oSIST prEN 1487:2026

• Abstract:

  This document specifies dimensions, materials and performance requirements, including methods of test, for hydraulic safety groups, of nominal sizes from DN 15 to DN 25, having working pressures from 0,1 MPa (1 bar) to 1,0 MPa (10 bar).; Hydraulic safety groups are intended for fitting to the potable water supply of storage water heaters, having a maximum storage temperature of 95 °C.; Hydraulic safety groups limit the pressure in hot water heaters, prevent the backflow of water into the main circuit and prevent the discharged water to get into contact with the water in the water heater.; Hydraulic safety groups do not control the temperature. They ensure the hydraulic safety of water heaters if the mechanical resistance of the water heater remains at least equal to the rating pressure.; 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).

• Status: Not Published
• Public Enquiry End Date: 24-Nov-2026
• ICS: 23.060.01 - Valves in general
• ICS: 91.140.60 - Water supply systems
• Technical Committee: IOVO - Water supply and waste water engineering
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 02-Oct-2026
• Due Date: 19-Feb-2027
• Ref Project: prEN 1487 - Building valves - Hydraulic safety groups - Tests and requirements

• Revises: SIST EN 1487:2014 - Building valves - Hydraulic safety groups - Tests and requirements
• Effective Date: 18-Dec-2024

SLOVENSKI STANDARD
01-november-2026
Ventili v stavbah - Varnostni hidravlični bloki - Preskusi in zahteve
Building valves - Hydraulic safety groups - Tests and requirements
Gebäudearmaturen - Hydraulische Sicherheitsgruppen - Prüfungen und Anforderungen
Robinetterie de bâtiment - Groupes de sécurité - Essais et exigences
Ta slovenski standard je istoveten z: prEN 1487
ICS:
23.060.01 Ventili na splošno Valves in general
91.140.60 Sistemi za oskrbo z vodo Water supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2026
ICS 91.140.60 Will supersede EN 1487:2014
English Version
Building valves - Hydraulic safety groups - Tests and
requirements
Robinetterie de bâtiment - Groupes de sécurité Gebäudearmaturen - Hydraulische Sicherheitsgruppen
hydraulique - Essais et exigences - Prüfungen und Anforderungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 164.
If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Türkiye and
United Kingdom.
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 supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1487:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Materials and surface finishes . 11
4.1 General. 11
4.2 Materials . 11
4.3 Detection of residual stress . 11
4.3.1 General. 11
4.3.2 Principle . 11
4.3.3 Procedure . 11
4.3.4 Requirements . 12
4.4 Corrosion resistance test . 12
4.4.1 General. 12
4.4.2 Procedure . 12
4.4.3 Requirements . 12
4.5 Coating adherence test (excluding cosmetic coatings) . 13
4.5.1 General. 13
4.5.2 Procedure . 13
4.5.3 Requirements . 13
5 Compatibility of the valve with disinfection . 13
5.1 General. 13
5.2 Requirements . 13
5.3 Procedure . 13
6 Design and dimensional characteristics . 14
6.1 General. 14
6.2 Dimensional characteristics . 14
6.2.1 End connections . 14
6.2.2 Test port . 15
6.2.3 Pressure tapping . 16
6.2.4 Pressure safety valve outlet connection to air break to drain . 16
6.2.5 Pressure safety valve discharge connection to drain device . 16
6.2.6 Connections . 16
6.2.7 Replacing the cartridge of the pressure safety valve . 16
6.2.8 Check valve . 16
6.2.9 Operating control . 16
7 Tolerances of parameters and accuracy of measure instruments . 17
7.1 General. 17
7.2 Tolerances on set parameters . 17
7.3 Accuracy of measuring instruments . 17
7.4 Test media . 17
8 Hydraulic tests . 17
8.1 Flow rate test . 17
8.1.1 Procedure . 17
8.1.2 Requirements . 18
8.2 Tightness tests . 18
8.2.1 General . 18
8.2.2 Tightness test of the isolating valve at a pressure of 1,6 MPa (16 bar) . 18
8.2.3 Tightness test of the hydraulic safety group . 18
9 Mechanical tests and requirements . 18
9.1 Mechanical strength . 18
9.1.1 Pressure test of the hydraulic safety group . 18
9.1.2 Bending test of the body and pull-out test of the drainage of the hydraulic safety
