SIST EN 15280:2013
(Main)Evaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically protected pipelines
Evaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically protected pipelines
This European Standard is applicable to buried cathodically protected metallic structures that are influenced by a.c. traction systems and/or a.c. power lines. In this document, a buried pipeline (or structure) is a buried or immersed pipeline (or structure), as defined in EN 12954. In the presence of a.c. interference, the protection criteria given in EN 12954:2001, Table 1, are not sufficient to demonstrate that the steel is being protected against corrosion. This European Standard provides limits, measurement procedures, mitigation measures and information to deal with long term a.c. interference for a.c voltages at frequencies between 16,7 Hz and 60 Hz and the evaluation of a.c. corrosion likelihood. This European Standard deals with the possibility of a.c. corrosion of metallic pipelines due to a.c. interferences caused by inductive, conductive or capacitive coupling with a.c. power systems and the maximum tolerable limits of these interference effects. It takes into account the fact that this is a long-term effect, which occurs during normal operating conditions of the a.c. power system. This European Standard does not cover the safety issues associated with a.c. voltages on pipelines. These are covered in national standards and regulations (see EN 50443).
Beurteilung der Korrosionswahrscheinlichkeit durch Wechselstrom an erdverlegten Rohrleitungen - Anwendung für kathodisch geschützte Rohrleitungen
Diese Europäische Norm gilt für erdverlegte kathodisch geschützte metallische Anlagen, die durch Wechselstrom-Fahrleitungssysteme und/oder Wechselstromleitungen beeinflusst werden.
Eine erdverlegte Rohrleitung (oder Anlage) im Sinne dieses Dokuments ist eine im Boden oder Wasser verlegte Rohrleitung (oder Anlage), wie in EN 12954 festgelegt.
Bei Anwesenheit einer Wechselstrombeeinflussung sind die in EN 12954:2001, Tabelle 1, gegebenen Kriterien nicht ausreichend, um nachzuweisen, dass der Stahl gegen Korrosion geschützt ist.
Diese Europäische Norm liefert Grenzwerte, Messverfahren, Einrichtungen zur Reduzierung der Beeinflussung und Informationen zum Umgang mit Langzeitwechselstrombeeinflussung für Wechsel¬spannungen bei Frequenzen zwischen 16,7 Hz und 60 Hz und zur Beurteilung der Korrosions¬wahrscheinlichkeit durch Wechselstrom.
Diese Europäische Norm behandelt die mögliche Wechselstromkorrosion von metallischen Rohrleitungen aufgrund der Wechselstrombeeinflussung der durch Wechselstromsysteme verursachten Streuströme durch induktive, leitende oder kapazitive Kopplung mit Wechselstromnetzen und die maximal zulässigen Grenzwerten dieser beeinflussenden Effekte. Sie berücksichtigt die Tatsache, dass das ein Langzeiteffekt ist, der nur bei normalen Betriebsbedingungen des Wechselstromsystems auftritt.
Diese Europäische Norm behandelt nicht die mit Wechselspannungen an Rohrleitungen verbundenen Sicherheitsaspekte. Diese werden in nationalen Normen und Rechtsvorschriften behandelt (siehe EN 50443).
Évaluation du risque de corrosion occasionnée par les courants alternatifs des canalisations enterrées protégées cathodiquement
La présente Norme européenne est applicable aux structures métalliques enterrées qui sont protégées cathodiquement et influencées par des systèmes de traction à courant alternatif et/ou des lignes électriques haute tension en courant alternatif.
Dans le présent document, une canalisation (ou une structure) enterrée est une canalisation (ou une structure) enterrée ou immergée, telle que définie dans l’EN 12954.
En présence d’une influence due aux courants alternatifs, les critères de protection spécifiés dans le Tableau 1 de l’EN 12954:2001 sont insuffisants pour démontrer que l’acier est protégé contre la corrosion.
La présente Norme européenne spécifie les limites, les modes opératoires de mesurage, les mesures d’atténuation et les informations relatives à l’influence en régime de fonctionnement permanent des courants alternatifs pour les tensions de courant alternatif à des fréquences comprises entre 16,7 Hz et 60 Hz et à l’évaluation du risque de corrosion engendré par ces courants.
La présente Norme européenne traite de la possible corrosion des canalisations métalliques due à l’influence par les courants alternatifs provoquée par le couplage inductif, conductif ou capacitif avec des systèmes à courant alternatif, ainsi que des limites maximales admissibles des effets de cette influence. Elle prend en compte le fait qu’il s’agit d’un effet à long terme qui se produit uniquement lors de conditions normales d’exploitation du système électrique à courant alternatif.
