SIST EN 1491:2022

SLOVENSKI STANDARD
SIST EN 1491:2022
01-september-2022
Nadomešča:
SIST EN 1491:2000
Ventili v stavbah - Ekspanzijski ventili - Preskusi in zahteve
Building valves - Expansion valves - Tests and requirements
Gebäudearmaturen - Sicherheitsventile für Expansionswasser - Prüfungen und
Anforderungen
Robinetterie de bâtiment - Soupapes d'expansion - Essais et exigences
Ta slovenski standard je istoveten z: EN 1491:2022
ICS:
23.060.01 Ventili na splošno Valves in general
91.140.60 Sistemi za oskrbo z vodo Water supply systems
SIST EN 1491:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 1491:2022

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SIST EN 1491:2022


EN 1491
EUROPEAN STANDARD

NORME EUROPÉENNE

July 2022
EUROPÄISCHE NORM
ICS 91.140.60 Supersedes EN 1491:2000
English Version

Building valves - Expansion valves - Tests and
requirements
Robinetterie de bâtiment - Soupapes d'expansion - Gebäudearmaturen - Sicherheitsventile für
Essais et exigences Expansionswasser - Prüfungen und Anforderungen
This European Standard was approved by CEN on 13 June 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1491:2022 E
worldwide for CEN national Members.

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SIST EN 1491:2022
EN 1491:2022 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Materials and surface finishes . 8
4.1 General . 8
4.2 Materials . 9
4.3 Detection of residual stress . 9
4.3.1 General . 9
4.3.2 Test . 9
4.3.3 Test method (Procedure) . 9
4.3.4 Requirements .10
4.4 Corrosion resistance test .10
4.4.1 General .10
4.4.2 Test method .10
4.4.3 Requirements .10
4.5 Coating adherence test .10
4.5.1 General .10
4.5.2 Test method .10
4.5.3 Requirements .11
4.6 Compatibility with the products used for shock disinfection of the networks.11
4.6.1 General .11
4.6.2 Test method .11
4.6.3 Requirements .11
5 Design, dimensional and pressure requirements .12
5.1 General guidance .12
5.2 Dimensional characteristics.12
5.2.1 Nominal outlet diameter .12
5.2.2 End connections .12
5.3 Expansion valve outlet connection to air break to drain.12
5.4 Expansion valve discharge connection to drain service .12
5.5 Connections .12
5.6 Pressures .13
5.6.1 General .13
5.6.2 Nominal set pressure (P ) .13
nr
5.6.3 Water tightness pressure (P ) .13
e
5.6.4 Opening pressure (Po) .13
5.6.5 Rating pressure (P ) .13
dn
5.6.6 Clossing pressure (P ) .13
f
5.6.7 Initial opening pressure (P ) .13
dc
6 Apparatus .13
6.1 General .13
6.2 Tolerances of parameters and accuracy of measure instruments .14
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SIST EN 1491:2022
EN 1491:2022 (E)
6.2.1 Tolerances on set parameters . 14
6.2.2 Accuracy of measuring instruments . 14
6.2.3 Test media . 14
7 Hydraulic tests and requirements . 14
7.1 Cold water pressure tests . 14
7.1.1 General . 14
7.1.2 Water tightness pressure (P ) test . 14
e
7.1.3 Repeat tests . 15
7.2 Endurance test . 15
7.2.1 Procedure . 15
7.2.2 Requirement . 16
7.3 Easing gear (manual control device) . 16
7.3.1 Operation of the easing gear. 16
7.3.2 Easing gear endurance test . 16
8 Mechanical tests and requirements . 16
8.1 Mechanical strength . 16
8.1.1 Pressure test of the body of the expansion valve . 16
8.1.2 Bending moment test of the body of the expansion valve . 17
8.2 Mechanical strength of the easing gear . 18
8.2.1 Procedure . 18
8.2.2 Requirement . 18
8.3 Torsional strength of the expansion valve's body . 18
8.3.1 General . 18
8.3.2 Procedure . 18
8.3.3 Requirement . 19
8.4 Torque test of the captive rotating nuts/tail pieces . 19
8.4.1 General . 19
8.4.2 Procedure . 19
8.4.3 Requirement . 19
9 Classification . 19
10 Designation . 20
11 Marking . 20
12 Technical documents and presentation at delivery . 21
Annex A (informative) Classification of water heaters according to heating method . 22
A.1 Indirect heating . 22
A.2 Classification of water heaters according to heating method . 22
A.2.1 Indirect heating . 22
A.2.2 Direct heating . 23
Bibliography . 24