group . 19
9.1.3 Torsional strength test of the hydraulic safety group’s body . 20
9.1.4 Tensile strength test of the captive rotating nuts . 21
9.1.5 Mechanical strength test of the operating control of the pressure safety valve . 21
10 Hydraulic safety group tests . 22
10.1 Isolating valve . 22
10.1.1 General . 22
10.1.2 Manual operation test . 22
10.1.3 Endurance test . 22
10.1.4 Resistance test for manual operation . 22
10.2 Check valve . 23
10.2.1 Verification of the leaktightness between the group’s body and the check valve at
low pressure . 23
10.2.2 Verification of the leaktightness between the group’s body and the check valve
under high pressure . 23
10.3 Pressure safety valve . 23
10.3.1 Pressures . 23
10.3.2 Cold water pressure test . 24
10.3.3 Steam test . 25
10.4 Endurance test . 26
10.4.1 Procedure . 26
10.4.2 Requirements . 26
10.5 Operating control . 27
10.5.1 Operation test . 27
10.5.2 Endurance test . 27
10.6 Manual drainage device . 27
10.6.1 General . 27
10.6.2 Flow rate test . 27
10.7 Air break to drain . 27
10.8 Resistance to thermal shocks test for plastic components. 28
10.8.1 Procedure . 28
10.8.2 Requirements . 28
11 Acoustic tests . 29
12 Classification . 29
13 Designation . 30
14 Marking . 30
15 Technical documents and presentation at delivery . 31
Annex A (informative) Test sequences . 32
Annex B (informative) Classification of water heaters according to heating method . 35
Annex C (informative) Disinfection of test rig . 37
Bibliography . 38

European foreword
This document (prEN 1487:2026) has been prepared by Technical Committee CEN/TC 164 “Water
supply”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1487:2014.
— chapter on materials was completely revised;
— testing with disinfectant was introduced;
— coating test procedure was revised;
— normative references were updated;
— editorial changes have been made throughout the entire document.
Introduction
With regard to potential adverse effect on the quality of water intended for human consumption, caused
by the product covered by this document:
a) 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.
b) 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.
1 Scope
This document specifies dimensions, materials and performance requirements, including methods of test,
for hydraulic safety groups, of nominal sizes from DN 15 to DN 25, having working pressures from
0,1 MPa (1 bar) to 1,0 MPa (10 bar).
Hydraulic safety groups are intended for fitting to the potable water supply of storage water heaters,
having a maximum storage temperature of 95 °C.
Hydraulic safety groups limit the pressure in hot water heaters, prevent the backflow of water into the
main circuit and prevent the discharged water to get into contact with the water in the water heater.
Hydraulic safety groups do not control the temperature. They ensure the hydraulic safety of water
heaters if the mechanical resistance of the water heater remains at least equal to the rating pressure.
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 806-5, Specifications for installations inside buildings conveying water for human consumption —
Part 5: Operation and maintenance
EN 1254-2, Copper and copper alloys - Plumbing fittings - Part 2: Compression fittings for use with copper
tubes
EN 1717, Protection against pollution of water intended for human consumption in potable water
installations and general requirements for 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 13959:2004, Anti-pollution check valves - DN 6 to DN 250 inclusive family E, type A, B, C and D
EN ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads - Part 1: Dimensions,
tolerances and designation (ISO 228-1:2000)
EN ISO 6509-1, Corrosion of metals and alloys - Determination of dezincification resistance of copper alloys
with zinc - Part 1: Test method (ISO 6509-1)
EN ISO 9227, Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2022)
ISO 691, Assembly tools for screws and nuts — Wrench and socket openings — Tolerances for general use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

All pressures are gauge unless otherwise stated.
