Soil to Air Interface – Zone of Corrosion on API 570 Piping;
The area where the pipelines fall underground, or soil-to-air interface, is the area that has a high chance of external corrosion if Wrapping or Coating is damaged. Due to the difference in temperature, humidity and oxygen in the area, the API 570 stipulates that 6 inches above and 12 inches below the soil surface is the Soil-to-air Interface zone that should be Reviewed.
Inspection of Soil-to-air Interface for Underground Piping;
For example, to monitor underground pipes ( Underground, Piping) in a pipe underground or Soil-to-air Interface by digging tube down to about 12 inches from the ground to detect Visual The Case found Wrapping there. Damage and Corrosion (Corrosion Product) visible and when removing Wrapping found that External Localized Corrosion occurs on the pipe surface, especially where the Wrapping is damaged. In this case, allow us to measure the depth of Corrosion Pits and check that the remaining thickness of the pipe is still acceptable. If the thickness is still within the acceptable criteria, do new coating and wrapping before drown-out.