ISO 10522:2021

Agricultural irrigation equipment — Direct-acting pressure-regulating valves

This document specifies construction and performance requirements and test methods for direct-acting pressure-regulating valves (hereinafter "pressure regulators") intended for operation in irrigation systems, with water at temperatures not exceeding 60 °C, which can contain fertilizers and chemicals of types and in concentrations commonly used in agricultural irrigation. This document applies to pressure regulators in nominal sizes up to and including 100 mm (4 in).

Matériel agricole d'irrigation — Vannes de régulation de la pression à action directe

General Information

• Status: Published
• Publication Date: 24-Aug-2021
• ICS: 65.060.35 - Irrigation and drainage equipment
• Technical Committee: ISO/TC 23/SC 18 - Irrigation and drainage equipment and systems
• Drafting Committee: ISO/TC 23/SC 18 - Irrigation and drainage equipment and systems
• Current Stage: 6060 - International Standard published
• Start Date: 25-Aug-2021
• Due Date: 18-Mar-2022
• Completion Date: 25-Aug-2021

Relations

• Revises: ISO 10522:1993 - Agricultural irrigation equipment — Direct-acting pressure-regulating valves
• Effective Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10522
Second edition
2021-08
Agricultural irrigation equipment —
Direct-acting pressure-regulating
valves
Matériel agricole d'irrigation — Vannes de régulation de la pression à
action directe
Reference number
ISO 10522:2021(E)
©
ISO 2021

---------------------- Page: 1 ----------------------
ISO 10522:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 10522:2021(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Pressure regulator classification . 3
4.1 According to construction of regulation assembly . 3
4.2 According to construction of pressure regulator . 3
4.3 According to regulated pressure at zero flow . 3
4.4 According to accuracy level [see 7.5.2.4 b)] . 3
5 Marking . 4
6 Technical characteristics . 4
6.1 General . 4
6.2 Pressure regulator body . 4
6.3 Adjustment assembly . 5
6.4 Connections . 5
6.5 Adjustable stop . 5
7 Mechanical and functional tests . 5
7.1 Overview . 5
7.2 General . 6
7.3 Regulation uniformity (in non-adjustable pressure regulators) . 6
7.4 Tightness of pressure regulator with adjustable stop . 7
7.5 Regulation curve . 7
7.5.1 Installation . 7
7.5.2 Test results and requirements . 8
7.5.3 Single-range pressure regulators (class 4.1.1) . 9
7.5.4 Multi-range pressure regulators (class 4.1.2) . 9
7.5.5 Single-range adjustable pressure regulators (class 4.1.3) . 9
7.5.6 Multi-range adjustable pressure regulators (class 4.1.4) . 9
7.6 Regulated pressure as function of pressure regulator adjustment in pressure
regulators of classes 4.1.3 and 4.1.4 . 9
7.7 Regulated pressure at zero flow (in pressure regulators of class 4.3.2) . 9
7.8 Regulated pressure as function of inlet pressure at constant flow rate .10
7.8.1 General.10
7.8.2 Plotting pressure curves .10
7.9 Regulation curve of integral pressure regulators (class 4.2.2) .10
7.10 Pressure loss .11
7.11 Resistance of pressure regulator body to internal hydrostatic pressure .11
7.11.1 General.11
7.11.2 Metal-body pressure regulators .11
7.11.3 Plastics-body pressure regulators .11
8 Durability .12
8.1 On/off cycles .12
8.2 Changing condition cycles .12
8.2.1 General.12
8.2.2 For ordinary pressure regulators .12
8.2.3 For integral pressure regulators .12
8.2.4 Requirement for ordinary and integral pressure regulators .13
9 Information to be supplied by the manufacturer .13
9.1 General information .13
9.2 Operational data .13
Annex A (informative) Figures .14
© ISO 2021 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 10522:2021(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 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.
This second edition cancels and replaces the first edition (ISO 10522:1993), which has been technically
revised.
The main changes compared to the previous edition are as follows.
— The range of pressure regulators sizes has been extended up to DN 100 (4").
— The water temperature of the irrigation system has been harmonized to 60 °C.
— The normative references have been updated.
— The terms and definitions have been updated.
— The testing water temperature range has been updated to 4 °C to 35 °C.
— The face-to-face distance of the flanged bodies of the pressure regulators has been updated to
±4 mm for plastics-body regulators.
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.
iv © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 10522:2021(E)
Agricultural irrigation equipment — Direct-acting
pressure-regulating valves
1 Scope
This document specifies construction and performance requirements and test methods for direct-
acting pressure-regulating valves (hereinafter "pressure regulators") intended for operation in
irrigation systems, with water at temperatures not exceeding 60 °C, which can contain fertilizers and
chemicals of types and in concentrations commonly used in agricultural irrigation.
This document applies to pressure regulators in nominal sizes up to and including 100 mm (4 in).
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 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
ISO 7005-1, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
ISO 7005-2, Metallic flanges — Part 2: Cast iron flanges
ISO 9644, Agricultural irrigation equipment — Pressure losses in irrigation valves — Test method
1)
ISO 24649:—, Agricultural irrigation equipment — Manually and hydraulically operated plastics valves
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 https:// www .electropedia .org/
3.1
direct-acting pressure-regulating valve
pressure regulator
valve in which the water passage widens or narrows automatically without an external device to
maintain the pressure at the outlet of the valve close to a pre-set value under varying pressures or flow
rates at the inlet of the valve
Note 1 to entry: It is also called direct-acting pressure regulator.
3.2
ordinary pressure regulator
pressure regulator intended for installation upstream from an irrigation device and not integrated into
the irrigation device or fitted specifically to it
1) Under preparation. Stage at the date of publication: ISO/DIS 24649:2021.
© ISO 2021 – All rights reserved 1

