Cathodic protection (CP) coupons and soil corrosion probes (SCPs) can be effective tools in applying CP criteria under challenging operating environments. These situations include measuring off-potentials using coupons in cross-bonded systems or structures influenced by interference from CP systems not controlled by the main protected system operator, or where CP potentials cannot be reliably measured and corrosion rate measurements using electrical resistance (ER) soil corrosion probes are used as an alternative to conventional CP criteria for buried pipelines.

This paper looks at the various scenarios where CP coupons and SCPs can be used, using field data from installations on buried pipelines, and also with reference to the requirements of the new ISO standard ISO/FDIS 15589-1 on different CP criteria for varying soil resistivities. Information is also given on the recent work by the NACE International Technical Committee TG-321 draft report on soil corrosion probes.

Subject
CP coupons, Corrosion rate, Structures, Pipelines, Soil resistivity, Installation, Potential measurements, Corrosion probes, Below ground pipelines, Electrical resistance probes, Polarized potential, Soil, Electrode potential
Keywords:
CP coupons, soil corrosion probes, CP criteria, CP potential measurement, corrosion rate, buried pipelines, storage tanks
© 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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