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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals .3 ( __ CF, 12 <br /> 2. Select perforation spacing= 3•0 f I <br /> ft of nick <br /> Perf Sizing 3/16"-1/4" <br /> 3. Since perforations should not be placed closer than 1 foot to Perf Spacing 1.5'-5' <br /> the edge of the rock layer (see diagram),subtract 2 feet from <br /> the rock layer length. E-4: Maximum allowable number of 1/4-inch perforations <br /> Z per lateral to guarantee<10%discharge variation <br /> Rock layer length -2 ft =, (pc) ft perforation <br /> spacing4. Determine the number of spaces between perforations. <br /> Divide the length(3)by perforation spacing(2) and round (feet) 1 Inch 1.25 inch 1.5 inch 2.0 inch <br /> down,to nearest whole number. <br /> 2.5 8 14 18 28 <br /> Perforation spacing= (PO it+ 3 ft= -At) spaces 3.0 8 13 17 <br /> 5. Number of perforations is equal to one plus the number of 3.3 7 12 16 25 <br /> perforation spaces(4). Check figure E-4 to assure the number of 4.0 7 11 15 23 <br /> perforations per lateral guarantees <lp%discharge variation. 5.0 6 10 14 22 <br /> a' spaces+1 = a 1 ,perforations/lateral E-6: Perforation Discharge in gpm <br /> 6. A. Total number of perforations =I perforations per lateral (5) perforation diameter <br /> times number of laterals (1) head inches) <br /> (feet) 3/16 7/32 1/4 <br /> 2.1 perfs/lat x lat= (o' perforations <br /> 1.00 0.42 0.56 COQ) <br /> B. Calculate the square footage per perforation. 2.Ob 0.59 0.80 1.04 <br /> Should be 6-10 sqft/perf. Does not apply to at-grades. <br /> Rock bed area = rock width (ft)Dc rock length(ft) 5.0 0.94 1.26 1.65 <br /> i 1, ft x 1,2- ft= (.90 sqft ° Use 1.0 foot for single-family homes. <br /> Square foot per perforation=Rock bed area+number of perfs(6) b Use 2.0 feet for anything else. <br /> e a0 sqft+ t•3 perfs= 07, 44 sqft/perf MANIFOLD LOCATED AT EMD OF PRESSURE DISTRIBUTION SYSTEM <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation(see figure E-6) <br /> PM <br /> to perfs x . -+ gpm/iperfs= -4 0 gpm ,I.W <br /> • <br /> 8. If laterals are connected to heade pipe as shown on upper • 1 <br /> example,to select minimum required lateral diameter;enter a '° <br /> figure E-4 with perforation spacing(2)and number of perforations \�`"�M <br /> per lateral(5) Select minimum di4meter for <br /> LAYOUT CO PERMUTED PIPE LATERALS FOR <br /> perforated lateral= a inches. PRESSURE msTRMAITRIN w MOUND <br /> PWAOMTRO R.STM PRI <br /> 9. If perforated lateral system is attached to manifold pipe near E� , Aa ,,,� ` <br /> the center,lower diagram,perforated lateral length(3) and <br /> M. '` �` R Y ° <br /> number of perforations per later (5)will be approximately one --car.».---R. <br /> half of that in step 8. Using these values,select minimum �" '• -,*,m,m,.., <br /> diameter for perforated lateral= l inches. 2 <br /> _p& <br /> N-t- <br /> I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. <br /> ,p r' <br /> V~`�(1� ' % `(signature) 3°1 4 (license#) a -c'1 -1 .5.-- (date) <br />