Steel pipe should be coated and provided with cathodic protection under what soil conditions?

• A. Essentially all
• B. Only acidic soil
• C. Only alkaline soil
• D. Only damp soil

Answer: (A)

Buried steel pipe faces corrosion in virtually any soil environment because soil moisture, oxygen, and ions create an electrochemical attack. A coating acts as a barrier to slow or stop the flow of moisture and ions to the steel, while cathodic protection actively prevents corrosion by making the pipe a protected cathode in the electrochemical process. Since soil conditions vary and coatings can develop defects over time, using both protection methods provides reliable, ongoing protection across essentially all soil conditions. Even in drier or less aggressive soils, the combined approach ensures corrosion is controlled as moisture and soil resistivity change over time.