kSIST FprEN 18268:2026
(Main)Chemicals used for treatment of water intended for human consumption - Antiscalants for membranes - Citric Acid
- Abstract
This document is applicable to citric acid used as an antiscalant for membranes in the treatment of water intended for human consumption. It describes the characteristics and specifies the requirements and the corresponding analytical methods for citric acid. It gives information on its use as an antiscalant for membranes in water treatment.
General information on citric acid is given in Annex A (informative).
- Status
- Not Published
- Public Enquiry End Date
- 19-Jan-2026
- Technical Committee
- IOVO - Water supply and waste water engineering
- Current Stage
- 5020 - Formal vote (FV) (Adopted Project)
- Start Date
- 04-Sep-2026
- Due Date
- 23-Oct-2026
- Completion Date
- 07-Sep-2026
kSIST FprEN 18268:2026 is a SIST draft European standard for citric acid used as an antiscalant for membranes in the treatment of water intended for human consumption. It specifies the product description, purity criteria, analytical methods, labelling, transport, storage and safety information for manufacturers, suppliers, laboratories and water-treatment users.
What does kSIST FprEN 18268:2026 specify?
kSIST FprEN 18268:2026 applies to citric acid used as an antiscalant for membranes in drinking-water treatment. It covers the product characteristics, the required purity and the analytical methods used to verify them, and it also gives guidance on handling and use.
The document is organized into clauses 1 to 7, with two annexes.
| Annex | What it covers |
|---|---|
| Annex A | General information on citric acid, including origin, manufacture, use and application |
| Annex B | General rules relating to safety, including handling and emergency actions |
What are the key requirements of kSIST FprEN 18268:2026?
Product identification and purity
Clause 4 identifies citric acid by its chemical name, common names, commercial forms, and key physical properties. For practice, this helps buyers and laboratories confirm that they are dealing with the correct material, whether it is anhydrous solid, monohydrate or an aqueous solution.
Clause 5.2 sets the minimum citric acid content for the different commercial forms on a dry-mass basis. That matters because acceptance checks must be made against the active citric acid content, not just the gross product weight.
Clause 5.3 and Table 1 set impurity limits for sulfate, fluoride and oxalates, and the product shall not contain anti-caking agents. This gives purchasers a clear quality screen and tells suppliers which by-products must be controlled.
Clause 5.4 and Table 2 set limits for trace chemical parameters such as Sb, As, Cd, Cr, Pb, Hg, Ni and Se. These limits matter because the product is used in treatment of water intended for human consumption, so trace contamination has to be controlled at source and by testing.
Sampling and analytical control
Clause 6.1 requires representative sampling from fresh manufacture or from a newly opened package, with clear sample identification and retained reference samples. In practice, this supports traceability if a batch is later questioned.
Clause 6.2 links the specification to named test methods and requires analytical-grade reagents and EN ISO 3696 water. The standard also explains how to convert elemental test results to the content in the dry product, so laboratories report results in the same form as the limits.
Delivery, marking, storage and safety
Clause 7 covers delivery forms, labelling, transport and storage. It allows bulk, containers, plastic drums, bags and big bags, and it requires delivery equipment that does not contaminate the product.
The labelling section uses EU hazard classification for serious eye irritation and the GHS07 pictogram with the signal word Warning. It also states that citric acid is not classified as dangerous goods for transport under RID, ADR, IMDG or IATA, which simplifies logistics.
Storage guidance is specific: plastics or stainless steel are suitable materials, and the product should be kept under controlled conditions to protect quality. Annex B adds first aid, spill response and fire guidance for site use.
What terms does kSIST FprEN 18268:2026 define?
- Citric Acid Anhydrous - the water-free form of citric acid used in the specification.
- Citric Acid Monohydrate - the solid form that contains one molecule of water of crystallization.
- Active matter - the citric acid content counted as free acid when concentrations are stated or calculated.
- Dry mass basis - a way of reporting content after removing water, so results can be compared fairly.
- Antiscalant - a treatment chemical used to limit scale deposition on membranes.
- Reverse osmosis (RO) - the membrane process highlighted as a main use area for the product.
- Clean in Place (CIP) - the offline cleaning arrangement where citric acid may be dosed.
- GHS07 - the hazard pictogram used with the Warning signal word for eye irritation.
Who uses kSIST FprEN 18268:2026?
Chemical producers and suppliers use this standard to control product form, purity, packaging and marking. Water-treatment operators and membrane-cleaning contractors use it when selecting and handling citric acid for offline cleaning and antiscaling, especially in RO systems.