ISO and IEC maintain terminology 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
hydraulic safety group
safety device that limits the pressure in hot water heaters, prevents the backflow of water into the main
circuit, prevents the discharged water from coming into contact with the water in the water heater, allows
the function of the backflow prevention to be controlled and isolates and drains the water heater for
maintenance services
Note 1 to entry: A hydraulic safety group comprises at least the following items in a single unit, in an upstream
to downstream order, as shown in Table 1.
Note 2 to entry: For the purposes of this document, the hydraulic safety group is hereafter referred to as ‘the
device’.
Note 3 to entry: It also incorporates the safety group’s valve seat.
Table 1 — Components of hydraulic safety groups
Component Quantity
isolating valve 1
test port for monitoring the check valve 1
b
antipollution check valve 1
a
isolating valve 1
a
additional outlet connection 1
pressure safety valve 1
a
drain device or drain function 1
air break to drain 1
pressure tapping 1
a
optional
b
replaceable or non-replaceable
3.2
isolating valve
valve that allows the water heater to be isolated from the potable water supply
Note 1 to entry: If a second valve is fitted, it is placed between the check valve and safety valve.
3.3
antipollution check valve
device which allows water to flow just in one direction and prevent water to return back
Note 1 to entry: Anti-pollution check valve is usually called check valve in a short-term.
3.4
additional outlet connection
outlet connection that allows cold potable water to be supplied to an additional device
Note 1 to entry: For example, inline hot water supply tempering valves etc.
3.5
pressure safety valve
valve that limits the pressure of the water in the water heater to a predetermined value by discharging
water to the drain and in case of temperature control failure, discharging the energy stored as water or
steam
3.6
drain device or drain function
device that allows the water heater to be drained without removing the hydraulic safety group and the
outlet connection which is also used to discharge water or steam from the pressure safety valve
3.7
air break to drain
vertical distance realised by air inlets or full disconnection between the lowest point of the outlet and the
spill-over level of the atmospheric drain overflow
3.8
pressure tapping
tapping that allows pressure measuring equipment to be connected
3.9
nominal set pressure
P
nr
pressure of the pressure safety valve which is set on production
Note 1 to entry: The “nominal set pressure” (Pnr) is often called “set pressure”.
3.10
water tightness pressure
P
e
pressure up to which the pressure safety valve is closed
Note 1 to entry: See Figure 1.
3.11
initial opening pressure
Pdc, water
pressure at which the pressure safety valve opens for the first time, as indicated by the first
droplet of water at the outlet of the safety group, after a period of storage
Note 1 to entry: See Figure 1.
3.12
initial opening pressure
P
dc, steam
pressure at which the pressure safety valve opens for the first time, as indicated by the first
appearance of steam at the outlet of the safety group, after a period of storage
Note 1 to entry: See Figure 1.
3.13
opening pressure
P
o, water
pressure at which the pressure safety valve opens as indicated by the appearance of water at
the discharge connection of the hydraulic safety group
Note 1 to entry: See Figure 1.
3.14
opening pressure
P
o, steam
pressure at which the pressure safety valve opens as indicated by the appearance of steam at
the discharge connection of the hydraulic safety group
3.15
rating pressure
Pdn
pressure at which the discharged flow is above the limit given in Table 9 and Table 10
Note 1 to entry: See Figure 1.
3.16
closing pressure
P
f
pressure at which the pressure safety valve closes after having reached the rating pressure
Note 1 to entry: See Figure 1.

Key
Y pressure
X time
Figure 1 — Pressures
4 Materials and surface finishes
4.1 General
The selection of materials is not specified in this document, provided the materials satisfy the following
requirements:
a) The materials and coatings used shall not contaminate the potable water;
b) The nature of the materials and coatings used shall be stated in a technical document;
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 used, and in particular copper alloys, for which recommendations or international
standards exist, shall comply with the relevant recommendations or international standards.
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.
Copper-zinc alloys containing more than 15 % 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 6509-1
and the product shall be marked in compliance with the indications according to Clause 14.
4.3 Detection of residual stress
4.3.1 General
This test shall be performed for bodies made out of material potentially susceptible to stress corrosion
cracking and with female threads in accordance with EN 10226-1 and compression ends in accordance
with EN 1254-2.
