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Pump Selection Procedure <br /> A. Determine pump capacity: <br /> Gravity Distribution <br /> 1. Minimum use is 600 aallons per hour(10 gpm) to stay <br /> ahead of water use rate. <br /> ?. Maximum suggested for delivery to a drop box of a home <br /> system is ?,700 gallon per hour (45 gpm) to prevent build-up <br /> of pressure in the drop bo�c. <br /> Pressure Distribution <br /> 3. <br /> a. The number of perforated laterals is 3. <br /> b. The perforation spacing will be 3 feet on center. <br /> c. Subtract 2 ft. from the rock layer len�h; <br /> �0 - 2 = =�8feet <br /> d. Determine the number of spaces between perforations; <br /> by dividing 3.c by 3.b; <br /> 48 / 3 = 16 spaces <br /> e. 16 spaces + 1 = 17 �erforations per lateral <br /> £ Vlultiply the 3.a and 3.e to determine <br /> the total number of perforations; <br /> 3 � 17 = 5� total perforations <br /> g. Multiply 3.f and 0.74 to determine the gpm; <br /> �4 x 0.74 = 39 aallons per minute <br /> SELECTED PUyIP MI�1II�II;NI CAPACITY = 39 GP1�T <br /> B. Determine the head pressure requirements. <br /> 1. Elevation difference between the pump <br /> and the point of discharge is 8 feet. <br /> 2. Add 5 feet of head for pressure required at the <br /> manifold if this is a pressure distribution system. <br /> 3. Friction loss; <br /> a. Enter the friction loss multiplier from <br /> the table wit gpm & pipe diameter. <br /> 1.55 <br /> b. Determine the pipe length from the <br /> pump to the discharge point. Add 25°�0 <br /> to the pipe length for fitting loss. <br /> 50 x 1.2� = 63 feet <br /> c. Calculate the total friction loss by muitiplying <br /> B.3a by B.3b and dividing by 100 and rounding up; <br /> (1.55 Y 63)/ 100 = 1 feet <br /> 4. Calculate the total head required by totaling B.l, B.2, and B.3c; <br /> � 8 + 5 + 1 = 14feetofhead <br /> TOT�L REQUIRED NI�VI HEAD IS 14 FEET. <br /> The pump installed must be able to deliver at least 39 gallons per minute with at <br /> least 14 feet of head. <br />