EN 12496-2013 en Galvanic anodes for cathodic protection in seawater and saline mud《海水和盐泥中阴极保护的牺牲阳极》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 12496:2013Galvanic anodes for cathodicprotection in seawater andsaline mudBS EN 12496:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation o

2、f EN 12496:2013.The UK participation in its preparation was entrusted to TechnicalCommittee GEL/603, Cathodic protection.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a cont

3、ract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 72889 1ICS 77.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authorit

4、y of theStandards Policy and Strategy Committee on 30 June 2013.Amendments issued since publicationDate Text affectedBS EN 12496:2013EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12496 June 2013 ICS 77.060 English Version Galvanic anodes for cathodic protection in seawater and saline mud Anod

5、es galvaniques pour la protection cathodique dans leau de mer et les boues salines Galvanische Anoden fr den kathodischen Schutz in Seewasser und salzhaltigem Schlamm This European Standard was approved by CEN on 25 April 2013. CEN members are bound to comply with the CEN/CENELEC Internal Regulation

6、s 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. Th

7、is 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 mem

8、bers 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, Portu

9、gal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by an

10、y means reserved worldwide for CEN national Members. Ref. No. EN 12496:2013: EBS EN 12496:2013EN 12496:2013 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Galvanic anode materials and their properties 8 4.1 General 8 4.2 Anode alloy com

11、position 8 4.3 Electrochemical properties 9 4.3.1 General 9 4.3.2 Potential 9 4.3.3 Current capacity.9 4.3.4 Anode consumption rate . 10 5 Anode design and acceptance criteria . 10 5.1 General . 10 5.2 Chemical composition . 11 5.3 Physical properties . 11 5.4 Electrochemical testing . 11 5.5 Anode

12、core materials . 12 5.6 Cable connections 13 Annex A (normative) Physical tolerances for galvanic anodes . 14 A.1 Anode mass . 14 A.2 Anode dimensions and straightness 14 A.3 Steel core . 15 A.4 Anode surface irregularities 15 A.5 Cracks in cast anodic material 15 A.5.1 General . 15 A.5.2 Stand-off

13、and flush mounting anodes 16 A.5.3 Bracelet anodes 16 A.6 Internal defects and destructive testing . 16 Annex B (informative) Composition and performance properties for galvanic anodes . 18 B.1 Aluminium alloys 18 B.1.1 Anode material 18 B.1.2 Electrochemical properties 19 B.2 Magnesium alloy . 20 B

14、.2.1 Anode material 20 B.2.2 Electrochemical properties 21 B.3 Zinc alloy . 22 B.3.1 Anode material 22 B.3.2 Electrochemical properties 23 Annex C (informative) Description of various electrochemical tests . 24 C.1 Free running test. 24 C.2 Galvanostatic test . 24 C.3 Potentiostatic test . 24 C.4 Qu

15、ality control testing 25 Bibliography . 26 BS EN 12496:2013EN 12496:2013 (E) 3 Foreword This document (EN 12496:2013) 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 sta

16、ndard, either by publication of an identical text or by endorsement, at the latest by December 2013, and conflicting national standards shall be withdrawn at the latest by December 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig

17、hts. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,

18、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, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the Un

19、ited Kingdom. BS EN 12496:2013EN 12496:2013 (E) 4 Introduction The anticipated performance, including design life, of the cast galvanic anodes for use in sea water and saline mud is determined by their composition and the quality of their manufacture. This European Standard specifies the minimum req

20、uirements for the galvanic anodes quality levels and verification procedures. BS EN 12496:2013EN 12496:2013 (E) 5 1 Scope This European Standard specifies the minimum requirements and gives recommendations for the chemical composition, the electrochemical properties, the physical tolerances, and the

21、 test and inspection procedures for cast galvanic anodes of aluminium, magnesium and zinc based alloys for cathodic protection in sea water and saline mud. This European Standard is applicable to the majority of galvanic anodes used for seawater and saline mud applications, i.e. cast anodes of trape

22、zoidal, “D“, or circular cross section and bracelet type anodes. The general requirements and recommendations of this European Standard may also be applied to other anode shapes, e.g. half-spherical, button, etc., which are sometimes used for seawater applications. 2 Normative references The followi

23、ng documents, in whole or in part, are normatively referenced in this document and are indispensable 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 287-1, Qualific

24、ation test of welders Fusion welding Part 1: Steels EN 12473, General principles of cathodic protection in sea water EN ISO 8044, Corrosion of metals and alloys Basic terms and definitions (ISO 8044) EN ISO 8501-1, Preparation of steel substrates before application of paints and related products Vis

25、ual assessment of surface cleanliness Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings (ISO 8501-1) EN ISO 15607, Specification and qualification of welding procedures for metallic materials General rules (ISO

26、15607) EN ISO 15609-1, Specification and qualification of welding procedures for metallic materials Welding procedure specification Part 1: Arc welding (ISO 15609-1) ISO 10474:1991, Steel and steel products Inspection documents 3 Terms and definitions For the purposes of this document, the terms and

27、 definitions given in EN ISO 8044 and EN 12473 and the following apply. 3.1 acidity presence of an excess of hydrogen ions over hydroxyl ions (pH 300 mm and 610 mm; iii) -0 / + 1 % for pipeline diameters 610 mm. 3) The dimensional tolerances on the anode thickness shall be 3 mm. At least 10 % of the

28、 total number of anodes shall be checked to confirm compliance with these requirements. BS EN 12496:2013EN 12496:2013 (E) 15 Anodes shall be free from excessive bowing or twisting. This shall be verified on a completely assembled bracelet by fitting to a full-length former or by any other agreed met

