SIST EN 15074:2026

Chemicals used for treatment of swimming pool water - Ozone

This document is applicable to ozone used for treatment of water for swimming pools and spas. It describes the composition of ozone. It gives information on its use in swimming pool and spas water treatment. It also determines the rules relating to safe handling and use (see Annex B).

Produkte zur Aufbereitung von Schwimm- und Badebeckenwasser - Ozon

Dieses Dokument gilt für Ozon zur Aufbereitung von Schwimm- und Badebeckenwasser. Es beschreibt die Zusammensetzung von Ozon. Es enthält Angaben zu dessen Anwendung in der Aufbereitung von Schwimm  und Badebeckenwasser. Es legt darüber hinaus Regeln für die sichere Handhabung und Verwendung fest (siehe Anhang B).

Produits chimiques utilisés pour le traitement de l'eau des piscines - Ozone

Le présent document s’applique à l’ozone utilisé pour le traitement de l’eau des piscines et des spas. Il décrit la composition de l’ozone. Il donne des informations sur son emploi dans le traitement de l’eau des piscines et des spas. Il détermine également les règles relatives à la manipulation et à l’utilisation en toute sécurité (voir l’Annexe B).

Kemikalije, ki se uporabljajo za pripravo bazenske vode - Ozon

Ta dokument se uporablja za ozon, ki se uporablja za obdelavo vode v plavalnih bazenih in zdraviliščih. Opisuje sestavo ozona. Ponuja informacije o njegovi uporabi pri obdelavi vode v plavalnih bazenih in zdraviliščih. Prav tako določa pravila, povezana z varnim ravnanjem in uporabo (glej Prilogo B).

General Information

• Status: Published
• Public Enquiry End Date: 30-Jul-2024
• Publication Date: 07-Apr-2026
• ICS: 13.060.25 - Water for industrial use
• ICS: 71.100.80 - Chemicals for purification of water
• Technical Committee: IOVO - Water supply and waste water engineering
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 31-Mar-2026
• Due Date: 05-Jun-2026
• Completion Date: 08-Apr-2026
• Ref Project: EN 15074:2026 - Chemicals used for treatment of swimming pool and spas water - Ozone

Relations

• Referred By: SIST EN 17971:2024 - Devices for in-situ generation of biocides - Ozone
• Effective Date: 25-Mar-2026
• Referred By: SIST EN 16713-3:2016 - Domestic swimming pools - Water systems - Part 3: Water treatment - Requirements
• Effective Date: 25-Mar-2026
• Referred By: SIST EN ISO 15798:2022 - Ophthalmic implants - Ophthalmic viscosurgical devices (ISO 15798:2022)
• Effective Date: 28-Jan-2026
• Referred By: SIST EN ISO 16671:2025 - Ophthalmic implants - Irrigating solutions for ophthalmic surgery (ISO 16671:2025)
• Effective Date: 28-Jan-2026
• Referred By: SIST EN ISO 5840-1:2021 - Cardiovascular implants - Cardiac valve prostheses - Part 1: General requirements (ISO 5840-1:2021)
• Effective Date: 28-Jan-2026
• Referred By: SIST EN ISO 14630:2025 - Non-active surgical implants - General requirements (ISO 14630:2024)
• Effective Date: 28-Jan-2026
• Referred By: SIST EN ISO 22442-1:2021 - Medical devices utilizing animal tissues and their derivatives - Part 1: Application of risk management (ISO 22442-1:2020)
• Effective Date: 28-Jan-2026
• Revises: SIST EN 15074:2015 - Chemicals used for treatment of swimming pool water - Ozone
• Effective Date: 28-Jan-2023

Overview

The kSIST FprEN 15074:2025:2024 standard, developed by the European Committee for Standardization (CEN), addresses the use of ozone as a chemical treatment for swimming pool and spa water. This standard replaces EN 15074:2014 and focuses on the composition, usage, safety, and handling of ozone when applied in water treatment for pools and spas. Ozone is recognized for its strong oxidizing and disinfecting properties, and this standard provides essential guidance to ensure effective and safe application in recreational water environments.

Key Topics

• Scope and Application
  The standard is applicable exclusively to ozone generated on-site (in situ) for water treatment in swimming pools and spas. It defines the chemical characteristics and purity requirements of ozone gas utilized in this context.

• Chemical and Physical Properties
  Ozone (O₃) is a bluish, highly unstable gas with a relative molecular mass of 48. It is generated on-site due to its instability and short half-life in both gas and water phases. The standard details ozone’s physical properties like boiling point (-112 °C), solubility in water, and vapor pressure relevant for handling and application.

