1、BSI Standards PublicationBS ISO 18086:2015Corrosion of metals andalloys Determination of ACcorrosion Protection criteriaBS ISO 18086:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18086:2015.The UK participation in its preparation was entrusted to Technic
2、alCommittee ISE/NFE/8, Corrosion of metals and alloys.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 contract. Users are responsible for its correctapplication. The British
3、 Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79664 7ICS 77.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 June 2015.Ame
4、ndments issued since publicationDate Text affectedBS ISO 18086:2015 ISO 2015Corrosion of metals and alloys Determination of AC corrosion Protection criteriaCorrosion des mtaux et alliages Dtermination de la corrosion occasionne par les courants alternatifs Critres de protectionINTERNATIONAL STANDARD
5、ISO18086First edition2015-06-01Reference numberISO 18086:2015(E)BS ISO 18086:2015ISO 18086:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized o
6、therwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright offi
7、ceCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18086:2015ISO 18086:2015(E)Foreword vIntroduction vi1 Scope . 12 Normative references 13 Terms and definitions . 14 Cathodic protection persons competence 45 Ass
8、essment of the AC influence . 55.1 General . 55.2 Assessment of the level of interference . 56 Evaluation of the AC corrosion likelihood 66.1 Prerequisite . 66.1.1 General 66.1.2 AC voltage on the structure 66.2 AC and DC current density 76.2.1 General 76.2.2 AC current density 76.2.3 High cathodic
9、DC current density . 76.2.4 Low cathodic DC current density 76.2.5 Current ratio “Ia.c./Id.c” . 86.2.6 Soil resistivity . 86.3 Corrosion rate 86.4 Pipeline coatings . 86.5 Evaluation of the metal loss . 87 Acceptable interference levels . 88 Measurement techniques 98.1 Measurements . 98.1.1 General
10、98.1.2 Selection of test sites 98.1.3 Selection of measurement parameter 108.1.4 Sampling rate for the recording of interference levels 108.1.5 Accuracy of measuring equipment108.1.6 Installation of coupons or probes to calculate current densities108.2 DC potential measurements . 108.3 AC voltage me
11、asurements 108.4 Measurements on coupons and probes 118.4.1 Installation of coupons or probes 118.4.2 Current measurements118.4.3 Corrosion rate measurements. 128.5 Pipeline metal loss techniques . 139 Mitigation measures 139.1 General 139.2 Construction measures . 139.2.1 Modification of bedding ma
12、terial . 139.2.2 Installation of isolating joints 139.2.3 Installation of mitigation wires 139.2.4 Optimization of pipeline and/or powerline route .149.2.5 Power line or pipeline construction.149.3 Operation measures 149.3.1 Earthing 149.3.2 Adjustment of cathodic protection level 159.3.3 Repair of
13、coating defects 15 ISO 2015 All rights reserved iiiContents PageBS ISO 18086:2015ISO 18086:2015(E)10 Commissioning 1610.1 Commissioning 1610.2 Preliminary checking 1610.2.1 General. 1610.2.2 Coupon AC voltage and current startup .1710.2.3 Verification of effectiveness. 1710.2.4 Installation and comm
14、issioning documents .1711 Monitoring and maintenance .17Annex A (informative) Simplified description of the AC corrosion phenomenon 19Annex B (informative) Coupons and probes 21Annex C (informative) Coulometric oxidation .26Annex D (informative) Influence of soil characteristics on the AC corrosion
15、process .27Annex E (informative) Other criteria that have been used in the presence of AC influence 28Annex F (informative) Parameters to take into account to choose a DC decoupling device 32Annex G (informative) Method to determine the reference electrode location to remote earth .34Annex H (inform
16、ative) Simultaneous measurement on coupon current densities with high rate .36Bibliography .38iv ISO 2015 All rights reservedBS ISO 18086:2015ISO 18086:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies).
