1、September 2016 English price group 16No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 71.100.80This standard has bee
2、n included in the body of DVGW Technical Rules.!%$s“2560180www.din.deDIN EN 938Chemicals used for treatment of water intended for human consumption Sodium chlorite;English version EN 938:2016,English translation of DIN EN 938:2016-09Produkte zur Aufbereitung von Wasser fr den menschlichen Gebrauch N
3、atriumchlorit;Englische Fassung EN 938:2016,Englische bersetzung von DIN EN 938:2016-09Produits chimiques utiliss pour le traitement de leau destine la consommation humaine Chlorite de sodium;Version anglaise EN 938:2016,Traduction anglaise de DIN EN 938:2016-09SupersedesDIN EN 938:200904www.beuth.d
4、eDocument comprises 36 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.08.16 DIN EN 938:2016-09 2 A comma is used as the decimal marker. National foreword This document (EN 938:2016) has been prepared by Technical Committee CEN
5、/TC 164 “Water supply” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was DIN-Normenausschuss Wasserwesen (DIN Standards Committee Water Practice), DIN-DVGW Joint Working Committee NA 119-07-13 AA Aufbereitungsstoffe und -anlagen. Users of this standard are adv
6、ised of the reservations stated in the Introduction of the European Standard and should note that national regulations exist in Germany dealing with water for human consumption, in particular the Trinkwasserverordnung (TrinkwV 2001) (German Drinking Water Ordinance). The DIN Standards corresponding
7、to the International Standards referred to in this document are as follows, whereby EN ISO Standards are only listed below if these have not been published as DIN EN ISO Standards with the same number: EN ISO 3696 DIN ISO 3696 ISO 9174 DIN EN 1233 Amendments This standard differs from DIN EN 938:200
8、9-04 as follows: a) solids have been included; b) the minimum content of sodium chlorite has been reduced; c) the information regarding the risk and safety labelling has been replaced by a statement that, at the date of publication of this document, sodium chloride is not listed within Annex VI of E
9、U Regulation 1272/2008; d) normative references and the Bibliography have been updated. Previous editions DIN 19617: 1971-10 DIN EN 938: 2000-03, 2009-04 DIN EN 938:2016-09 3 National Annex NA (informative) Bibliography DIN EN 1233, Water quality Determination of chromium Atomic absorption spectrome
10、tric methods DIN ISO 3696, Water for analytical laboratory use Specification and test methods Verordnung ber die Qualitt von Wasser fr den menschlichen Gebrauch (Trinkwasserverordnung TrinkwV 2001) (German Drinking Water Ordinance), as of 10 March 2016 (BGBI. I, p. 459)*) *) Obtainable from: Bundesm
11、inisterium der Justiz (German Federal Ministry of Justice) (Internet: http:/www.gesetze-im-internet.de). DIN EN 938:2016-09 4 This page is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 938 May 2016 ICS 71.100.80 Supersedes EN 938:2009English Version Chemicals used for trea
12、tment of water intended for human consumption - Sodium chlorite Produits chimiques utiliss pour le traitement de leau destine la consommation humaine - Chlorite de sodium Produkte zur Aufbereitung von Wasser fr den menschlichen Gebrauch - Natriumchlorit This European Standard was approved by CEN on
13、18 March 2016. 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 b
14、e obtained on application to the CEN-CENELEC 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
15、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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, I
16、reland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management C
17、entre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 938:2016 EEN 938:2016 (E) 2 Contents Page European foreword . 4 Introduction 5 1 Scope 6 2 Normative references 6 3 Description 6 3.1 Ide
18、ntification 6 3.1.1 Chemical name . 6 3.1.2 Synonym or common name . 6 3.1.3 Relative molecular mass . 6 3.1.4 Empirical formula . 6 3.1.5 Chemical formula 6 3.1.6 CAS Registry Number 6 3.1.7 EINECS reference 7 3.2 Commercial form . 7 3.3 Physical properties . 7 3.3.1 Appearance 7 3.3.2 Density 7 3.
19、3.3 Solubility in water . 7 3.3.4 Vapour pressure 7 3.3.5 Boiling point at 100 kPa . 7 3.3.6 Crystallization point . 7 3.3.7 Specific heat 8 3.3.8 Viscosity (dynamic) 8 3.3.9 Critical temperature 8 3.3.10 Critical pressure 8 3.3.11 Physical hardness . 8 3.4 Chemical properties . 8 4 Purity criteria
20、. 8 4.1 General 8 4.2 Composition of commercial product 9 4.3 Impurities and main by-products . 9 4.4 Chemical parameters . 9 5 Test methods . 10 5.1 Sampling 10 5.1.1 General . 10 5.1.2 Sampling from drums and bottles 10 5.1.3 Sampling from tanks and tankers 10 5.2 Analysis 11 5.2.1 Determination o
21、f sodium chlorite (main product) 11 5.2.2 Impurities . 12 5.2.3 Chemical parameters 15 6 Labelling - Transportation - Storage . 17 6.1 Means of delivery . 17 6.2 Labelling according to the EU Legislation 17 DIN EN 938:2016-09 EN 938:2016 (E) 3 6.3 Transportation regulations and labelling . 17 6.4 Ma
22、rking 18 6.5 Storage 18 6.5.1 General . 18 6.5.2 Long term stability . 18 6.5.3 Storage incompatibilities . 18 Annex A (informative) General information on sodium chlorite . 19 A.1 Origin 19 A.1.1 Raw materials 19 A.1.2 Manufacturing process . 19 A.2 Use 19 A.2.1 Function . 19 A.2.2 Form in which it
23、 is used 19 A.2.3 Treatment dose . 19 A.2.4 Means of application 19 A.2.5 Secondary effects 19 A.2.6 Removal of excess product 20 A.3 Routine analyses . 20 A.3.1 Determination of sodium chlorite (NaClO2) . 20 A.3.2 Determination of chlorate ion (ClO3-) 22 A.3.3 Determination of chemical parameters .