• Purity Criteria and Composition
  Purity depends on feed gas quality (clean air or oxygen) and ozone generation technology, typically dielectric barrier discharge devices. The concentration of ozone in generated gas varies - typically 1.5% w/w from air and up to 21% w/w from oxygen feed gas. The standard references FprEN 17971 for ozone generation device requirements.

• Safety and Risk Classification
  Ozone is classified as a hazardous oxidizing gas with acute toxicity and potential mutagenic and carcinogenic effects. The standard incorporates harmonized classification aligned with EU CLP regulations, prescribing mandatory safety handling and emergency procedures found in Annex B.

• Handling, Storage, and Transportation
  Ozone’s instability prevents storage and transportation. It must be generated and used on-site, with close adherence to material compatibility and operator safety to prevent exposure to toxic levels.

Applications

• Swimming Pool and Spa Water Treatment
  Ozone is widely utilized for its effective disinfection and oxidation capabilities, helping reduce pathogens and organic contaminants in pool and spa water. Its use complements other disinfectants such as chlorine or bromine.

• Biocidal Use
  Under the EU Biocidal Products Regulation (BPR), ozone is authorized as a biocidal agent specifically for disinfection purposes in both public and private pools. Users should verify compliance with BPR and REACH regulations when applying ozone.

• Water Quality Management
  The continuous treatment cycle in pools benefits from ozone’s rapid oxidation of organics and disinfecting properties, which contribute to improved water clarity, reduced chemical residues, and better overall swimmer safety.

Related Standards

• FprEN 17971
  Details ozone generation devices, including operational safety, purity of feed gases, and testing methods.

• EU Regulations and Directives

  • Regulation (EU) No 528/2012 (BPR) - Biocidal product authorization
  • REACH Regulation - Chemical safety and registration
  • EU CLP Regulation (EC) No 1272/2008 - Classification, labeling, and packaging

• ISO and IEC Terminology Resources

  • ISO Online Browsing Platform for standard terms
  • IEC Electropedia for electrotechnical and chemical terminology

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By following kSIST FprEN 15074:2025:2024, operators and manufacturers can ensure that ozone used in swimming pool and spa water treatment is effective, compliant with regulatory requirements, and safely handled, offering an advanced chemical solution for improved water hygiene and swimmer safety.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2026
Kemikalije, ki se uporabljajo za pripravo bazenske vode - Ozon
Chemicals used for treatment of swimming pool water - Ozone
Produkte zur Aufbereitung von Schwimm- und Badebeckenwasser - Ozon
Produits chimiques utilisés pour le traitement de l'eau des piscines - Ozone
Ta slovenski standard je istoveten z: EN 15074:2026
ICS:
13.060.25 Voda za industrijsko uporabo Water for industrial use
71.100.80 Kemikalije za čiščenje vode Chemicals for purification of
water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 15074
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2026
EUROPÄISCHE NORM
ICS 71.100.80 Supersedes EN 15074:2014
English Version
Chemicals used for treatment of swimming pool and spas
water - Ozone
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Schwimm- und
des piscines et des spas - Ozone Badebeckenwasser - Ozon
This European Standard was approved by CEN on 26 January 2026.

