oSIST prEN 1717:2023
(Main)Protection against pollution of water intended for human consumption in potable water installations and general requirements for devices to prevent pollution by backflow
Protection against pollution of water intended for human consumption in potable water installations and general requirements for devices to prevent pollution by backflow
This document specifies a methodology for protecting potable water in potable water installations within and outside buildings but within premises from the risk of pollution by backflow of non-potable water and gives recommendations on the design, risk analysis, backflow prevention devices and their installation methods.
This methodology is also intended to be used outside premises for all potable water systems connected to a potable water distribution system up to and including the point of use.
The product standards for the specific backflow prevention devices or arrangements are intended to be used in conjunction with this document. In the absence of a product standard, this document is intended to be used as a reference to draw up a specification for the development of new devices or arrangements.
Schutz des Trinkwassers vor Verunreinigungen in Trinkwasser-Installationen und allgemeine Anforderungen an Sicherungseinrichtungen zur Verhütung von Trinkwasserverunreinigungen durch Rückfließen
Dieses Dokument legt eine Methodik fest, um Trinkwasser in Trinkwasser-Installationen innerhalb von Gebäuden und außerhalb von Gebäuden, aber innerhalb von Grundstücken vor dem Risiko von Verunreinigungen durch das Rückfließen von Nichttrinkwasser zu schützen, und es gibt Empfehlungen zur Konstruktion, zur Risikoanalyse, zu Sicherungseinrichtungen gegen Rückfließen und zu deren Einbauverfahren.
Diese Methodik ist auch zur Anwendung außerhalb von Grundstücken bei allen Trinkwasser-Installationen gedacht, die mit einem Trinkwasser-Verteilungssystem verbunden sind, bis einschließlich der Entnahmestelle.
Es ist vorgesehen, die Produktnormen für die jeweiligen Armaturen oder Vorrichtungen zur Verhinderung des Rückfließens zusammen mit diesem Dokument zu verwenden. Falls keine Produktnormen vorhanden sind, ist dieses Dokument dazu vorgesehen, als Grundlage für die Beschreibung neuentwickelter Armaturen oder Vorrichtungen zu dienen.
Protection contre la pollution de l’eau destinée à la consommation humaine dans les installations d’eau potable et exigences générales applicables aux dispositifs de protection contre la pollution par retour
Le présent document spécifie une méthode de protection de l’eau potable dans des installations d’eau potable à l’intérieur et à l’extérieur des bâtiments, mais aussi dans les locaux, contre le risque de pollution par retour de l’eau non potable. Il donne également des recommandations sur la conception, l’analyse des risques, les dispositifs de protection contre les retours et leurs méthodes d’installation.
Cette méthode est également destinée à être utilisée en dehors des locaux, dans tous les réseaux d’eau potable raccordés à un réseau de distribution d’eau potable jusqu’au point d’utilisation inclus.
Les normes de produits concernant les dispositifs ou les systèmes de protection contre les retours spécifiques sont destinées à être utilisées conjointement avec le présent document. En l’absence d’une norme de produit, le présent document est destiné à être utilisé comme référence pour établir une spécification pour le développement de nouveaux dispositifs ou systèmes.
