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1、BRITISH STANDARD BS EN 14505:2005 Cathodic protection of complex structures The European Standard EN 14505:2005 has the status of a British Standard ICS 77.060 ? BS EN 14505:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 19 May 2005 BSI
2、 19 May 2005 ISBN 0 580 46033 9 National foreword This British Standard is the official English language version of EN 14505:2005. Reference should also be made to BS 7361, Code of practice for land and marine applications, which will eventually be withdrawn when all the CEN standards relating to ca
3、thodic 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 represented on this committee can be obtained on request to its secretary. Cr
4、oss-references The 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”, or by using the “Search” facility of the BSI Electronic Catalogue or o
5、f 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 immunity from legal obligations. aid enquirers to understand the text;
6、present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover,
7、 an inside front cover, the EN title page, pages 2 to 24, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments 标准分享网 w w w .b z f x w .c o m 免费下载 EUROPEAN STAN
8、DARD NORME EUROPENNE EUROPISCHE NORM EN 14505 April 2005 ICS 77.060 English version Cathodic protection of complex structures Protection cathodique des structures complexesKathodischer Korrosionsschutz komplexer Anlagen This European Standard was approved by CEN on 15 March 2005. CEN members are bou
9、nd to comply with the CEN/CENELEC 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 such national standards may be obtained on application to the C
10、entral Secretariat 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 and notified to the Central Secretariat has the same status
11、as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia,
12、Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2005 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN nation
13、al Members. Ref. No. EN 14505:2005: E EN 14505:2005 (E) 2 Contents Page Foreword 3 1 Scope.4 2 Normative references .4 3 Terms and definitions.4 4 Criteria for the cathodic protection of complex structures .4 5 Prerequisites for the application of cathodic protection to a complex structure 5 6 Base
14、data for design.6 7 Design and prerequisites .7 8 Installation of cathodic protection systems10 9 Commissioning.11 10 Inspection and maintenance12 Annex A (informative) Principle scheme of a complex structure .14 Annex B (informative) Example of an industrial complex structure.15 Annex C (informativ
15、e) Reinforced concrete data in complex structures .16 Annex D (informative) Increasing soil potential.17 Annex E (informative) Groundbed data 21 Bibliography.24 标准分享网 w w w .b z f x w .c o m 免费下载 EN 14505:2005 (E) 3 Foreword This European Standard (EN 14505:2005) has been prepared by Technical Commi
16、ttee 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 October 2005, and conflicting national standards shall be withdrawn
17、at the latest by October 2005. It may be difficult to obtain complete cathodic protection of certain structures when following the general guidelines in EN 12954. This may be due to an electrical connection to one or more metal structures (electrodes) situated in the same electrolyte as the structur
18、e, which is to be protected. In particular, the structure may be earthed in order to mitigate electrical hazards or the connection to the other structures may be dictated by construction or operational requirements. An electrical connection to a foreign structure can result in a significantly increa
19、sed cathodic protection current demand, since the current flows not only to the structure to be protected but also to the foreign structure. This unwanted increased current demand is enhanced when the foreign structure consists of a metal, which is more noble (having a more positive resting potentia
20、l) than the metal in the structure to be protected. Connection to a copper earthing electrode or to the steel reinforcement in a concrete structure are examples of the latter. These difficulties can mean that a significantly increased cathodic protection current is required because of structures ele
21、ctrically connected to the structure to be protected, resulting in inadequate cathodic protection, current distribution and shielding effects. For this reason, the term “complex structure” has been used. It does not refer to the complexity of the structure or to the complexity of the cathodic protec
22、tion system. In such conditions the prerequisites, the criteria and the methods described in the present document expand those given in EN 12954. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European St
23、andard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14505:2005 (E) 4
24、1 Scope This European Standard applies to the cathodic protection of complex structures. It is applicable to structures, which are to be cathodically protected, but cannot be electrically isolated, whether for technical or safety reasons, from foreign metallic structures situated in the same electro
25、lyte as the structure to be protected. Such a structure is referred to as a “complex structure”. This European Standard is not applicable to structures that can be protected in accordance with EN 12954. When contacts with foreign structures or defective isolation from foreign structures exist, but c
26、an be corrected, EN 12954 is applicable instead of this document. As an example pipeline network distribution systems are not considered to be complex structures It is assumed in this document that the design, installation, commissioning, inspection and maintenance are entrusted to adequately traine
27、d, experienced, competent and reliable personnel in order to achieve effective and efficient cathodic protection. Annexes A and B show the principle scheme of a complex structure with examples. 2 Normative references The following referenced documents are indispensable for the application of this do
28、cument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12954:2001, Cathodic protection of buried or immersed metallic structures General principles and application for pipelines. EN 50
29、162, Protection against corrosion by stray current from direct current systems. 3 Terms and definitions For the purposes of this European Standard, the terms and definitions given in EN 12954:2001 and the following apply. NOTE For other definitions related to corrosion, refer to EN ISO 8044:1999. 3.
