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PRESSURE DISTRIBUTION SYSTEM <br /> All boxed rectangles must be entered,the rest wi be calculated. <br /> 1. Select number of perforated laterals: 3 �c•x«k� � <br /> r4..._..,....._..,.....,..ead_,. 11. 72" <br /> 2. Select perforation spacing= 3 ft <br /> rbrf Si zi ns,.IR-I/�" <br /> 3. Since perforations should not be placed closer that 1 foot to <br /> the edge of the rock layer(see diagram),subtract 2 feet from <br /> the rock layer - r h <br /> 3-8 -2ft= 36 ft <br /> 4 Determine the number of spaces between perforations. <br /> Divide the length(3)by perforation spacing(2)and round down to nearest whole number. <br /> Perforation spacing= 36 ft/ 3 ft= 12 <br /> 5. Number of perforations is equal to one plus the number of perforation spaces(4). <br /> Check figure E-4 to assure the number of perforations per lateral guarantees <br /> <10%discharge variation. <br /> 12 spaces+1 = 13 perforations/lateral <br /> E-4 Maximum Number of 1/4 inch perforations E-6 Perforation Discharge he GPM <br /> per lateral to guarantee<10%discharge variation Head Perforations diameter <br /> Perforation (feet) (inches) <br /> Spacing 3/16 7/32 1/4 <br /> feet 1 inch 1.25 inch 1.5 inch 2.0 inch 1° 0.42 0.56 0.74 <br /> 2.5 8 14 18 28 2° 0.59 0.80 1.04 <br /> 3.0 8 13 17 26 5 0.94 1.26 1.65 <br /> 3.3 7 12 16 25 a Use f.o foot for singlafamiy homes. <br /> 4.0 7 11 15 23 b.Use 2.0 feet for anything else <br /> 5.0 6 10 14 22 <br /> 6. A.Total number of perforations=perforations per lateral(5)times number of laterals(1). <br /> 13 perfs/lot x 3 laterals= 39 perforations <br /> B.Calculate the square footage per perforation. <br /> Recommended value is 6-10 sgft/perf.Does not apply to at-grades. <br /> 1. Rock bed area=rock width(ft)x rock length(ft) <br /> 10 ft x 38 ft= 380 ft2 <br /> 2. Square foot per perforation=Rock Bed Area/number of perfs(6) <br /> 380.0 ft2 / 39 perfs = 9.7 ft2/perf <br /> 7. Determine required flow rate by mukipying the total number <br /> of perforations(6A)by flow per perforations(see figure E-6) <br /> 39 perfs x ( 0.74 Igpm/perfs= 29.0 gpm <br /> • <br /> 8. If laterals are connected to header pipe as shown <br /> in Figure E-1,to select minimum required lateral ( ' <br /> diameter;enter figure E-4 with perforation spacing(2)and I <br /> number of perforations per lateral(5). Lam.E-I:ManlbW LaoaMa al End of°ysa«n <br /> Select minimum diameter for perforated laterals= 2 inches <br /> 9. If perforated lateral system is attached to manifold pipe ^ En„^�° <br /> near the center,like Figure E-2,perforated lateral length(3) •-- <br /> and number of perforations per lateral(5)will be approximately <br /> one half of that in step 8. Using these values,select <br /> minimum diameter for perforated lateral= 2 inches. . �--,, <br /> I hereby certify that I have completed this work in accordance with all applicable ordinances,rules and laws. <br /> (signature) 810 (license#) gel/7/U7 (date) <br /> Page 1of1 <br />