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ISO 10522:2021(E)

3.3
single-range pressure regulator
pressure regulator with a fixed non-adjustable pressure setting which cannot be varied
Note 1 to entry: See also see Annex A, Figure A.1.
3.4
multi-range pressure regulator
pressure regulator with alternative pressure settings and regulation ranges that may be changed by
replacing pressure regulator components such as springs and discs but not by external adjustment
3.5
adjustable pressure regulator
pressure regulator in which the pressure setting can be adjusted externally without requiring
replacement of parts in the regulation assembly
3.6
integral pressure regulator
pressure-regulating valve which is an integral part of an irrigation device or is fitted specifically to the
particular irrigation device
3.7
regulated pressure
water pressure at the outlet of a pressure regulator
3.8
regulation range
all of the working pressures at the inlet of a pressure regulator within which the pressure regulator is
declared by the manufacturer to regulate pressure within a specified accuracy
Note 1 to entry: See also Annex A, Figure A.2.
3.9
nominal pressure
PN
maximum static working pressure at which a piping component is stated to operate under normal
service conditions
3.10
nominal diameter
DN
numerical designation used to refer to the size of a pressure regulator approximately equal to the
diameter of the pipe or pipes to which the pressure regulator is to be connected directly
3.11
minimum flow rate
q
min
lowest flow rate at which the pressure regulating valve is designed to operate within the maximum
permissible error
3.12
initial regulation pressure
lowest pressure at the inlet of a pressure regulator at which the regulated pressure (3.7) is within the
range of regulation
3.13
declared pre-set pressure
P
s
pressure at the outlet of a pressure regulator pre-set and declared by the manufacturer using a reference
velocity (3.16) of 1 m/s
2 © ISO 2021 – All rights reserved

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ISO 10522:2021(E)

