Buried service station tanks corrode and leak. Sewers may fill with gasoline; a fire or explosion may ensue. Leaking tanks may lead to violation of anti-pollution laws and safety codes. The oil company faces economic losses due to tank replacement, station downtime, customer ill-will and product loss (at today's prices, who can afford gasoline leaks?).

Corrosion on underground storage tanks continues to be a problem. We hear reports of tanks failing within 6 to 12 years in various urban areas. Some cities, recognizing the dangers associated with leaking gasoline, have enacted codes requiring corrosion control measures for buried storage tanks. The U. S. Department of Transportation, already the author of federal corrosion control regulations for gas and hazardous liquid pipelines, may someday issue similar standards for service stations.

Buried tanks can be protected from corrosion, yielding safety and economic benefits. This paper has been written to provide a basic understanding of tank corrosion and various preventative measures.

Steel tanks should be provided with coating and cathodic protection. Coating alone is insufficient protection because accelerated corrosion will occur at the inevitable breaks in the coating. Both galvanic and impressed current cathodic protection systems are used, and various configurations are shown herein. The importance of maintenance is stressed because cathodic protection is likely to become ineffective if not maintained.

Internal corrosion is considered. It contributes significantly to tank failures. Preventative measures include coatings and proper tank installation procedures. Dip sticks should have soft tips.

Some experimental methods of protection are covered. These include plastic wrappers, special backfills and pre-engineered cathodic protection. The pitfalls of each are discussed.

Economics should be considered when choosing a corrosion protection system. Evaluation of overall costs covering the life of the station will aid the engineer in choosing the best method of corrosion control.

Subject
Costs, Water, Coatings, Insulation, Impressed current cathodic protection, Cathodic protection, Installation, Internal corrosion, Steel, Corrosion protection, Impressed current, Maintenance, Soil
© 1975 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).
1975
Association for Materials Protection and Performance (AMPP)
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