La présente Norme européenne ne traite pas des problèmes de sécurité liés aux tensions de courant alternatif sur les canalisations. Ceux-ci sont traités dans les normes et réglementations nationales (voir EN 50443).
Ovrednotenje verjetnosti nastanka korozije vkopanih cevovodov - Uporaba pri katodno zaščitenih cevovodih
Ta evropski standard se uporablja za vkopane katodno zaščitene kovinske konstrukcije pod vplivom izmeničnih vlečnih sistemov in/ali izmeničnih napajalnih vodov. Vkopani cevovod (ali konstrukcija) v tem dokumentu je vkopani ali potopljeni cevovod (ali konstrukcija), kot je določeno v standardu EN 12954. Če je prisotna izmenična motnja, kriteriji zaščite, ki so podani v standardu EN 12954:2001 (tabela 1), ne zadostujejo kot dokaz, da je jeklo zaščiteno pred korozijo. Ta evropski standard določa omejitve, merilne postopke, ukrepe za ublažitev in informacije za obravnavo dolgoročne izmenične motnje za izmenične napetosti s frekvenco med 16,7 Hz in 60 Hz ter ovrednotenje verjetnosti nastanka korozije. Ta evropski standard obravnava verjetnost nastanka korozije kovinskih cevovodov zaradi izmeničnih motenj, ki jih povzroča induktivni, konduktivni ali kapacitivni sklop s sistemom za izmenično napajanje, in največje sprejemljive omejitve vplivov teh motenj. Upošteva, da gre za dolgoročni vpliv, do katerega pride med običajnimi delovnimi pogoji sistema za izmenično napajanje. Ta evropski standard ne zajema varnostnih vprašanj v zvezi z izmenično napetostjo v cevovodih. Varnostna vprašanja obravnavajo nacionalni standardi in predpisi (glej EN 50443).
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Beurteilung der Korrosionswahrscheinlichkeit durch Wechselstrom an erdverlegten Rohrleitungen - Anwendung für kathodisch geschützte RohrleitungenÉvaluation du risque de corrosion occasionnée par les courants alternatifs des canalisations enterrées protégées cathodiquementEvaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically protected pipelines77.060Korozija kovinCorrosion of metals23.040.01Deli cevovodov in cevovodi na splošnoPipeline components and pipelines in generalICS:Ta slovenski standard je istoveten z:EN 15280:2013SIST EN 15280:2013en,fr,de01-oktober-2013SIST EN 15280:2013SLOVENSKI
STANDARDSIST-TS CEN/TS 15280:20061DGRPHãþD
SIST EN 15280:2013
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15280
August 2013 ICS 23.040.99; 77.060 Supersedes CEN/TS 15280:2006English Version
Evaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically protected pipelines
Évaluation du risque de corrosion occasionnée par les courants alternatifs des canalisations enterrées protégées cathodiquement
Beurteilung der Korrosionswahrscheinlichkeit durch Wechselstrom an erdverlegten Rohrleitungen anwendbar für kathodisch geschützte Rohrleitungen This European Standard was approved by CEN on 5 July 2013.