3.14
regulated pressure at zero flow
regulated pressure (3.7) when pressure is applied at the inlet of a pressure regulator and the outlet of
the pressure regulator is closed
3.15
regulation assembly
portion of the pressure regulator consisting mainly of working parts that narrow or widen the water
passages in the pressure regulator to maintain a constant pressure
3.16
reference velocity
ν
ref
velocity of flow through the valve calculated from the actual flow rate through the valve divided by the
area of a circle with diameter equal to the nominal DN
3.17
accuracy level
deviation of the outlet pressure from the pressure setting or from the setting declared by the
manufacturer
3.18
adjustable stop
device used for adjusting the range of movement of the operating mechanism up to full opening or
closing of a hydraulically operated valve
4 Pressure regulator classification
4.1 According to construction of regulation assembly
Class 4.1.1 Single-range pressure regulator
Class 4.1.2 Multi-range pressure regulator
Class 4.1.3 Single-range adjustable pressure regulator
Class 4.1.4 Multi-range adjustable pressure regulator
4.2 According to construction of pressure regulator
Class 4.2.1 Ordinary pressure regulator
Class 4.2.2 Integral pressure regulator
4.3 According to regulated pressure at zero flow
Class 4.3.1 Pressure regulator in which the regulated pressure equals the inlet pressure at zero flow
Class 4.3.2 Pressure regulator in which the regulated pressure does not equal (is less than) the inlet
pressure at zero flow
4.4 According to accuracy level [see 7.5.2.4 b)]
Class 4.4.1 Pressure regulators with accuracy level A (±10 %)
Class 4.4.2 Pressure regulators with accuracy level B (±20 %)
© ISO 2021 – All rights reserved 3

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ISO 10522:2021(E)

5 Marking
With the exception of integral pressure regulators (which are an integral part of the irrigation device
and bear its marking), each pressure regulator shall bear readily visible, clear and durable marking
including the following:
a) manufacturer's name and/or trademark;
b) nominal size;
c) nominal pressure;
d) arrow indicating direction of flow;
e) markings to indicate direction of adjustment, for classes 4.1.3 and 4.1.4:
— + to increase regulated pressure,
— − to reduce regulated pressure.
In addition, each pressure regulator or package of pressure regulator(s) shall carry a label specifying:
f) the declared pre-set pressure;
g) the accuracy level — A or B — of the regulator (see 4.4);
h) allowable temperature range.
The declared pre-set pressure given on the attached label or on the label to the packaging may be
indicated by colour or by any other marking, as explained in the manufacturer's catalogue.
In multi-range pressure regulators (class 4.1.2) and in multi-range adjustable pressure regulators
(class 4.1.4), the parts that can be replaced to vary the regulated pressure shall be marked by colour or
by any other marking, as explained in the manufacturer's catalogue.
6 Technical characteristics
6.1 General
The parts of the pressure regulator that are in contact with water shall be of non-toxic materials, and
shall be resistant to, or protected against, corrosion in the working conditions for which the pressure
regulator is intended.
All parts belonging to pressure regulators of the same size, type and model designed to allow
dismantling and produced by the same manufacturer shall be interchangeable.
Plastics parts of the pressure regulator that are exposed to ultraviolet (UV) radiation in the normal
working conditions under which the pressure regulators operate shall include additives to improve
their resistance to UV radiation. Plastics parts that enclose waterways shall be opaque or shall be
provided with an opaque cover designed to block all light from reaching clear waterway enclosures.
6.2 Pressure regulator body
Pressure regulators with threaded ends shall be provided with a hexagonal boss or with other means
for gripping. The face-to-face distance of the flanged bodies of the pressure regulators shall not deviate
from the length declared by the manufacturer in his catalogue, or other material describing the
specifications of the pressure regulator, by more than ±2 mm for metal-body regulators or ±4 mm for
plastics-body regulators.
4 © ISO 2021 – All rights reserved

---------------------- Page: 8 ----------------------
ISO 10522:2021(E)

6.3 Adjustment assembly
Balancing the regulated pressure to the pressure regulator set point is accomplished by means of a
spring. The chamber containing the spring shall be sealed to prevent
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 10522
ISO/TC 23/SC 18
Agricultural irrigation equipment —
Secretariat: SII
Direct-acting pressure-regulating
Voting begins on:
2021­06­01 valves
Voting terminates on:
Matériel agricole d'irrigation — Vannes de régulation de la pression à
2021­07­27
action directe
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 10522:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2021

