1、 STD-BSI BS EN 12954-ENGL 2001 9 Lb24bbS 0912b8b O31 BRITISH STANDARD Cathodic protection of buried or immersed metallic structures - General principles and application for pipelines The European Standard EN 12954:2001 has the status of a British Standard ICs 23.040.01; 77.060 BS EN 12954:2001 NO CO
2、PYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesSTD-BSI BS EN 1275Li-ENGL 2001 lb2qbb7 0712b87 T78 W BS EN 12954:2001 Amd. No. Date National foreword Comments This British Standard is the offic
3、ial English language version of EN 12954:2001. Reference should also be made to BS 7361, Code ofpractice for land and marine applications, which will eventually be withdrawn when all the CEN Standards relating to cathodic protection currently being prepared, are published. The UK participation in it
4、s preparation was entrusted to Technical Committee GEU603, Cathodic protection, which has the responsibility to: - - aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; m
5、onitor related international and European developments and promulgate them in the UK. - A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this
6、 document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users
7、 of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. This British Standard, having been prepared under the direction of the Electrotechnical Sector Committee, was published under the authori
8、ty of the Standards Committee and comes into effect on 15June2001 Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 31 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. O BSI 06-
9、2001 ISBN O 580 37665 6 COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12954 January 2001 ICs 23.040.99; 77.060 English version Cathodic protection of buried or immersed metallic structures - General princ
10、iples and application for pipelines Protection cathodique des structures mtalliques enterres ou immerges - Principes gnraux et application pour les canalisations Kathodischer Korrosionsschutz von metallenen Anlagen in Bbden oder Wassern - Grundlagen und Anwendung fr Rohrleitungen This European Stand
11、ard was approved by CEN on 1 December 2000. CEN members are bound to comply with the CENKENELEC 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 s
12、uch national standards 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 other language made by translation under the responsibility of a CEN member into its own language
13、and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzer
14、land and United Kingdom. EUROPEAN COMMEE FOR STANDARDIZATION EUROPISCHES KOMITEE FUR NORMUNG COMITE EUROPEEN DE NORMALISATION Management Centre: rue de Stassart, 36 8-1050 Brussels O 2001 CEN All rights of exploitation in any form and by any means resewed worldwide for CEN national Members. Ref. No.
15、 EN 12954.2001 E COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 2 EN 12954:2001 Contents Page Foreword Introduction 1 Scope 2 Normative references 3 Symbols, terms and definitions 3.1 Symbols 3.2 Terms and definitions 4 Principle and criteria of cathodi
16、c protection 4.1 Principle of cathodic protection 4.2 Criteria of cathodic protection 4.3 Influence of alternating current on cathodically protected structures 5 Prerequisites for application of cathodic protection 5.1 General 5.2 Electrical continuity 5.3 Electrical isolation 5.4 External coating 6
17、 Base data for design 6.1 General 6.2 Structure details 6.3 Coating 6.4 Environment 6.5 Pipelines specific data 7 Design and prerequisites 7.1 General 7.2 Electrical isolation 7.3 Test stations 7.4 Bonding 7.5 Buried sleeve pipes for pipelines 7.6 Wall entries, restraints, saddles and anchors for pi
18、pelines 7.7 Bridges 7.8 Electrically operated equipment 7.9 Lightning protection 7.10 Equipment for the reduction of a.c. interference 7.1 1 Cathodic protection systems 7.1 2 Drainage stations 7.1 3 Design and design documents 8 Installation of cathodic protection systems 8.1 General 8.2 Cables 8.3
19、Galvanic anodes 8.4 Impressed current systems 8.5 Test stations 8.6 Drainage stations 8.7 As built documentation 4 4 5 5 6 6 6 12 12 12 15 15 15 15 15 15 15 15 16 16 16 16 17 17 17 18 18 18 19 19 19 19 19 20 22 22 22 22 23 23 23 24 24 24 9 Commissioning 25 COPYRIGHT European Committee for Standardiz
20、ationLicensed by Information Handling ServicesSTD*BSI BS EN 12954-ENGL 2001 = Lb24bb7 0712b90 5b2 H Page 3 EN 12954:2001 9.1 Preliminary checking 9.2 Start up 9.3 Verification of the cathodic protection effectiveness 9.4 Installation and commissioning documents 1 O Inspection and maintenance 10.1 Ge
21、neral 10.2 Factors influencing inspection frequency 10.3 Inspection 10.4 Maintenance 10.5 Results of inspection Annex A (informative) a.c. interference Bibliography 25 25 25 26 26 26 26 27 29 29 30 31 Table 1 - Free corrosion potentials, protection potentials and limiting critical potential of some
22、common metals in soil and in fresh and salt water 14 Table 2 - Frequency of functional checks 28 COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 4 EN 12954:2001 Foreword This European Standard has been prepared by Technical Committee CEN/TC 21 9 “Cathodi
23、c 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 July 2001, and conflicting national standards shall be withdrawn at the latest by July 2001.