CEN members are bound 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 CEN-CENELEC 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 and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members 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, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15280:2013: ESIST EN 15280:2013
EN 15280:2013 (E) 2 Contents Page Foreword . 4 1 Scope . 5 2 Normative references . 5 3 Terms and definitions . 5 4 Cathodic protection personnel competence . 8 5 Assessment of the a.c. influence . 9 5.1 General . 9 5.2 Assessment of the level of interference . 9 6 Evaluation of the likelihood of a.c. corrosion . 10 6.1 Prerequisite . 10 6.1.1 General . 10 6.1.2 A.c. voltage on the structure . 10 6.2 A.c. and d.c. current density . 11 6.2.1 General . 11 6.2.2 A.c. current density . 11 6.2.3 High cathodic d.c. current density . 11 6.2.4 Low cathodic d.c. current density . 11 6.2.5 Current ratio "Ia.c./Id.c. " . 12 6.2.6 Soil resistivity . 12 6.3 Corrosion rate . 12 6.4 Pipeline coatings . 12 6.5 Evaluation of the metal loss . 12 7 Acceptable interference levels . 12 8 Measurement techniques . 13 8.1 Measurements . 13 8.1.1 General . 13 8.1.2 Selection of test sites . 13 8.1.3 Selection of measurement parameter . 14 8.1.4 Sampling rate for the recording of interference levels . 14 8.1.5 Accuracy of measuring equipment . 14 8.1.6 Installation of coupons or probes to calculate current densities . 14 8.2 D.c. potential measurements . 14 8.3 A.c. voltage measurements . 15 8.4 Measurements on coupons and probes . 15 8.4.1 Installation of coupons or probes . 15 8.4.2 Current measurements . 15 8.4.3 Corrosion rate measurements . 16 8.5 Pipeline metal loss techniques . 17 9 Mitigation measures . 17 9.1 General . 17 9.2 Construction measures . 17 9.2.1 Modification of bedding material . 17 9.2.2 Installation of isolating joints . 17 9.2.3 Installation of mitigation wires . 17 9.2.4 Optimisation of pipeline and/or powerline route . 18 9.2.5 Power line or pipeline construction . 18 9.3 Operation measures . 18 9.3.1 Earthing . 18 9.3.2 Adjustment of cathodic protection level . 19 SIST EN 15280:2013
EN 15280:2013 (E) 3 9.3.3 Repair of coating defects . 19 10 Commissioning . 19 10.1 Commissioning . 19 10.2 Preliminary checking . 20 10.2.1 General . 20 10.2.2 Start up . 20 10.2.3 Verification of effectiveness . 21 10.2.4 Installation and commissioning documents . 21 11 Monitoring and maintenance . 21 Annex A (informative)
Simplified description of the a.c. corrosion phenomenon . 23 A.1 Cathodically protected pipeline . 23 A.2 Cathodically protected pipeline with a.c. voltage . 23 A.2.1 Description of the phenomena . 23 A.2.2 Reduction of the a.c. corrosion rate . 24 Annex B (informative)
Coupons and probes . 25 B.1 Use and sizes of coupons and probes . 25 B.1.1 Use of coupons or probes . 25 B.1.2 Sizes of coupons or probes . 25 B.2 Installation of buried coupons and probes. 25 B.2.1 General . 25 B.2.2 Before installing the coupon or probe . 25 B.2.3 Installation of the buried coupon or probe . 26 B.3 ER probes principles. 27 B.3.1 Assessment of the corrosion using the electrical resistance (ER) probe technique . 27 B.3.2 ER probe application in the field . 29 B.4 Perforation probes . 29 Annex C (informative)
Coulometric oxidation . 31 Annex D (informative)
Influence of soil characteristics on the a.c. corrosion process . 32 D.1 Influence of electrical parameters . 32 D.2 Influence of the electrochemical process . 32 D.3 Influence of alkaline ions and cations . 32 Annex E (informative)
Other criteria that have been used in the presence of a.c. influence . 33 E.1 General . 33 E.2 ON-potential approach . 33 E.2.1 General . 33 E.2.2 More negative (Eon) cathodic protection level . 33 E.2.3 Less negative (Eon) cathodic protection level . 33 E.2.4 Criteria . 34 Annex F (informative)
Parameters to take into account to choose a d.c. decoupling device . 36 F.1 General aspects to be taken into account . 36 F.2 Electrical parameters . 36 Annex G (informative)
Method to determine the reference electrode location to remote earth . 37 Bibliography . 38
SIST EN 15280:2013
EN 15280:2013 (E) 4 Foreword This document (EN 15280:2013) 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 standard, either by publication of an identical text or by endorsement, at the latest by February 2014 and conflicting national standards shall be withdrawn at the latest by February 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 supersedes CEN/TS 15280:2006. With this document, CEN/TS 15280:2006 is converted into a European Standard. The main modification concerns the criteria assumed in the presence of a.c. interference on a pipeline. While CEN/TS 15280:2006 represented a collection of various experiences in the field of a.c. corrosion, this European Standard has incorporated these criteria and thresholds together with experience gained from the most recent data. Various European countries have a different approach to the prevention of a.c. corrosion depending primarily on the d.c. interference situation. These different approaches are taken into account in two different ways: either in the presence of “low” ON-potentials (less negative than -1,2 V CSE), which allows a certain level of a.c. voltage (up to 15 V), or in the presence of “high” ON-potentials (more negative than -1,2 V CSE ; with d.c. stray current interference on the pipeline for instance) which requires the reduction of the a.c. voltage towards the lowest possible levels. This European Standard gives also some parameters to consider when evaluating the a.c. corrosion likelihood, as well as detailed measurement techniques, mitigation measures and measurements to carry out for commissioning of any a.c corrosion mitigation system. Note that Annex E proposes other parameters and thresholds that require further validation based on practical experiences. 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, 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 United Kingdom. SIST EN 15280:2013
