.2 Leak-tightness.21
7.2.1 General.21
7.2.2 Requirements .21
7.2.3 Test .21
7.3 Torsion and bending .24
7.3.1 General.24
7.3.2 Torsion .24
7.3.3 Bending moment .24
7.3.4 Torsion and bending tests .24
7.4 Rated flow rate .28
7.4.1 General.28
7.4.2 Requirements .28
7.4.3 Test .28
7.5 Durability .30
7.5.1 Elastomers in contact with gas .30
7.5.2 Resistance of elastomers to lubricants and gases .30
7.5.3 Marking resistance .31
7.5.4 Resistance to scratching .31
7.5.5 Resistance to humidity .32
7.6 Functional requirements .
...