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Desigoed By:Septic Evaluations Inc. September 17, 1998 <br /> Chanhassen, MN Ann Carpentier <br /> (612) 470-4024 PUMP SELECTION PROCEDURE 301 Willow Drive <br /> Lic. #890 Orono, Hennepin Co. <br /> A. Determine pump capacity: <br /> Gravity Distribution <br /> 1. Minimum suggested is 20 gpm <br /> 2. Maximum suggested is 45 gpm Perforation Mchargesm GPM <br /> Pressure Distibution Head Perforation diameter <br /> 3 feet inches <br /> 3.a. Select number of perforated laterals 32 1/4 <br /> b. Select perforation spacing= 3 feet. 1.0a 0.56 0.74 <br /> C. Subtract 2 ft.from the rock layer length. 1.5 0.69 0.90 <br /> 37 _2 ft = 35 feet. 20b 0.80 1.04 <br /> d. Determine the number of spaces between perforations. a use 1.0 foot single homes. <br /> Length perf.spacing= 35 ft.i. 3 ft.= 11.8 spaces b use 2.0 feet for anything else. <br /> e. 11.8 spaces t 1 = 13.0 perforationsJUteral <br /> Header Pipe Connected in the: <br /> f. Multiply perforations per lateral by number f laterals to Middle <br /> et total number of perforations, s x ..0= 39.0 perforations. Middle----- <br /> 39.0 0.56 _21.8 m <br /> g 7r 59W SP Min. diameter for perferated <br /> 21 8 Laterals is: 1 114 <br /> SELECTED PUMP CAPACITY gpm <br /> B.Determine head requirements: <br /> I. Elevation difference between pump and point of discharge. <br /> '15 feet <br /> 2. If pumping to a pressure distribution system,five feet for pressure son, <br /> required at manifold if gravity system,zero. <br /> 5.0 feet Ibw pip kng* <br /> 3. Friction loss <br /> a. Enter friction loss table with gpm and pipe diameter. <br /> Read friction loss in feet per 100 feet from table(F-14). <br /> F.L.= 1.11 ft./100 ft of pipe 1:2 <br /> b. Determine total pipe length from pump to discharge ..........'-"--'-""'....-'-- - <br /> point. Estimate by adding 25 percent to pipe length for fitting <br /> loss,or use a fitting loss chart(F-15 150 feet). <br /> Equivalent pipe length-1.25 times piTe length <br /> 150 x 1.25= 18feet Friction Loss in Plastic Pipe <br /> c. Calculate total friction loss by multiplying Nominal <br /> friction loss in ft/100 ft by equivalent pipe length <br /> Total friction loss= 1.11 x 187.5 +100= 2.08 feet Ratepipe dia. <br /> 4. Total head required is the sum of elevation difference, Flow 2" 3" <br /> special head requirements,and total friction loss. <br /> gpm <br /> 20 2.47 0.73 0.11 <br /> 15 + 5.0 + 2.08 25 3.73 1.11 0.16 <br /> (1) (2) (30 30 5.23 1.55 0.23 <br /> 35 6.96 2.06 030 <br /> TOTAL HEAD 22.1 feet 455 8.91 2.64 0.39. <br /> 4 11.07 3.28 0.48 <br /> 50 13.46 3.99 038 <br /> C. Pump selection 60 5.60 0.8822 <br /> 65 6.48 0.95 <br /> 70 7.44 1.09 <br /> 1. A pump must be selected to deliver at least <br /> FPn- <br /> [11, <br /> (Step A)with at least 22.1 feet of total head(Step B). 1997 Melonie L. Elvebak <br />