Varovanje pitne vode pred onesnaževanjem v napeljavah za pitno vodo in splošne zahteve za varovala za preprečitev onesnaževanja pitne vode zaradi povratnega toka
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 1717:2023
01-julij-2023
Varovanje pitne vode pred onesnaževanjem v napeljavah za pitno vodo in splošne
zahteve za varovala za preprečitev onesnaževanja pitne vode zaradi povratnega
toka
Protection against pollution of water intended for human consumption in potable water
installations and general requirements for devices to prevent pollution by backflow
Schutz des Trinkwassers vor Verunreinigungen in Trinkwasser-Installationen und
allgemeine Anforderungen an Sicherungseinrichtungen zur Verhütung von
Trinkwasserverunreinigungen durch Rückfließen
Protection contre la pollution de l’eau destinée à la consommation humaine dans les
installations d’eau potable et exigences générales applicables aux dispositifs de
protection contre la pollution par retour
Ta slovenski standard je istoveten z: prEN 1717
ICS:
13.060.20 Pitna voda Drinking water
91.140.60 Sistemi za oskrbo z vodo Water supply systems
oSIST prEN 1717:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 1717:2023
DRAFT
EUROPEAN STANDARD
prEN 1717
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2023
ICS 13.060.20; 91.140.60 Will supersede EN 1717:2000
English Version
Protection against pollution of water intended for human
consumption in potable water installations and general
requirements for devices to prevent pollution by backflow
Protection contre la pollution de l'eau potable dans les Schutz des Trinkwassers vor Verunreinigungen in
réseaux intérieurs et exigences générales des Trinkwasser-Installationen und allgemeine
dispositifs de protection contre la pollution par retour Anforderungen an Sicherungseinrichtungen zur
Verhütung von Trinkwasserverunreinigungen durch
Rückfließen
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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1717:2023 E
worldwide for CEN national Members.
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Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Pollution of potable water: general observations . 9
4.1 General. 9
4.2 Backflow of non-potable water . 9
4.3 Cross-connection . 9
4.4 External influences . 9
4.5 Materials . 9
4.6 Stagnation . 9
4.7 Inadequate or improper maintenance . 9
5 Analysis method of the pollution risks and choice of protection . 10
5.1 General remarks . 10
5.2 Determination of fluid categories . 10
5.2.1 General. 10
5.2.2 Category 1 . 10
5.2.3 Category 2 . 10
5.2.4 Category 3 . 10
5.2.5 Category 4 . 10
5.2.6 Category 5 . 10
5.2.7 Mixture of fluids . 11
5.3 Determination of the installation characteristics . 11
5.3.1 General. 11
5.3.2 Pressure . 11
5.3.3 Connections . 11
5.3.4 Risk attenuation . 12
5.4 Separation by single or double walls . 12
5.4.1 General. 12
5.4.2 Rules . 12
5.4.3 Leakage test on double-wall-separation . 12
5.5 Air break to drain . 13
5.6 Installation matrix . 13
5.7 Protection units . 13
5.7.1 Generalities . 13
5.7.2 Functional requirements for protection units against pollution . 14
5.7.3 Description and installation requirements of the protection units . 15
5.8 Matrix of the protection units appropriate to fluid categories . 15
5.9 Summary of analysis method . 16
6 Protection of equipment installed at the draw off point (Point-of-Use systems) . 16
6.1 General. 16
6.2 Special provisions for domestic Point-of-Use systems . 17
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7 Protection at the connection point to the public potable water system . 17
8 Air break to drain . 17
Annex A (informative) Reference list of the protection units . 19
Annex B (informative) Guide table for determining the fluid category from which
protection is required . 54
Annex C (informative) Example for the selection of protection devices for the domestic and
non-domestic use . 56
C.1 Example – Care lift bath . 56
C.2 Example – Utilization of rain water . 57
C.3 Example – Detergent dosing system . 59
C.4 Example – Filling station for heating systems . 61
C.5 Example – Animal drinking trough . 62
C.6 Example – Flushing compressor for sewages systems . 63
C.7 Example – Tank filling for vehicles with water tanks . 64
Bibliography . 66
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European foreword
This document (prEN 1717:2023) 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.
The UK Matrix of the protection units appropriate to fluid categories (Table 2) and the determination of
fluid categories (5.2) differs to that detailed within the body of this document. The British Standard
version of EN 1717 therefore contains an A deviation to cover the limited technical deviations to ensure
compliance with the Water Supply (fittings) Regulations 1999.
This document supersedes EN 1717:2000.
