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REQUEST FOR PROPOSAL <br />/,NT <br />On -Call Water Resources Engineering Services <br />(RFP N0. 79-100) N �';�r¢i �„ <br />�tL.i yam} lka , �k <br />the end customer. Hydraulic analysis and head losses through the system will be conducted to <br />establish required Total Dynamic Head (TDH) for each pump station. The system curve will be <br />plotted and will be used to design the pump. Pumps will be selected and evaluated to meet the <br />range of operating conditions anticipated for the pump station against the system head curves for <br />current and future conditions. <br />• Pump Type: Variable frequency drive operated pumps are preferred to provide relatively constant <br />service pressure to the customers by increasing pump speed during high demand periods and <br />reducing speed during low demand periods. The most appropriate pump type for this kind of <br />application is multi -stage vertical turbine pump because of its steep pump characteristic curve. If <br />more than two impellers are needed, enclosed impellers are recommended in order to eliminate <br />the possibility of impeller vane wear due to misalignment between the bowls and impellers. <br />• Pump Barrels: Pump barrels will be sized to maintain velocities at or below one -to -two feet per <br />second between the pump barrel lining and the bowls, with consideration of pump removal and re- <br />installation operations. The bowl outside diameter for the selected pumps will be determined and a <br />barrel with a clear interior diameter that meets these requirements will be selected. Barrels with <br />fusion bonded epoxy (FBE) lining will be selected in order to provide adequate space for removal <br />and re -installation of the pumps without damaging the barrel lining. The lowest impeller should be <br />a minimum of two times the suction pipe diameter below the suction pipe invert. Suction basket <br />strainers should be provided to preclude the entry of large debris into the impellers. The bottom of <br />the suction strainers should be 12 inches above the bottom of the pump barrels. The actual length <br />of the pump barrels will be determined based upon the final pump selection. <br />• Column Pipes: The standard pump column pipes will be used for each pump. Column pipes will <br />be same diameter threaded, fusion bonded epoxy lined and coated steel to maintain relatively <br />similar velocities in the pump column and the discharge piping. Pump shafts will be product <br />lubricated, 416 stainless steel. <br />• Surge Analysis: A transient analysis will be performed, and mitigation measures will be designed <br />for each pump station design (unless specifically determined that surge will not be an issue). <br />• Other Pump Station Components: Such as suction/discharge, headers, isolation valves, check <br />valves, ventilation, etc., will be designed in accordance with the City Standards, HIS and other <br />industry standards. In general, pipes and valves will be sized to limit the flow velocities to a <br />maximum of three feet per second on suction side and a maximum of seven feet per second on <br />the discharge side of the pump station. <br />Design - Tanks/Reservoirs <br />Structural/Seismic/Safety Evaluation: We will determine the condition of the reservoir for seismic <br />and structural reliability, related operating parameters, safety and sanitary compliance, and to <br />recommend corrective and preventive measures, including filing of a report. <br />• Existing Facilities Rehabilitation: We will inspect the existing conditions of the existing structure, <br />such as identifying and measuring existing cracks in the concrete structure and will recommend <br />the most effective rehabilitation based on the severity and location of the discovered cracks. <br />• Corrosion Protection: Our team will determine the condition of the reservoir related to corrosion <br />factors, including coatings, paints, and cathodic protection and to recommend corrective and <br />preventive measures, including filing of individual reports with cost estimates and photographs. <br />• Laboratory Analyses: We will determine the levels of heavy metals within the coatings and paints <br />to assist in planning the work to ensure all personnel health and safety measures and <br />environmental controls are implemented. <br />Proposal I Page 14 On -Call Water Resources RFP No. 19-100 <br />I N T E R N R T 1 0 N A <br />