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Item No. 7N Meeting Date: May 14, 2007 Type of Business: CB WK: Work Session; PH: Public Hearing; CA: Consent Agenda; CB: Council Business City Administrator Review _______ City of Mounds View Staff Report To: Honorable Mayor and City Council From: Michael Schnur, Lead Utility Operator Item Title/Subject: Resolution 7054 Approving the Purchase of a Frost Breaker Background: The age and original construction material of the City’s water supply system has made it more susceptible to cracks, breaks, and other catastrophic failures. These events are particularly prevalent during the winter months. During this period, frost in the upper soil layers expand, pushing up pipe segments connected to hydrants and gate valves. This creates stresses on the piping below the frost line, causing it to fracture and break. Typically, the deeper the frost, the greater the probably is for failure. Likewise, the deeper the frost, the greater the difficulty Staff has in excavating the site to take corrective measures. During the 2006 / 2007 winter season, the City performed nine (9) excavations to repair the City water mains. There are two ways in which the City can penetrate the frost to access the water break areas. The first way is to scrape through the frost with a frost bucket mounted on the City’s backhoe loader. This method is very time consuming and extremely difficult – especially with deep frost layers. Safety is also a major concern. There are numerous private utilities such as gas, electric, telephone, cable television, fiber optics, etc. that are located above most water lines. The bucket on the backhoe is 30” wide. Attempting to remove frost adjacent to or between these utilities using the backhoe bucket is extremely difficult and dangerous. The second method to remove the frost is with the aid of a single point hydraulic frost breaker. This is an implement that attaches to a backhoe or skidsteer and functions similar to a large jack hammer.