4.3.2 Principle
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 device in an atmosphere loaded with
ammonia vapour.
4.3.3 Procedure
NOTE This subclause integrates elements from 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:
a) 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:
a) Rinse the test specimens with a clean non-chlorinated solvent (for example, ethanol).
b) Let it dry in the air.
c) 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.
d) 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).
e) 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.
After an exposure of (24 ± 2) h, remove the test specimens and rinse them.
4.3.4 Requirements
After the test, the devices shall be inspected visually for stress corrosion cracking. No cracking shall occur
on any component. The device shall be tested and comply with the requirements of 8.2.3.
4.4 Corrosion resistance test
4.4.1 General
The purpose of the corrosion resistance test is to qualify all used materials of the external part of the
product. The whole device shall be tested, not only the parts in contact with potable water. Positioning
restriction given by the manufacturer shall be taken into account by placing the device into the tank.
4.4.2 Procedure
Samples shall be prepared for the corrosion resistance test as described as follows.
Carry out the test in accordance with the neutral saline-spray test of EN ISO 9227 and the following:
a) Subject the device with closed in- and outlet connection 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 device shall comply with the requirements as included in cold water pressure test (10.3.2). The
results shall not deviate by more than 10 % from the original values.
4.5 Coating adherence test (excluding cosmetic coatings)
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 Procedure
At three 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 Vs 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 electrolytic deposit, without forcing that coating into the base metal. Proceed
test according 4.4.2.
a) Front view b) Side view
Figure 2 — Cutting tool
4.5.3 Requirements
The coating shall neither scale nor unstick.
5 Compatibility of the valve with disinfection
5.1 General
The disinfection test is carried out to ensure that a valve/device can continue to fulfil its function after
several curative disinfection measures (shock disinfection) in a drinking water installation (see Table 2).
NOTE See Annex C.
5.2 Requirements
The entire valve/device shall remain functional after carrying out the disinfection test with one of the
three disinfectant solutions (Table 2).
The device shall comply with the requirements as included in 10.3.2 of this standard. The results shall
not deviate by more than 10 % from the original requirements (same as for steam).
5.3 Procedure
The test circuit with the integrated valve/device (Figure C.1) shall be filled with one of the disinfectant
solutions listed in Table 1 maintaining a circulation at a pressure of 3 bar.
Monitor all the values in Table 1 and maintain all parameters constant during the entire testing time
(contact time).
Verify that the device satisfies the main functional requirements of 10.3.2.
Table 2 — Test chemicals
Chemical Contact pH-value test
Chemical solution Concentration Temperature
formula time solution
100 mg ± 10 % Cl
sodium
NaOCl 24 h (active chlorine) in 6,5 to 7,5 (20 ± 5) °C
hypochlorite
1 l water
1 000 mg ± 10 %
H O hydrogen peroxide 24 h 6,5 to 7,5 (20 ± 5) °C
2 2
H O in 1 l water
2 2
6 mg ± 10 % ClO in
ClO chlorine dioxide 12 h 6,5 to 7,5 (20 ± 5) °C
1 l water
The test shall be carried out with one of the given chemicals as defined in Table 2.
6 Design and dimensional characteristics
6.1 General
a) All sliding elements of the pressure safety valve shall be designed to prevent any risk of seizure or
sticking.
b) Sliding or rotating parts of pressure safety valves shall not be in contact with water.
c) The components controlling the setting of the pressure safety valve shall not be accessible to the end
user without damage to the valve.
d) Wing or similar guides for pressure safety valves shall not be used on the inlet side of the pressure
safety valve.
e) The normal operation of the pressure safety valve shall not be changed by external forces.
f) The body of the device shall have a minimum of two suitable flats to apply a spanner.
g) The safety valve shall have a technical mean for checking its function at regular intervals.
6.2 Dimensional characteristics
6.2.1 End connections
The size of the end connections shall be of the same size or one DN smaller than the nominal DN size of
the hydraulic safety group.
The end connection shall be in accordance with relevant European Standards, e.g. EN 10226-1,
EN ISO 228-1 or EN 1254-2, EN 1254-20.