EN 15280:2013 (E) 5 1 Scope This European Standard is applicable to buried cathodically protected metallic structures that are influenced by a.c. traction systems and/or a.c. power lines. In this document, a buried pipeline (or structure) is a buried or immersed pipeline (or structure), as defined in EN 12954. In the presence of a.c. interference, the protection criteria given in EN 12954:2001, Table 1, are not sufficient to demonstrate that the steel is being protected against corrosion. This European Standard provides limits, measurement procedures, mitigation measures and information to deal with long term a.c. interference for a.c voltages at frequencies between 16,7 Hz and 60 Hz and the evaluation of a.c. corrosion likelihood. This European Standard deals with the possibility of a.c. corrosion of metallic pipelines due to a.c. interferences caused by inductive, conductive or capacitive coupling with a.c. power systems and the maximum tolerable limits of these interference effects. It takes into account the fact that this is a long-term effect, which occurs during normal operating conditions of the a.c. power system. This European Standard does not cover the safety issues associated with a.c. voltages on pipelines. These are covered in national standards and regulations (see EN 50443). 2 Normative references The following 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 12954:2001, Cathodic protection of buried or immersed metallic structures General principles and application for pipelines EN 13509:2003, Cathodic protection measurement techniques EN 50443, Effects of electromagnetic interference on pipelines caused by high voltage a.c. electric traction systems and/or high voltage a.c. power supply systems EN 61010-1, Safety requirements for electrical equipment for measurement, control and laboratory use Part 1: General requirements (IEC 61010-1) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 a.c. electric traction system a.c. railway electrical distribution network used to provide energy for rolling stock Note 1 to entry: The system can comprise: contact line systems; return circuit of electric railway systems; running rails of non-electric railway systems, which are in the vicinity of, or conductively connected to, the running rails of an electric railway system. SIST EN 15280:2013
EN 15280:2013 (E) 6 3.2 a.c. power supply system a.c. electrical system devoted to electrical energy transmission and including overhead lines, cables, substations and all apparatus associated with them 3.3 a.c. power system a.c. electric traction system or a.c. power supply system Note 1 to entry: Where it is necessary to differentiate, each interfering system is clearly indicated with its proper term. 3.4 copper/copper sulphate reference electrode (CSE) reference electrode consisting of copper in a saturated solution of copper sulphate 3.5 a.c. voltage voltage measured to earth between a metallic structure and a reference electrode. 3.6 interfering system general expression encompassing an interfering high voltage a.c. electric traction system and/or high voltage a.c. power supply system 3.7 interfered system system on which the interference effects appear Note 1 to entry: In this European Standard, it is the pipeline system. 3.8 pipeline system system of pipe network with all associated equipment and stations Note 1 to entry: In this European Standard, pipeline system refers only to metallic pipeline system. Note 2 to entry: The associated equipment is the equipment electrically connected to the pipeline. 3.9 earth conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to zero [SOURCE: IEC 60050 826-04-01] 3.10 operating condition fault free operation of any system Note 1 to entry: Transients are not to be considered as an operating condition. 3.11 fault condition non intended condition caused by short-circuit to earth, the fault duration being the normal clearing time of the protection devices and switches Note 1 to entry: The short circuit is an unintentional connection of an energised conductor to earth or to any metallic part in contact with earth. SIST EN 15280:2013
EN 15280:2013 (E) 7 3.12 conductive coupling coupling which occurs when a proportion of the current belonging to the interfering system returns to the system earth via the interfered system or when the voltage to the reference earth of the ground in the vicinity of the influenced object rises because of a fault in the interfering system, and the results of which are conductive voltages and currents 3.13 inductive coupling phenomenon whereby the magnetic field produced by a current carrying circuit influences another circuit; the coupling being quantified by the mutual impedance of the two circuits, and the results of which are induced voltages and hence currents that depend for example on the distances, length, inducing current, circuit arrangement and frequency 3.14 capacitive coupling phenomenon whereby the electric field produced by an energised conductor influences another conductor, the coupling being quantified by the capacitance between the conductors and the capacitances between each conductor and earth, and the results of which are interference voltages into conductive parts or conductors insulated from earth, these voltages depend for example on the voltage of the influencing system, distances and circuit arrangement 3.15 interference phenomenon resulting from conductive, capacitive, inductive coupling between systems, and which can cause malfunction, dangerous voltages, damage, etc. 3.16 disturbance malfunction of an equipment losing its capability of working properly for the duration of the interference Note 1 to entry: When the interference disappears, the interfered system starts again working properly without any external intervention. 3.17 damage permanent reduction in the quality of service, which can be suffered by the interfered system EXAMPLE coating perforation, pipe pitting, pipe perforation, permanent malfunction of the equipment connected to the pipes, etc. Note 1 to entry: A reduction in the quality of service could also be the complete cancellation of service. 3.18 danger state of the influenced system which is able to produce a threat to human life 3.19 interference situation maximum distance between the pipeline system and a.c. power system for which an interference is considered 3.20 interference voltage voltage caused on the interfered system by the conductive, inductive and capacitive coupling with the nearby interfering system between a given point and the earth or across an insulating joint SIST EN 15280:2013