30、1 complex structure structure composed of the structure to be protected and of one or more foreign electrodes, which, for safety or technical reasons, cannot be electrically separated from it 3.2 foreign electrode electrode (anode or cathode), in contact with the structure under consideration NOTE a
31、 foreign anode is a foreign electrode, which has a more negative potential than the structure, a foreign cathode is a foreign electrode, which has a more positive potential than the structure. 4 Criteria for the cathodic protection of complex structures For complex structures, the cathodic protectio
32、n criteria defined in EN 12954 should be used where possible. Indeed, the characteristics of complex structures and the special influential factors (see Clause 5) which can occur means that it is not always possible on every part of the complex structure to determine by measurement whether these cri
33、teria of cathodic protection are met. In this case alternative methods of verification may be selected to 标准分享网 w w w .b z f x w .c o m 免费下载 EN 14505:2005 (E) 5 ensure an adequate reduction of the corrosion rate. Particular attention should be paid to the selection of these alternative methods, and
34、these will depend upon the structure and the soil characteristics. The following three alternative methods may be used as criteria. They are based upon practical experience and are widely used. All structure to electrolyte potential measurements are stated with respect to a copper/saturated copper s
35、ulphate reference electrode. a) Potential measurement method An on potential Eon equal to or more negative than 1,2 V, if the measuring point is outside the area of influence of the large foreign cathode (e.g. reinforced concrete or copper earthing system) and if the soil resistivity is sufficiently
36、 low (less than about 100 m) with the exception that an on potential Eon more negative than 0,8 V could be acceptable at entries to, and in the vicinity (within 0,5 m) of large foreign cathodes (demonstrating that the effect of a galvanic cell with the large foreign cathode is mitigated). b) Current
37、 method The purpose of this method is to demonstrate that current is able to enter the structure at critical locations either: 1) directly (i.e. when the protection current is switched on, a negative shift from the free corrosion potential En by at least 0,3 V indicating that probably sufficient cur
38、rent is entering the structure); or 2) by means of either current density or potential shift measurements at test probes or coupons. NOTE A critical location is location where the probability to have an anodic current leaving the structure to be protected is high (e.g., vicinity of foreign cathode d
39、ue to galvanic couple, heterogeneity of the soil or shielding effect). c) Depolarisation measurement method A positive shift (depolarisation) on test probes or coupons of at least 0,1 V measured from immediately after disconnection (Eoff) to 1 h after disconnection from the structure indicates that
40、the structure is polarized. These test probes/coupons are disconnected only for measurements. One of these alternative criteria shall be used as a minimum. More than one of these alternative criteria may be required to verify adequate protection over the entire complex structure. Other criteria can
41、be used if they can be shown to reduce the external corrosion rate to an acceptable level. 5 Prerequisites for the application of cathodic protection to a complex structure 5.1 General The cathodic protection system depends on the size and shape of the complex structure, the type of coating, the agg
42、ressive action of the soil and its resistivity, d.c. and a.c interference, national regulations, and also on the technical and economic criteria. To achieve cathodic protection, the conditions given in 5.2 to 5.4 should be satisfied. 5.2 Electrical continuity In the case of a complex structure, all
43、metallic parts of the structure to be protected should be electrically continuous. Foreign electrodes should also be electrically continuous. 5.3 Electrical isolation For the cathodic protection system to be properly designed, the form and extent of the structure should be clearly defined in terms o
44、f its location and electrical isolation from foreign structures. EN 14505:2005 (E) 6 If the electrical isolation is ineffective and cannot be restored to its original condition, then the extent of the complex structure should be revised to take this into account. 5.4 External coating Protective coat
45、ings are not always applied to components in a complex structure (e.g. earthing systems). Uncoated components significantly increase protection current demands and thus add to the difficulties of the application of cathodic protection and increase the risk of interference. Wherever possible, buried
46、metallic components should be suitably coated. 6 Base data for design 6.1 General In addition to following the principles laid out in EN 12954, other specific data, as given in 6.2 to 6.8, should be used when dealing with complex structures. 6.2 Structure details The surface area of all buried or im
47、mersed components of a complex structure should be ascertained as well as the status of the coating (if any). 6.3 Coatings Types of the different coating applied on all components of a complex structure should be taken into account. 6.4 Environment Depending on the composition of some parts of a com
48、plex structure, particular environmental conditions should be considered, for example, the chloride content of the electrolyte when an integral part of a complex structure is made of stainless steel, or reinforcement steel in concrete (rebar). 6.5 Shielding All relevant information should be obtaine
49、d on any feature that might act as a shield to the cathodic protection current or its distribution, e.g. reinforced concrete foundations, pits, ducts, any geotextiles, and pipe sleeves. The location of the anodes with respect to the shields should be selected such that shielding is minimized. A shield can be either conductive or non-conductive. A conductive shield can be either a part of the complex structure itself or a foreign structure such as steel sleeves for pipes, large conducting structures (s