Significance of logarithmic averaging of soil resistivity data for underground pipelines using impressed current cathodic protection system

Soil resistivity is conventionally measured by the Wenner four - pin method by pipeline services for determining the corrosivity of the soil along the Right Of Way (ROW). Determining absolute soil resistivity is practically impossible due to the continuous changing nature of the soil. So the average soil resistivity is actually found out. A comparative analysis between two methods of averaging viz. general and logarithmic, in determining average soil resistivity has been done in the present paper. The relationship between soil resistivity and soil corrosivity has been used in determining the rate of corrosion suffered by an underground coal tar enamel coated pipeline, with impressed current cathodic protection system.