EN 17971:2024

SLOVENSKI STANDARD
oSIST prEN 17971:2023
01-julij-2023
Naprave za generiranje in doziranje biocidov za čiščenje pitne vode in vode v
bazenih na kraju samem - Ozon
In-situ generating and dosing devices of biocides for drinking and swimming pool water
treatment - Ozone
Anlagen zur In-Situ-Erzeugung und Dosierung von Bioziden zur Aufbereitung von Trink-
und Schwimm- und Badebeckenwasser - Ozon
Dispositifs de génération et de dosage in situ de biocides pour le traitement de l’eau -
Ozone
Ta slovenski standard je istoveten z: prEN 17971
ICS:
13.060.20 Pitna voda Drinking water
13.060.25 Voda za industrijsko uporabo Water for industrial use
71.100.80 Kemikalije za čiščenje vode Chemicals for purification of
water
oSIST prEN 17971:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 17971:2023
oSIST prEN 17971:2023
DRAFT
EUROPEAN STANDARD
prEN 17971
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2023
ICS
English Version
In-situ generating and dosing devices of biocides for
drinking and swimming pool water treatment - Ozone
Anlagen zur In-Situ-Erzeugung und Dosierung von
Bioziden zur Aufbereitung von Trink- und Schwimm-
und Badebeckenwasser - Ozon
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 17971:2023 E
worldwide for CEN national Members.

oSIST prEN 17971:2023
prEN 17971:2023 (E)
Contents Page
European foreword . 3
Annex A (informative) Examples for mixing devices . 29
A.1 Mixing by injector and static mixer . 29
A.2 Multiphase pumps . 30
A.3 Direct injection and static mixer . 30
A.4 Additional mixing methods . 31
Annex B (normative) Methods to determine ozone in water . 33
B.1 DPD Method . 33
B.2 Indigo Method . 34
Bibliography . 35
oSIST prEN 17971:2023
prEN 17971:2023 (E)
European foreword
This document (prEN 17971:2023) 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.
If devices according to this standard are to be used in other fields of application (e.g. wastewater and air
treatment and surface disinfection), additional requirements shall be observed, if relevant. In particular,
the requirements for feed gas can differ for other applications.
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.
oSIST prEN 17971:2023
prEN 17971:2023 (E)
1 Scope
This document is applicable to devices for the generation and dosing of the biocide ozone. The ozone is
generated in these devices according to the technology of dielectric barrier discharge. According to
EN 1278 and EN 15074, ozone is suited for the use of the treatment of water intended for human
consumption (drinking water), respectively for the treatment of swimming pool water. Ozone can be
added to the water for disinfection and for oxidative purposes. This standard may be also applied for
other technologies to generate ozone, e.g. electrolysis or UV irradiation, as far as reasonable or applicable.
This standard specifies the devices construction, and test methods for the equipment used for in situ
generation of ozone. It specifies requirements for instructions for installation, operation, maintenance,
safety and for documentation to be provided with the product.
The in situ generation of active substances, in particular ozone, is subject to the specifications of the
Biocidal Products Regulation (EU) 528/2012 (BPR) [10]. The use of ozone for the purpose of
disinfection/microbiological preservation of water requires compliance with the provisions of the BPR,
in particular access by the user or his device manufacturer to a data set required for the authorization of
ozone under the BPR.
The in situ generation of ozone for the predominant purpose of oxidation of ingredients of water is subject
to the specifications of the REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)
[11] Regulation (EC) 1907/2006. The use for oxidative purposes requires access by the user to the data
set provided for the authorization of ozone under REACH.
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 12876, Chemicals used for treatment of water intended for human consumption - Oxygen
EN 60529, Degrees of protection provided by enclosures (IP Code)
EN 10088-3, Stainless steels - Part 3: Technical delivery conditions for semi-finished products, bars, rods,
wire, sections and bright products of corrosion resisting steels for general purposes
EN ISO 385, Laboratory glassware - Burettes (ISO 385)
EN ISO 648, Laboratory glassware - Single-volume pipettes (ISO 648)
EN ISO 4788, Laboratory glassware - Graduated measuring cylinders (ISO 4788)
EN ISO 7393-2, Water quality - Determination of free chlorine and total chlorine - Part 2: Colorimetric
method using N,N-dialkyl-1,4-phenylenediamine, for routine control purposes (ISO 7393-2)
EN ISO 13849-1, Safety of machinery - Safety-related parts of control systems - Part 1: General principles
for design (ISO 13849-1)
EN ISO 13849-2, Safety of machinery - Safety-related parts of control systems - Part 2: Validation (ISO
13849-2)
EN ISO 24450, Laboratory glassware - Wide-necked boiling flasks (ISO 24450)
oSIST prEN 17971:2023
prEN 17971:2023 (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
NOTE In addition, the terminology contained in Article 3 of the BPR [10] is useful for the application of this
document.
