AgdaPkt 2005-07-25 - Laserfiche WebLink

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5/ ð- / REPORT To the Honorable Mayor and City Council From the Ci Mana er July 25, 2005 Subject Award of Contract - Cathodic Protection System Upgrades for the Topaz and Redwood Shores Water Transmission Pipelines Project Recommendation Approve the Contract Documents and award the Contract for the Cathodic Protection System Upgrades for the Topaz and Redwood Shores Water Transmission Pipelines Project to the lowest responsible bidder, Corrpro Companies, Inc. of San Leandro, California, for their low bid of $529,000.00. Background Our City has three classified zones of soil corrosion. Zone 3 is all the area west of Alameda de Las Pulgas and is considered to be the least corrosive of the three zones. Zone 2 is the area between Alameda de Las Pulgas Zone and EJ Camino Real. Zone 1 is the area east of EI Camino Real and is considered to be the most corrosive to all buried metal infrastructures. Metal structures buried in Zone 1 soil will experience a much higher detrimental and unacceptable rate of deterioration - if not protected. In the C ìse of Redwood City, the critical infrastructure at risk is the thousands of feet of buried, 'ging, metal water pipes delivering drinking water to homes and businesses in the Ci~ . With the assistance of V&A Consulting Engineers, Inc., an expert group in the field of infrastructure preservation, staff has completed a comprehensive corrosion assessment of the water distribution system. This review ranked all the metal water mains in Zone 1 based on the level of risk to water service disruption and cost to repair or replace. A management program for future preservation of the water mains was developed. Corrosion is a natural process to bring manmade metals into a neutral balanced state of existence, It is an electrochemical reaction where a more positively charged metal is giving off its electrons, evidenced by rusting and loss of metal materials, to a more negatively charged metal as they create a natural electrical circuit. The relatively more positively charged metal is called an anode, and the relatively more negatively charged metal is called a cathode. To prevent corrosion to the pipelines, one needs to create an environment where the pipelines becom~ the cathodes to protect them from corrosion, hence the name Cathodic Protection Sys.:em. A standard cathodic protection system for metal pipeline systems primarily consists of rectifiers and anode materials. The cathodes are the pipelines, which are to be protected. The rectifier - an above ground electrical power converter and regulator device about the size of a post office mailbox - is used to artificially create the electrical circuit, and turn the pipelines into a cathodic system (two (2) new rectifiers will be added to the existing seven (7) in the Redwood Shores Area). The anode - long lasting Page 1 of 2