1、BS EN 938:2009ICS 13.060.20; 71.100.80NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDChemicals used fortreatment of waterintended for humanconsumption Sodium chloriteCopyright European Committee for Standardization Provided by IHS under license with CENNot for
2、ResaleNo reproduction or networking permitted without license from IHS-,-,-This British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 30 June2009. BSI 2009ISBN 978 0 580 58599 9Amendments/corrigenda issued since publicationDate CommentsBS EN 938:2009Nationa
3、l forewordThis British Standard is the UK implementation of EN 938:2009. Itsupersedes BS EN 938:2000 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/59, Chemicals for drinking water treatment.A list of organizations represented on this committee can
4、 be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.Copyright European Committee for Standardi
5、zation Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 938January 2009ICS 71.100.80 Supersedes EN 938:1999 English VersionChemicals used for treatment of water int
6、ended for humanconsumption - Sodium chloriteProduits chimiques utiliss pour le traitement de leaudestine la consommation humaine - Chlorite de sodiumProdukte zur Aufbereitung von Wasser fr denmenschlichen Gebrauch - NatriumchloritThis European Standard was approved by CEN on 5 December 2008.CEN memb
7、ers are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application
8、 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the s
9、ame status as theofficial 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,Rom
10、ania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworl
11、dwide for CEN national Members.Ref. No. EN 938:2009: ECopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 2 Contents Page Foreword 3 Introduction . 4 1
12、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 met
13、hods . 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
14、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 Copyright European Committee for Standardization Provided by IHS under license wi
15、th CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 3 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
16、 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 b
17、e 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
18、/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 coun
19、tries 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, Spa
20、in, Sweden, Switzerland and the United Kingdom. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 4 Introduction In respect of potential adverse effec
21、ts 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
22、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 u
23、se of the product covered by this European Standard is subject to regulation or control by National Authorities. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN
24、938:2009 (E) 5 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 o
25、n 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) applie
26、s. 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 prod
27、ucts 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 Descrip
28、tion 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 NaClO2. 3.1.5 Chemical formula NaClO2. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo
29、reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 6 3.1.6 CAS Registry Number 1)7758-19-2. 3.1.7 EINECS reference 2)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
30、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 % (mass fraction) Density g/ml at 20 C 25 1,21031 1,2703.3.3 Solubility in water The solubility of sodium chlorite de
31、pending on temperature is given in Table 2 Table 2 Solubility of sodium chlorite Temperature C Solubility g/l 5 34017 39030 46045 530 60 5503.3.4 Vapour pressure Not applicable. 1)Chemical Abstracts Service Registry Number 2)European Inventory of Existing Commercial Chemical Substances Copyright Eur
32、opean Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 7 3.3.5 Boiling point at 100 kPa 3)Not applicable. 3.3.6 Crystallization point The crystallization point of sodiu
33、m chlorite depending on concentration is given in Table 3. Table 3 Crystallization point of sodium chlorite Aqueous solution concentration % (mass fraction) Crystallization point C 25 - 14,531 3 3.3.7 Specific heat Not known. 3.3.8 Viscosity (dynamic) The viscosity of sodium chlorite depending on co
34、ncentration is given in Table 4. Table 4 Viscosity of sodium chlorite Aqueous solution concentration % (mass fraction) Viscosity mPa.s at 20 C 25 2,3331 3,263.3.9 Critical temperature Not applicable. 3.3.10 Critical pressure Not applicable. 3.3.11 Physical hardness Not applicable. 3.4 Chemical prope
35、rties 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 Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking p
36、ermitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 8 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
37、 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
38、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
39、 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 co
40、mmercial 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 o
41、f 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 requirements specified in Table 5. Table 5 Impurities Impurity Limit g/kg sodium chlorite 100 % mass fraction Sodium chlorate (NaClO3) max. 40 So
42、dium nitrate (NaNO3) max. 1 NOTE Sodium chlorate can be a by-product of the manufacturing process. Sodium nitrate is used as a corrosion inhibitor in the sodium chlorite special grade for the textile industry. 4.4 Chemical parameters NOTE For the purpose of this standard, “chemical parameters“ are t
43、hose defined in the EU Directive 98/83/EC of November 13,1998 (see 1). The content of chemical parameters shall conform to the requirements specified in Table 6. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitt
44、ed without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 9 Table 6 chemical parameters Parameter Limit in mg/kg of sodium chlorite 100 % of mass fraction Type 1 Type 2 Arsenic (As) max. 1,1 7,5 Cadmium (Cd) max. 1,5 7,5 Chromium (Cr) max. 1,1 7,5 Mercury (Hg) max. 1,1 3,7 Nickel (Ni) max. 1,1 7
45、,5 Lead (Pb) max. 1,1 7,5 Antimony (Sb) max. 1,1 7,5 Selenium (Se) max. 1,1 7,5 NOTE Cyanide which does not exist in a strong oxidizing medium such as sodium chlorite is not a relevant chemical parameter. Pesticides and polycyclic aromatic hydrocarbons are not by-products of the manufacturing proces
46、s. 5 Test methods 5.1 Sampling 5.1.1 General Observe the general recommendations of ISO 3165 and take account of ISO 6206. 5.1.2 Sampling from drums and bottles 5.1.2.1 General 5.1.2.1.1 Mix the contents of the container to be sampled by shaking the container, by rolling it or by rocking it from sid
47、e to side, taking care not to damage the container or spill any of the liquid. 5.1.2.1.2 If the design of the container is such (for example, a narrow-necked bottle) that it is impracticable to use a sampling implement, take a sample by pouring after the contents have been thoroughly mixed. Otherwis
48、e, proceed as described in 5.1.2.3. 5.1.2.1.3 Examine the surface of the liquid. If there are signs of surface contamination, take samples from the surface as described in 5.1.2.2; otherwise, take samples as described in 5.1.2.3. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN 938:2009EN 938:2009 (E) 10 5.1.2.2 Surface sampling Take a sample using a suitable ladle. Lower the ladle into the liquid until the
