Corrosion of metals and alloys - Determination of AC corrosion - Protection criteria (ISO 18086:2019)

This document specifies protection criteria for determining the AC corrosion risk of cathodically protected pipelines.
It is applicable to buried cathodically protected pipelines that are 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 document provides limits, measurement procedures, mitigation measures, and information to deal with long-term AC interference for AC voltages at frequencies between 16,7 Hz and 60 Hz and the evaluation of AC corrosion likelihood.
This document deals with the possibility of AC corrosion of metallic pipelines due to AC interferences caused by conductive, inductive 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 conditions of the AC power system.
This document 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).

Korrosion von Metallen und Legierungen - Bestimmung der Wechselstromkorrosion - Schutzkriterien (ISO 18086:2019)

Dieses Dokument legt Schutzkriterien für die Bestimmung des Wechselstromkorrosionsrisikos von kathodisch geschützten Rohrleitungen fest.
Es ist anzuwenden für erdverlegte kathodisch-geschützte Rohrleitungen, die durch Wechsel-strom Fahrleitungssysteme und/oder Wechselstromleitungen beeinflusst werden.
Bei Vorhandensein einer Beeinflussung durch Wechselstrom sind die in ISO 15589 1 angegebenen Schutzkriterien nicht ausreichend, um nachzuweisen, dass der Stahl vor Korrosion geschützt ist.
Dieses Dokument liefert Grenzwerte, Messverfahren, Schutzmaßnahmen und Informationen zum Umgang mit Langzeitbeeinflussung durch Wechselstrom für Wechselspannungen bei Frequenzen zwischen 16,7 Hz und 60 Hz und zur Beurteilung der Korrosionswahrscheinlichkeit durch Wechselstrom.
Dieses Dokument behandelt die mögliche Wechselstromkorrosion von metallischen Rohrleitungen aufgrund der Beeinflussung durch Wechselstrom der durch Wechselstromsysteme verursachten Streuströme durch ohmsche, induktive oder kapazitive Kopplung mit Wechselstromnetzen und die maximal zulässigen Grenz¬werte dieser beeinflussenden Effekte. Es wird die Tatsache berücksichtigt, dass das ein Langzeiteffekt ist, der bei normalen Betriebsbedingungen des Wechselstromsystems auftritt.
Dieses Dokument behandelt nicht die mit Wechselspannungen an Rohrleitungen verbundenen Sicherheitsaspekte. Diese werden in nationalen Normen und Rechtsvorschriften behandelt (siehe z. B. EN 50443).

Corrosion des métaux et alliages - Détermination de la corrosion occasionnée par les courants alternatifs - Critères de protection (ISO 18086:2019)

Le présent document spécifie des critères de protection pour la détermination du risque de corrosion due aux courants alternatifs pour les canalisations protégées cathodiquement.
Il s'applique aux canalisations 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.
En présence d'une influence due aux courants alternatifs, les critères de protection spécifiés dans l'ISO 15589‑1 sont insuffisants pour démontrer que l'acier est protégé contre la corrosion.
Le présent document 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 due aux courants alternatifs.
Le présent document traite de la possible corrosion des canalisations métalliques due à l'influence des courants alternatifs provoquée par le couplage conductif, inductif ou capacitif avec des systèmes électriques à courant alternatif, ainsi que des limites maximales admissibles des effets de cette influence. Il 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.
Le présent document 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 par exemple l'EN 50443).

Korozija kovin in zlitin - Ugotavljanje nastanka AC korozije - Merila zaščite (ISO 18086:2019)

General Information

Status
Published
Publication Date
22-Dec-2020
Withdrawal Date
29-Jun-2021
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
23-Dec-2020
Completion Date
23-Dec-2020

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SLOVENSKI STANDARD
01-februar-2021
Nadomešča:
SIST EN ISO 18086:2017
Korozija kovin in zlitin - Ugotavljanje nastanka AC korozije - Merila zaščite (ISO
18086:2019)
Corrosion of metals and alloys - Determination of AC corrosion - Protection criteria (ISO
18086:2019)
Korrosion von Metallen und Legierungen - Bestimmung der Wechselstromkorrosion -
Schutzkriterien (ISO 18086:2019)
Corrosion des métaux et alliages - Détermination de la corrosion occasionnée par les
courants alternatifs - Critères de protection (ISO 18086:2019)
Ta slovenski standard je istoveten z: EN ISO 18086:2020
ICS:
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18086
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2020
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 18086:2017
English Version
Corrosion of metals and alloys - Determination of AC
corrosion - Protection criteria (ISO 18086:2019)
Corrosion des métaux et alliages - Détermination de la Korrosion von Metallen und Legierungen -
corrosion occasionnée par les courants alternatifs - Bestimmung der Wechselstromkorrosion -
Critères de protection (ISO 18086:2019) Schutzkriterien (ISO 18086:2019)
This European Standard was approved by CEN on 13 December 2020.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18086:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 18086:2019 has been prepared by Technical Committee ISO/TC 156 "Corrosion of
metals and alloys” of the International Organization for Standardization (ISO) and has been taken over
as EN ISO 18086:2020 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 June 2021, and conflicting national standards shall be
withdrawn at the latest by June 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 18086:2017.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: 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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 18086:2019 has been approved by CEN as EN ISO 18086:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 18086
Second edition
2019-12
Corrosion of metals and alloys —
Determination of AC corrosion —
Protection criteria
Corrosion des métaux et alliages — Détermination de la corrosion
occasionnée par les courants alternatifs — Critères de protection
Reference number
ISO 18086:2019(E)
©
ISO 2019
ISO 18086:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise 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 ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 18086:2019(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Cathodic protection persons competence . 5
5 Assessment of the AC influence . 5
5.1 General . 5
5.2 Assessment of the level of interference . 6
6 Evaluation of the AC corrosion likelihood. 6
6.1 Prerequisite . 6
6.1.1 General. 6
6.1.2 AC voltage on the structure . 7
6.2 AC and DC current density . 7
6.2.1 General. 7
6.2.2 AC current density . 7
6.2.3 High cathodic DC current density . 7
6.2.4 Low cathodic DC current density . 8
6.2.5 Current ratio “I /I ” . 8
a.c. d.c.
6.2.6 Soil resistivity . 8
6.3 Corrosion rate . 8
6.4 Pipeline coatings . 8
6.5 Evaluation of the metal loss . 9
7 Acceptable interference levels . 9
8 Measurement techniques . 9
8.1 Measurements . 9
8.1.1 General. 9
8.1.2 Selection of test sites . 9
8.1.3 Selection of measurement parameter .10
8.1.4 Sampling rate for the recording of interference levels .10
8.1.5 Accuracy of measuring equipment.10
8.1.6 Installation of coupons or probes to calculate current densities.10
8.2 DC potential measurements .10
8.3 AC voltage measurements .11
8.4 Measurements on coupons and probes .11
8.4.1 Installation of coupons or probes .11
8.4.2 Current measurements.12
8.4.3 Corrosion rate measurements.12
8.5 Pipeline metal loss techniques .13
9 Mitigation measures .13
9.1 General .13
9.2 Construction measures .13
9.2.1 Modification of bedding material .13
9.2.2 Installation of isolating joints .13
9.2.3 Installation of mitigation wires .14
9.2.4 Optimization of pipeline and/or powerline route .14
9.2.5 Power line or pipeline construction.14
9.3 Operation measures .
...

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