Materials Performance Supplements

TANK 2018

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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16 MAY 2018 W W W.MATERIALSPERFORMANCE.COM TANK CORROSION CONTROL SUPPLEMENT TO MP Corrosion Monitoring of Aboveground Storage Tanks MetriCorr Corrosion related failures in aboveground storage tanks (ASTs) can be catastrophic both environmentally as well as financially. In order to reduce this risk, a number of solutions can be imple- mented during construction, including coating, special foundation design, liners, different cushion materials, inhibitors, cathodic pro- tection (CP), etc. Effective monitoring of the conditions experienced by tank bot- toms can highlight risks associated with corrosion and provide an early warning system allowing for preemptive mitigation, while regular monitoring can ensure that preventative measures remain effective. Monitoring hardware is often only installed in applications where tank bottoms are protected by means of CP and is used for the measurement of tank bottom potential. However, depending on the environment and other external factors, such as AC interference, potential (ON & OFF/IR-free) alone is not necessarily a good indicator of the likelihood of corro- sion (or coating degradation indicated by increased current required to maintain a potential). This is due to the nature of a tank farm environment: it is possible that the conditions under the tank change over time (contamination, new construction, etc.). As such, measurement of the corrosion rate at a certain poten- tial/current output can be indicative of changes in the environment and can highlight the requirement for additional investigation such as soil sampling to check for contamination, etc. The corrosion rate at different points under a tank can be used as an early warning system for leaks due to external corrosion. Depending on the product contained and the tank history, the fre- quency of tank bottom thickness and other surveys may be reduced if an accurate history of corrosion rate is maintained. The measured corrosion rate is perhaps the most useful param- eter in checking the status of a tank bottom "at-a-glance." It can be used in applications with or without any form of corrosion protec- tion (inhibitor, coating, etc.) as an indicator of corrosion risk. It is also a good tool to use in the reporting of the status to non-experts in the field of corrosion/CP as it is a physically relatable measure- ment and can easily be compared to the tank bottom thickness and the design life of the tank. Coupling measurement of corrosion rate and other electrical fingerprints (DC & AC potential, DC & AC current densities, spread resistance, and IR-free potential) yields an extremely powerful and versatile tool in the fight against tank bottom and other submerged structure corrosion. The MetriCorr solution includes WebService presenting and storing data online for the client's exclusive use. Data can be Tørringvej 7 2610 Rødovre, Denmark Tel: +45 9244 8080 Email: uploaded automatically using remote monitoring devices or man- ually uploaded. Once on the WebService, data can be viewed, treated, stored, and downloaded using an intuitive, user friendly interface. Contact MetriCorr for your corrosion monitoring needs.

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