24、 23 Annex B (normative) General rules relating to safety . 24 B.1 Rules for safe handling and use . 24 B.2 Emergency procedures . 24 B.2.1 First aid 24 B.2.2 Spillage . 24 B.2.3 Fire . 24 Annex C (normative) Determination of arsenic, antimony and selenium (atomic absorption spectrometry hydride tech
25、nique) 25 C.1 Safety precautions 25 C.2 General principle 25 C.3 Interferences 25 C.4 Reagents . 25 C.5 Apparatus 27 C.6 Procedure 29 C.6.1 Preparation of the apparatus . 29 C.6.2 Preparation of calibration solutions . 30 C.6.3 Preparation of test solutions and standard solutions . 30 C.6.4 Determin
26、ation of arsenic with sodium borohydride . 30 C.6.5 Determination of selenium with sodium borohydride . 30 C.6.6 Determination of antimony with sodium borohydride 31 C.7 Calculation. 31 Bibliography . 32 DIN EN 938:2016-09 EN 938:2016 (E) 4 European foreword This document (EN 938:2016) has been prep
27、ared 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 November 2016, and conflicting national standards
28、shall be withdrawn at the latest by November 2016. 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 938:200
29、9. Significant technical differences between this edition and EN 938:2009 are as follows: a) deletion of reference to EU Directive 67/548/EEC of June 27, 1967 in order to take into account the latest Regulation in force (see 2); b) use of the changed classification and labelling (see 2). According t
30、o the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greec
31、e, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. DIN EN 938:2016-09 EN 938:2016 (E) 5 Introduction In respect of potential adverse effects on the q
32、uality 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 awaiti
33、ng 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
34、. The use of the product covered by this European Standard is subject to regulation or control by National Authorities. DIN EN 938:2016-09 EN 938:2016 (E) 6 1 Scope This European Standard is applicable to sodium chlorite used for treatment of water intended for human consumption. It describes the ch
35、aracteristics 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 documents, in whole or in part, are normatively referenced in this document and are indispe
36、nsable 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 ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) EN ISO 12846, Water q
37、uality 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 8288, Water quality Determina
38、tion of cobalt, nickel, copper, zinc, cadmium and lead Flame atomic absorption spectrometric methods ISO 9174, Water quality Determination of 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.
39、3 Relative molecular mass 90,44. 3.1.4 Empirical formula NaClO2. 3.1.5 Chemical formula Na-O-Cl = O. 3.1.6 CAS Registry Number 1)7758-19-2. 1) Chemical Abstracts Service Registry Number. DIN EN 938:2016-09 EN 938:2016 (E) 7 3.1.7 EINECS reference 2)231-836-6. 3.2 Commercial form The product is suppl
40、ied as a powder or as an aqueous solution of sodium chlorite. 3.3 Physical properties 3.3.1 Appearance The products are either a white powder or a greenish-yellow aqueous solution. 3.3.2 Density The density of sodium chlorite solutions is given in Table 1. Table 1 Density of sodium chlorite solution
41、s 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
42、.4 Vapour pressure Not applicable. 3.3.5 Boiling point at 100 kPa 3)Not applicable. 3.3.6 Crystallization point The crystallization point of sodium chlorite depending on concentration is given in Table 3. 2) European Inventory of Existing Commercial Chemical Substances. 3) 100 kPa = 1 bar. DIN EN 93
43、8:2016-09 EN 938:2016 (E) 8 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.
44、 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 str
45、ong oxidizing agent. It generates chlorine dioxide with acidic solutions or chlorine and reacts with organic compounds. 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. L
46、imits 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. Users of this product should check the national r
47、egulations 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
48、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 DIN EN 938:2016-09 EN 938:2016 (E) 9 or raw materials leads to significant quantities of impurities, by-products or
49、additives being present, this shall be notified to the user. 4.2 Composition of commercial product The sodium chlorite is available as a powder or as an aqueous solution with sodium chlorite content of 7,5 percent by mass fraction to 35 percent by mass fraction. The content of sodium chlorite shall be equal to or greater than the manufacturers declared value. 4.3 Impurities and main by-products The product shall conform to the r
