prEN 17821

SLOVENSKI STANDARD
01-november-2026
Ventili v stavbah - Proti zmrzali odporne pipe za zunanjo uporabo (FRT) - Splošna
tehnična specifikacija
Building valves - Frost resistant taps for outdoor use (FRT) - General technical
specification
Gebäudearmaturen - Frostbeständige Armaturen für den Außenbereich (FRT) -
Allgemeine technische Spezifikation
Robinetterie de bâtiment - Robinets résistant au gel pour une utilisation en extérieur
(FRT) - Spécifications techniques générales
Ta slovenski standard je istoveten z: prEN 17821
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 23.060.01; 91.140.60 Will supersede EN 17821:2023
English Version
Building valves - Frost resistant taps for outdoor use (FRT)
- General technical specification
Robinetterie de bâtiment - Robinets résistant au gel Gebäudearmaturen - Frostbeständige Armaturen für
pour une utilisation en extérieur (FRT) - Spécifications den Außenbereich (FRT) - Allgemeine technische
techniques générales Spezifikation
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 17821:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Materials . 7
4.1 General . 7
4.2 Dezincification resistant copper alloy . 7
4.3 Corrosion . 7
4.3.1 General . 7
4.3.2 Corrosion resistance test . 7
5 Characteristics . 8
5.1 Dimensions and design . 8
5.2 Protection against backflow unit . 9
5.3 Resistance to damage by frost .10
5.3.1 General .10
5.3.2 FRT with automatic drainage .10
5.3.3 FRT with controlled expansion (without drainage function) .10
5.4 Types of connection.10
5.5 General tolerances .10
5.5.1 Tolerance of set parameters .10
5.5.2 Accuracy of measuring instruments .11
6 Test methods and requirements .11
6.1 Determination of automatic drainage .11
6.1.1 Principle .11
6.1.2 Procedure.11
6.1.3 Requirements .11
6.2 Determination of resistance against damage by frost by controlled expansion .11
6.2.1 Principle .11
6.2.2 Procedure.12
6.2.3 Requirements .12
6.3 Leak tightness characteristics .12
6.3.1 Principle .12
6.3.2 Apparatus .13
6.3.3 Leak tightness of the tap upstream of the obturator .13
6.3.4 Leak tightness of the tap downstream of the obturator .13
6.4 Bending test .13
6.4.1 Principle .13
6.4.2 Procedure.13
6.5 Torsion strength of control elements .15
6.5.1 Principle .15
6.5.2 Apparatus .16
6.5.3 Procedure.16
6.5.4 Requirements .16
6.6 Mechanical endurance characteristics of the operating mechanism .16
6.6.1 Principle .16
6.6.2 Apparatus . 16
6.6.3 Procedure . 17
6.6.4 Requirements . 17
6.7 Resistance under internal pressure . 17
6.7.1 Principle . 17
6.7.2 Apparatus . 18
6.7.3 Mechanical behaviour upstream of the obturator — Obturator in closed position . 18
6.7.4 Mechanical behaviour downstream of the obturator — Obturator in open position
(leaktightness) . 18
6.8 Flow rate . 19
6.8.1 General . 19
6.8.2 Principle . 19
6.8.3 Procedure . 19
6.8.4 Requirements . 19
6.9 Acoustic behaviour . 19
6.9.1 General . 19
6.9.2 Procedure . 19
6.9.3 Expression of results . 19
6.9.4 Determination of acoustic group . 19
7 Marking and technical product information . 20
7.1 General . 20
7.2 Marking . 20
7.3 Technical product information. 20
Annex A (informative) Tests and sampling . 22
Bibliography . 23

