When designing anode retrofits for offshore structures with depleted sacrificial anode systems, the engineer usually relies on proven rules of thumb for predicting the current demand used in the design calculations. While this is a safe approach, especially in well understood areas such as the Gulf of Mexico, it often results in a very conservative, over-designed retrofit program. By using the modified Dwight's equation given in NACE RP-01-76, Appendix D, to calculate actual jacket current demand from anode potential surveys, it is possible to design a more optimum sacrificial anode retrofit. This method allows a considerable cost savings to be achieved while maintaining a significant safety factor in the design. We believe that in many cases the amount saved on the retrofit using this method can greatly exceed the cost of the jacket potential survey, especially for large structures.

Subject
Cathodes, Electric current, Costs, Water, Galvanic anodes, Anode potential, Cathodic potential, Structures, Current densities, Anodic current, Surveys, Jackets, Anodes
© 1993 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).
1993
Association for Materials Protection and Performance (AMPP)
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