ISO 23555-1:2022

INTERNATIONAL ISO
STANDARD 23555-1
First edition
2022-01
Gas pressure safety and control
devices for use in gas transmission,
distribution and installations for
inlet pressures up to and including 10
MPa —
Part 1:
General requirements
Reference number
© ISO 2022
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Published in Switzerland
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Contents Page
Foreword . vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 3
3.1 Terms and definitions . 3
3.1.1 General terms . 3
3.1.2 Terms related to components . 5
3.1.3 Terms related to components of functional performance. 6
3.1.4 Terms related to design and tests . 8
3.2 Symbols and abbreviated terms . 9
4 Classification .10
4.1 General . 10
4.2 Temperature classes . 10
4.3 Strength types . 11
5 Materials .11
5.1 General . 11
5.2 Requirements . 11
5.2.1 Requirements for metallic materials . 11
5.2.2 Requirements for non-metallic materials . 13
5.3 Validation and test of materials .13
5.3.1 Material inspection documents of metallic pressure-containing parts and
inner metallic partition walls . 13
5.3.2 Material inspection documents of threaded sealing plugs, integral process
and sensing lines, connectors and metallic fasteners . 14
5.3.3 Material inspection documents of non-metallic functional parts. 14
5.3.4 Non-destructive testing for steel bodies . 14
6 Design .14
6.1 General . 14
6.1.1 Design approach . 14
6.1.2 Basic requirements . 15
6.1.3 Hazard identification and residual risks . 15
6.1.4 End connections . 15
6.1.5 Flange ratings . 16
6.1.6 Nominal sizes and face-to-face dimensions . 16
6.1.7 Sealing of the adjusting device . 18
6.1.8 Replaceable parts that can be affected by erosion or abrasion . 18
6.1.9 Integral strength pressure controls . 18
6.1.10 Differential strength pressure controls . 18
6.1.11 Metallic flanges . 18
6.1.12 Minimum values of safety factor . 19
6.1.13 Springs requirements . 19
6.2 Strength of metallic body and its inner metallic partition walls . 19
6.2.1 General . 19
6.2.2 Requirements . 19
6.2.3 Design strength verification for metallic body and its inner metallic
partition walls . 20
6.3 Other pressure-containing metallic parts of integral and differential strength
controls. 22
6.3.1 General .22
6.3.2 Requirements . 22
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6.3.3 Design strength verification for other pressure-containing parts of
integral and differential strength controls . 23
6.4 Strength of parts transmitting actuating forces . 24
6.4.1 General . 24
6.4.2 Requirements . 24
6.4.3 Design strength verification for parts transmitting actuating forces . 24
6.5 Strength of diaphragms (elastomeric parts) . 24
6.5.1 General . 24
6.5.2 Requirements . 24
6.5.3 Design strength verification for diaphragms (elastomeric parts) . 24
6.6 Welding . . 25
6.6.1 General . 25
6.6.2 Requirements . 25
6.6.3 Non-destructive testing of fabrication welds . 25
7 Performance and testing requirements .27
7.1 General . 27
7.1.1 Approach to stable production phase . 27
7.1.2 Test conditions . 27
7.1.3 Test tolerances . . . 27
7.1.4 Overview table .28
7.2 Requirements .29
7.2.1 Test rig .29
7.2.2 Classification of stable production tests . 32
7.2.3 Dimensional check and visual inspection . 32
7.2.4 Shell strength . 32
7.2.5 External/Internal tightness . 33
7.2.6 Antistatic characteristics . 33
7.2.7 Sound emission . 33
7.2.8 Resistance of external surfaces to corrosion .
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