European foreword
This document (prEN 17821:2026) 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 17821:2023.
1 Scope
This document specifies application, general construction, performance and material requirements for
frost resistant taps for outdoor use (FRT), PN 10.
This document is applicable to potable water installations with a static pressure of maximum 1,0 MPa
(10 bar) and a distribution temperature of maximum 25 °C (PWC).
NOTE See Annex A for a general overview of this document’s organization and test sequence.
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 248:2002, Sanitary tapware — General specification for electrodeposited coatings of Ni-Cr
EN 1254-2, Copper and copper alloys — Plumbing fittings — Part 2: Compression fittings for use with
copper tubes
EN 1254-3, Copper and copper alloys — Plumbing fittings — Part 3: Compression fittings for use with
plastics and multilayer pipes
EN 1254-4, Copper and copper alloys — Plumbing fittings — Part 4: Threaded fittings
EN 1254-6, Copper and copper alloys — Plumbing fittings — Part 6: Push-fit fittings for use with metallic
tubes, plastics and multilayer pipes
EN 1254-7, Copper and copper alloys — Plumbing fittings — Part 7: Press fittings for use with metallic
tubes
EN 1254-8, Copper and copper alloys — Plumbing fittings — Part 8: Press fittings for use with plastics and
multilayer pipes
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 ISO 3822-1, Acoustics — Laboratory tests on noise emission from appliances and equipment used in
water supply installations — Part 1: Method of measurement (ISO 3822-1)
EN ISO 3822-3, Acoustics — Laboratory tests on noise emission from appliances and equipment used in
water supply installations — Part 3: Mounting and operating conditions for in-line valves and appliances
(ISO 3822-3)
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)
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation
ISO 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1717 and the following apply.
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
FRT
frost resistant tap for outdoor use
Note 1 to entry: FRTs can be categorized in the following ways:
— method of achieving frost resistance (for example by drainage or by controlled expansion);
— pre-assembled or assembled on-site;
— fixed and adjustable length;
— one or two outlets (if FRTs use multiple outlets, the FRT shall be safe for every outlet used).
3.2
PWC
cold potable water
Note 1 to entry: The temperature of cold potable water shall be less than 25 °C. This definition is in line with the
European Drinking Water Directive, Directive (EU) 2020/2184.
3.3
indoor area
area inside the walls of a building
Note 1 to entry: The air temperature of the indoor area shall be higher than 0 °C.
3.4
wall area
interior area of the walls of a building
Note 1 to entry: Locally, the temperature of the wall area can be lower than 0 °C.
3.5
outdoor area
area outside the walls of a building
3.6
M
weight of a completely empty tap
3.7
M
1A
weight of a tap including water between closing-part and the backflow part
3.8
M
weight of a tap filled with water
3.9
M
weight of an empty tap
4 Materials
4.1 General
The end connection in the indoor area (1) and the body in front of the wall (3), as indicated in Figure 1,
shall be made of metallic materials.
All materials which come 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 noted 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.
4.2 Dezincification resistant copper alloy
Copper-zinc alloys containing more than 15 % zinc are subject to dezincification when submitted to
water capable of dezincification. When 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 accordance with Clause 7.
4.3 Corrosion
4.3.1 General
The applied materials shall be corrosion resistant or protected against corrosion. The materials used shall
not have an adverse effect on other materials being used.
4.3.2 Corrosion resistance test
4.3.2.1 Principle
The corrosion resistance test tests the materials used in the external part of the FRT (Figure 1, area 3),
especially when the intended use is in a humid atmosphere where condensation can occur. The FRT under
test shall be fully assembled, and not only include the parts intended to be in contact with potable water,
e.g. springs, spring caps.
4.3.2.2 Procedure
The test shall be conducted in accordance with the neutral saline-spray test of EN ISO 9227.
Conduct the test in accordance with the following:
a) Subject the device to spraying for at least 100 h.
b) Halt the spraying treatment for (48 ± 1) h while maintaining the heat in the tank.
c) Resume the spraying treatment for another (100 ± 1) h.
For the duration of the test, the tank should only be opened to check and maintain the conditions, rest
periods from spraying should be no longer than 30 minutes per day, heating should not be interrupted,
and samples under test should not be handled, washed or checked.
After treatment and before visual examination, rinse the test samples with water to remove any salt
residue.
4.3.2.3 Requirements
The FRT shall comply with the requirements given in EN 248:2002, 5.1.
5 Characteristics
5.1 Dimensions and design
FRT valves consist of the 3 areas shown in Figure 1.

Key
1 indoor area
2 wall area
3 outdoor area
Figure 1 — The different areas of FRT
The conditions of use shall be in accordance with Table 1.
Table 1 — Conditions of use
Supply Dimension Operating range
Pressure recommended limits
DN 15
Pressure static — max. ≤ 1,0 MPa (10,0 bar)
to
Pressure dynamic 0,1 to 0,5 MPa (1 to 5 bar) ≥ 0,05 MPa (0,5 bar)
DN 20
Temperature cold — PWC ≤ 25 °C

Internal or external threads at the inlet and outlet of the FRT shall comply with ISO 228-1 or ISO 7-1.
The
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