This paper presents the case of a cathodic protection retrofit undertaken on four steel gravity platforms, installed off the coast of West Africa in 86 m deep waters. The platforms, originally protected with galvanic anodes with a design life of 20 years, experienced insufficient protection conditions after only 10 years. A retrofit was planned in 1987 using an impressed current system with LIDA TSA(TM)1 MMO anodes impressed current system, and the system was successfully commissioned in 1987. Protection conditions were achieved and continuously maintained from start-up for 18 years until 2005. It was decided to extend the life of the four platforms for an additional 20 years and to fully renew the CP system using the same technology. After 18 years of operation the entire CP system was replaced using MMO Anodes tensioned ropes; the new impressed current systems was commissioned in 2005 with a 20 years expected design life.

Subject
Steel structures, Water, Coatings, Anodic protection, Cathodic protection, Cables, Impressed current anodes, Rectifiers, Anodic current, Steel, Impressed current, Jackets, Anodes
© 2007 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).
2007
Association for Materials Protection and Performance (AMPP)
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