DIN EN 12473-2014 General principles of cathodic protection in seawater German version EN 12473 2014《海水中阴极保护的一般原理》.pdf

1、July 2014 Translation by DIN-Sprachendienst.English price group 17No 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 4

2、7.020.01; 77.060!%7Av“2203083www.din.deDDIN EN 12473General principles of cathodic protection in seawater;English version EN 12473:2014,English translation of DIN EN 12473:2014-07Allgemeine Grundstze des kathodischen Korrosionsschutzes in Meerwasser;Englische Fassung EN 12473:2014,Englische bersetzu

3、ng von DIN EN 12473:2014-07Principes gnraux de la protection cathodique en eau de mer;Version anglaise EN 12473:2014,Traduction anglaise de DIN EN 12473:2014-07SupersedesDIN EN 12473:2000-04www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprise

4、s 42 pages 06.14 DIN EN 12473:2014-07 2 A comma is used as the decimal marker. National foreword This document (EN 12473:2014) has been prepared by Technical Committee CEN/TC 219 “Cathodic protection”, Working Group WG 3 “Cathodic protection of steel structures in seawater” (Secretariat: BSI, United

5、 Kingdom). The responsible German body involved in its preparation was the Normenstelle Schiffs- und Meerestechnik (Shipbuilding and Marine Technology Standards Committee), Working Committee NA 132-04-04 AA Korro-sion. The present standard is a process standard for cathodic protection in seawater. T

6、he European Standards referred to in this document have been published as DIN EN or DIN EN ISO Standards with the same number. Amendments This standard differs from DIN EN 12473:2000-04 as follows: a) Clause 3 “Terms, definitions, abbreviations and symbols” has been revised; b) the standard has been

7、 completely restructured; c) all clauses have been revised; d) new Annexes B, C and D have been added. Previous editions DIN EN 12473: 2000-04 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12473 February 2014 ICS 47.020.01; 77.060 Supersedes EN 12473:2000English Version General principles of

8、cathodic protection in seawater Principes gnraux de la protection cathodique en eau de mer Allgemeine Grundstze des kathodischen Korrosionsschutzes in Meerwasser This European Standard was approved by CEN on 16 November 2013. CEN members are bound to comply with the CEN/CENELEC Internal Regulations

9、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-CENELEC Management Centre or to any CEN member. This

10、 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-CENELEC Management Centre has the same status as the official versions. CEN membe

11、rs 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, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portuga

12、l, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form

13、 and by any means reserved worldwide for CEN national Members. Ref. No. EN 12473:2014 EEN 12473:2014(E)2 Contents Page Foreword 4 1 Scope 5 2 Normative references 5 3 Terms, definitions, abbreviations and symbols .5 4 Application of cathodic protection in seawater 9 4.1 General 9 4.2 Galvanic anode

14、method 9 4.3 Impressed current method 10 4.4 Hybrid systems . 10 5 Determination of level of cathodic protection . 12 5.1 Measurement of protection level . 12 5.2 Reference electrodes . 12 5.3 Potentials of reference electrodes 12 5.4 Verification of reference electrodes 12 5.5 Potential measurement

15、 12 6 Cathodic protection potential criteria . 13 6.1 General . 13 6.2 Carbon-manganese and low alloy steels . 13 6.3 Other metallic materials . 15 6.3.1 General . 15 6.3.2 Stainless steels . 15 6.3.3 Nickel alloys 16 6.3.4 Aluminium alloys 16 6.3.5 Copper alloys 17 7 Design considerations . 17 7.1

16、Introduction . 17 7.2 Technical and operating data 17 7.2.1 Design life 17 7.2.2 Materials of construction . 17 7.3 Surfaces to be protected 18 7.4 Protective coatings . 18 7.5 Availability of electrical power 18 7.6 Weight limitations . 18 7.7 Adjacent structures 18 7.8 Installation considerations

