oSIST prEN 16409:2026

• Abstract:

  This European Standard is applicable to Dolomitic lime used for treatment of water intended for human consumption. It describes the characteristics of magnesium oxide and specifies the requirements and the corresponding test methods for Dolomitic lime. It gives information on its use in water treatment.

• Status: Not Published
• Public Enquiry End Date: 14-Dec-2026
• 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: 26-Oct-2026
• Due Date: 15-Mar-2027
• Ref Project: prEN 16409 - Chemicals used for treatment of water intended for human consumption - Dolomitic lime

• Revises: SIST EN 16409:2014 - Chemicals used for treatment of water for human consumption - Dolomitic lime
• Effective Date: 29-Apr-2026

oSIST prEN 16409:2026 is a draft European Standard from CEN for dolomitic lime used in the treatment of water intended for human consumption. It specifies how the product is identified, what purity it must meet, how it is tested, and how it is labelled, transported and stored. It is written for manufacturers, laboratories, water-treatment operators and others who need a common technical basis for specifying and checking the product.

What does oSIST prEN 16409:2026 specify?

oSIST prEN 16409:2026 applies to dolomitic lime for water intended for human consumption. It covers the product description, requirements, test methods, use information, and rules for safe handling and use.

The document is organised into:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Terms and definitions
• Clause 4 - Description / Identification
• Clause 5 - Purity criteria
• Clause 6 - Test methods
• Clause 7 - Labelling, transportation and storage
• Annex A - Informative general information
• Annex B - Normative safety rules

Annex	What it covers
A	General information on dolomitic lime, including origin, impact on drinking water, use, safe handling and emergency procedures
B	General rules relating to safety, including safe handling and use and emergency procedures

What are the key requirements of oSIST prEN 16409:2026?

Product identification

Clause 4 identifies the product by its chemical names, common names, molecular data, formulae, registry references, commercial forms and physical and chemical properties. In practice, this lets suppliers and buyers describe the same product consistently and distinguish the hydrated and non-hydrated forms.

Purity criteria

Clause 5 sets minimum purity requirements for dolomitic lime used in drinking-water treatment. It covers major constituents, impurities and chemical parameters, so users can check that the material is suitable for the intended water-treatment duty and compare products against one set of criteria.

Major constituents and grading

Clause 5.2 requires the commercial product to meet limits for calcium and magnesium content, carbon dioxide content, and sieve retention. In practice, this controls both chemical strength and particle size, which affect how the product dissolves, handles and performs in treatment systems.

Impurities and chemical parameters

Clause 5.3 limits impurities such as silicon, aluminium, iron and manganese, while Clause 5.4 limits chemical parameters including arsenic, cadmium, chromium, mercury, nickel, lead, antimony and selenium. This matters because these substances can transfer into treated water and must stay within the product limits set by the standard.

Sampling and analysis

Clause 6 requires laboratory samples to be prepared in accordance with EN 12485 and the analytical methods in EN 12485 to be used. That gives users a shared test basis for compliance checks, procurement testing and quality control.

Delivery, labelling and transport

Clause 7.1 allows delivery in bags, containers or bulk, provided the delivery means do not contaminate the product. Clause 7.2 sets labelling requirements linked to hazard classification, and Clause 7.3 gives transport classifications for the two product forms. This is important for safe logistics, packaging choice and hazard communication.

Storage and safety

Clause 7.5 and Annex B cover storage, safe handling and emergency actions. The document calls for dry storage, keeping the product away from acids and moisture, and gives first-aid, spill and fire guidance. For users, this means the document is not only about product quality but also about safe on-site handling.

What terms does oSIST prEN 16409:2026 define?

• Dolomitic lime - the product family covered by the standard, used for treatment of water intended for human consumption.
• Calcium magnesium dihydroxide oxide - one of the two identified product forms, described as a powder and linked to the hydrated form of the material.
• Calcium magnesium dioxide - the other identified product form, described as the non-hydrated form used in water treatment.
• CAS Registry Number - the chemical identifier used to reference a substance unambiguously.
• EINECS reference - the European inventory reference used to identify the substance in regulatory and technical contexts.
• GHS - the Globally Harmonized System used here for hazard pictograms and precautionary labelling.
• ADR / RID / IMDG / IATA - the transport systems used to classify road, rail, sea and air carriage of the product.

Who uses oSIST prEN 16409:2026?

CEN oSIST prEN 16409:2026 is used by chemical manufacturers, water-treatment suppliers, laboratory staff, water utility operators, procurement teams and regulators. They use it to specify product quality, test incoming batches, prepare labels and shipping documents, and write safe handling instructions for sites that mineralize or condition drinking water.

What changed in oSIST prEN 16409:2026 from the previous edition?

oSIST prEN 16409:2026 supersedes EN 16409:2013. The changes listed in the document are:

• the unit g/mol was deleted in 3.1.4
• coarse as grading was deleted in 3.3.1 b)
• the note to Table 3 was adjusted in 4.4
• a new Annex A.2 was added on the impact of commercial products on drinking water quality, including a new table
• the term consumer was replaced by user in A.3.3
• the bibliography was updated to the revised Drinking Water Directive

Which standards are used with oSIST prEN 16409:2026?

• EN 12485 - provides the sampling and analytical methods used in Clause 6 for laboratory preparation and analysis.
• Directive 2020/2184 - is cited for drinking-water parametric values and for comparing the product's impact on water quality.
• Regulation (EC) No 1272/2008 - provides the classification, labelling and packaging framework referenced for hazard communication.

What does the oSIST prEN 16409:2026 document contain?

Clause 4 contains the product identification data: chemical names, common names, molecular data, formulae, registry references, commercial forms and physical and chemical properties. Clause 5 contains the main purity tables for constituents, impurities and chemical parameters.

