BS EN 12499-2003 Internal cathodic protection of metallic structures《金属结构的内部阴极保护》.pdf

1、BRITISH STANDARDBS EN12499:2003Incorporating Corrigenda Nos. 1 and 2Internal cathodic protection of metallic structuresThe European Standard EN 12499:2003 has the status of a British StandardICS 77.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g4

2、0g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 12499:2003This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2003 BSI 2006ISBN 0 580 41349 7National forewordThis British Stan

3、dard is the official English language version of EN 12499:2003, including Corrigendum June 2006. Attention is drawn to the fact that BS 7361-1:1991, Cathodic protection Part 1: Code of practice for land and marine applications, provides general information on cathodic protection. Note that BS 7361-1

4、:1991 will eventually be withdrawn when all the CEN standards relating to cathodic protection currently being prepared are published.The UK participation in its preparation was entrusted to Technical Committee GEL/603, Cathodic protection, which has the responsibility to: A list of organizations rep

5、resented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”

6、, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer

7、immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them

8、 in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 39 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments14828 Co

9、rrigendum No. 11 December 2003 Changes to National foreword16497 Corrigendum No. 231 July 2006 Changes to ScopeEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12499January 2003ICS 77.060English versionInternal cathodic protection of metallic structuresProtection cathodique interne des structures m

10、talliques Kathodischer Korrosionsschutz fr die Innenflchen vonmetallischen AnlagenThis European Standard was approved by CEN on 7 November 2002.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a na

11、tional standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any

12、other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Gre

13、ece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2003

14、 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12499:2003 EIncorporating Corrigendum June 2006EN 12499:2003 (E)2ContentspageForeword31 Scope 42 Normative references 43 Symbols, terms and definitions44 Principle and criteria for int

15、ernal cathodic protection.95 Factors affecting design and application116 Design and application of internal cathodic protection.137 Measurements188 Commissioning 199 Operation and maintenance2010 Cathodic protection of domestic water heater .2111 Cathodic protection of appliances for heating and sto

16、rage of hot water 2612 Cathodic protection of structures with variable level feed tanks condensates and similarappliances.2813 Cathodic protection of filtering tanks2914 Internal cathodic protection of wells .3115 Internal cathodic protection of pipes.3216 Cathodic protection of tubular heat exchang

17、ers33Annex A (normative) Test of the electrode potential of galvanic anodes .36Annex B (informative) Protection potential ranges for low alloy steel compared with Ag/AgClelectrodes in different types of water 38Bibliography 39EN 12499:2003 (E)3ForewordThis document (EN 12499:2002) has been prepared

18、by Technical Committee CEN/TC 219 “Cathodic protection“,the secretariat of which is held by BSI.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by July 2003, and conflicting national standards shall b

19、e withdrawn at the latest byJuly 2003.Annex A is normative. Annex B is informative.According to the CEN/CENELEC Internal Regulations, the national standards organisations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,Franc

20、e, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.EN 12499:2003 (E)41 ScopeThis European Standard specifies the structures, metals and surfaces which can be protected against corrosion by

21、the application of internal cathodic protection, the electrolytic solutions and the conditions necessary for theapplication of internal cathodic protection and gives guidance on the application and operation of an effectiveinternal cathodic protection system.This standard is applicable to metallic s

22、tructures made from the following on their own or with others:iron and low alloy steel;galvanised steel;copper and copper alloys;lead;tin;stainless steels;aluminium and zinc;titanium.This standard is applicable to the cathodic protection of uncoated metals, and of metals already coated with low orhi

23、gh insulation resistance coatings.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, su

24、bsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 50014, Electrical apparatus for potentially

25、 explosive atmospheres General requirements.EN 60335-2-21, Safety of household and similar electrical appliances - Part 2: Particular requirements for storagewater heaters (IEC 60335-2-21:1997 + Corrigendum 1998, modified).EN ISO 8044:1999, Corrosion of metals and alloys - Basic terms and definition

26、s (ISO 8044:1999).3 Symbols, terms and definitionsFor the purposes of this standard the symbols, terms and definitions of EN ISO 8044:1999 and the following apply.This standard applies to the internal cathodic protection of domestic water heaters, hot and cold water tanks,circulating water pipes, co

27、ndensers and heat exchangers. This standard applies to metallic structures which contain stored or circulating water, which can be stagnant or renewed, cold or hot, drinking water or industrial water and also to aqueous suspension.NOTE Cathodic protection is considered to be technically feasible for

28、 electrolytic solutions with a conductivity and a pH 4,5. Where the pH 10-3Siemens m ,This standard is not applicable to oil and gas process plant and equipment or to industrial heating or cooling water systems. -1EN 12499:2003 (E)53.1 SymbolsI CurrentR ResistanceJ Current densityU Voltagea YearEAgM

29、etal-to-electrolytic solution potential with respect to a silver/silver chloride reference electrodeElLimiting critical potentialEnFree corrosion potentialEoffInstantaneous off potentialEonOn potentialEpProtection potentialEHMetal-to-electrolytic solution potential with respect to a standard hydroge