17、18 7.9 Current demand 19 8 Effect of environmental factors on current demand . 19 8.1 Introduction . 19 8.2 Dissolved oxygen . 19 8.3 Sea currents 19 8.4 Calcareous deposits . 19 8.5 Temperature 20 8.6 Salinity . 20 8.7 pH . 21 8.8 Marine fouling . 21 8.9 Effect of depth . 21 8.10 Seasonal variation

18、s and storms 21 DINEN 12473:2014-07EN 12473:2014(E)3 9 Secondary effects of cathodic protection . 21 9.1 General . 21 9.2 Alkalinity . 22 9.3 Environmentally-assisted cracking . 22 9.3.1 General . 22 9.3.2 Hydrogen embrittlement . 22 9.3.3 Corrosion fatigue . 22 9.4 Chlorine 23 9.5 Stray currents an

19、d interference effects 23 10 Use of cathodic protection in association with coatings 24 10.1 Introduction 24 10.2 Coating selection . 24 10.3 Coating breakdown . 25 Annex A (informative) Corrosion of carbon-manganese and low-alloy steels . 26 A.1 Nature of metallic corrosion . 26 A.2 Polarization 27

20、 Annex B (informative) Principles of cathodic protection 30 Annex C (informative) Reference electrodes . 33 C.1 General . 33 C.2 Silver/silver chloride/seawater electrode 33 C.3 The zinc/seawater electrode . 35 C.4 Verification of reference electrodes 35 Annex D (informative) Corrosion of metallic m

21、aterials other than carbon-manganese and low-alloy steels typically subject to cathodic protection in seawater 37 D.1 Stainless steels 37 D.2 Nickel alloys . 37 D.3 Aluminium alloys . 37 D.4 Copper alloys . 38 Bibliography 39 DIN EN 12473:2014-07 EN 12473:2014 (E) 4 Foreword This document (EN 12473:

22、2014) has been prepared 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 or by endorsement, at the latest by August 2014, and conflicti

23、ng national standards shall be withdrawn at the latest by August 2014. 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 s

24、upersedes EN 12473:2000. 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, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic

25、of Macedonia, France, Germany, Greece, 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 12473:2014-07 EN 12473:2014 (E) 5 1 Scope This European

26、 Standard covers the general principles of cathodic protection when applied in seawater, brackish waters and marine mud. It is intended to be an introduction, to provide a link between the theoretical aspects and the practical applications, and to constitute a support to the other European Standards

27、 devoted to cathodic protection of steel structures in seawater. This European Standard specifies the criteria required for cathodic protection. It provides recommendations and information on reference electrodes, design considerations and prevention of the secondary effects of cathodic protection.

28、The practical applications of cathodic protection in seawater are covered by the following standards: EN 12495, Cathodic protection for fixed steel offshore structures; EN ISO 13174, Cathodic protection of harbour installations (ISO 13174); EN 12496, Galvanic anodes for cathodic protection in seawat

29、er and saline mud; EN 13173, Cathodic protection for steel offshore floating structures; EN 16222, Cathodic protection of ship hulls; EN 12474, Cathodic protection of submarine pipelines; ISO 15589-2, Petroleum, petrochemical and natural gas industries Cathodic protection of pipeline transportation

30、systems Part 2: Offshore pipelines. For cathodic protection of steel reinforced concrete whether exposed to seawater or to the atmosphere, EN ISO 12696 applies. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for

31、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 50162, Protection against corrosion by stray current from direct current systems EN ISO 8044, Corrosion of metals and al

32、loys Basic terms and definitions (ISO 8044) 3 Terms, definitions, abbreviations and symbols For the purposes of this document, the terms and definitions given in EN ISO 8044 and the following apply. NOTE The definitions given below prevail on their versions in EN ISO 8044. 3.1 acidity presence of an

33、 excess of hydrogen ions over hydroxyl ions (pH 7) DIN EN 12473:2014-07 EN 12473:2014 (E) 6 3.3 anaerobic condition absence of free oxygen dissolved in the electrolyte 3.4 calcareous deposits minerals precipitated on the metallic cathode because of the increased alkalinity caused by cathodic protect

