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010 <br /> A. Area and UtDities Data <br /> B. Soil Properties <br /> 1. Resistivity (conductivity) <br /> 2. pH <br /> 3. Ch1cride Iran Concentration <br /> 4. Sulfide Ion Concentration <br /> 5. Moisture Content <br /> 6. Aeration <br /> C. Stray Current <br /> D. Structure-to-Soil Potential <br /> The area and utilities data considers the potential hazard related to a <br /> corrosion failure. The nature of the area (e.g. residential, industrial, <br /> rural, near a school) as well as the location of possible points of <br /> contamination of the water supply (e.g. streams, lakes) are evaluated. <br /> Note that no potable water sources were reported in the vicinity. <br /> The soil conditions are inputed which include resistivity (conductivity), <br /> pH, chlic rides, sulfides, aeration and moisture content. Each parameter <br /> is individually weighted in acccrdance with the significance of the <br /> particular variable on the raise of oo=sion on underground storage <br /> tanks. For example, in a fairly broad range, pH has little effect on the <br /> corrosion of mild steel at ambient temperature. Outside this range, the <br /> impact is significant and can either greatly accelerate or trend to <br /> passivate the Win. <br /> The presence and severity of stray DC earth currents are analyzed <br /> based upon the electrical measurements recorded at the site. Stray <br /> current corrosion was not found to be a factor at this location. <br /> The program that models M T C F cannot account for improper• tank <br /> installation. For example, if at one location along the tank, natural clay <br /> soil is in contact with the tank wall, neither the field testing ncfr <br /> computer model would necessarily detect the improper backfilling <br /> procedures. <br />