ISO 23551-2:2018
(Main)Safety and control devices for gas burners and gas-burning appliances — Particular requirements — Part 2: Pressure regulators
Safety and control devices for gas burners and gas-burning appliances — Particular requirements — Part 2: Pressure regulators
This document specifies safety, construction, performance and testing requirements for pressure regulators and pneumatic gas/air ratio pressure regulators intended for use with gas burners and gas-burning appliances. This document applies to pressure regulators and pneumatic gas/air ratio pressure regulators of nominal connection size up to and including DN 250 at inlet pressures up to and including 500 kPa, for use with natural gas, manufactured gas or liquefied petroleum gas (LPG). It is not applicable to corrosive and waste gases. This document is specifically applicable to: — positive, zero and negative pressure regulators which can use auxiliary energy to change the outlet pressure setting; — pneumatic gas/air ratio pressure regulators, which function by controlling a gas outlet pressure in response to an air signal pressure, air signal differential pressure, and/or to a combustion chamber pressure signal; — gas/air ratio pressure regulators, which function by controlling an air outlet pressure in response to a gas signal pressure or a gas signal differential pressure. This document does not cover: — pressure regulators connected directly to gas distribution network or to a container that maintains a standard distribution pressure; — pressure regulators intended to be installed in the open air and exposed to the environment; — mechanically linked gas/air ratio controls; — electronic pressure regulators and gas/air ratio regulators, which are contained in ISO 23552-1. This document covers type testing only. NOTE Annexes A to H reference the relevant annexes of ISO 23550, general requirements and are applicable where required.
Dispositifs de commande et de sécurité pour brûleurs à gaz et appareils à gaz — Exigences particulières — Partie 2: Régulateurs de pression
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Standards Content (Sample)
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 23551-2:2018(E)
©
ISO 2018
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ISO 23551-2:2018(E)
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ii © ISO 2018 – All rights reserved
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ISO 23551-2:2018(E)
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
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ISO 23551-2:2018(E)
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 .12
7.10 Endurance .12
7.11 Lock-up pressure .12
7.11.1 Requirement .12
7.11.2 Lock-up pressure test .12
7.12 Optional EP-rating .13
7.12.1 General.13
7.12.2 External leakage resistance .13
7.12.3 Internal flow resistance .13
8 Electrical requirements .13
9 Electromagnetic compatibility (EMC) .14
10 Marking, installation and operating instructions .14
10.1 Marking .14
10.2 Installation and operating instructions .14
10.3 Warning notice .15
Annex A (informative) Leak-tightness test — Volumetric method .16
Annex B (informative) Leak-tightness test — Pressure-loss method .17
Annex C (normative) Conversion of pressure loss into leakage rate .18
Annex D (normative) Gas quick connector (GQC) .19
Annex E (normative) Elastomers/requirements resistance to lubricants and gas .20
Annex F (normative) Specific regional requirements in European countries .21
Annex G (normative) Specific regional requirements in Canada and USA .22
Annex H (normative) Specific regional requirements in Japan .23
Annex I (informative) Regulator application examples .24
Annex J (normative) Functional requirements and regulator performance testing — Method A .27
Annex K (normative) Functional requirements and regulator performance testing — Method B .39
Annex L (normative) Pneumatic gas/air ratio pressure regulator performance .53
Annex M (informative) Typical pressure regulators and pressure regulator parts .60
Bibliography .62
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ISO 23551-2:2018(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 of 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 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.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
This second edition cancels and replaces the first edition (ISO 23551-2:2006), which has been technically
revised. The main changes compared to the previous edition are as follows:
a) this document has been aligned with the structure of ISO 23550:2018;
b) the following have been merged into one document:
— pressure regulators (ISO 23551-2),
— zero pressure regulators (new functions), and
— gas/air ratio controls, pneumatic types (ISO 23551-3);
c) the Introduction has been rewritten;
d) Clause 1 now extends to pressure regulators and pneumatic gas/air ratio pressure regulators at
inlet pressures up to and including 500 kPa; auxiliary energy may be used to change the set point;
e) Clause 2 has been updated;
f) Clause 3 has been updated and new definitions have been updated;
g) in Clause 4, new regulator class D has been added for supply situations with low fluctuations;
h) Clause 5 now refers to Annexes including the new Annex L for gas/air ratio pressure regulators;
i) requirements for breather holes have been moved from Clause 6 to ISO 23550:2018;
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ISO 23551-2:2018(E)
k) Clause 7 has been structured into “General”, “Requirements” and “Test”;
l) Clause 8 has been added without reflecting structure and requirements as in ISO 23550:2018;
m) Clause 9 has been renumbered;
n) Clause 10 has been renumbered and amended to cover the additional regulator types;
o) new Annex I has been added;
p) former Annex B has been updated and renumbered into Annex J;
q) former Annex C has been updated and renumbered into Annex K;
r) new Annex L has been added;
s) former Annex E has been updated and renumbered into Annex M;
t) new Annexes F, G and H have been added for regional requirements.
