Sacrificial anodes for building foundation
System with capacity and lifespan limitations.
Sacrificial anodes may be used for smaller building foundations, and where replacement of anodes are simple. As the surrounding electrolyte resistance is rather high, magnesium high grade anodes are recommended, due to the high driving voltage. The anodes are pre-packed in a cotton bag, surrounded by a special chemical backfill with high carbon content, for low anode-to-soil resistance. The number of anodes required depends on the number and size of the steel foundations, and the expected current distribution from each of the anodes.
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To verify the effect of the applied cathodic protection, monitoring equipment should be installed close to one or more of the foundations. Cu/CuSO4 reference electrode is normally suited for this application. Alternatively, arrangement for manual reference potential measurements should be made for better system maintenance and follow up. Such arrangement could be made by installing an empty pipe where a portable reference electrode could be lowered down close to the steel foundations.