---------------------- Page: 1 ----------------------
ISO/FDIS 10522:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 10522:2021(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Pressure regulator classification . 3
4.1 According to construction of regulation assembly . 3
4.2 According to construction of pressure regulator . 3
4.3 According to regulated pressure at zero flow . 3
4.4 According to accuracy level [see b)] . 3
5 Marking . 4
6 Technical characteristics . 4
6.1 General . 4
6.2 Pressure regulator body . 4
6.3 Adjustment assembly . 5
6.4 Connections . 5
6.5 Adjustable stop . 5
7 Mechanical and functional tests . 5
7.1 Overview . 5
7.2 General . 6
7.3 Regulation uniformity (in non-adjustable pressure regulators) . 6
7.4 Tightness of pressure regulator with adjustable stop . 7
7.5 Regulation curve . 7
7.5.1 Installation . 7
7.5.2 Test results and requirements . 8
7.5.3 Single­range pressure regulators (class 4.1.1) . 9
7.5.4 Multi­range pressure regulators (class 4.1.2) . 9
7.5.5 Single­range adjustable pressure regulators (class 4.1.3) . 9
7.5.6 Multi­range adjustable pressure regulators (class 4.1.4) . 9
7.6 Regulated pressure as function of pressure regulator adjustment in pressure
regulators of classes 4.1.3 and 4.1.4 . 9
7.7 Regulated pressure at zero flow (in pressure regulators of class 4.3.2) . 9
7.8 Regulated pressure as function of inlet pressure at constant flow rate .10
7.8.1 General.10
7.8.2 Plotting pressure curves .10
7.9 Regulation curve of integral pressure regulators (class 4.2.2) .10
7.10 Pressure loss .11
7.11 Resistance of pressure regulator body to internal hydrostatic pressure .11
7.11.1 General.11
7.11.2 Metal-body pressure regulators .11
7.11.3 Plastics-body pressure regulators .11
8 Durability .12
8.1 On/off cycles .12
8.2 Changing condition cycles .12
8.2.1 General.12
8.2.2 For ordinary pressure regulators .12
8.2.3 For integral pressure regulators .12
8.2.4 Requirement for ordinary and integral pressure regulators .13
9 Information to be supplied by the manufacturer .13
9.1 General information .13
9.2 Operational data .13
Annex A (informative) Figures .14
© ISO 2021 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/FDIS 10522:2021(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 non­governmental, 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 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.
This second edition cancels and replaces the first edition (ISO 10522:1993), which has been technically
revised.
The main changes compared to the previous edition are as follows.
— The range of pressure regulators sizes has been extended up to DN 100 (4").
— The water temperature of the irrigation system has been harmonized to 60 °C.
— The normative references have been updated.
— The terms and definitions have been updated.
— The testing water temperature range has been updated to 4 °C to 35 °C.
— The face-to-face distance of the flanged bodies of the pressure regulators has been updated to
±4 mm for plastics-body regulators.
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.
iv © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 10522:2021(E)
Agricultural irrigation equipment — Direct-acting
pressure-regulating valves
1 Scope
This document specifies construction and performance requirements and test methods for direct-
acting pressure-regulating valves (hereinafter "pressure regulators") intended for operation in
irrigation systems, with water at temperatures not exceeding 60 °C, which can contain fertilizers and
chemicals of types and in concentrations commonly used in agricultural irrigation.
This document applies to pressure regulators in nominal sizes up to and including 100 mm (4 in).
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 7­1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
ISO 7005­1, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
ISO 7005­2, Metallic flanges — Part 2: Cast iron flanges
ISO 9644, Agricultural irrigation equipment — Pressure losses in irrigation valves — Test method
1)
ISO 24649:—, Agricultural irrigation equipment — Manually and hydraulically operated plastics valves
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 https:// www .electropedia .org/
3.1
direct-acting pressure-regulating valve
pressure regulator
valve in which the water passage widens or narrows automatically without an external device to
maintain the pressure at the outlet of the valve close to a pre-set value under varying pressures or flow
rates at the inlet of the valve
Note 1 to entry: It is also called direct-acting pressure regulator.
3.2
ordinary pressure regulator
pressure regulator intended for installation upstream from an irrigation device and not integrated into
the irrigation device or fitted specifically to it
1) Under preparation. Stage at the date of publication: ISO/DIS 24649:2021.
© ISO 2021 – All rights reserved 1

