oSIST prEN 936:2021

• Abstract:

  This document is applicable to carbon dioxide used for treatment of water intended for human consumption. It describes the characteristics of carbon dioxide and specifies the requirements and corresponding analytical methods for carbon dioxide. It also gives information on its use in water treatment.

• Status: Not Published
• Public Enquiry End Date: 24-Apr-2021
• ICS: 13.060.20 - Drinking water
• ICS: 71.100.80 - Chemicals for purification of water
• Technical Committee: IOVO - Water supply and waste water engineering
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 09-Mar-2021
• Due Date: 27-Jul-2021
• Completion Date: 28-May-2021
• Ref Project: prEN 936 - Chemicals used for treatment of water intended for human consumption - Carbon dioxide

• Revised: SIST EN 936:2014 - Chemicals used for treatment of water intended for human consumption - Carbon dioxide
• Effective Date: 18-Jan-2023
• Revised: SIST EN 936:2014 - Chemicals used for treatment of water intended for human consumption - Carbon dioxide
• Effective Date: 01-Apr-2021

Overview

The oSIST prEN 936:2021:2021 standard, developed by the European Committee for Standardization (CEN), defines the requirements and specifications for the use of carbon dioxide (CO2) in the treatment of water intended for human consumption. This standard replaces EN 936:2013 and provides updated purity criteria, test methods, and guidelines on transportation, storage, and labelling of carbon dioxide utilized in water treatment processes.

Carbon dioxide plays a crucial role in water treatment by adjusting pH and aiding in corrosion control without introducing harmful contaminants. This standard ensures that CO2 used is of suitable quality, free from impurities that could compromise water safety or treatment efficiency.

Key Topics

• Scope and Application
  oSIST prEN 936:2021 applies specifically to carbon dioxide used as a chemical agent in treating potable water. It focuses on identifying chemical and physical properties, purity requirements, and analytical methods to verify compliance.

• Identification and Physical Properties
  Carbon dioxide is identified by its chemical formula CO2, with a molecular mass of 44.011 g/mol. It is supplied commercially as a pressurized liquefied or refrigerated gas, appearing as a colorless gas or liquid. Critical physical parameters include:

  • Density: approximately 1.9768 kg/m³ (gas, 0 °C, 101.3 kPa)
  • Solubility in water: 1.72 g/l (at 20 °C)
  • Vapour pressure of liquid: 5733 kPa (at 20 °C)
  • Critical temperature: 31 °C
  • Critical pressure: 7383 kPa

• Purity and Impurities
  The standard mandates a minimum carbon dioxide volume fraction of 99.9%. Strict limits are set on by-products and impurities such as moisture, ammonia, oxygen, nitrogen oxides, particulates, oils, phosphine, and volatile hydrocarbons to ensure safety and compliance with EU regulations (e.g., EU Regulation 231/2012). For instance, moisture content must not exceed 20 ppm by volume, and ammonia must be below 2.5 ppm.

• Testing and Analytical Methods
  oSIST prEN 936:2021 prescribes sampling procedures and analytical techniques to measure concentrations of CO2 and contaminants accurately. This ensures consistent product quality and facilitates regulatory compliance.

• Labeling, Transportation, and Storage
  Clear guidelines are provided for labelling CO2 products in accordance with EU legislation as well as transport and storage requirements to prevent accidental contamination or chemical incompatibilities. The standard stresses awareness of incompatibilities between transported chemicals.

Applications

Carbon dioxide described in oSIST prEN 936:2021 is primarily used for treating potable water to adjust pH, reduce corrosion in water distribution systems, and optimize overall water quality. Its use is favored because it avoids adding harmful substances while addressing water chemistry challenges.

Key applications include:

• pH control in drinking water treatment plants
• Maintaining water stability in pipelines and storage tanks
• Reduction of scaling and corrosion in distribution networks
• Carbonation processes in food and beverage water purification setups

Users and water utilities applying this standard should verify compliance with relevant national regulations and assess their source water quality to determine appropriate CO2 dosing and purity needs.

