EN 938:2009
(Main)Chemicals used for treatment of water intended for human consumption - Sodium chlorite
Chemicals used for treatment of water intended for human consumption - Sodium chlorite
This European Standard is applicable to sodium chlorite used for treatment of water intended for human consumption. It describes the characteristics of sodium chlorite and specifies the requirements and the corresponding test methods for sodium chlorite. It gives information on its use in water treatment.
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Natriumchlorit
Diese Europäische Norm gilt für Natriumchlorit zur Aufbereitung von Wasser für den menschlichen Gebrauch. Sie beschreibt die Eigenschaften von Natriumchlorit und legt die Anforderungen sowie die entsprechenden Prüfverfahren für Natriumchlorit fest. Sie enthält Angaben zu dessen Anwendung in der Wasseraufbereitung.
Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation humaine - Chlorite de sodium
La présente Norme européenne est applicable au chlorite de sodium utilisé pour le traitement de l'eau destinée à la consommation humaine. Elle décrit les caractéristiques du produit et spécifie les prescriptions et les méthodes d'essai correspondant au chlorite de sodium. Elle donne des informations pour son emploi dans le traitement de l'eau.
Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev klorit
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2009
1DGRPHãþD
SIST EN 938:2000
Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev klorit
Chemicals used for treatment of water intended for human consumption - Sodium
chlorite
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Natriumchlorit
Produits chimiques utilisés pour le traitement de l'eau destinée à la cnosommation
humaine - Chlorite de sodium
Ta slovenski standard je istoveten z: EN 938:2009
ICS:
13.060.20 Pitna voda Drinking water
71.100.80 .HPLNDOLMH]DþLãþHQMHYRGH Chemicals for purification of
water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 938
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2009
ICS 71.100.80 Supersedes EN 938:1999
English Version
Chemicals used for treatment of water intended for human
consumption - Sodium chlorite
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Chlorite de sodium menschlichen Gebrauch - Natriumchlorit
This European Standard was approved by CEN on 5 December 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 938:2009: E
worldwide for CEN national Members.
Contents Page
Foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Description . 5
3.1 Identification . 5
3.2 Commercial form . 6
3.3 Physical properties . 6
3.4 Chemical properties . 7
4 Purity criteria . 8
4.1 General . 8
4.2 Composition of commercial product . 8
4.3 Impurities and main by-products . 8
4.4 Chemical parameters . 8
5 Test methods . 9
5.1 Sampling . 9
5.2 Analysis . 10
6 Labelling - Transportation - Storage . 20
6.1 Means of delivery . 20
6.2 Risk and safety labelling according to the EU Directives . 20
6.3 Transportation regulations and labelling . 21
6.4 Marking . 21
6.5 Storage . 21
Annex A (informative) General information on sodium chlorite . 22
Annex B (normative) General rules relating to safety . 27
Annex C (normative) Determination of arsenic, antimony and selenium (atomic absorption
spectrometry hydride technique) . 28
Bibliography . 34
Foreword
This document (EN 938:2009) 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 July 2009, and conflicting national standards shall be withdrawn at the
latest by July 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 938:1999.
The significant technical differences between this edition and EN 938:1999 are as follows:
a) Deletion of reference to EU Directive 80/778/EEC of July 15, 1980 in order to take into account the
latest Directive in force (see [1]).
b) Replacement of ISO 5666-1 by EN 1483.
Annex A is informative.
Annexes B and C are normative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Introduction
In respect of potential adverse effects on the quality of water intended for human consumption, caused by the
product covered by this Standard:
1) this Standard provides no information as to whether the product may be used without restriction in any of
the Member States of the EU or EFTA;
2) 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 the standard 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 European Standard is subject to regulation or
control by National Authorities.
1 Scope
This European Standard is applicable to sodium chlorite used for treatment of water intended for human
consumption. It describes the characteristics of sodium chlorite and specifies the requirements and the
corresponding test methods for sodium chlorite. It gives information on its use in water treatment.