EN 15280:2013 (E) 8 3.21 IR drop voltage, due to any current, developed in an electrolyte such as the soil, between the reference electrode and the metal of the structure, in accordance with Ohm's Law 3.22 IR free potential (EIR free) structure to electrolyte potential measured without the voltage error caused by the IR drop due to the protection current or any other current 3.23 OFF-potential (EOFF) structure to electrolyte potential measured immediately after synchronous interruption of all sources of applied cathodic protection current 3.24 ON-potential (EON) structure to electrolyte potential measured with the cathodic protection current flowing 3.25 spread resistance ohmic resistance through a coating defect to earth or from the exposed metallic surface of a coupon to earth Note 1 to entry: This is the resistance which controls the d.c. or a.c. current through a coating defect or an exposed metallic surface of a coupon for a given d.c. or a.c. voltage. 3.26 coupon representative metal sample with known dimensions Note 1 to entry: A coupon may be electrically connected to the pipeline. Note 2 to entry: Examples of coupons are given in Annex B. 3.27 probes device incorporating a coupon that provides measurements of key parameters to assess the corrosion risk Note 1 to entry: Examples of probes are given in Annex B. 4 Cathodic protection personnel competence Personnel who undertake the design, supervision of installation, commissioning, supervision of operation, measurements, monitoring and supervision of maintenance of cathodic protection systems shall have the appropriate level of competence for the tasks undertaken. EN 15257 constitutes suitable methods of assessing competence of cathodic protection personnel, which may be utilised. Competence of cathodic protection personnel to the appropriate level for the tasks undertaken should be demonstrated by certification in accordance with qualification procedures such as EN 15257 or any other equivalent scheme. SIST EN 15280:2013
EN 15280:2013 (E) 9 5 Assessment of the a.c. influence 5.1 General This European Standard is applicable to all metallic pipelines and all high voltage a.c. traction systems and high voltage a.c. power supply systems and all major modifications that can significantly change the a.c. interference effect. The effects considered within EN 50443 are the following: a) danger to people who come in direct contact or contact through conductive parts with the metallic pipeline or the connected equipment; b) damage of the pipeline or to the connected equipment; c) disturbance of electrical/electronic equipment connected to the pipeline. Electrical/electronic systems installed on a pipeline network shall be chosen such that they will neither become dangerous, nor interfere with normal operating conditions, because of short term voltages and currents, which appear during short circuits on the a.c. power system. Long term a.c. interference on a buried pipeline can cause corrosion due to an exchange of a.c. current between the exposed metal of the pipeline and the surrounding electrolyte. This exchange of current depends on an a.c. voltage whose amplitude is related to various parameters such as: the configuration of a.c. power line phase conductors; the presence and the configuration of the earthing conductor; the distance between the a.c. power line / traction system and the pipeline; the current flowing in the a.c. power line / traction system phase conductors; the average coating resistance of the pipeline; the thickness of the coating; the soil resistivity; the presence of earthing systems; the voltage of the a.c. railway system or the a.c. power line system. 5.2 Assessment of the level of interference Calculations can be carried out according to EN 50443 by mathematical modelling to determine the earthing requirements necessary to maintain touch voltages within acceptable safe levels. Their results can also be used to determine voltages necessary to reduce the a.c. corrosion likelihood. During the design phase of new influencing systems (electricity power line
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SLOVENSKI STANDARD
oSIST prEN 15280:2012
01-marec-2012
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Evaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically
protected pipelines
Beurteilung der Korrosionswahrscheinlichkeit durch Wechselstrom an erdverlegten
Rohrleitungen - Anwendung für kathodisch geschützte Rohrleitungen
Évaluation du risque de corrosion occasionnée par les courants alternatifs des
canalisations enterrées protégées cathodiquement
Ta slovenski standard je istoveten z: prEN 15280
ICS:
23.040.99 Drugi sestavni deli za Other pipeline components
cevovode
77.060 Korozija kovin Corrosion of metals
oSIST prEN 15280:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 15280:2012
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oSIST prEN 15280:2012
EUROPEAN STANDARD
DRAFT
prEN 15280
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2011
ICS 23.040.99; 77.060 Will supersede CEN/TS 15280:2006
English Version
Evaluation of a.c. corrosion likelihood of buried pipelines
applicable to cathodically protected pipelines
Beurteilung der Korrosionswahrscheinlichkeit durch
Wechselstrom an erdverlegten Rohrleitungen - Anwendung
für kathodisch geschützte Rohrleitungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 219.
