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6.1.B. - Page 16 <br /> TASK 4 — SURFACE POTENTIAL PROFILE & DATA ANALYSIS <br /> • Consultant shall perform a surface potential profile over the selected sections of <br /> the water transmission pipeline in accordance with NACE Standard SP0207- <br /> 2007 entitled "Performing Close-Interval Potential Surveys and DC Surface <br /> Potential Gradient Surveys on Buried or Submerged Metallic Pipelines". GPS <br /> coordinates and markings in the field will be used to record the locations of <br /> potential anodic peaks along the section of pipeline being surveyed. Side drains <br /> and remote reference electrodes will be utilized to confirm potential anodic <br /> locations where necessary. <br /> • After completion of the surface potential profile and the data analysis, consultant <br /> shall select two locations for excavation and further analysis via direct <br /> assessment. <br /> TASK 5 — PIPELINE DIRECT ASSESSMENT <br /> • Consultant shall collect the following information at each excavation location: <br /> • Soil sample collected for chemical analysis <br /> • Ultrasonic thickness measurements will be made around the entire <br /> circumference of the pipe in order to determine the remaining wall <br /> thickness at each location. <br /> • Quantity and depths of corrosion pits will be documented. A three- <br /> dimensional view of the surface of the pipe can be developed if <br /> desired. <br /> • Degree of graphitization will be determined. <br /> • Prior to inspection of the exposed pipe, the City will sand blast the exposed <br /> section of pipe to remove all graphitized ductile and cast iron from the surface of <br /> the pipe. <br /> TASK 6 — TECHNICAL MEMORANDUM <br /> • Consultant shall prepare a technical memorandum at the conclusion of the field <br /> testing for each phase that contains a listing of all field data collected and an <br /> analysis of this data. Recommendations for any follow-up work including <br /> additional confirmatory excavations and non-destructive testing for the pipeline <br /> will be made as warranted. Consultant shall provide opinion as to the overall <br /> condition of the subject water transmission pipeline and its useful life expectancy <br /> will be provided along with recommendations for life extension strategies and the <br /> estimated costs associated with each strategy. A schedule for the <br /> implementation of any life extension strategies will also be recommended. <br /> TIME SCHEDULE: <br /> ATTY/AGR/2013.014/JDH CORROSION CONSULTANTS, INC. <br /> REV:01-25-13 VR <br /> Page 12 of 16 <br />