34、ion 3.5 cathodic disbondment failure of adhesion between a coating and a metallic surface that is directly attributable to the application of cathodic protection 3.6 cathodic protection system entire installation that provides cathodic protection Note 1 to entry: It may include anodes, power source,

35、 cables, test facilities, isolation joints, electrical bonds. 3.7 coating breakdown factor fc ratio of cathodic current density for a coated metallic material to the cathodic current density of the bare material 3.8 copper/copper sulphate reference electrode reference electrode consisting of copper

36、in a saturated solution of copper sulphate 3.9 dielectric shield alkali resistant organic coating applied to the structure being protected in the immediate vicinity of an impressed current anode to enhance the spread of cathodic protection and minimize the risk of hydrogen damage to the protected st

37、ructure in the vicinity of the anode 3.10 driving voltage difference between the structure/electrolyte potential and the anode/electrolyte potential when the cathodic protection is operating 3.11 electro-osmosis passage of a liquid through a porous medium under the influence of a potential differenc

38、e 3.12 environmentally assisted cracking cracking of a susceptible metal or alloy due to the conjoint action of an environment and stress 3.13 groundbed system of immersed electrodes connected to the positive terminal of an independent source of direct current and used to direct the cathodic protect

39、ion current onto the structure being protected 3.14 hydrogen embrittlement process resulting in a decrease of the toughness or ductility of a metal due to absorption of hydrogen DIN EN 12473:2014-07 EN 12473:2014 (E) 7 3.15 hydrogen stress cracking HSC cracking that results from the presence of hydr

40、ogen in a metal and tensile stress (residual and/or applied) Note 1 to entry: HSC describes cracking in metals which may be embrittled by hydrogen produced by cathodic polarization without any detrimental effect caused by specific chemicals such as sulphides. 3.16 isolating joint (or coupling) elect

41、rically discontinuous joint or coupling between two lengths of pipe, inserted in order to provide electrical discontinuity between them 3.17 master reference electrode reference electrode, calibrated with the primary calibration reference electrode, used for verification of reference electrodes used

42、 for field or laboratory measurements 3.18 over-polarization occurrence in which the structure to electrolyte potentials are more negative than those required for satisfactory cathodic protection Note 1 to entry: Over-polarization provides no useful function and might even cause damage to the struct

43、ure. 3.19 pitting resistance equivalent PREN indication of the resistance of a corrosion resistant alloy to pitting in the presence of water, chlorides and oxygen or oxidation environment, accounting for the beneficial effects of nitrogen Note 1 to entry: For the purposes of this standard, PREN is c

44、alculated as follows: PREN = % Cr + 3,3(% Mo) + 0,5 (% W) + 16 (% N). 3.20 potential gradient difference in potential between two separate points in the same electric field 3.21 primary calibration reference electrode reference electrode used for calibration of master reference electrodes is the nor

45、mal hydrogen electrode (N.H.E.) Note 1 to entry: The official reference electrode, standard hydrogen electrode (S.H.E.), which considers the fugacity coefficient for hydrogen gas and the activity coefficient for H+ions, is practically impossible to manufacture. 3.22 protection current current made t

46、o flow into a metallic structure from its electrolytic environment in order to achieve cathodic protection of the structure 3.23 reference electrode electrode having a stable and reproducible potential that is used as a reference in the measurement of electrode potentials DIN EN 12473:2014-07 EN 124

47、73:2014 (E) 8 Note 1 to entry: Some reference electrodes use the electrolyte in which the measurement is carried out. Their potential varies according to the composition of this electrolyte. 3.24 resistivity (of an electrolyte) resistivity is the resistance of an electrolyte of unit cross section an

48、d unit length Note 1 to entry: It is expressed in ohm.metres (.m). The resistivity depends, amongst other things, upon the amount of dissolved salts in the electrolyte. 3.25 saturated calomel reference electrode reference electrode consisting of mercury and mercurous chloride in a saturated solution of potassium chloride 3.26 silver/silver chloride reference electrode reference electrode consisting of silver, coated with silver chloride, in an electrolyte containing a known concentration of chloride ions Note 1 to entry: Silver/silv