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Unleaded Tank (West): <br /> Potentials measured on the fill tube and test lead were -1.179V and -1.184V, respectively. <br /> These values indicate proper level of cathodic protection. The anode connected to test <br /> lead #3 appears to be consumed, but is not impacting the level of cathodic protection at <br /> this time <br /> Unleaded Tank (East): <br /> Potentials measured on the initial evaluation on February 18, 2005, on the fill tube and <br /> test lead were -0.265V and -0.261V, respectively. These values are significantly below <br /> proper level of cathodic protection. These low potentials are indicative of interconnection <br /> (short) to the electrical copper ground or reinforced concrete. The anode connected to test <br /> lead #5 is not functioning and appears to be consumed. <br /> During our March 4, 2005 field evaluation, current requirement tests were performed to <br /> determine whether additional anodes could overcome the shorted condition identified in <br /> the earlier testing. Current was applied to the tank using a portable d.c. power source and <br /> the existing galvanic anodes. At an applied current of 0.53 amperes, the potential of the <br /> tank shifted to -0.321 V, (Table 2) which is still well below proper levels of cathodic <br /> protection. Based upon this test the current required to properly protect this unleaded tank <br /> would be approximated 5.0 amperes. This level of current demand is estimated to be over <br /> 1000 times the expected current to provide adequate cathodic protection. This again <br /> verified the shorted condition and that additional practical levels of current could not <br /> overcome that condition. <br /> City staff then began isolating components to identify the connection causing the short <br /> condition. The short was found to be caused by a copper tube interconnecting the pump <br /> to the tank structure. A non-metallic tube was installed and final testing was performed <br /> on March 25, 2005 (Table 3). Potentials were measured at -1.343 V which is well above <br /> minimum level of cathodic protection. Also total current to provide this level of <br /> protection is 2.19 mA reduced from initially measured values. The actual current demand <br /> of 2.19 mA is approximately 2000 times less than the shorted current estimate above of <br /> 5.0 amperes. <br /> CONCLUSIONS <br /> The Waste Oil Tank;Diesel Tank; Unleaded Tank (West) and Unleaded Tank (East): <br /> • The cathodic protection systems are all providing proper levels of cathodic protection <br /> at this time. <br /> Blackstone 3 <br /> Group <br /> Ltd. <br />