30、n electrodeEZnMetal-to-electrolytic solution potential with respect to a zinc electrodeIaAnode current outputIpProtection currentJpProtection current density (A/m2)rcSpecific coating resistance ( m2)T Temperaturet Timer Resistivity ( m)3.2 Terms and definitions3.2.1anaerobicwithout free oxygen in th

31、e electrolytic solution adjacent to a metallic structure3.2.2anodic areapart of a structure surface which acts as an anode3.2.3cathodic areapart of a structure surface which acts as a cathodeEN 12499:2003 (E)63.2.4cathodic protection systementire installation, including passive and active elements,

32、that provides cathodic protection to a structure3.2.5coating defectdiscontinuity in the protective coating3.2.6coating resistanceelectrical resistance between a coated metal and the electrolytic solutionNOTE It is determined largely by the size and number of coating defects and coating pores and is

33、therefore indicative ofthe condition of the coating (see also specific coating resistance).3.2.7continuity bondbond designed and installed specifically to ensure electrical continuity3.2.8continuous anodelong flexible anode3.2.9couponrepresentative metal sample of known weight and dimensions used to

34、 quantify the extent of corrosion or theeffectiveness of applied cathodic protection3.2.10drinking waterwater in conformity with European directive 98/83/CE from November 3, 19983.2.11electrical continuitystate within a protected structure in which the circulating current does not produce a signific

35、ant voltage drop3.2.12electrical isolationstate in which there is no metallic electrical path between structures or components3.2.13electrical shieldingintervening objects that prevent the flow of the current through the electrolytic solution to a structure3.2.14equalising currentcurrent that flows

36、between two separate points after interruption of the protection currentNOTE Equalising currents can flow, for example, as a result of removing cathodic protection current from a structure withcomponents exposed to different depolarisation conditions.3.2.15foreign cathodemetal part fitted in the pro

37、tected structure which has a more positive free corrosion potential than the protectedstructure and which requires a greater current density than the protected structure to achieve cathodic polarisationNOTE Foreign cathodes can seriously impair the cathodic protection of the rest of the structure.3.

38、2.16impressed current anodeanode in an impressed current stationEN 12499:2003 (E)7NOTE Impressed current anodes can be permanent anodes or soluble anodes.3.2.17impressed current stationequipment and materials required to provide cathodic protection by impressed currentNOTE Such materials and equipme

39、nt will include impressed current anodes, cables, sensing electrodes, and transformerrectifiers.3.2.18off potentialstructure to electrolytic solution potential measured immediately after synchronous interruption of all sources ofapplied cathodic protection current3.2.19IR dropvoltage developed acros

40、s a resistance, or resistive path, in accordance with Ohms Law (U = I R V)3.2.20IR -free potentialpotential measured without the voltage error caused by the IR drop (EIR FREE)3.2.21isolating jointelectrically discontinuous joint or coupling between two lengths of pipe, inserted in order to provide e

41、lectricaldiscontinuity between them3.2.22measuring pointpoint at which the actual measurement takes placeNOTE In the case of structure to electrolytic solution potentials this refers to the location of the reference electrode.3.2.23on potentialstructure to electrolytic solution potential measured wi

42、th the structure cathodic protection current flowing3.2.24overprotectionstate in which the structure to electrolytic solution potentials are more negative than those recommended forsatisfactory cathodic protectionNOTE Overprotection provides no useful function and can cause damage to the structure b

43、y excessive production of gaseswhich can constitute an explosion hazard, embrittlement of metals, or protective coating damage.3.2.25permanent anodesimpressed current anodes for which the rate of corrosion is much smaller than the rate calculated in accordancewith Faradays Law3.2.26permanent referen

44、ce electrodepermanent installed reference electrode designed for a long life3.2.27potential gradientdifference in potential between two separate points in the same electrolytic solutionEN 12499:2003 (E)83.2.28potentiostatprotection current device by means of which the structure/electrolytic solution

45、 potential is brought and maintained toa prescribed level despite variations in polarisation conditionsNOTE The current delivered by the generator, the protection current, is controlled by the structure potential measured by areference electrode.3.2.29protected structurestructure to which cathodic p

46、rotection is effectively applied3.2.30protection current (Ip)current made to flow into a metallic structure from its electrolytic environment in order to effect cathodic protectionof the structure3.2.31resistance bondbond with significant resistance to limit the flow of current to within prescribed

47、limitsNOTE Resistance can be achieved by the insertion of resistors into the bond connection.3.2.32soluble anodeimpressed current anode which is consumed in accordance with Faradays Law by the impressed anodic currentNOTE The adjectives soluble and sacrificial used alone do not specify if anodes are

48、 working by galvanic action or byimpressed current. To avoid confusion it is proposed to apply the following convention: “galvanic anode“ for sacrificial galvanicanode; “soluble anode“ for soluble impressed current anode.3.2.33standard reference electrodereference electrode whose potential does not

49、depend on the concentrations of various elements in the electrolyticsolution of the corrosion system3.2.34sensing electrodepermanently installed reference electrode used to measure the structure to electrolytic solution potential and toprovide a signal to control the protection current of an automatic impressed current system3.2.35silver/silver chloride reference electrodeAg/AgCl reference electrodeelectrode consisting of silver, coated with silver chloride, in an electrolytic solution containing chloride ionsNOTE The potential of this electrode changes when the ele