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SIST EN 1491:2022
EN 1491:2022 (E)
European foreword
This document (EN 1491:2022) has been prepared by Technical Committee CEN/TC 164 “Water supply”,
the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2023, and conflicting national standards shall
be withdrawn at the latest by January 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 1491:2000.
In comparison with the previous edition, the following technical modifications have been made:
— chapter on materials was completely revised;
— testing with disinfectant was introduced;
— torque test was added;
— testing of the expansion valve was changed and optimized;
— coating test procedure was revised;
— normative references were updated;
— editorial changes have been made throughout the entire document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
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SIST EN 1491:2022
EN 1491:2022 (E)
Introduction
With regard to potential adverse effect on the quality of water intended for human consumption, caused
by the product covered by this document:
1) This document provides no information as to whether the product may be used without restriction
in any of the Member States of the EU or EFTA.
2) It should be noted that, whilst awaiting the adoption of verifiable European criteria, existing national
regulations concerning the use and or the characteristics of this product remain in force.
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SIST EN 1491:2022
EN 1491:2022 (E)
1 Scope
This document specifies dimensions, materials and performance requirements (including methods of
1
test) for expansion valves, of nominal sizes from DN 15 to DN 32, having working pressures ) from
0,1 MPa (l bar) to 1,0 MPa (10 bar).
Expansion valves are intended for fitting to the cold potable water supply of storage water heaters, having
a maximum distribution temperature of 95 °C, for all energy sources.
Expansion valves do not control the temperature and alone do not constitute the protection required for
storage water heaters. Expansion valves limit pressure, in the water heaters to what they are fitted, that
is produced by thermal expansion of the water.
NOTE The use of the device specified in this document does not override the need to use controls (e.g.
thermostats and cut-outs) which act directly on the power sources of water heaters (for more information see
Annex A).
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.
EN 806 (all parts), Specifications for installations inside buildings conveying water for human consumption
EN 1254-2, Copper and copper alloys - Plumbing fittings - Part 2: Compression fittings for use with copper
tubes
EN 1717, Protection against pollution of potable water in water installations and general requirements of
devices to prevent pollution by backflow
EN 10226-1, Pipe threads where pressure tight joints are made on the threads - Part 1: Taper external
threads and parallel internal threads - Dimensions, tolerances and designation
EN ISO 6509 (all parts), Corrosion of metals and alloys - Determination of dezincification resistance of brass
(ISO 6509)
EN ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads - Part 1: Dimensions,
tolerances and designation (ISO 228-1)
EN ISO 9227, Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227)
ISO 6957, Copper alloys — Ammonia test for stress corrosion resistance

1
 All pressures are gauge unless otherwise stated.
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SIST EN 1491:2022
EN 1491:2022 (E)
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:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
expansion valve
valve that limits the pressure of the water in the water heater to a predetermined value by discharging
water to drain
3.2
air break to drain
device that prevents discharged water from returning to the expansion valve and thus to the water heater
3.3
nominal set pressure
Pnr
pressure of the expansion valve which is set on production
Note 1 to entry: The “nominal set pressure” (P ) is often called “set pressure”.
nr