Quality control laboratories use it for sampling and analysis, and buyers use it to set purchase specifications and check batch acceptance. National authorities may also use its product and safety information when assessing treatment chemicals for drinking-water applications.
Which standards are used with kSIST FprEN 18268:2026?
- EN ISO 3696 - provides the laboratory water quality used for the analytical work.
- ISO 3165, ISO 6206 and ISO 8213 - support safe sampling, sampling vocabulary and sampling techniques for chemical products.
- ISO 2997 and ISO 3360 - are used for determining sulfate and fluoride.
- EN 1233, EN ISO 5961, EN ISO 11969, EN ISO 11885, EN ISO 12846, ISO 8288:1986 and ISO/TS 17379-2 - provide the methods used for the trace elements listed in Table 2.
What does the kSIST FprEN 18268:2026 document contain?
The document contains identification data, commercial forms, physical properties and chemical properties for citric acid. It includes Table 1 for impurities, Table 2 for chemical parameters, and Figure 1 for the chemical formula.
It also gives sampling procedures for solids and liquids, analytical methods for sulfate, fluoride, oxalate and trace elements, and an equation for reporting elemental content in the dry product. The last clause covers labelling, transportation, marking and storage, while Annex A and Annex B provide background information and safety rules.
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Frequently Asked Questions
kSIST FprEN 18268:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Chemicals used for treatment of water intended for human consumption - Antiscalants for membranes - Citric Acid". This standard covers: This document is applicable to citric acid used as an antiscalant for membranes in the treatment of water intended for human consumption. It describes the characteristics and specifies the requirements and the corresponding analytical methods for citric acid. It gives information on its use as an antiscalant for membranes in water treatment. General information on citric acid is given in Annex A (informative).
This document is applicable to citric acid used as an antiscalant for membranes in the treatment of water intended for human consumption. It describes the characteristics and specifies the requirements and the corresponding analytical methods for citric acid. It gives information on its use as an antiscalant for membranes in water treatment. General information on citric acid is given in Annex A (informative).
kSIST FprEN 18268:2026 is classified under the following ICS (International Classification for Standards) categories: 13.060.20 - Drinking water; 71.100.80 - Chemicals for purification of water. The ICS classification helps identify the subject area and facilitates finding related standards.
kSIST FprEN 18268:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 18268:2026
01-januar-2026
Kemikalije, ki se uporabljajo za pripravo pitne vode - Sredstva proti apnencu na
membranah - Citronska kislina
Chemicals used for treatment of water intended for human consumption - Antiscalants
for membranes - Citric Acid
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Antikalkmittel
für Membranen - Zitronensäure
Produits chimiques utilisés pour le traitement de l’eau destinée à la consommation
humaine - Produits antitartres pour membranes - acide citrique
Ta slovenski standard je istoveten z: prEN 18268
ICS:
13.060.20 Pitna voda Drinking water
71.100.80 Kemikalije za čiščenje vode Chemicals for purification of
water
oSIST prEN 18268:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 18268:2026
oSIST prEN 18268:2026
DRAFT
EUROPEAN STANDARD
prEN 18268
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2025
ICS 71.100.80
English Version
Chemicals used for treatment of water intended for human
consumption - Antiscalants for membranes - Citric Acid
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Produits menschlichen Gebrauch - Antikalkmittel für
antitartres pour membranes - acide citrique Membranen - Zitronensäure
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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18268:2025 E
worldwide for CEN national Members.
oSIST prEN 18268:2026
prEN 18268:2025(E)
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 names . 6
4.1.3 Relative molecular mass . 7
4.1.4 Empirical formula . 7
4.1.5 Chemical formula . 7
4.1.6 CAS Registry Number) . 7
4.1.7 EINECS reference) . 7
4.2 Commercial forms . 7
4.3 Physical properties . 7
4.3.1 Appearance . 7
4.3.2 Density . 7
4.3.3 Solubility in water . 8
4.3.4 Vapour pressure . 8
4.3.5 Boiling point at 100 kPa) . 8
4.3.6 Melting point . 8
4.3.7 Specific heat . 8
4.3.8 Viscosity (dynamic) . 8
4.3.9 Critical temperature . 8
4.3.10 Critical pressure . 8
4.3.11 Physical hardness . 8
4.4 Chemical properties . 8
5 Purity criteria . 8
5.1 General. 8
5.2 Composition if commercial product . 9
5.3 Impurities and main by-products . 9
5.4 Chemical parameters. 10
6 Test methods . 10
6.1 Sampling . 10
6.1.1 General. 10
6.1.2 Liquid . 10
6.2 Analyses. 11
6.2.1 Citric Acid content (main product) - General . 11
6.2.2 Impurities . 11
6.2.3 Chemical parameters. 12
7 Labelling - Transportation – Storage . 13
7.1 Means of delivery . 13
oSIST prEN 18268:2026
prEN 18268:2025 (E)
7.2 Risk and safety labelling according to the EU legislation[2]) . 14
7.3 Transportation regulations and labelling . 14
7.4 Marking . 14
7.5 Storage . 14
7.5.1 Material . 14
7.5.2 Long term stability . 14
7.5.3 Storage incompatibilities . 14
Annex A (informative) General information on citric acid . 15
Annex B (normative) General rules relating to safety . 17
Bibliography . 18
oSIST prEN 18268:2026
prEN 18268:2025(E)
European foreword
This document (prEN 18268:2025) 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.
