Laserfiche WebLink
sit <br />SEW lk RATE STUDY I City of Santa Ana, CA <br />Figure B -12: QSR Ratings by Percent of Total System Main Length <br />Figure B 13 shows the length of sewer mains by year pipe was installed and colored by QSR rank. On <br />initial review, one might conclude that there are two periods of structurally problematic pipe (in the <br />1920s and 1950 -70s). However, this conclusion is misleading without considering the amount of pipe <br />installed. By comparing the proportion of red / brown (high QSR rank) to the total column heights (total <br />installed pipe), you can better appreciate the magnitude of problem pipe. This consideration is <br />addressed in the Probability of Failure (PoF) section below. <br />[INTENTIONALLY LEFT BLANK] <br />65B -241 <br />NOVEMBER 2014 <br />