Key
Y pressure
X time
Figure 1 — Pressures
3.4
water tightness pressure
P
e
pressure up to which the expansion valve is closed
Note 1 to entry: See Figure 1.
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SIST EN 1491:2022
EN 1491:2022 (E)
3.5
initial opening pressure
P
dc
pressure at which the expansion valve opens for the first time, as indicated by the first droplet of water
at the outlet of the expansion valve, after a period of storage
Note 1 to entry: See Figure 1.
3.6
opening pressure
P
o
pressure at which the expansion valves opens as indicated by the appearance of water at the outlet of the
expansion valve
Note 1 to entry: See Figure 1.
3.7
rating pressure
P
dn
pressure at which the discharged flow is above the limit
Note 1 to entry: See Figure 1 and Table 2.
3.8
closing pressure
P
f
pressure at which the expansion valve closes after having reached the rating pressure
Note 1 to entry: See Figure 1.
4 Materials and surface finishes
4.1 General
The selection of materials is the responsibility of the manufacturer, provided they satisfy the following
requirements:
a) materials and coatings shall not contaminate the potable water;
b) in a technical document, the manufacturer shall state the nature of the materials and coatings used;
c) materials with insufficient corrosion resistance (e.g. cast iron, aluminium) shall have additional
protection;
d) the materials used shall be suitable for the temperatures specified in the tests in this document;
e) the materials, and in particular copper alloys, for which recommendations or international standards
exist, shall comply with the relevant recommendations or international standards.
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EN 1491:2022 (E)
4.2 Materials
All materials coming into contact with water intended for human consumption shall present no health
risk nor cause any change to the water in terms of quality, appearance, smell or taste.
NOTE It is pointed out that while awaiting the adoption of verifiable European criteria for testing materials in
contact with water intended for human consumption, existing national regulations concerning the use and/or the
characteristics of these products remain in force.
Copper-zinc alloys containing more than 10 % zinc are subject to dezincification when submitted to
water capable of dezincification. In the countries where the use of products made of dezincification
resistant materials is required, the materials used shall guarantee a dezincification depth less than
200 μm in any direction. For this purpose, materials shall be tested in accordance with
EN ISO 6509 (all parts) and the product shall be marked in compliance with the indications according to
Clause 11.
4.3 Detection of residual stress
4.3.1 General
This test shall be performed for bodies made out of brass materials and with female threads according to
EN 10226-1 and compression ends according to EN 1254-2.
4.3.2 Test
This test is based on ISO 6957. Its purpose is to verify the resistance to cracking under stress corrosion
in ammonia medium (as described in 4.3.3, b).
The test entails exposing test specimens consisting of the assembled expansion valve in an atmosphere
loaded with ammonia vapour.
4.3.3 Test method (Procedure)
The paragraph below details ISO 6957.
Test solution:
a) Use solutions of analysis quality and of distilled water.
b) Solution of ammonia at 20 % (in weight).
c) The pH of the test solution shall be adjusted to 9,5 by using hydrochloric acid.
d) The test temperature shall be (23 ± 2) °C with a measurement uncertainty of ± 1 K.
Test specimen:
e) The test specimen consists of three samples of a single assembled product. The test specimen shall
be inserted into the test enclosure under no stress.
Instructions:
f) Rinse the test specimens with a clean non-chlorinated solvent (for example, ethanol).
g) Let it dry in the air.
h) Insert the test specimens into the test enclosure along with the ammonia solution. The volume of the
container made of glass (e.g. desiccator) shall be minimum (10 ± 1) l.
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EN 1491:2022 (E)
i) The volume of the solution inserted shall be (200 ± 10) ml per 3 l of total volume of the container
(e.g. for a 10 l container it means (667 ± 33) ml).
j) Place the test specimens in the container in such a way that they will not touch each other and that
they will not be in contact with the solution.
+2
After an exposure of 24 h , remove the test specimens and rinse them.
−0
4.3.4 Requirements
After the test, the expansion valve shall be disassembled and inspected visually for stress corrosion
cracking. No crackings shall occur on any component.
At least two samples shall be in accordance with the test in 7.1.2.
4.4 Corrosion resistance test
4.4.1 General
The purpose of the corrosion resistance test is to qualify all used materials of an expansion valve,
especially when used in a humid atmosphere where condensation water can occur. The whole expansion
valve shall be tested, not only the parts in contact with potable water, e.g. springs, spring caps, etc.
4.4.2 Test method
Samples shall be prepared for the corrosion resistance test as described as follows.
Carry out the test under the conditions described in EN ISO 9227 specifically for the neutral saline-spray
test, in the following way:
a) Subject the device to spraying for at least 100 h, interrupt the spraying treatment for (48 ± 1) h while
maintaining the heat in the tank and resume the spraying treatment for another (100 ± 1) h.
b) For the duration of the tests, the tank should only be opened to check and maintain the conditions,
the maximum rest period in spraying being 30 min per day. The heating should not be interrupted;
samples under test should not be handled, washed or checked.
After treatment and before visual examination, rinse the test samples in water to remove any salt residue.
4.4.3 Requirements
The expansion valve shall comply with the requirements as included in 7.1.
After the test, the expansion valve shall be disassembled and inspected visually for corrosion. No
corrosion shall occur on any component.
4.5 Coating adherence test
4.5.1 General
The coating adherence test is only applicable for the valve housing and if the purpose of the coating is
corrosion protection as specified in 4.1 c).
4.5.2 Test method
At 3 different locations on the coated surface, cut with a cutting tool with a tungsten carbide tip of the
type shown on Figure 2, crosses or V’s approximately 10 mm × 10 mm in length. The crosses or V’s shall
be cut by pulling the handle of the chisel parallel to the surface. The depth shall be such that they
completely cut through the coating layer, without forcing the coating into the base metal.
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EN 1491:2022 (E)

a) Front view b) Side view
Figure 2 — Cutting tool
4.5.3 Requirements
The coating shall neither scale nor unstick.
4.6 Compatibility with the products used for shock disinfection of the networks
4.6.1 General
All the constituent parts of the device, and in particular those made of elastomer, shall be compatible with
the treated water used for the shock disinfection of the networks using sodium hypochlorite, hydrogen
peroxide or chlorine dioxide.
4.6.2 Test method
The compatibility is checked by exposing the internal parts of the device to the chemicals as specified in
Table 1.
Table 1 — Test chemicals
Chemical Chemical Contact
Concentration Temperature
formula solution time
sodium 100 mg in 1 l demineralized
NaOCl 24 h ambient
hypochlorite water
H O
hydrogen peroxide 24 h 1 g in 1l demineralized water ambient
2 2
6 mg in 1 l demineralized
ClO
chlorine dioxide 12 h ambient
2
water
The quality of the water used for this test shall be pH (7 ± 0,5).
Each of the contacts being carried out under a static pressure of 0,3 MPa ± 0,1 MPa (3 bar ± 1 bar)
measured upstream.
The test shall be carried out with at least one of the given chemicals as specified in Table 1.
4.6.3 Requirements
After the performance of the test the valve shall comply with 7.1.
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SIST EN 1491:2022
EN 1491:2022 (E)
5 Design, dimensional and pressure requirements
5.1 General guidance
a) The expansion valve shall be of the type where the spring is isolated from the water by a diaphragm
or equivalent.
b) All sliding elements of the expansion valve shall be designed to prevent any risk of seizure or sticking.
c) Sliding or rotating parts of expansion valves shall not be in contact with water.
d) The components controlling the setting of the expansion valve shall no
...