FprEN 18268
(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
- Publication Date
- 16-Dec-2026
- Technical Committee
- CEN/TC 164 - Water supply
- Drafting Committee
- CEN/TC 164/WG 9 - Drinking water treatment
- Current Stage
- 5020 - Submission to Vote - Formal Approval
- Start Date
- 27-Aug-2026
- Due Date
- 11-Feb-2027
- Completion Date
- 27-Aug-2026
FprEN 18268 is a draft European Standard from CEN 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 guidance for suppliers, laboratories, and water-treatment users. In practice, it helps buyers and operators check whether a citric acid product is suitable for membrane cleaning or scaling control in drinking-water treatment.
What does FprEN 18268 specify?
FprEN 18268 applies to citric acid used as an antiscalant for membranes in treatment of water intended for human consumption. It covers the product’s characteristics, the required purity levels, the corresponding analytical methods, and information on use in water treatment.
The document is organized into clauses for scope, normative references, terms and definitions, description, purity criteria, test methods, and labelling, transportation, and storage. It also includes an informative annex with general information on citric acid and a normative annex with safety rules.
| Annex | What it covers |
|---|---|
| Annex A | General information on citric acid, including origin, manufacture, use, form of use, dosing, and secondary effects |
| Annex B | General rules relating to safety, including safe handling, first aid, spillage, and fire response |
The introduction also reminds users that national regulations still apply and that conformity with the document does not itself mean approval in every country.
What are the key requirements of FprEN 18268?
FprEN 18268 sets out what the product is, how pure it must be, how to test it, and how to identify, store, and ship it. The main practical point is that the buyer or laboratory can check both product quality and traceability against the same document.
- Identification and commercial forms - Clause 4 identifies citric acid by chemical name, common names, formula information, and registry references. It also allows anhydrous solid, monohydrate solid, and aqueous solution forms. This matters because specifications and test results are linked to the form supplied.
- Product concentration - Clause 4.2 and 5.2 state minimum citric acid content for the commercial product, including a minimum for aqueous solutions. All concentrations refer to active matter. In practice, users must compare the declared product against the active acid content, not just the total solution weight.
- Purity criteria - Clause 5.3 sets limits for impurities such as sulfate, fluoride, and oxalates, and notes that anti-caking agents are not permitted. Clause 5.4 sets limits for chemical parameters including Sb, As, Cd, Cr, Pb, Hg, Ni, and Se. This is the core quality screen for drinking-water use.
- Sampling - Clause 6.1 requires representative sampling and retention of reference samples for the claimed shelf life. It gives separate guidance for solid products and liquid products taken from drums, bottles, tanks, and tankers. This helps prevent disputes caused by a non-representative sample.
- Analysis methods - Clause 6.2 ties each impurity or element to a specified analytical method, including atomic absorption and ICP-OES-based methods. Water quality grade and reagent quality are also specified. In practice, this tells the laboratory which method to use and how to prepare the test portion.
- Labelling, transport, and storage - Clause 7 covers delivery forms, hazard labelling, transport status, marking, and storage conditions. It states that citric acid is not classified as dangerous goods for transport under RID, ADR, IMDG, or IATA. For users, this affects packaging choice, warehouse conditions, and shipping documents.
- Safety guidance - Annex B gives handling and emergency guidance, including first aid for eye or skin contact, spill cleanup, and fire-related decomposition products. This supports site procedures and safety training.
What terms does FprEN 18268 use?
FprEN 18268 uses several operational abbreviations that matter for membrane cleaning and logistics.
- RO - Reverse osmosis, a membrane process specifically mentioned as a main use area in Annex A.
- CIP - Clean in Place, a dosing point named for offline cleaning systems.
- GHS07 - The hazard pictogram used with the warning for serious eye irritation.
- RID - Rail transport rules for dangerous goods, named in the transport statement.
- ADR - Road transport rules for dangerous goods, named in the transport statement.
- IMDG - Maritime dangerous goods code, named in the transport statement.
- IATA - Air transport rules used in the transport statement.
- E330 - The food additive designation cited in the introduction as a related citric acid use.
Who uses FprEN 18268?
FprEN 18268 is used by water-treatment operators, membrane system users, citric acid suppliers, and laboratory staff who test product quality. It is also relevant for quality managers and buyers who need to specify a citric acid grade for drinking-water applications. Annex A is useful for engineers setting dosing points, concentrations, and cleaning practice, especially for RO systems.
Which standards are used with FprEN 18268?
FprEN 18268 relies on a set of sampling and analytical standards to measure impurities and trace elements.
- EN ISO 3696 - Specifies the water quality used in the analytical work.
- ISO 8213, ISO 3165, ISO 6206 - Support sampling of chemical products and safe sampling practice.
- ISO 2997 - Used for sulfate determination.
- ISO 3360 - Used for fluoride determination.
- ISO 8288:1986, EN ISO 5961, EN 1233, EN ISO 11969, ISO/TS 17379-2, EN ISO 11885, EN ISO 12846 - Used for metal and element determinations including Ni, Pb, Cd, Cr, As, Se, Sb, and Hg.
What does the FprEN 18268 document contain?
FprEN 18268 contains product identification data, physical property data, purity tables, sampling instructions, analytical procedures, and storage and marking guidance. It includes one figure for the chemical formula, two main tables for impurity and chemical-parameter limits, and a worked analytical expression for converting test results to product concentration. Annex A adds practical use information for membrane cleaning and antiscaling, while Annex B gives safety instructions for handling, spills, first aid, and fire response.
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Frequently Asked Questions
FprEN 18268 is a draft published by the European Committee for Standardization (CEN). 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).
FprEN 18268 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.
FprEN 18268 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.
...