24、 According to the CENKENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Por
25、tugal, Spain, Sweden, Switzerland and the United Kingdom. Annex A is informative. Introduction This standard is applicable to the protection of all types of buried or immersed metallic structures especially pipelines. However, in order to allow for structures having specific features with regards to
26、 construction, commissioning or operation, provision has been made for complementary standards to be used in conjunction with this one to deal with the peculiarities of such structures. Cathodic protection is a technique based on the application of electrochemical principles and covers a wide range
27、of materials and equipment together with a variety of measurement techniques. In order to achieve effective and efficient cathodic protection, the design, installation, commissioning, inspection and maintenance should be performed by adequately trained, experienced and responsible personnel. This st
28、andard aims to ensure effective cathodic protection and is therefore directed primarily to the above personnel. COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 5 EN 12954:2001 1 Scope This European Standard specifies the general principles for the implem
29、entation of a system of cathodic protection against corrosive attacks on buried or immersed metal structures with and without the influence of external electrical sources. NOTE 1 The protection against stray current from direct current system influences is dealt in prEN 501 62:2000. This standard in
30、dicates conditions and parameters that should be met to achieve cathodic protection as well as rules and procedures that should be followed for design, installation, commissioning and maintenance of the protective systems. NOTE 2 Clauses 5 to 10 deal mainly with the cathodic protection of pipelines
31、but they are applicable to other structures This standard is applicable to external surfaces of buried or immersed structures. It is not applicable to the protection of internal parts of structures containing corrosive liquids. NOTE 3 This is covered by prEN 12499:1996. When cathodic protection is n
32、ecessary, this standard is applicable to structures covered with concrete which are then buried or immersed. It is not applicable to the protection of steel in reinforced concrete which is buried or immersed. NOTE 4 This is covered by EN 12696 This standard is applicable only to those constructions
33、in sea water for which the protective systems would be installed and can be inspected on land. NOTE 5 they form a part of a larger underground network. Such constructions in sea water are generally of smaller length, whether or not NOTE 6 submarine pipelines see EN 12473. Other constructions in sea
34、water are dealt with in other standards, e.g. for 2 Normative references This European Standard incorporates, by dated or undated references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
35、dated references, subsequent amendments to or revision of any of these publications apply to this standard only when incorporated in this standard by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). prEN 501 62:2000, Prot
36、ection against corrosion by stray current from DC systems EN 12696, Cathodic protection of steel in concrete prEN 1 3509: 1 999, Cathodic Protection Measurement Techniques EN 60079-1 O, Electrical apparatus for explosive gas atmospheres - Part 10: Classification of hazardous areas (IEC 60079-10:1995
37、) COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 6 EN 12954:2001 EN 60079-1 4, Electrical apparatus for explosive gas atmospheres - Part 14: Electrical installations in hazardous areas (other than mines) (IEC 60079-1 4:1996) EN IS0 8044, Corrosion of me
38、tals and alloys; vocabulaty 3 Symbols, terms and definitions 3.1 Symbols I Current E Potential Resistance J Current density U Voltage a.c. Alternating current d.c. Direct current Ag Metal or structure to electrolyte potential with respect to a silverlsilver chloride reference electrode cu Metal or s
39、tructure to electrolyte potential with respect to a copperkaturated copper sulphate reference electrode EI free IR free potential EKCI Metal or structure to electrolyte potential with respect to a silver/silver chloride/saturated potassium chloride electrode Limiting critical potential Free corrosio
40、n potential Off potential On potential Protection potential Metal or structure to electrolyte potential with respect to a mercury/calomeVsaturated potassium chloride electrode Metal or structure to electrolyte potential with respect to a standard hydrogen electrode Metal or structure to electrolyte
41、potential with respect to a zinc electrode Anode current output Protection current Stray current Alternating current density Protection current density Coating resistance or structure to soil resistance (fi) Average coating resistance or average structure to soil resistance (Om2) Temperature Time Re
42、sistivity (Q-m) 3.2 Terms and definitions For the purposes of this European Standard the following terms and definitions apply. For other terms and definitions related to corrosion refer to EN IS0 8044. 3.2.1 anaerobic lack of free oxygen in the electrolyte adjacent to a metallic structure 3.2.2 ano
43、de backfill material with a low resistivity, which may be moisture-retaining, immediately surrounding a buried anode for the purpose of decreasing the effective resistance of the anode to the electrolyte COPYRIGHT European Committee for StandardizationLicensed by Information Handling Services STD-BS
44、I BS EN 12954-ENGL 2001 1b2Libb9 09L2b7Li 108 Page 7 EN 12954:2001 3.2.3 average coating resistance or average structure to soil resistance( rco) value derived from the ratio of the difference between the ON and OFF potentials to the protection current and the surface area of the structure in questi
45、on. It is usually expressed in 0hm.square meter (Q-m2) 3.2.4 backfill see anode backfill 3.2.5 blistering formation of swellings on the surface of an unbroken thin coating caused by permeation of water, gases and by migration of ions in the presence of an electric field between the metal and the coa
46、ting 3.2.6 bond metal conductor, usually of copper, connecting two points on the same or on different structures usually with the intention of making the points equipotential 3.2.7 buried structure any metal construction built or laid beneath ground level or built on ground level and then covered wi
47、th earth 3.2.8 cathodic protection station impressed current or galvanic anode station 3.2.9 cathodic protection system entire installation, including active and passive elements, that provides cathodic protection 3.2.1 O coating defect deficiency in the protective coating (e.g. holidays, porosity)
48、3.2.1 1 coating resistance or structure to soil resistance( FIco) electrical resistance between a coated metal and the electrolyte expressed in ohms. It is determined largely by the size and number of coating defects, coating pores and the electrolyte resistivity 3.2.1 2 continuity bond bond designe
49、d and installed specifically to ensure electrical continuity of a structure 3.2.13 copperkaturated copper sulphate reference electrode reference electrode consisting of copper in a saturated solution of copper sulphate 3.2.14 coupon representative metal sample used to quantify the extent of corrosion or the effectiveness of applied cathodic protection 3.2.15 d.c. decoupling device protective device that will conduct when pre-determined threshold voltage levels are exceeded COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 8 EN