3.1
ozone generator
part of the ozone generation device where feed gas is carried through a dielectric barrier discharge field
with the purpose of generating ozone
3.2
ozone generation device
entire device that is necessary for the generation of ozone from the feed gas, including e. g., power supply
and ozone generator
3.3
ozone system
combination of devices which, in addition to the ozone generation device and ozone dosing device, both
described in this document, also comprises devices for the distribution of and reaction with ozone
Note 1 to entry: All ozone exposed equipment or devices, e.g. reaction vessels, pumps, pipes, tanks or heat
exchangers, are considered as part of the ozone system.
3.4
closed ozone system
ozone system where ozone does not leave the ozone system, or such that only negligible release of ozone
into the building or into the environment occurs
3.5
open ozone system
any system not considered as a closed ozone system according to 3.4
3.6
feed gas
substance that is fed to the ozone generation device to generate ozone
3.7
dew point
parameter, in °C, to indicate the content of humidity in a gas
Note 1 to entry: The dew point refers to the temperature to which a gas shall be cooled to become saturated with
water vapor, assuming constant air pressure and water content.
Note 2 to entry: When air is cooled below the dew point, its moisture capacity is reduced and airborne water
vapor will condense to form liquid water known as dew. When this occurs via contact with a colder surface, dew
will form on that surface.
oSIST prEN 17971:2023
prEN 17971:2023 (E)
3.8
residual ozone destructor
device for the destruction of residual ozone that has not been consumed in the ozone system and is
accumulating in gaseous form in an off-gas flow
Note 1 to entry: The destruction takes places in the gas phase by converting the ozone (O ) into oxygen (O ).
3 2
When the application/use of a residual ozone destructor is required, the ozone destructor shall be considered as an
integral part of the ozone system.
3.9
normal temperature and pressure of gas
gas under the conditions of normal temperature t = 0 °C and normal pressure p = 101 325 Pa
n n
3.10
normal cubic meter
m
n
cubic meter of gas, usually dry, referenced to 1 atmosphere (101 325 kPa) and 0 °C, i.e. to normal
temperature and pressure of gas
3 3
Note 1 to entry: the unit is expressed m . In other documents the unit Nm is sometimes used
n
[SOURCE: EN ISO 20675:2021, 3.41]
3.11
ozone systems operating at negative pressure
system whose parts and pipes, as far as they carry an ozone-containing gas, are all under negative
pressure from the ozone generation device up to the mixing device
3.12
ozone systems operating at positive pressure
system whose parts and pipes, as far as they carry an ozone-containing gas, are all or partly under positive
pressure from the ozone generation device up to the mixing device
3.13
expert
person who, due to their technical scientific training, work experience and knowledge of applicable
standards and regulations, is able to assess an ozone system with regards to functions and safety
Note 1 to entry: This person can be from the manufacturer or an independent third-party organization (such as
a test institution) without limitations, an inspector according to, EN ISO/IEC 17020 Type C, fulfils this criterion.
3.14
separate lockable installation room
lockable technical room with access for a restricted group of persons, in which the ozone generation
device, and eventually other parts of the ozone system are installed, and furthermore in which other
technical equipment can be installed
3.15
individual installation room
technical room in which only the ozone generation device is installed and operated
Note 1 to entry: term includes also enclosures for installation
oSIST prEN 17971:2023
prEN 17971:2023 (E)
4 Technology of Dielectric Barrier Discharge to generate Ozone
Dielectric barrier discharge (DBD) is the basis for most of the commercial ozone generators. In practise,
several other terms of the same meaning are in use instead of DBD: silent discharge, silent electrical
discharge, silent arc discharge, corona discharge.
In dielectric barrier discharge, ozone is generated using energy from electrons in an electrical field
between two electrodes. The electrodes are usually two parallel plates or concentric cylinders arranged
with a certain distance to each other to form a single- or a double discharge gap. The electrodes are
isolated from each other by a dielectric (non-conducting) barrier material and the discharge gap, see
Figure 1.
The precursor is ambient air or oxygen gas, also called feed gas. Ozone (O ) is generated from oxygen (O )
3 2
of the feed gas that is piped through the discharge gap, see Figure 1. When the electrical field generated
by the high voltage applied at the electrodes exceeds the insulation field strength of the feed gas in the
discharge gap, the discharge in the feed gas initiates. The discharge creates a current of electric charged
particles, consisting of electrons and ions. In the discharge area, the intended chemical reaction takes
place: 3 O2 → 2 O3 (summarized). After a short time, i.e. some microseconds, the discharge current is
interrupted by the dielectric being polarized by the discharge current, because the polarization of the
dielectric compensates the driving electrical field. As the applied high voltage is an alternating voltage,
...