---------------------- Page: 5 ----------------------
ISO/FDIS 10522:2021(E)

3.3
single-range pressure regulator
pressure regulator with a fixed non-adjustable pressure setting which cannot be varied
Note 1 to entry: See also see Annex A, Figure A.1.
3.4
multi-range pressure regulator
pressure regulator with alternative pressure settings and regulation ranges that may be changed by
replacing pressure regulator components such as springs and discs but not by external adjustment
3.5
adjustable pressure regulator
pressure regulator in which the pressure setting can be adjusted externally without requiring
replacement of parts in the regulation assembly
3.6
integral pressure regulator
pressure-regulating valve which is an integral part of an irrigation device or is fitted specifically to the
particular irrigation device
3.7
regulated pressure
water pressure at the outlet of a pressure regulator
3.8
regulation range
all of the working pressures at the inlet of a pressure regulator within which the pressure regulator is
declared by the manufacturer to regulate pressure within a specified accuracy
Note 1 to entry: See also Annex A, Figure A.2.
3.9
nominal pressure
PN
maximum static working pressure at which a piping component is stated to operate under normal
service conditions
3.10
nominal diameter
DN
numerical designation used to refer to the size of a pressure regulator approximately equal to the
diameter of the pipe or pipes to which the pressure regulator is to be connected directly
3.11
minimum flow rate
q
min
lowest flow rate at which the pressure regulating valve is designed to operate within the maximum
permissible error
3.12
initial regulation pressure
lowest pressure at the inlet of a pressure regulator at which the regulated pressure (3.7) is within the
range of regulation
3.13
declared pre-set pressure
P
s
pressure at the outlet of a pressure regulator pre-set and declared by the manufacturer using a reference
velocity (3.16) of 1 m/s
2 © ISO 2021 – All rights reserved

---------------------- Page: 6 ----------------------
ISO/FDIS 10522:2021(E)

3.14
regulated pressure at zero flow
regulated pressure (3.7) when pressure is applied at the inlet of a pressure regulator and the outlet of
the pressure regulator is closed
3.15
regulation assembly
portion of the pressure regulator consisting mainly of working parts that narrow or widen the water
passages in the pressure regulator to maintain a constant pressure
3.16
reference velocity
ν
ref
velocity of flow through the valve calculated from the actual flow rate through the valve divided by the
area of a circle with diameter equal to the nominal DN
3.17
accuracy level
deviation of the outlet pressure from the pressure setting or from the setting declared by the
manufacturer
3.18
adjustable stop
device used for adjusting the range of movement of the operating mechanism up to full opening or
closing of a hydraulically operated valve
4 Pressure regulator classification
4.1 According to construction of regulation assembly
Class 4.1.1 Single­range pressure regulator
Class 4.1.2 Multi­range pressure regulator
Class 4.1.3 Single­range adjustable pressure regulator
Class 4.1.4 Multi­range adjustable pressure regulator
4.2 According to construction of pressure regulator
Class 4.2.1 Ordinary pressure regulator
Class 4.2.2 Integral pressure regulator
4.3 According to regulated pressure at zero flow
Class 4.3.1 Pressure regulator in which the regulated pressure equals the inlet pressure at zero flow
Class 4.3.2 Pressure regulator in which the regulated pressure does not equal (is less than) the inlet
pressure at zero flow
4.4 According to accuracy level [see b)]
Class 4.4.1 Pressure regulators with accuracy level A (±10 %)
Class 4.4.2 Pressure regulators with accuracy level B (±20 %)
© ISO 2021 – All rights reserved 3

---------------------- Page: 7 ----------------------
ISO/FDIS 10522:2021(E)