The main changes compared to the previous edition are listed below:
a) the scope has been made more precise, extended and revised;
b) terms and definitions have been amended;
c) all Figures have been updated and re-drawn;
d) Table 2 has been updated;
e) Clause “Air break to drain” has been revised;
f) Annex A and Annex B have been completely revised;
g) Annex C has been revised and provides application examples.
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Introduction
In respect of potential adverse effects on the quality of water intended for human consumption, caused
by the products covered by this document:
1) this document provides no information as to whether the products may be used without restriction
in any of the Member state of the EU or EFTA;
2) it should be noted that, while awaiting the adoption of verifiable European criteria, existing
national regulations concerning the use and/or the characteristics of these products remain in
force.
Annex A, Annex B and Annex C of this document are informative.
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1 Scope
This document specifies a methodology for protecting potable water in potable water installations
within and outside buildings but within premises from the risk of pollution by backflow of non-potable
water and gives recommendations on the design, risk analysis, backflow prevention devices and their
installation methods.
This methodology is also intended to be used outside premises for all potable water systems connected
to a potable water distribution system up to and including the point of use.
The product standards for the specific backflow prevention devices or arrangements are intended to be
used in conjunction with this document. In the absence of a product standard, this document is
intended to be used as a reference to draw up a specification for the development of new devices or
arrangements.
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), Specification for installations inside buildings conveying water for human consumption
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
air break to drain
vertical air gap realised by air inlets or full disconnection between the lowest point of the outlet and the
spillover level of the atmospheric drain overflow
3.2
air gap
permanent atmospheric separation between the upstream fluid supply and the downstream fluid
3.3
air inlet
orifice designed to admit air from the atmosphere into a hydraulic circuit
3.4
appliance
equipment
device in which the potable water is used and/or is modified e.g. water heater, coffee-machine, WC-pan
3.5
backflow
movement of the fluid from downstream to upstream within an installation
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3.6
backflow protection device
device which is intended to prevent pollution of potable water by backflow
3.7
disconnection
break in a hydraulic circuit creating an atmospheric area between two elements, one carrying or
containing potable water (upstream) and another carrying or containing another fluid (downstream)
3.8
domestic use
intended use of applications and appliances that are common for a potable water installation in a
household environment
Note 1 to entry: The same use of these appliances and applications in e.g. flats, hotels, schools, offices and
collective residences (student and nurse accommodations or similar) is considered to be domestic use (see
also 6.2)
3.9
downstream
side to which fluid flows under normal conditions
3.10
potable water system
water system located downstream of the delivery point specified by the water supply authorities or
regulations
Note 1 to entry: In DIRECTIVE (EU) 2020/2184 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 16
December 2020 on the quality of water intended for human consumption the potable water system is
denominated as “domestic distribution system”.
3.11
family of protection
general identification of a backflow protection device principle
3.12
fluid
all substances which can be deformed by small forces
Note 1 to entry: Fluids are divided into liquids and gases.
3.13 Different liquid levels
3.13.1
critical level
physical or piezometric level of the liquid reached in any part of the appliance 2 s after closing the water
inlet, starting from maximum level
3.13.2
maximum level
highest water level reached above the spillover level under positive pressure fault conditions with all
outlets closed but with the overflow open
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3.13.3
spillover level
level at which water will start to overflow the receiving vessel with all outlets closed
3.14
LD
50
calculated value, based on OECD 423 test method, of the quantities of substances or mixture which,
given on one intake through oral and parental path, bring about within 15 days (the required time to
consider potential delayed effects) the death of 50 out of 100 treated animals
Note 1 to entry: One should realize that the LD50-test method is used only as a tool for selecting appropriate
family and types of backflow preventers. The LD -method is not sufficient for conducting a full toxicological
50
evaluation.