A list of all the parts in the ISO 23551 series can be found on the ISO website.
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ISO 23551-2:2018(E)
Introduction
This document is designed to be used in combination with ISO 23550. Together with ISO 23550, this
document establishes the full requirements as they apply to the product covered by this document.
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.
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INTERNATIONAL STANDARD ISO 23551-2:2018(E)
Safety and control devices for gas burners and gas-burning
appliances — Particular requirements —
Part 2:
Pressure regulators
1 Scope
This document specifies safety, construction, performance and testing requirements for pressure
regulators and pneumatic gas/air ratio pressure regulators intended for use with gas burners and gas-
burning appliances.
This document applies to pressure regulators and pneumatic gas/air ratio pressure regulators of
nominal connection size up to and including DN 250 at inlet pressures up to and including 500 kPa,
for use with natural gas, manufactured gas or liquefied petroleum gas (LPG). It is not applicable to
corrosive and waste gases.
This document is specifically applicable to:
— positive, zero and negative pressure regulators which can use auxiliary energy to change the outlet
pressure setting;
— pneumatic gas/air ratio pressure regulators, which function by controlling a gas outlet pressure in
response to an air signal pressure, air signal differential pressure, and/or to a combustion chamber
pressure signal;
— gas/air ratio pressure regulators, which function by controlling an air outlet pressure in response
to a gas signal pressure or a gas signal differential pressure.
This document does not cover:
— pressure regulators connected directly to gas distribution network or to a container that maintains
a standard distribution pressure;
— pressure regulators intended to be installed in the open air and exposed to the environment;
— mechanically linked gas/air ratio controls;
— electronic pressure regulators and gas/air ratio regulators, which are contained in ISO 23552-1.
This document covers type testing only.
NOTE Annexes A to H reference the relevant annexes of ISO 23550, general requirements and are applicable
where required.
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 23550, Safety and control devices for gas burners and gas-burning appliances — General requirements
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ISO 23551-2:2018(E)
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 Pressure regulators
3.1.1
pressure regulator
device that maintains the outlet pressure constant within given limits, independently of the variations
in inlet pressure and/or flow rate
Note 1 to entry: For examples refer to Annex I.
3.1.2
adjustable pressure regulator
pressure regulator (3.1.1) provided with means for changing the outlet pressure setting
3.1.3
pneumatic gas
air ratio pressure regulator
pressure regulator (3.1.1) which supplies gas at specified pressure at its outlet in response to control
pressure
3.1.4
zero pressure regulator
pressure regulator (3.1.1) which maintains the outlet pressure constant at or below atmospheric
pressure
3.2 Pressures
3.2.1
test pressure
pressure to be applied during a test
3.2.2
pressure drop
differential pressure with the control member open to its fullest extent
3.2.3
maximum inlet pressure
p
1max
highest inlet pressure at which tests have been conducted to determine that the regulator is able to
control the outlet pressure within acceptable limits as declared by the manufacturer
3.2.4
minimum inlet pressure
p
1min
lowest inlet pressure at which tests have been conducted to determine that the regulator is able to
control the outlet pressure within acceptable limits declared by the manufacturer
3.2.5
inlet pressure range
difference between the minimum and the maximum values of the inlet pressure
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ISO 23551-2:2018(E)
3.2.6
maximum outlet pressure
p
2max
highest outlet pressure at which tests have been conducted to determine that the regulator is able to
control the outlet pressure within acceptable limits declared by the manufacturer
3.2.7
minimum outlet pressure
p
2min
lowest outlet pressure at which tests have been conducted to determine that the regulator is able to
control the outlet pressure within acceptable limits declared by the manufact
...
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