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PUMP SELECTION PROCEDURE <br />Determine pump capacity! <br />Gravity Distribution <br />1. Minimum suggested is 600 gallons per hour (10 gpm) to stay ahead of <br />water use rate. <br />2. Maximum suggested for delivery to a drop box of a home system is 2,700 <br />gallons per hour (45 gpm) to prevent build-up of pressure in drop box. <br />Pressure Distibution <br />3. a. Select number of perforated laterals 3 <br />b. Select perforation spacing= :::S feet. <br />c. Subtract 2 ft. from the rock layer length. <br />~1.~-~ -2 ft. -I ,,,Q) · feet. <br />d. Dete"nnine the number of spaces between perforations. <br />Length perf. spacing=(.£)___ ft. +~ft. = -Z..O spaces <br />e. :zn_ spaces+ 1 = _g_j__ perforationsnateral <br />f. Multiply perforations per lateral by number of laterals to ,,,) L/ · c,1 µ _ <br />get total number of perforations.~ x ;:,h.,..-.1 = ~ perforations; <br />g. ~ x~=-=D...gpm. <br />SELECTED PUMP CAPACITY Y ') gpm <br />B. Determine head requirements: <br />1. Elevation difference between pump and point of discharge. <br />~0'?"0;;~~ l::, feet <br />G,; 1 2. If pumping to a pressure distribution system, five feet for pressure <br />required at manifold if gravity system, zero. ~ I S:-:: feet <br />3. Friction loss ----1-i ~ ~;;:;, a. Enter friction loss table with gpm and pipe diameter. <br />\ ---z_, . Read frictio_;}-loss in feet per 1_00 feet from table. <br />F.L. = ":> •:J ft./100 ft of pipe <br />b. Detennine total pipe length from pump to discharge <br />point. Add 25 percent to pipe length for fitting <br />loss, or use a fitting loss chart. Equivalent pipe <br />length-1.25 times pipe length= <br />I -SO x 1.25 = / VJ, feet <br />c. Calculate total friction loss by multiplying <br />friction loss in ft/100 ft by equivalent pipe length. <br />Total friction loss= '3, .S--x I v 2 +100 = (,.., feet <br />4. Total head required is the sum of elevation difference, <br />special head requirements, and total friction loss. <br />l ~ (/ / -~~-"-__ + _ _e,,,~'--+--~'-- <br />(1) (2) (3d <br />TOTAL HEAD ?'-t feet <br />C. Pump selection <br />1. A pump must be selected to deliver at least <br />~ gpm '(Step A) with at least ~ feet of total head (Step B). <br />F-17 <br />ENO PERFORATION OF A P£RFORATED LATERAL <br />.. -AJ Leo•• 12• ro Ed9« <br />"'-""'!!!,.<,!'""-"'~~....,.,..,....,_,;:,.:;:",'· · of Roell. l.Dyff <br />Required Perforation Discharge <br />in gallons per minute (gpm) <br />D~e <br />Head <br />(feet) <br />~2 ind,p.,f % ind>p.,f <br />1.0a 0.56 0.74 <br />2.0b 0.80 1.04 <br />a. Use for single family homes <br />b. Use for all other applications <br />Pipe Length <br />□Pump <br />Point of ID1~7~ge <br />Elevation Difference <br /><£~ <br />F-18b <br />1.5 inch 2.0 inch 3.0 inch <br />gpm Friction loos pa I 00 ft of pipe <br />10 0.69 0.20 <br />12 0.96 0.28 <br />14 1.28 0.38 <br />16 . 1.63 0.48 <br />18 2.03 0.60 <br />20 2.47 0.73 0.11 <br />25 3.73 1.11 0.16 <br />30 5.23 1.55 0.23 <br />35 7.90 2.06 0.30 <br />40 11.07 2.64 0.39 <br />45 14.73 3.28 0.48 50 ... -··-··· ·3_99 0.58 <br />55 4.76 0.70 <br />60 5.60 0.82