3.15
non-domestic use
every application not covered by definition 3.8
3.16
overflow
means for discharging naturally excess fluid from an appliance when it has reached a specified level
3.17
point of use
point where water is drawn by the user either directly or by connecting an apparatus
3.18
pollution of potable water
reduction in aesthetic (turbidity, odour and taste), chemical or biological quality of potable water due to
raising its temperature or the introduction of contaminating substances
3.19
protection point
location in a hydraulic circuit where a protection unit is installed
3.20
protection unit
device or a device in combination with other hydraulic components which constitutes the protection
against backflow
3.21
type of protection
identified operating principle applied to a protection device belonging to a given family
3.22
upstream
side from which fluid flows under normal conditions
3.23
potable water
water intended for human consumption (according to DIRECTIVE (EU) 2020/2184 OF THE EUROPEAN
PARLIAMENT AND OF THE COUNCIL of 16 December 2020 on the quality of water intended for human
consumption) including hot water, wholesome water and abbreviated to PWC (potable water cold) and
PWH (potable water hot)
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4 Pollution of potable water: general observations
4.1 General
This clause is to be used when undertaking the risk analysis for determining the protection to be used
to prevent the pollution by backflow of the potable water network and potable water installations.
The following conditions can give raise to pollution of the potable water.
4.2 Backflow of non-potable water
The quality of the potable water distributed can be impaired when non-potable water flows back into
the potable water system.
4.3 Cross-connection
The quality of the potable water distributed can be impaired by a cross-connection, this can be an actual
or potential physical connection between a potable water supply and any other non-potable water
system.
4.4 External influences
Potable water cisterns, pipes and protection units shall be protected from external pollution (see
the EN 806 series).
No other fluid shall be conveyed in a potable water installation (gas, compressed air, ventilation
conduct, vapour, chemicals, water used in heating equipment, recycled water, drainage or run-off water,
waste water, etc.) other than potable water. If it is considered possible that under the prescribed
operation any contaminant could enter through the protection device (for example air gap, air inlet)
into the potable water installation, corresponding protection measures are to be provided.
4.5 Materials
The quality of the potable water distributed can be impaired by the use of inappropriate materials.
4.6 Stagnation
Stagnation (e.g. as a result of interruptions to operation and disconnection, see the EN 806 series) of
water in the systems can result in impairment of the water quality due to a significant concentration of
dissolved substances or substances in suspension or to bacterial growth.
The level of impairment depends on the materials used, the water quality, the temperature (for example
pipes in boiler rooms) and the duration of stagnation.
4.7 Inadequate or improper maintenance
Any insufficient or improper maintenance of the potable water installation including backflow
protection devices can result in an impaired water quality. For proper maintenance see EN 806-5.
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5 Analysis method of the pollution risks and choice of protection
5.1 General remarks
Pollution in a potable water supply system can occur by:
a) backsiphonage: by partial vacuum (drop in pressure) in the potable water supply system (due for
example to the operation of a valve, the bursting of a pipe, the operation of a booster pump,
excessive water demands in a part of the system, water taken for emergency use from a fire
hydrant);
b) back pressure: originated in a non-potable water system in which the pressure exceeds the
pressure in the potable water system;
c) back growth: pollution in the potable water system as a result of back growth of microorganisms;
d) stagnation, see 4.6.
5.2 Determination of fluid categories
5.2.1 General
Fluids which could be in contact with potable water are classified in five categories as defined below.
5.2.2 Category 1
Cold water to be used for human consumption coming from a potable water distribution system.
5.2.3 Category 2
Fluid recognized as being fit for human consumption, including water taken from a potable water
distribution system, which has undergone a change in taste, odour, colour or a temperature (heating or
cooling).
5.2.4 Category 3
Fluid representing a slight human health hazard due to the presence of one or more harmful substances
1
of low acute toxicity to be determined by the LD -method > 200 mg/kg, see 3.14 .
50
5.2.5 Category 4
Fluid presenting a significant human health hazard due to the presence of one or more toxic or very
toxic substances of high acute toxicity to be determined by the LD -method ≤ 200 mg/kg, see 3.14. or
50
one or more carcinogenic mutagenic and reprotoxic (CMR) substances.