oSIST prEN 18268:2026
prEN 18268:2025 (E)
Introduction
In respect of potential adverse effects on the quality of water intended for human consumption, caused
by the products covered by this document:
a) this document provides no information as to whether the products 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 these products remain in force.
NOTE 1 Conformity with this document does not confer or imply acceptance or approval of the products in any
of the Member States of the EU, EFTA, or other European countries that are part of CEN.
The use of the product covered by this document is subject to regulation or control by National
Authorities.
NOTE 2 Attention is also drawn to citric acid products used as food additives meeting the high purity requirements
[3].
of E330 citric acid
WARNING – The use of this document may involve hazardous materials, operations and equipment. This
document does not purport to address all the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use.
oSIST prEN 18268:2026
prEN 18268:2025(E)
1 Scope
This document is applicable to citric acid used as an antiscalant for membranes in the treatment of water
intended for human consumption. It describes the characteristics and specifies the requirements and the
corresponding analytical methods for citric acid. It gives information on its use as an antiscalant for
membranes in water treatment. It also provides guidance relating to safe handling and use (see Annex B).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 1233, Water quality — Determination of chromium — Atomic absorption spectrometric methods
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696)
EN ISO 5961, Water quality - Determination of cadmium by atomic absorption spectrometry (ISO 5961)
EN ISO 11885, Water quality - Determination of selected elements by inductively coupled plasma optical
emission spectrometry (ICP-OES) (ISO 11885)
EN ISO 12846, Water quality - Determination of mercury - Method using atomic absorption spectrometry
(AAS) with and without enrichment (ISO 12846)
ISO 3165, Sampling of chemical products for industrial use — Safety in sampling
ISO 6206, Chemical products for industrial use — Sampling — Vocabulary
ISO 8213, Chemical products for industrial use — Sampling techniques — Solid chemical products in the
form of particles varying from powders to coarse lumps
ISO 8288:1986, Water quality — Determination of cobalt, nickel, copper, zinc, cadmium and lead — Flame
atomic absorption spectrometric methods
ISO/TS 17379-2, Water quality — Determination of selenium — Part 2: Method using hydride generation
atomic absorption spectrometry (HG-AAS)
3 Terms and definitions
No terms and definitions are listed in this document.
4 Description
4.1 Identification
4.1.1 Chemical name
2-hydroxypropane-1,2,3-tricarboxylic acid
4.1.2 Synonym or common names
Citric Acid
Citric Acid Anhydrous
oSIST prEN 18268:2026
prEN 18268:2025 (E)
Citric Acid Monohydrate
4.1.3 Relative molecular mass
Citric Acid Anhydrous: 192,12
Citric Acid Monohydrate: 210,14
4.1.4 Empirical formula
C H O
6 8 7
C H O .H O
6 8 7 2
4.1.5 Chemical formula
C H O
6 8 7
Figure 1 — Chemical formula
4.1.6 CAS Registry Number )
Citric Acid Anhydrous 77-92-9
Citric Acid Monohydrate: 5949-29-1
4.1.7 EINECS reference )
Citric Acid Anhydrous 201-069-1
Citric Acid Monohydrate 691-328-9
4.2 Commercial forms
Citric Acid is available in a number of different forms (see 4.3.1).
Different commercial forms, anhydrous solids, monohydrate solid or dissolved in water are possible.
Commercial, stable aqueous solutions are available at a minimum 45 % weight/weight Citric Acid. All
concentrations mentioned refer to the active matter (active acid) and shall be calculated accordingly.
4.3 Physical properties
4.3.1 Appearance
Solid: The product is a colourless / white powder or crystalline granulate.
Liquid: The product is a clear, colourless solution.
4.3.2 Density
Solid: The bulk density of the product varies from 750 g/dm3 to 900 g/dm3.
...