If this draft becomes a European Standard, CEN members are bound 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.
This draft European Standard was established by CEN 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 members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15280:2011: E
worldwide for CEN national Members.
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oSIST prEN 15280:2012
prEN 15280:2011 (E)
Contents Page
Foreword .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .7
4 Cathodic protection personnel competence . 10
5 Parameters to be considered in case of a.c. interference . 10
5.1 Parameters . 10
5.1.1 General . 10
5.1.2 A.C. interferences evaluation . 11
5.1.3 New pipelines . 11
5.1.4 Existing pipelines . 11
5.2 New interference cases (pipelines/power lines/traction systems in the design phase) –
Condition for calculation . 11
6 Evaluation of the a.c. corrosion likelihood . 12
6.1 Prerequisite . 12
6.1.1 General . 12
6.1.2 A.C. voltage on the structure . 12
6.2 A.C. and d.c. current density . 13
6.2.1 General . 13
6.2.2 A.C. current density . 13
6.2.3 High d.c. current density . 13
6.2.4 Low d.c. current density . 13
6.2.5 Current ratio "Ia.c./Id.c. " . 14
6.2.6 Corrosion rate . 14
6.3 Pipeline coatings . 14
6.4 Evaluation of the metal loss . 14
7 Acceptable interference levels . 14
8 Measurement techniques . 15
8.1 Measurements . 15
8.1.1 General . 15
8.1.2 Selection of test sites . 15
8.1.3 Selection of measurements . 15
8.1.4 Sampling rate . 15
8.1.5 Accuracy of measuring equipment . 15
8.1.6 Installation of coupons or probes . 16
8.2 D.C. potential measurements . 16
8.3 A.C. voltage measurements . 16
8.4 Measurements on coupons and probes . 16
8.4.1 Installation of coupons or probes . 16
8.4.2 Potential measurements . 18
8.4.3 Current measurements . 18
8.4.4 Corrosion rate measurements . 18
8.5 Pipeline metal loss techniques . 19
9 Mitigation measures . 19
9.1 General . 19
9.2 Construction measures . 19
9.2.1 Modification of bedding material . 19
2
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oSIST prEN 15280:2012
prEN 15280:2011 (E)
9.2.2 Installation of isolating joints . 19
9.2.3 Installation of mitigation wires . 20
9.2.4 Optimisation of pipeline and/or powerline route . 20
9.2.5 Power line or pipeline construction . 20
9.3 Operation measures . 20
9.3.1 Direct earthing . 20
9.3.2 Indirect earthing of the pipeline via d.c.-decoupling devices . 21
9.3.3 A.C. compensation method . 21
9.3.4 Repair of coating defects. 21
10 Commissioning . 21
10.1 Commissioning . 21
10.2 Preliminary checking . 22
10.2.1 General . 22
10.2.2 Start up . 22
10.2.3 Verification of effectiveness . 23
10.2.4 Installation and commissioning documents . 23
11 Monitoring and maintenance . 23
Annex A (informative) Simplified description of the a.c. corrosion phenomenon . 25
A.1 Cathodically protected pipeline . 25
A.2 Cathodically protected pipeline with a.c. voltage . 25
A.2.1 Description of the phenomena . 25
A.2.2 Reduction of the a.c. corrosion rate . 26
Annex B (informative) ER probe principles . 27
B.1 Assessment of the corrosion using the electrical resistance (ER) probe technique. 27
B.1.1 General theory . 27
B.1.2 Mathematical development to determine V . 28
corr
B.1.3 V assessment . 28
corr
B.1.4 Specific recommendation for ER probe . 29
B.2 ER probe application in the field . 29
Annex C (informative) Coupons and probes . 30
C.1 Use of coupons or probes . 30
C.2 Sizes of coupons or probes . 30
Annex D (informative) Coulometric oxidation . 31
Annex E (informative) Perforation probe . 32
Annex F (informative) Influence of soil characteristics on a.c. corrosion process . 33
F.1 Influence of electrical parameters . 33
F.2 Influence of the electrochemical process . 33
F.3 Influence of alkaline ions and cations . 33
Annex G (informative) Other criteria that have been used in presence of a.c. influence . 34
G.1 General . 34
G.2 On potential approach . 34
G.2.1 General . 34
G.2.2 High electronegative (Eon) cathodic protection level . 34
G.2.3 Low electronegative (Eon) cathodic protection level . 34
G.2.4 Criteria . 35
G.3 IR-free potential approach . 35
G.3.1 General . 35
G.3.2 High electronegative cathodic protection level. 35
G.3.3 Low electronegative cathodic protection level . 36
G.3.4 Assumption . 36
G.3.5 Acceptance criteria . 36
Annex H (informative) Parameters to take into account to choose an a.c. mitigation device . 37
