This is a case history of a large diameter pipeline with fusion bonded epoxy coating that experienced AC corrosion after being in operation within six (6) years while the existing 67-year-old large diameter pipeline with coal tar enamel coating experienced no AC corrosion. An AC study was completed after installation of the newer pipeline but showed no immediate threat. This paper presents a post mortem assessment after 17 years of what is required and the importance of not taking adequate data when AC load factors were not posing a threat condition. If it were not for the operator's due diligence to run an in-line-inspection device, this ongoing condition would have gone unnoticed. This paper provides the understanding of the need for complete information, data required for AC modeling, corrosion threats and mitigation. AC mitigation modeling was in already in place which could have been used effectively. The first AC modeling was developed by Dr. John Dabkowski for the Pipeline Research Council International1 (PRCI).

Subject
Piping, Voltage, Modeling, Cathodic protection, Industries, Pipelines, Wiring, Fusion bonded epoxy coating, Current densities, Equipment, Electric potential, Alternating current corrosion, Copper
Keywords:
Steady State Conditions, Fault Conditions, Alternating Current (AC) Current Density, Mitigation, Interference, Fusion Bonded Epoxy (FBE), Coat Tar Enamel (CTE), High Consequence Areas (HCAs)
© 2018 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2018
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.