Clause 6 points users to EN 12485 for sampling and analysis. Clause 7 covers delivery forms, labels, transport classifications, marking and storage conditions.

Annex A gives background information on origin, manufacture, drinking-water impact, use, dosage and emergency procedures. Annex B turns the safety rules into normative requirements for handling, first aid, spillage and fire response.

SLOVENSKI STANDARD
01-december-2026
Kemikalije, ki se uporabljajo za pripravo pitne vode - Dolomitno apno
Chemicals used for treatment of water intended for human consumption - Dolomitic lime
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Dolomitkalk
Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation
humaine - Chaux dolomitique
Ta slovenski standard je istoveten z: prEN 16409
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
October 2026
ICS Will supersede EN 16409:2013
English Version
Chemicals used for treatment of water intended for human
consumption - Dolomitic lime
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Chaux menschlichen Gebrauch - Dolomitkalk
dolomitique
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 16409:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Description Identification. 5
4.1 General. 5
4.2 Chemical names . 5
4.3 Synonym or common names . 5
4.4 Relative molecular mass . 5
4.5 Empirical formula . 5
4.6 Chemical formula . 6
4.7 CAS Registry Number . 6
4.8 EINECS reference . 6
4.9 Commercial forms . 6
4.10 Physical properties . 6
4.11 Chemical properties . 7
5 Purity criteria . 7
5.1 General. 7
5.2 Composition of commercial product . 8
5.3 Impurities . 8
5.4 Chemical parameters. 8
6 Test methods . 9
6.1 Sampling . 9
6.2 Analyses. 9
7 Labelling - Transportation - Storage . 9
7.1 Means of delivery . 9
)
7.2 Labelling . 10
7.3 Transportation regulations and labelling . 11
7.4 Marking . 11
7.5 Storage . 11
Annex A (informative) General information on dolomitic lime . 12
A.1 Origin . 12
A.2 Impact of commercial products on drinking water . 12
A.3 Use . 13
A.4 Rules for safe handling and use . 13
A.5 Emergency procedures . 13
Annex B (normative) General rules relating to safety . 15
B.1 Rules for safe handling and use . 15
B.2 Emergency procedures . 15
Bibliography . 16
European foreword
This document (prEN 16409:2026) 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 16409:2013.
a) in 3.1.4 the unit g/mol was deleted (figure relative, without any unit);
b) in 3.3.1 b) coarse as grading was deleted;
c) in 4.4 adjusting the NOTE to Table 3;
d) inserting a new subclause ‘A.2 Impact of commercial products on drinking water quality’ with a
new ‘Table A.1 Maximum impact of Calcium magnesium carbonate on chemical parameter contents
of water. Drinking water limit values based on Drinking Water Directive.’
e) in A.3.3 the term consumer is substituted with user;
f) in the Bibliography, the older Drinking Water Directive was replaced with the revised one.
Introduction
In respect of potential adverse effects on the quality of water intended for human consumption, caused
by the product covered by this document:
— 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;
— 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 use of the product covered by this document is subject to regulation or
control by National Authorities.
1 Scope
This document is applicable to dolomitic lime used for treatment of water intended for human
consumption. It describes the characteristics of dolomitic lime and specifies the requirements and the
corresponding test methods. It gives information on its use in 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 12485, Chemicals used for treatment of water intended for human consumption - Calcium carbonate,
high-calcium lime, half-burnt dolomite, magnesium oxide, calcium magnesium carbonate and dolomitic lime
- Test methods
3 Terms and definitions
No terms and definitions are listed in this document.
4 Description Identification
4.1 General
Dolomitic limes are calcium magnesium dihydroxide oxide and calcium magnesium dioxide.
4.2 Chemical names
a) Calcium magnesium dihydroxide oxide
b) Calcium magnesium dioxide
4.3 Synonym or common names
a) Calcium magnesium dihydroxide oxide, semi-hydrated dolomitic lime, half-hydrated dolomitic lime,
dolomitic hydrated lime
b) Calcium magnesium dioxide, calcium magnesium oxide, dolomitic lime, dolomitic quicklime.
4.4 Relative molecular mass
a) Calcium magnesium dihydroxide oxide: 114,40
b) Calcium magnesium dioxide: 96,39
4.5 Empirical formula
a) Calcium magnesium dihydroxide oxide: CaMgH O
2 3
b) Calcium magnesium dioxide: CaMgO
4.6 Chemical formula
a) Calcium magnesium dihydroxide oxide: Ca(OH) MgO
b) Calcium magnesium dioxide: CaOMgO
1)
4.7 CAS Registry Number
a) Calcium magnesium dihydroxide oxide: 58398-71-3
b) Calcium magnesium oxide: 37247-91-9
2)
4.8 EINECS reference
a) Calcium magnesium dihydroxide oxide: 261-235-4
b) Calcium magnesium oxide: 253-425-0
4.9 Commercial forms
Calcium magnesium dihydroxide oxide and calcium magnesium dioxide are available in the following
commercial form:
— coarse material or powder.
4.10 Physical properties
4.10.1 Appearance
a) Calcium magnesium dihydroxide oxide: powder
b) Calcium magnesium dioxide: powder
4.10.2 Density
a) Calcium magnesium dihydroxide oxide: 2,2 – 2,6 kg/dm at 20 °C;
3 3
Bulk density: 400 kg/m to 600 kg/m ;
b) Calcium magnesium dioxide: 3,3 – 3,6 kg/dm at 20 °C;
3 3
Bulk density: 700 to 1200 kg/m to kg/m ;
4.10.3 Solubility (in water)
a) Calcium magnesium dihydroxide oxide: 1000 mg/l at 20 °C;
b) Calcium magnesium dioxide: 1385 mg/l at 20 °C
4.1
...