H.1 General aspects to be taken into account . 37
H.2 Electrical parameters . 37
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Annex I (informative) Method to determine the reference electrode location to remote earth . 38
Annex J (informative) Installation of coupons or probes. 39
J.1 General . 39
J.2 Before installing the coupon or probe. 39
J.3 Installation of the coupon or probe . 40
Bibliography . 41
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Foreword
This document (prEN 15280:2011) has been prepared by Technical Committee CEN/TC 219 “Cathodic
protection”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede CEN/TS 15280:2006.
With this document, CEN/TS 15280:2006 is converted into an European Standard.
The main modification concerns the criteria assumed in presence of a.c. interference on a pipeline. While
CEN/TS 15280:2006 represented a collection of various experiences in the field of a.c. corrosion, this draft
European Standard has incorporated these criteria and thresholds together with most recent data. Various
European countries have a very different approach to the prevention of a.c. corrosion depending primarily on
the d.c. interference situation. These different approaches are taken into account in two different ways:
either in presence of “low” d.c. potential, which allows a certain level of a.c. voltage (up to 15 V),
or in presence of “high” d.c. potential (with d.c. stray currents interference on the pipeline for instance)
which requires to reduce the a.c. voltage towards the lowest possible levels.
This draft European Standard gives also some parameters to consider to evaluate the a.c. corrosion
likelihood, as well as detailed measurement techniques, detailed mitigation measures and detailed measure to
carry out for the commissioning. Note that an annex proposes other criteria that require further validation
based on practical experiences.
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1 Scope
This European Standard is applicable to buried cathodically protected metallic structures that are influenced
by a.c. traction systems and/or a.c. power lines.
In this document, a buried pipeline (or structure) is a buried or immersed pipeline (or structure), as defined in
EN 12954.
In the presence of a.c. interference, the criteria given in EN 12954, Table 1, are not sufficient to demonstrate
that the steel is being protected against corrosion.
This European Standard provides limits, measurements procedures, mitigation measures and information to
deal with long term a.c. interference and the evaluation of a.c. corrosion likelihood.
This standard deals with possible a.c. corrosion of metallic pipelines due to a.c. interferences caused by
inductive, conductive or capacitive coupling with a.c. power systems and with the maximum tolerable limits of
these interference effects. It takes into account the fact that this is a long-term effect which occurs only during
normal operating conditions.
Short term a.c. interferences appearing during fault conditions in the a.c. power system will not cause a.c.
corrosion.
This standard does not deal with the safety issues associated with a.c. voltages. These are covered in
national standards and regulations (see FprEN 50443).
2 Normative references
The following referenced documents are indispensable for the application of this document. 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 13509:2003, Cathodic protection measurement techniques
EN 15257, Cathodic protection — Competence levels and certification of cathodic protection personnel
FprEN 50443, Effects of electromagnetic interference on pipelines caused by high voltage a.c. electric traction
systems and/or high voltage a.c. power supply systems
ISO 8407:2009, Corrosion of metals and alloys — Removal of corrosion products from corrosion test
specimens
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3 Terms and definitions
For the purposes of this document, the terms and definitions given in the IEC (International Electrotechnical
Commission) and the following apply.
3.1
a.c. electric traction system
a.c. railway electrical distribution network used to provide energy for rolling stock
NOTE The system may comprise:
- contact line systems;
- return circuit of electric railway systems;
- running rails of non-electric railway systems, which are in the vicinity of, and conductively connected, to the running
rails of an electric railway system.