5 Marking
With the exception of integral pressure regulators (which are an integral part of the irrigation device
and bear its marking), each pressure regulator shall bear readily visible, clear and durable marking
including the following:
a) manufacturer's name and/or trademark;
b) nominal size;
c) nominal pressure;
d) arrow indicating direction of flow;
e) markings to indicate direction of adjustment, for classes 4.1.3 and 4.1.4:
— + to increase regulated pressure,
— − to reduce regulated pressure.
In addition, each pressure regulator or package of pressure regulator(s) shall carry a label specifying:
f) the declared pre-set pressure;
g) the accuracy level — A or B — of the regulator (see 4.3);
h) allowable temperature range.
The declared pre-set pressure given on the attached label or on the label to the packaging may be
indicated by colour or by any other marking, as explained in the manufacturer's catalogue.
In multi­range pressure regulators (class 4.1.2) and in multi­range adjustable pressure regulators
(class 4.1.4), the parts that can be replaced to vary the regulated pressure shall be marked by colour or
by any other marking, as explained in the manufacturer's catalogue.
6 Technical characteristics
6.1 General
The parts of the pressure regulator that are in contact with water shall be of non-toxic materials, and
shall be resistant to, or protected against, corrosion in the working conditions for which the pressure
regulator is intended.
All parts belonging to pressure regulators of the same size, type and model designed to allow
dismantling and produced by the same manufacturer shall be interchangeable.
Plastics parts of the pressure regulator that are exposed to ultraviolet (UV) radiation in the normal
working conditions under which the pressure regulators operate shall include additives to improve
their resistance to UV radiation. Plastics parts that enclose waterways shall be opaque or shall be
provided with an opaque cover designed to block all light from reaching clear waterway enclosures.
6.2 Pressure regulator body
Pressure regulators with threaded ends shall be provided with a hexagonal boss or with other means
for gripping. The face-to-face distance of the flanged bodies of the pressure regulators shall not deviate
from the length declared by the manufacturer in his catalogue, or other material describing the
specifications of the pressure regulator, by more than ±2 mm for metal-body regulators or ±4 mm for
plastics-body regulators.
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ISO/FDIS 10522:2021(E)

6.3 Adjustment assembly
Balancing the regulated pressure to the pressure regulator set point is accomplished by means of a
spring. The chamber containing the spring shall be sealed to prevent entry of water except in those cases
where all the components within the chamber are constructed from corrosion­resistant materials. The
housing of the adjustment assembly shall be constructed to prevent locking of the pressure regulator
due to entry of water.
If the housing of the adjustment assembly is threaded to the pressure regulator body, it shall be
equipped with a hexagonal boss or similar means to facilitate disassembly and reassembly.
The adjustment assembly of the pressure regulators shall be equipped with a handle, slot, a polygonal
part, or similar means to permit adjustment.
6.4 Connections
The manufacturer shall use one of the following connection methods:
a) threaded ends for direct connection to the supply line: these shall be in accordance with ISO 7-1;
however, other threads shall be allowed, provided that a suitable adaptor is supplied with each
threaded connection making it conform with ISO 7-1;
b) flanged connections: these shall conform with ISO 7005-1 or ISO 7005-2;
c) other suitable means of connection.
6.5 Adjustable stop
Where the pressure regulator has an adjustable stop, it shall permit adjustment of the regulation
assembly to full opening and full closing of the water passages.
The adjustable stop shall be easily adjusted, positive, and not subject to loosening by vibration. When
assembled on a stem, the handle shall be mechanically secured to the stem.
The adjustable stop and its parts shall effectively resist an opening or a closing torque, in newton
metres, numerically equal to the nominal size in millimetres or to 25 times the nominal size in inches.
7 Mechanical and functional tests
7.1 Overview
Integral pressure regulators shall be tested only according to 7.2, 7.3, 7.4, 7.8, 7.9, 7.10 and 7.11.
The test sample size and the acceptance number shall be in accordance with Table 1.
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ISO/FDIS 10522:2021(E)