Related Standards

• EN 936:2013 – Previous version of this standard, now superseded by oSIST prEN 936:2021:2021
• EU Regulation 231/2012 – Defines food-grade CO2 purity requirements referenced in the standard
• Other CEN standards on water treatment chemicals and safety requirements
• ISO standards relevant to water quality and chemical testing (refer to ISO Online Browsing Platform)
• IEC Electropedia for standardized terminology related to chemical substances

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Keywords: carbon dioxide water treatment, potable water chemicals, CO2 purity standard, water treatment gases, water pH control, European standard carbon dioxide, oSIST prEN 936:2021, CEN water supply standard, CO2 impurities limits, water treatment chemical safety

SLOVENSKI STANDARD
01-april-2021
Kemikalije, ki se uporabljajo za pripravo pitne vode - Ogljikov dioksid
Chemicals used for treatment of water intended for human consumption - Carbon dioxide
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch -
Kohlenstoffdioxid
Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation
humaine - Dioxyde de carbone
Ta slovenski standard je istoveten z: prEN 936
ICS:
13.060.20 Pitna voda Drinking water
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.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2021
ICS 71.100.80 Will supersede EN 936:2013
English Version
Chemicals used for treatment of water intended for human
consumption - Carbon dioxide
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Dioxyde de menschlichen Gebrauch - Kohlenstoffdioxid
carbone
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, Turkey 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 936:2021 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 . 6
4.1.7 EINECS reference . 6
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 . 7
4.3.5 Boiling point at 100 kPa . 7
4.3.6 Melting point . 7
4.3.7 Specific heat . 7
4.3.8 Viscosity (dynamic) . 7
4.3.9 Critical temperature . 7
4.3.10 Critical pressure . 7
4.3.11 Physical hardness . 7
4.4 Chemical properties . 7
5 Purity criteria . 8
5.1 General. 8
5.2 Composition of commercial product . 8
5.3 By-products . 8
5.4 Chemicals parameters. 9
6 Test methods . 10
6.1 Sampling . 10
6.2 Analysis . 10
6.2.1 Carbon dioxide . 10
6.2.2 Impurities . 10
7 Labelling - Transportation - Storage . 10
7.1 Means of delivery . 10
7.2 Labelling according to the EU legislation . 11
7.3 Transportation regulations and labelling . 11
7.4 Marking . 12
7.5 Storage . 12
Annex A (informative) General information on carbon dioxide. 13
A.1 Origin . 13
A.1.1 Raw materials . 13
A.1.2 Manufacturing process . 13
A.2 Use . 13
A.2.1 Function . 13
A.2.2 Form in which it is used . 13
A.2.3 Treatment dose . 13
A.2.4 Means of application. 13
A.2.5 Secondary effects . 13
A.2.6 Removal of excess of product . 13
A.3 General rules relating to safety . 13
A.3.1 Rules for safe handling and use . 13
A.3.2 Emergency procedures . 14
Bibliography . 15

European foreword
This document (prEN 936:2021) 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 936:2013.
In comparison with the previous edition, the following technical modifications have been made:
— possible impurities are taken into account and partly changed in Table 2;
— update of the references quoted in the Bibliography;
— modification of 7.3 on transportation regulations and labelling, adding the sentence “The user shall
be aware of the incompatibilities between transported products.”;
— modification of 7.4 on marking. The requirements of marking are also applied to the accompanying
documents, and the regulation [6] is now quoted.
Introduction
In respect to the potential adverse effects 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, while awaiting the adoption of verifiable European criteria, existing
national regulations concerning the use and/or the characteristics of this product remain in force.
NOTE Conformity with this document does not confer or imply acceptance or approval of the product in any
of the Member States of the EU or EFTA. The us
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