3.2
a.c. power supply system
a.c. electrical system devoted to electrical energy transmission and including overhead lines, cables,
substations and all apparatus associated with them
NOTE This includes the HV transmission lines with 16,7 Hz.
3.3
a.c. power system
a.c. electric traction system or a.c. power supply system
NOTE Where it is necessary to differentiate, each interfering system is clearly indicated with its proper term.
3.4
interfering system
interfering high voltage a.c. railway system and/or high voltage a.c. power supply system
3.5
interfered system
system on which the interference effects appear
NOTE In this standard, it is the pipeline system.
3.6
pipeline system
system of metallic pipework with all associated equipment and stations up to and including the point of
delivery
NOTE 1 In this standard pipeline system refers only to metallic pipeline system.
NOTE 2 The associated equipment is the equipment electrically connected to the pipeline.
3.7
earth
conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to zero
[IEC 60050 826-04-01]
3.8
operating condition
fault free operation of any system
NOTE Transients are not to be considered as an operating condition.
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3.9
fault condition
unintentional condition caused by a short-circuit to earth
NOTE 1 The fault duration is the normal clearing time of the protection devices and switches.
NOTE 2 The short circuit is an unintentional connection of an energized conductor to earth or to any metallic part in
contact with earth
3.10
conductive coupling
situation occurring when a part of the current belonging to the interfering system returns to the system earth
via the interfered system or when the voltage to the reference earth of the ground in the vicinity of the
influenced object rises because of a fault in the interfering system
NOTE The results of conductive coupling are conductive voltages and currents.
3.11
inductive coupling
phenomenon whereby the magnetic field produced by a current carrying circuit influences another circuit; the
coupling being quantified by the mutual impedance of the two circuits
NOTE The results of inductive coupling are induced voltages and hence currents. These voltages and currents
depend, for example, on the distances, length, inducing current, circuit arrangement and frequency.
3.12
capacitive coupling
phenomenon whereby the electric field produced by an energized conductor influences another conductor; the
coupling being quantified by the capacitance between the conductors and the capacitances between each
conductor and earth
NOTE The results of capacitive coupling are interference voltages into conductive parts or conductors insulated from
earth. The interference voltages depend, for example, on the voltage of the influencing system, distances and circuit
arrangement
3.13
interference
phenomenon resulting from conductive, capacitive, inductive coupling between systems, and which can cause
malfunction, dangerous voltages, damage, etc.
3.14
disturbance
equipment malfunction due to interference, whereby the equipment loses its capability of working properly for
the duration of the interference but, when the interference disappears, starts working properly again without
any external intervention
3.15
damage
permanent reduction in the quality of service which can be suffered by the interfered system
NOTE 1 Examples of damage are: coating perforation, pipe pitting, pipe perforation, permanent malfunction of the
equipment connected to the pipes, etc.
NOTE 2 A reduction in the quality of service could also be the complete cancellation of service.
3.16
danger
state of the influenced system which is able to produce a threat to human life
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3.17
interference situation
situation in which an interference can appear (permanently or intermittently) between an a.c. power system
and a metallic pipeline system
NOTE 1 A given interference situation is defined by the geometrical and electrical characteristics of the a.c. power
system and of the metallic pipeline system, as well as by the medium between the two systems.
NOTE 2 An interference situation can cause:
- danger to persons;
- damage to the pipeline and/or to the connected equipment;
- disturbance of the electrical and/or electronic equipment connected to the pipeline.
3.18
interfering current
vectorial sum of the currents flowing through the conductors relevant to the a.c. power system (i.e. catenaries,
feeders, return conductors, phase conductors, earth wires)
NOTE This interfering current is used to simplify the calculations when the distances between the interfering system
and the interfered system are high when compared to the distances between the conductors of the interfering system.
3.19
interference voltage
voltage on the interfered system by the conductive, inductive and capacitive coupling with the nearby
interfering system between a given point and the earth or across an insulating joint
3.20
prospective touch voltage
voltage between simultaneously accessible conductive parts when those conductive parts are not being
touched by a person or an animal
[IEC 60050-195-05-09]
NOTE In the case covered in this standard, the prospective touch voltage coincides with the interference voltage.
This is due to the fact that in the worst case the interfered pipe might not discharge the current to ground.
3.21
spread resistance
ohmic resistance through a coating defect to remote earth or from the exposed metallic surface of a coupon
towards remote earth. This is the resistance which controls the d.c. or a.c. current through a coating defect or
an exposed metallic surface of a coupon for a given d.c. or a.c. voltage
3.22
coupon
representative metal sample with known dimensions
3.
...
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