29、hod. The external diameter should at no point exceed the summation of the tolerances given above. A.3 Steel core The cross section dimensions of the anode core shall comply with the appropriate specification. The tolerances for the position of the core for bracelet and flush mounting anodes shall be

30、 5 mm and for stand-off type anodes 10 % of anode material thickness covering the core. Anode core protrusions and any other specified critical dimensions shall be measured on samples of all anodes of each type and shall conform to specified requirements. A.4 Anode surface irregularities All anodes

31、shall be inspected visually to confirm compliance with the following requirements. Shrinkage depressions shall not exceed 10 % of the nominal thickness or depth of the anode, as measured from the uppermost corner to the bottom of the depression. Shrinkage depressions that expose the anode core are n

32、ot acceptable. In the topping up area the maximum shrinkage shall not be more than 10 mm depth measured from a straight edge across the topping up face and not more than 0,5 % of the gross anode volume. Any additional topping up materials or casting surface irregularities shall be fully bonded with

33、the bulk anode material. Cold shuts shall not exceed a depth of 10 mm and/or extend over a total length of more than 3 times the width of the anode (for stand-off and flush mounting anodes) or more than 150 mm (for bracelet anodes). All protrusions that are hazardous to personnel during handling sha

34、ll be removed. A.5 Cracks in cast anodic material A.5.1 General All anodes shall be inspected visually to confirm compliance with the following requirements. Even with good foundry practice, particular anode alloy composition (notably aluminium based) may suffer a degree of cracking. Cracks may occu

35、r while cooling during the casting of galvanic anodes because of the different coefficients of expansion of the anode and the core. These cracks are not detrimental, provided they do not converge in a manner to allow loss of anode material. A small amount of warpage is acceptable if it does not adve

36、rsely affect the anode installation. No treatment shall be applied to grind, peen, or in any other manner dress cracks before inspection and checks. Zinc and magnesium anodes shall be free from cracking visible without the aid of magnification. Small cracks in the anodes can be accepted in aluminium

37、 anodes provided the cracks would not cause any mechanical failure during installation, transportation or service of the anode. The combination of cracks and lack of bond to the core is detrimental. Visible cracks in the area where the anode material is not internally supported by the core shall not

38、 be accepted. Cracks penetrating to the steel core or penetrating through the anode are not permitted. BS EN 12496:2013EN 12496:2013 (E) 16 A.5.2 Stand-off and flush mounting anodes For transverse cracks within the section of an anode wholly supported by the core, the following acceptance criteria s

39、hall be applied: Cracks within the section of an anode supported by the core are not acceptable if the length is more than 100 mm and/or the width is more than 1 mm. Maximum 10 cracks per anode. Cracks which follow the longitudinal direction of long slender anodes shall not be accepted. A.5.3 Bracel

40、et anodes Cracks with a length of more than 100 mm or 50 % of the anode length (whichever is greater) and/or cracks with a width greater than 3 mm are not acceptable. Provided the above is satisfied, the following cracks are acceptable in transverse direction: A maximum number of two cracks is accep

41、table if they do not exceed the following criteria. Cracks with a length of less than 50 mm or less than 20 % of the anode diameter, whichever is less, and width less than 3 mm. Cracks with a length between 50 mm and 200 mm or between 20 % and 50 % of the anode diameter, whichever is less, and width

42、 less than 1 mm. Cracks with a length between 50 mm and 200 mm shall be limited to 2 per half bracelet or 4 per anode. Cracks which follow the longitudinal direction of the anodes shall not exceed 100 mm or 20 % of anode length, whichever is less, and/or 1 mm in width. Acceptance criteria for other

43、sizes of cracks would be dependent upon core and anode design. A.6 Internal defects and destructive testing The number and method of selection of anodes to be destructively tested (sectioned) within each anode type/size shall take into account anode design, and the total number of anodes. If the ano

44、de does not meet the requirements below, an additional anode shall be subjected to destructive testing. If this does not satisfy specified requirements, the whole anode lot should be rejected or other actions taken as agreed prior to fabrication. Slender and flush mounting anodes selected for examin

45、ation shall be sectioned transversely by single cuts at 25 %, 50 %, and 75 % of nominal length, or at other agreed locations for a particular anode design. Bracelet anodes selected for examination shall be sectioned transversely by single cuts at 25 % and 50 % of nominal length, or at other agreed l

46、ocations for a particular anode design. The cut faces, when examined visually without magnification, shall conform to the following criteria: Gas holes and porosities shall be limited to maximum 2 % of the total cut surface areas, and maximum 5 % of any individual cut surface area; no cavity shall e

47、xceed 1 cm for the cross-sectional area in the transverse section. Non-metallic inclusions shall be limited to maximum 1 % of the total cut surface areas and maximum 2 % of any individual cut surface area; no non-metallic inclusion shall exceed 1 cm. BS EN 12496:2013EN 12496:2013 (E) 17 Lack of bond

48、 (voids adjacent to the core) shall be limited to maximum 10 % of the total anode core perimeter and maximum 20 % of the perimeter for any individual cut. For non-tubular cores where prevention of voids may be particularly difficult, the limits may be otherwise agreed between the manufacturer and th

49、e purchaser. The core position within the anode should be confirmed by measurement on the cut faces. BS EN 12496:2013EN 12496:2013 (E) 18 Annex B (informative) Composition and performance properties for galvanic anodes B.1 Aluminium alloys B.1.1 Anode material Aluminium alloys for use in seawater and saline mud normally contain zinc together with small amounts of indium as an activator; however, there are a wide range of alloy compositions available. Some alloys are non-proprietary; some are proprietary and are covered by na