For captive rotating nuts the dimensional requirements are in Table 3 and Figure 3.
Table 3 — Dimensions for captive rotating nuts
D (mm) G 1/2 G 3/4 G 1 G 1 1/4
D (mm) min. 18 23,5 29,5 37
0 1,3 1,3 1,3
l (mm) 9,8 10 11,5 13
−1,8 −1,5 −1,5 −2
l (mm) Equal or bigger than l max
8 7
For this type of nut, the diameter of the nut shall be equal to or greater than one DN of the device higher.

Figure 3 — Dimensions for captive rotating nuts
6.2.2 Test port
For dimensions of the test port see Table 4 and Figure 4.
The bores of the test port shall have over their full length a minimum cross-section of 12,56 mm , the
smallest dimension shall be d ≥ 4 mm.
Table 4 — Dimensions of test port
Nominal size Thread size a
DN mm
DN ≤ 15 G 1/8 or G 1/4 > 6,5
15 < DN ≤ 25 G 1/4 > 6,5
The thread shall be in accordance with EN ISO 228-1.
The test port shall be produced so that the plug can be adequately sealed.

Figure 4 — Test port
6.2.3 Pressure tapping
When the hydraulic safety group is fitted with a pressure tapping for the connection of equipment to
measure pressure, the dimensions of the tapping shall be as follows (see Figure 3):
a) female thread diameter: G 1/4;
b) depth of thread: a > 6,5 mm;
c) diameter: d > 4 mm.
6.2.4 Pressure safety valve outlet connection to air break to drain
The smallest passage cross-section shall be ≥ 4 mm (passage cross-sections are validated by flow tests).
6.2.5 Pressure safety valve discharge connection to drain device
The dimensions shall be in accordance with EN 1717.
6.2.6 Connections
Connections requiring the use of heat to make or break a joint (e.g. capillary) are not permitted.
6.2.7 Replacing the cartridge of the pressure safety valve
If the pressure safety valve has a cartridge which is replaceable, it shall have the shape of a package
including the seat. Replacing this cartridge shall not affect the leak-tightness of the device. The
requirement of 8.2.3 shall be fulfilled.
6.2.8 Check valve
A check valve of family E type B according to EN 13959 shall be used. The check valve shall comply with
the tightness requirements of EN 13959. Replacement of the check valve shall not affect the performance
of the hydraulic safety group. See 10.2 of this document.
If the EB check valve built into the product does not comply with EN 13959, it shall be subjected to
endurance testing in accordance with EN 13959, according to the following sequence of tests:
a) pressure tightness under a low reverse pressure differential (EN 13959:2004, 11.5);
b) pressure tightness under a high reverse pressure differential and verification that the check valve
has not jammed (EN 13959:2004, 11.6);
c) pressure differential at which the check valve closes (EN 13959:2004, 11.7);
d) endurance (EN 13959:2004, 11.9);
e) pressure tightness under a low reverse pressure differential (EN 13959:2004, 11.10);
f) pressure tightness under a high reverse pressure differential and verification that the check valve
has not jammed (EN 13959:2004, 11.11);
g) pressure differential at which the check valve closes (EN 13959:2004, 11.12).
6.2.9 Operating control
The device shall have an operating control for checking its function at regular intervals and if there is
only one direction for operation of rotary controls of the device, it shall be counter clockwise.
The operating control shall be operated by either a lift handle or a rotary handle and shall be designed so
that the device cannot be locked in the open position when the manual effort is removed.
7 Tolerances of parameters and accuracy of measure instruments
7.1 General
Examples shown in the figures are for guidance only. Laboratory equipment shall be designed to ensure
that check valves can be tested in accordance with the requirements.
7.2 Tolerances on set parameters
In the absence of any particular specifications:
a) Flow rate (water) and pressure
— ±2 % of the value indicated;
b) Flow rate (steam)
— ±5 % of the value indicated;
c) Temperature
— cold water: ± 5 K of the value indicated;
— hot water: ± 2 K of the value indicated;
d) Time
+10
— % of the value indicated;
e) Force
— unless otherwise specified, all tolerances shall be ± 5 %.