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, Türkiye 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15074:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Description . 6
4.1 Identification . 6
4.1.1 Chemical name . 6
4.1.2 Synonym or common name . 6
4.1.3 Relative molecular mass . 6
4.1.4 Empirical formula . 6
4.1.5 Chemical formula . 6
4.1.6 CAS Registry Number . 7
4.1.7 EINECS reference . 7
4.2 Commercial form . 7
4.3 Physical properties . 7
4.3.1 Appearance . 7
4.3.2 Density . 7
4.3.3 Solubility in water . 7
4.3.4 Vapour pressure . 8
4.3.5 Boiling point at 1 000 hPa . 9
4.3.6 Melting point . 9
4.3.7 Specific heat (liquid) . 9
4.3.8 Viscosity (dynamic) . 9
4.3.9 Critical temperature . 9
4.3.10 Critical pressure . 9
4.3.11 Physical hardness . 9
4.4 Chemical properties . 9
5 Purity criteria . 10
5.1 General. 10
5.2 Composition of in situ generated Ozone gas . 10
5.3 Impurities and main by-products . 10
5.4 Chemical parameters. 10
6 Test methods . 10
7 Labelling - Transportation - Storage . 10
7.1 Materials in contact with Ozone . 10
7.2 Risk and safety classification . 10
7.3 Transportation regulations and labelling . 12
7.4 Marking . 12
7.5 Stability . 12
7.5.1 Temperature. 12
7.5.2 Self-decomposition of ozone . 12
7.5.3 Half-life of ozone in the gas phase . 12
7.5.4 Half-life of ozone in water phase . 12
7.5.5 pH range . 13
7.5.6 Advanced oxidation process . 13
Annex A (informative) General information on ozone . 14
A.1 Feed gas . 14
A.2 Use . 14
A.2.1 Function . 14
A.2.2 Form in which the product is used . 14
A.2.3 Treatment ozone concentration and reaction time . 14
A.2.4 Dosing of Ozone . 14
A.2.5 Secondary effects . 15
A.2.6 Removal of excess Ozone . 15
A.3 Operational control methods . 15
A.3.1 Ozone concentration measurement in the gas phase . 15
A.3.2 Ozone concentration measurement in water . 15
Annex B (normative) General rules relating to safety . 16
B.1 Rules for safe handling and use . 16
B.2 Emergency procedures . 16
B.2.1 Personal Protection Equipment (PPE) . 16
B.2.2 First aid . 16
B.2.3 Operational safety requirements . 17
B.2.4 Fire . 17
Bibliography . 18

European foreword
This document (EN 15074:2026) 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 September 2026, and conflicting national standards
shall be withdrawn at the latest by September 2026.
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 15074:2014.
— proposed harmonized classification of ozone according to EU CLP regulation is added;
— reference for use of ozone is made to EU BPR and EU REACH regulation;
— new threshold limit for ozone in air;
— reference is made to EN 17971, standard for ozone generation devices. Device related matters are
shifted to EN 17971, e.g. operational safety of the installation room. Matters of the chemical ozone
itself remain within this standard;
— the use of ozone in pool water treatment is specified.
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, Türkiye and the United
Kingdom.
Introduction
In respect of potential adverse effects on the quality of water for swimming pools, caused by the product
covered by this document, it provides no information as to whether the product may be used without
restriction in any of the Member States of the EU or EFTA.
NOTE While awaiting the adoption of verifiable European criteria, attention is drawn to national regulations.
Ozone is a biocidal product according to the regulation (EU) No 528/2012 [1]. The use of ozone for
disinfection purposes falls under the provisions of the BPR, requiring access by the user to a data set for
the product authorization of ozone under the BPR. This access may be achieved directly or indirectly
e.g. via the manufacturers’ authorization for the ozone generated by their devices.
Users of in situ generated ozone should verify with their device manufacturer, if they can use ozone in
accordance to his product authorization for the disinfection of swimming pool water (approved [2]
under the BPR for public and private/domestic use).
Non biocidal use of ozone, e.g. for oxidative purposes, falls under the provisions of the REACH Regulation
[3]. The use of ozone for non-biocidal purposes requires individual access by the user to the data set
provided for the authorization of ozone under REACH.
NOTE Conformity with the European Standard does not confer or imply authorization of the products in any
of the Member States of the EU or EFTA. The use of the product covered by this document is subject to regulation
or control by National Authorities.

1 Scope
This document is applicable to ozone used for treatment of water for swimming pools and spas. It
describes the composition of ozone. It gives information on its use in swimming pool and spas water
treatment. It also determines the rules relating to safe handling and use (see Annex B).
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 17971:2024, Devices for in-situ generation of biocides — Ozone
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
normal temperature and pressure of gas
NTP
gas under the conditions of normal temperature t = 0 °C and normal pressure p = 101 325 Pa
n n
3.2
feed gas
substance that is fed as gas to the ozone generation device to generate ozone
4 Description
4.1 Identification
4.1.1 Chemical name
Ozone.
General information on Ozone is described in Annex A.
4.1.2 Synonym or common name
None (has sometimes been called improperly “allotropic oxygen”).
4.1.3 Relative molecular mass
48.
4.1.4 Empirical formula
O .
4.1.5 Chemical formula
O .
4.1.6 CAS Registry Number )
10028-15-6.
4.1.7 EINECS reference )
Not applicable.
4.2 Commercial form
Ozone is very unstable; it is exclusively generated on-site nearby its use by ozone generation devices.
4.3 Physical properties
4.3.1 Appearance
Bluish gas; the liquid is dark blue.
NOTE A weak absorption in the visual range between 435 nm and 475 nm.
4.3.2 Density
— Gas: 2,144 kg/m at NTP (Normal Temperature Pressure, 273 K
...