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94 <br />SEWER RATE STUDY I City of Santa Ana, CA <br />Raw QSR Grade <br />Using the Raw QSR Grading Method described previously, each pipe segment was assigned a QSR grade <br />from 0 to 5. This grade simply uses the first digit of the QSR value reported during the CCTV inspection. <br />However, lined pipe was assigned a grade of 0 based on the assumption that the inspection predates the <br />lining. And that once lined, the pipe has been "fixed" and is currently in very good structure condition. <br />Since some mains have not been inspected, those pipe segments have no QSR grades to include in this <br />analysis. Since no date is available, it would be inappropriate to use a grade of 0. One option would be <br />to assign a high level grade using the assumption that since the condition is unknown it might be in poor <br />shape. However, this may artificially inflate the PoF scores. Another option would be to simply assign a <br />mid -level grade. A third option (used in this analysis) is to use the Cohort rank as a substitute for the <br />missing QSR values. These ranks were then multiplied by two to create a range of 0 to 10 (for overall PoF <br />calculation). <br />Figure B 22 provides a map of sewer mains highlighting those pipes that have not had CCTV inspections. <br />Depending on the asset management strategy used, the City may want to target future inspections on <br />those uninspected mains or on those mains having high risk conditions. Performing repeated inspections <br />every few years provides valuable insight into the rate of change. <br />[INTENTIONALLY LEFT BLANK] <br />65B -253 <br />NOVEMBER h'1;.= <br />