SIST EN 12124:2005

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev sulfitProdukte zur Aufbereitung von Wasser für den menschlichen Gebrauch - NatriumsulfitProduits chimiques utlisés pour le traitement de l'eau destiné a la consommation humaine - Sulfite de sodiumChemicals used for treatment of water intended for human consumption - Sodium sulfite71.100.80Chemicals for purification of water13.060.20Pitna vodaDrinking waterICS:Ta slovenski standard je istoveten z:EN 12124:2005SIST EN 12124:2005en01-september-2005SIST EN 12124:2005SLOVENSKI
STANDARDSIST EN 12124:20001DGRPHãþD



SIST EN 12124:2005



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12124
June 2005 ICS 71.100.80
Supersedes EN 12124:1998
English version
Chemicals used for treatment of water intended for human consumption - Sodium sulfite
Produits chimiques utlisés pour le traitement de l'eau destiné à la consommation humaine - Sulfite de sodium
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Natriumsulfit This European Standard was approved by CEN on 12 May 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36
B-1050 Brussels © 2005 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12124:2005: ESIST EN 12124:2005



EN 12124:2005 (E) 2 Contents Page Foreword.3 Introduction.4 1 Scope.5 2 Normative references.5 3 Description.5 4 Purity criteria.7 Table 1 – Chemical parameters.8 5 Test methods.8 Table 2 - Procedures for the determination of chemical parameters.9 Figure 1 — Calculation of the element concentration in the test solution.11 Figure 2 – Calculation of the element concentration in the blank solution.12 Table 3 — Standard solution.14 6 Labelling – Transportation – Storage.14 Annex A (informative)
General information on sodium sulfite.16 Bibliography.18
SIST EN 12124:2005



EN 12124:2005 (E) 3 Foreword This European Standard (EN 12124:2005) 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 December 2005, and conflicting national standards shall be withdrawn at the latest by December 2005. This document supersedes EN 12124:1998. Significant technical differences between this edition and EN 12124:1998 are as follows:  deletion of the reference to EU Directive 80/778/EEC of 15 July 1980 in order to take account of the latest Directive in force (see [1]). According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
SIST EN 12124:2005



EN 12124:2005 (E) 4 Introduction In respect of potential adverse effects on the quality of water intended for human consumption, caused by the product covered by this European Standard: a) this European 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; 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 European 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. SIST EN 12124:2005



EN 12124:2005 (E) 5 1 Scope This European Standard is applicable to sodium used for treatment of water intended for human consumption .It describes the characteristics and specifies the requirements of sodium sulfite and refers to the corresponding analytical methods. It gives information for 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 reference document (including any amendments) applies. EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987) ISO 418, Photography - Processing chemicals - Specifications for anhydrous sodium sulfite ISO 3165, Sampling of chemical products for industrial use – Safety in sampling ISO 5993, Sodium hydroxide for industrial use - Determination of mercury content - Flameless atomic absorption spectrometric method ISO 6206, Chemical products for industrial use – Sampling – Vocabulary ISO 6332, Water quality - Determination of iron - Spectrometric method using 1,10-phenanthroline ISO 6353-1, Reagents for chemical analysis - Part 1: General test methods ISO 8213, Chemical products for industrial use – Sampling techniques – Solid chemical products in the form of particles varying from powders to coarse lumps ISO 22743 (in preparation) Water quality -- Determination of sulfates by continuous flow analysis (CFA) 3 Description 3.1 Identification 3.1.1 Chemical name Sodium sulfite. 3.1.2 Synonym or common name Sodium sulfite. 3.1.3 Relative molecular mass 126,04. SIST EN 12124:2005



EN 12124:2005 (E) 6
3.1.4 Empirical formula Na2SO3. 3.1.5 Chemical formula Na2SO3. 3.1.6 CAS-Registry Number1)
7757-83-7 3.1.7 EINECS reference2)
231-821-4. 3.2 Commercial form The product is a crystalline powder. 3.3 Physical properties 3.3.1 Appearance and odour The product is a white, fine crystalline, odourless powder. 3.3.2 Density The density of the product is 2,63 g/cm³ at 20 °C. The bulk density is 1,2 g/cm³ to 1,5 g/cm³ at 20 °C.
3.3.3 Solubility in water The solubility of the product in water is 250 g/l at 20 °C. 3.3.4 Vapour pressure Not applicable. 3.3.5 Boiling point at 100 kPa3)
The product decomposes above 230 °C. 3.3.6 Crystallisation point See 3.3.5.
1) Chemical Abstracts Service Registry Number. 2) European Inventory of Existing Commercial Chemical Substances. 3) 100 kPa = 1 bar. SIST EN 12124:2005



EN 12124:2005 (E) 7 3.3.7 Specific heat Not known. 3.3.8 Viscosity, dynamic Not applicable. 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 The pH value of a saturated aqueous solution of sodium sulfite is in the range of 9,7 to 10,2. At elevated temperatures (> 100 °C) sulfur dioxide is generated. On contact with air, small amounts of sodium sulfate are formed. Sodium sulfite releases sulfur dioxide when mixed with acids. Sodium sulfite reacts violently with oxidizing agents; e.g. with sodium hypochlorite or hydrogen peroxide. 4 Purity criteria 4.1 General This European Standard specifies the minimum purity requirements for sodium sulfite 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 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 this product standard. Limits have been given for impurities and chemical 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 content of sodium sulfite shall not be less than a mass fraction of 95%. SIST EN 12124:2005



EN 12124:2005 (E) 8 4.3 Impurities and main by-products The content of sodium sulfate shall not exceed a mass fraction of 5 %. The content of iron (Fe) shall not exceed 25 mg/kg. 4.4 Chemical parameters The product shall conform to the requirements specified in Table 1.
Table 1 – Chemical parameters
Parameter Limit mg/kg of commercial product Antimony (Sb) max. 2 Arsenic (As) max. 1 Cadmium (Cd) max. 1 Chromium (Cr) max. 1 Lead (Pb) max. 2 Mercury (Hg) max. 0,5 Nickel (Ni) max. 1 Selenium (Se) max. 1 NOTE: Pesticides and polycyclic aromatic hydrocarbons and cyanides ( CN- ) are not relevant in sodium sulfite because the raw materials used in the manufacturing are free of them. For parametric values of sodium sulfite on trace metal content in drinking water, see [1].
5 Test methods 5.1 Sampling Observe the general recommendations of ISO 3165 and take account of ISO 6206. Prepare the laboratory sample(s) required by the relevant procedure described in ISO 8213. 5.2 Analyses 5.2.1 Main product The sodium sulfite content shall be determined in accordance with ISO 418. NOTE Both methods, direct titration and back titration, can be used. SIST EN 12124:2005



EN 12124:2005 (E) 9 5.2.2 Impurities 5.2.2.1 Sulfate The content of sodium sulfate (Na2SO4) shall be determined in accordance with ISO 22743. 5.2.2.2 Iron (Fe) The content of iron (Fe) shall be determined in accordanc
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