17、The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-g
18、overnmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described
19、 in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the
20、 possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO l
21、ist of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as wel
22、l as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The committee responsible for this document is ISO/TC 156, Corrosion of metal and alloys. ISO 2015 All rights reserved vBS ISO 18086:2015IS
23、O 18086:2015(E)IntroductionThis International Standard has incorporated criteria and thresholds together with experience gained from the most recent data. Various countries have a very different approach to the prevention of AC corrosion depending primarily on the DC interference situation. These di
24、fferent approaches are taken into account in two different ways either in presence of “low” on-potentials, which allows a certain level of AC voltage (up to 15 V), or in presence of “high” on-potentials (with DC stray current interference on the pipeline for instance) which requires the reduction of
25、 the AC voltage towards the lowest possible levels.This International Standard also gives some parameters to consider when evaluating the AC corrosion likelihood, as well as detailed measurement techniques, mitigation measures, and measurements to carry out for commissioning of any AC corrosion miti
26、gation system. Note that Annex E proposes other parameters and thresholds that require further validation based on practical experiences.vi ISO 2015 All rights reservedBS ISO 18086:2015Corrosion of metals and alloys Determination of AC corrosion Protection criteria1 ScopeThis International Standard
27、is applicable to buried cathodically-protected pipeline that is influenced by AC traction systems and/or AC power lines.In the presence of AC interference, the protection criteria given in ISO 15589-1 are not sufficient to demonstrate that the steel is being protected against corrosion.This Internat
28、ional Standard provides limits, measurement procedures, mitigation measures, and information to deal with long term AC interference for AC voltages at frequencies between 16,7 and 60 Hz and the evaluation of AC corrosion likelihood.This International Standard deals with the possibility of AC corrosi
29、on of metallic pipelines due to AC interferences caused by inductive, conductive or capacitive coupling with AC 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 condition
30、s of the AC power system.This International Standard does not cover the safety issues associated with AC voltages on pipelines. These are covered in national standards and regulations (see e.g. EN 50443).2 Normative referencesThe following referenced documents are indispensable for the application o
31、f this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 15589-1, Petroleum, petrochemical and natural gas industries Cathodic protection of pipeline systems Part 1: On-land pip
32、elinesISO 8044, Corrosion of metals and alloys Basic terms and definitionsIEC 61010-1, Safety requirements for electrical equipment for measurements, control, and laboratory use Part 1: General requirementsEN 13509, Cathodic protection measurement techniquesEN 15257, Cathodic protection Competence l
33、evels and certification of cathodic protection personnelEN 50443, Effects of electromagnetic interference on pipelines caused by high voltage AC electric traction systems and/or high voltage AC power supply systems3 Terms and definitionsFor the purposes of this document, the terms and definitions gi
34、ven in ISO 8044 and the following apply.3.1AC electric traction systemAC railway electrical distribution network used to provide energy for rolling stockNote 1 to entry: The system can comprise the following: contact line systems;INTERNATIONAL STANDARD ISO 18086:2015(E) ISO 2015 All rights reserved
35、1BS ISO 18086:2015ISO 18086:2015(E) 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.3.2AC power supply systemAC electrical system devoted to electrica
36、l energy transmission and includes overhead lines, cables, substations and all apparatus associated with them3.3AC power systemAC electric traction system or AC power supply systemNote 1 to entry: Where it is necessary to differentiate, each interfering system is clearly indicated with its proper te
37、rm.3.4copper/copper sulfate reference electrodeCSEreference electrode consisting of copper in a saturated solution of copper sulfate3.5AC voltagevoltage measured to earth between a metallic structure and a reference electrode3.6interfering systemgeneral expression encompassing an interfering high vo
38、ltage AC electric traction system and/or high voltage AC power supply system3.7interfered systemsystem on which the interference effects appearNote 1 to entry: In this International Standard, it is the pipeline system.3.8pipeline systemsystem of pipe network with all associated equipment and station
39、sNote 1 to entry: In this International Standard, pipeline system refers only to metallic pipeline system.Note 2 to entry: The associated equipment is the equipment electrically connected to the pipeline.3.9earthconductive mass of the earth, whose electric potential at any point is conventionally ta
40、ken as equal to zeroSOURCE: IEC 60050 8263.10operating conditionfault-free operation of any systemNote 1 to entry: Transients are not to be considered as an operating condition.2 ISO 2015 All rights reservedBS ISO 18086:2015ISO 18086:2015(E)3.11fault conditionnon-intended condition caused by short-c
41、ircuit to earth, the fault duration being the normal clearing time of the protection devices and switchesNote 1 to entry: The short circuit is an unintentional connection of an energized conductor to earth or to any metallic part in contact with earth.3.12conductive couplingcoupling which occurs whe
42、n 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 co
43、nductive voltages and currents3.13inductive couplingphenomenon whereby the magnetic field produced by a current carrying circuit influences another circuitNote 1 to entry: The coupling being quantified by the mutual impedance of the two circuits, and the results of which are induced voltages and hen
44、ce currents that depend on, for example, the distances, length, inducing current, circuit arrangement, and frequency.3.14capacitive couplingphenomenon whereby the electric field produced by an energized conductor influences another conductorNote 1 to entry: The coupling being quantified by the capac
45、itance 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 arrang
46、ement.3.15interferencephenomenon resulting from conductive, capacitive, inductive coupling between systems and which can cause malfunction, dangerous voltages, damage, etc.3.16disturbancemalfunction of an equipment losing its capability to work properly for the duration of the interferenceNote 1 to
47、entry: When the interference disappears, the interfered system starts working properly again without any external intervention.3.17damagepermanent reduction in the quality of service which can be suffered by the interfered systemNote 1 to entry: A reduction in the quality of service could also be th
48、e complete cancellation of service.EXAMPLE Coating perforation, pipe pitting, pipe perforation, permanent malfunction of the equipment connected to the pipes, etc.3.18dangerstate of the influenced system which is able to produce a threat to human life ISO 2015 All rights reserved 3BS ISO 18086:2015I
49、SO 18086:2015(E)3.19interference situationmaximum distance between the pipeline system and AC power system for which an interference is to be considered3.20interference voltagevoltage 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 joint3.21IR dropvoltage due to any current, developed in an electrolyte such as the soil, between the reference electrode and the metal of the structure, in acc