7.3 Accuracy of measuring instruments
All the measuring instruments shall have a measurement accuracy of ± 2 % of the measured value, except
for temperature measurement accuracy shall be ± 1 K.
7.4 Test media
In the absence of any particular specification the test media shall be water at ambient temperature (with
a maximum temperature of 30 °C.)
8 Hydraulic tests
8.1 Flow rate test
8.1.1 Procedure
The flow rate shall be determined at a pressure drop of 0,1 MPa (1 bar) across the device. The pressure
losses occurring in the test apparatus shall be taken into account when determining the flow
characteristics of the device.
8.1.2 Requirements
The flow rate measured shall be at least equal to the appropriate flow rate in Table 5.
Table 5 — Minimum flow rates
Nominal size DN 15 20 25
Flow rate (l/h) 1 500 3 500 5 000
8.2 Tightness tests
8.2.1 General
Subject the device, at ambient temperature, to a water pressure to determine:
a) the tightness of the isolating valve;
b) the tightness of the entire device.
8.2.2 Tightness test of the isolating valve at a pressure of 1,6 MPa (16 bar)
8.2.2.1 Procedure
Connect the device to a test circuit and purge the system. Supply the safety unit with water at ambient
temperature. Close the hydraulic safety group’s isolating valve and apply upstream of the seat a water
pressure of 1,6 MPa (16 bar) for a period of 60 s.
8.2.2.2 Requirements
There shall be no visible leakage during the test period.
8.2.3 Tightness test of the hydraulic safety group
8.2.3.1 Procedure
Connect the device to the test circuit by the inlet connection and purge the system. Close the hydraulic
safety group’s water heater connection, maintain the pressure safety valve disc closed and open the
isolating valve. Apply for a period of 60 s a water pressure of 0,02 MPa (0,2 bar) to the inlet connection
of the hydraulic safety group and then a water pressure of 1,6 MPa (16 bar) for a period of 60 s.
8.2.3.2 Requirements
There shall be no visible leakage from the hydraulic safety group during the test period.
9 Mechanical tests and requirements
9.1 Mechanical strength
9.1.1 Pressure test of the hydraulic safety group
9.1.1.1 Procedure
Connect the device to the test circuit by the valve’s inlet connection and blank off the valve’s water heater
connection. Open the isolating valve and maintain the pressure safety valve disc closed. Apply a static
cold-water pressure of 2,5 MPa (25 bar) and maintain this pressure for a period of (300+60) s.
9.1.1.2 Requirements
There shall be no breakage or permanent visible deformation of the safety group.
Following this test, the device shall not be the subject of further hydraulic testing.
9.1.2 Bending test of the body and pull-out test of the drainage of the hydraulic safety group
9.1.2.1 Procedure
9.1.2.1.1 Bending test
Attach the device under test to the test apparatus by its inlet connection, as shown in Figure 5 a), apply
(80 ± 2) % of the nominal set pressure P and apply gradually the bending moment according to Table 6
nr
and maintain it for a period of (60 ± 3) s.
9.1.2.1.2 Pull out test of the drainage
Attach the device under test to the test apparatus by its outlet connection, as shown in Figure 5 b), and
apply gradually the pull-out force according to Table 6 and maintain it for a period of (60 ± 3) s.
Table 6 — Bending moment of the body and pull out force of the drainage
Nominal size DN 15 20 25
Bending moment (Nm) (F × L) for the outlet connection 50 70 120
Pull out force (N) for the drainage connection 100 100 100
9.1.2.2 Requirements
9.1.2.2.1 Bending test
There shall be no leakage, no visible damage to the product (fractures, splits or permanent deformation),
including the point where the bending moment is applied (e.g. at the piping connection).
9.1.2.2.2 Pull out test of the drainage
During the test, the air break to drain is to remain in place and there shall be no visible damage to the
drainage.
a) Bending moment test
b) Pull out test
Key
1 hydraulic safety group
F force
L length of lever
Figure 5 — Bending moment test and pull out test for the drainage
9.1.3 Tors
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