2 Normative references
The following referenced documents are indispensable for the application 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 1483, Water quality - Determination of mercury - Method using atomic absorption spectrometry
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)
ISO 3165, Sampling of chemical products for industrial use - Safety in sampling
ISO 6206, Chemical products for industrial use - Sampling - Vocabulary
ISO 8288:1986, Water quality - Determination of cobalt, nickel, copper, zinc, cadmium and lead - Flame
atomic absorption spectrometric methods
ISO 9174, Water quality - Determination of total chromium - Atomic absorption spectrometric methods
3 Description
3.1 Identification
3.1.1 Chemical name
Sodium chlorite.
3.1.2 Synonym or common name
None.
3.1.3 Relative molecular mass
90,44.
3.1.4 Empirical formula
NaClO .
3.1.5 Chemical formula
NaClO .
1)
3.1.6 CAS Registry Number
7758-19-2.
2)
3.1.7 EINECS reference
231-836-6.
3.2 Commercial form
The product is supplied as an aqueous solution of sodium chlorite
3.3 Physical properties
3.3.1 Appearance
The products are greenish-yellow aqueous solution.
3.3.2 Density
The density of sodium chlorite is given in Table 1.
Table 1 — Density of sodium chlorite
Aqueous solution concentration Density
% (mass fraction) g/ml at 20 °C
25 1,210
31 1,270
3.3.3 Solubility in water
The solubility of sodium chlorite depending on temperature is given in Table 2
Table 2 — Solubility of sodium chlorite
Temperature Solubility
°C g/l
5 340
17 390
30 460
45 530
60 550
3.3.4 Vapour pressure
Not applicable.
1)
Chemical Abstracts Service Registry Number
2)
European Inventory of Existing Commercial Chemical Substances
3)
3.3.5 Boiling point at 100 kPa
Not applicable.
3.3.6 Crystallization point
The crystallization point of sodium chlorite depending on concentration is given in Table 3.
Table 3 — Crystallization point of sodium chlorite
Aqueous solution concentration Crystallization point
% (mass fraction) °C
25 - 14,5
31 3
3.3.7 Specific heat
Not known.
3.3.8 Viscosity (dynamic)
The viscosity of sodium chlorite depending on concentration is given in Table 4.
Table 4 — Viscosity of sodium chlorite
Aqueous solution concentration Viscosity
% (mass fraction) mPa.s at 20 °C
25 2,33
31 3,26
3.3.9 Critical temperature
Not applicable.
3.3.10 Critical pressure
Not applicable.
3.3.11 Physical hardness
Not applicable.
3.4 Chemical properties
Sodium chlorite is a strong oxidizing agent. It generates chlorine dioxide with acidic solutions or chlorine and
reacts with organic compounds.
3)
100 kPa = 1 bar
4 Purity criteria
4.1 General
This European Standard specifies the minimum purity requirements for Sodium chlorite used for the treatment
of water intended for human consumption. Limits are given for impurities commonly present in the product.
Depending on the raw material and the manufacturing process other impurities may be present and, if so, this
shall be notified to the user and when necessary to the relevant authorities.
NOTE Users of this product should check the national regulations in order to clarify whether it is of appropriate purity
for treatment of water intended for human consumption, taking into account raw water quality, required dosage, contents
of other impurities and additives used in the product not stated in the product standard.
Limits have been given for impurities and chemicals parameters where these are likely to be present in
significant quantities from the current production process and raw materials. If the production process or raw
materials leads to significant quantities of impurities, by-products or additives being present, this shall be
notified to the user.
4.2 Composition of commercial product
The sodium chlorite is available as an aqueous solution with sodium chlorite content of 24,5 percent by mass
fraction to 35 percent by mass fraction.
Solutions of 25 percent by mass fraction and 31 percent by mass fraction of sodium chlorite are the most
commonly used.
The content of sodium chlorite shall be equal to or greater than the manufacturer’s declared value.
4.3 Impurities and main by-products
The product shall conform to the requirements specified in Table 5.
Table 5 — Impurities
Impurity Limit
g/kg so
...
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