Table 1 — Required number of test specimens and acceptance number for mechanical,
functional and durability tests
Number of
Clause Acceptance
Name of test test
number number
specimens
7.3 Regulation uniformity 3 1
7.4 Tightness of pressure regulator with adjustable stop 3 1
7.5 Regulation curve 2 0
7.6 Regulated pressure as function of pressure regulator adjustment 2 0
7.7 Regulated pressure at zero flow 2 0
7.8 Regulated pressure as function of inlet pressures, at constant 2 0
flow rate
7.9 Regulation curve of integral pressure regulator 2 0
7.10 Pressure loss 2 0
7.11 Resistance of pressure regulator body to internal hydrostatic 5 0
pressure
Clause 8 Durability 2 0
7.2 General
It is considered that, with the exception of the test where work is done with small volumes of water, it
is possible to control the water temperature. The hydraulic characteristics test and the endurance test
shall be carried out at a water temperature of 4 °C to 35 °C.
Clean water shall be used in tests. The permissible deviation of the measuring devices from the actual
value shall be ±2 %. Calibrate the measuring devices according to the existing calibration rules of the
country concerned.
Before performing the functional tests, beginning with 7.3, condition the pressure regulator by
operating it for 5 min at the initial regulation pressure, for 5 min at nominal pressure, and then for
10 min at 1,5 times the declared pre-set pressure, using a flow rate equivalent to a reference velocity of
1 m/s.
7.3 Regulation uniformity (in non-adjustable pressure regulators)
7.3.1 Conduct the test according to the class of pressure regulator as follows:
a) For ordinary pressure regulators (class 4.2.1), measure the regulated pressure in each pressure
regulator of the sample at an inlet pressure of 1,5 times the declared pre-set pressure and at a flow
rate equivalent to a reference velocity of 1 m/s.
b) For integral pressure regulators (class 4.2.2), measure the flow rate through each pressure
regulator at an inlet pressure of 1,5 times the declared pre­set pressure.
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ISO/FDIS 10522:2021(E)

7.3.2 From the results obtained in the tests in 7.3.1, calculate the coefficient of variation, CV, Formula (1)
for ordinary pressure regulators:
s ×100
p
CV = (1)
p
or Formula (2) for integral pressure regulators:
s ×100
q
CV = (2)
q
where
s is the sample standard deviation of the regulated pressures;
p
s is the sample standard deviation of the flow rates;
q
p
is the mean regulated pressure of the sample;
q
is the mean flow rate of the sample.
The pressure regulators shall meet the following criteria.
a) For ordinary pressure regulators, the average regulated pressure of the sample shall not deviate
from the declared pre-set pressure by more than 7 %.
b) For integral pressure regulators, the average flow rate of the sample shall not deviate from the flow
rate declared by the manufacturer by more than 5 %.
c) For ordinary pressure regulators, the coefficient of variation, CV, shall not be greater than 10 %.
d) For integral pressure regulators, the coefficient of variation, CV, shall not be greater than 7 %.
7.4 Tightness of pressure regulator with adjustable stop
Move the adjustable stop to its fully closed position. When the adjustable stop is actuated by rotating
the stem, apply a closing torque, in newton metres, metrically equal to the nominal size in millimetres.
Apply a hydraulic pressure at the inlet of the pressure regulator, and raise it gradually to the nominal
pressure declared by the manufacturer. Maintain this pressure for 1 min.
The pressure regulator shall show no signs of leakage at the outlet of the pressure regulator.
7.5 Regulation curve
7.5.1 Installation
Install the pressure regulator in a test assembly similar to that shown in Figure 1. Take any steps
necessary to avoid air pockets in the test apparatus.
If difficulties arise in regulating the flow with valves D and D , an additional pressure regulator or a
1 2
flow regulator may be installed after the test specimen, R .
x
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ISO/FDIS 10522:2021(E)

7.5.2 Test results and requirements
7.5.2.1 Test the pressure regulator and plot a curve of the regulated pressure as a function of the flow
rate through the pressure regulator at a constant inlet pressure.
Each curve shall represent the measured regulated pressure at five different flow rates (reference
velocities), as follows:
a) the regulated pressure at: 0,5 m/s, 1 m/s, m/s and 2 m/s;
b) in addition, record the regulated pressure at zero flow.
7.5.2.2 The flow during the course of the test shall not vary by more than ±2 %.
7.5.2.3 Test the pressure regulator and plot the curves for three different inlet pressures, as follows:
a) 1,5 times the declared pre-set pressure;
b) 0,
...