5.2.6 Category 5
Fluid presenting a human health hazard due to the presence of microbiological or viral elements.
1
The border between fluid category 3 and 4 is in principle LD = 200 mg/kg body weight, in accordance with
50
OECD 423, December 17, 2001.
When the outcome of the calculation method indicates that a dose equal or less than 200 mg/kg body weight of a
fluid is deadly for at least 50 % of the animals, than the fluid is classified into category 4. When the calculation
indicates that a dose of more than 200 mg/kg is required the fluid is to be regarded as less harmful and the fluid is
classified into category 3.
Remark: In 2002 the original LD50-test, OECD 401 (8), has been deleted from the OECD guidelines.
The LD50-test method in this standard is just used as a means for selecting appropriate backflow preventers. It is
not intended as a replacement for undertaking a full toxicological evaluation of the health risk.
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5.2.7 Mixture of fluids
Mixing fluids of different categories will classify the mixture as the highest fluid category (independent
of the ratio) of the mixed fluids.
5.3 Determination of the installation characteristics
5.3.1 General
The analysis of an existing or projected installation provides information about its characteristics and
the fluid categories.
That information shall then be used to determine an appropriate protection unit to prevent pollution of
the potable water supply or installation.
The analysis is done as described in the following clauses.
The result of this analysis is fixed by a cross in the appropriate field of the installation matrix
(see Table 1).
5.3.2 Pressure
Locate the point(s) within the potable water system that need to be protected against pollution.
Determine whether downstream of the protection point is subjected to atmospheric pressure (P = atm)
or to a pressure exceeding atmospheric pressure (P > atm):
— the situation will be P = atm if the protection point is subject to backsiphonage only (see Figure 1);
— the situation will be P > atm if the protection point is subject to backsiphonage and back pressure
see Figure 2).
Figure 1 — Pressure equal atmosphere
Figure 2 — Pressure bigger atmosphere
5.3.3 Connections
All connections are considered permanent.
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5.3.4 Risk attenuation
The principle of risk attenuation is accepted only for certain facilities for domestic use listed
in Clause 6.2 and in conformity with Table 3.
5.4 Separation by single or double walls
5.4.1 General
A single wall separator consists of a single fixed and sealed partition or casing that can be in contact
with the potable water on one side, and with another fluid on the other.
A double wall separator consists of at least two fixed and sealed partitions or casings creating a neutral
intermediate zone between the potable water on one side and another fluid on the other.
The intermediate zone may be designed in two ways:
— containing a pressurized gaseous fluid or an inert porous material (open cells);
— containing a fluid of category 2 or 3.
5.4.2 Rules
5.4.2.1 With respect to pollution prevention
Category 2 or 3 fluids may be separated from the potable water by a single wall including permanently
fixed joints.
When the fluid from which potable water shall be protected against pollution is of category 4 or 5, a
single wall is not sufficient. A double wall with a safety medium in between (liquid or gas) is considered
to be able to separate the potable water from the second fluid.
5.4.2.2 With respect to direct consumer protection
When the fluid from which potable water shall be protected against is of category 4 or 5 and
downstream of the appliance the water is intended for sanitary or food related use, a double wall shall
be required.
5.4.3 Leakage test on double-wall-separation
Separation by a double-wall with a safety medium in between shall be constructed such that any
leakage from one of the walls shall be routed to the outside of the appliance to give a visual leakage
detection or that the leakage initiates a visible and/or acoustic signal.
The leakage test, conducted on a test sample is as follows:
1) drill a (2 ± 0,1) mm hole through the partition wall in contact with the fluid the potable water needs
to be protected against. For the position the most critical location in the double-wall is selected.
(normally the furthest point from the connections);
2) subject the hole in this side of the separation wall with a pressure of (50 ± 5) kPa and maintain that
pressure;
3) verify if a leakage detection is established within (300 ± 5) s after applying the pressure, e.g. by:
— observing that fluid emerges to the outside of the double wall construc
...
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