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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals 3 <br /> Quarter inch perforations spaced®3' U n <br /> 2 -► <br /> 2. Select perforation spacing= 3.0 ft a of.rocic <br /> 3. Since perforations should not be placed closer than 1 foot to Perf S Perf Sizing S g 1.15-51/4 <br /> the edge of the rock layer (see diagram),subtract 2 feet from <br /> the rock layer length. <br /> E-4: Maximum allowable number of 1/4-inch perforations <br /> Rock l ength -2 ft = s?� ft per lateral to guarantee<10%discharge variation <br /> perforation <br /> 4. Determine the number of spaces between perforations. spacing <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 /> Z5 8 14 1 <br /> Perforation spacing= S3 ft+ 3 ft= 17 spaces 3.0 _.__8 w13 _ 17 6 <br /> 5. Number of perforations is equal to one plus the number of 3'3 12 16 25 <br /> perforation spaces(4). Check figure E-4 to assure the number of 4'0 6 11 15 23 <br /> perforations per lateral guarantees <10%discharge variation. 50 6 10 14 22 <br /> 12 spaces + 1 = 14I perforations/lateral <br /> E-6: Perforation Discharge in gpm <br /> 6. A. Total number of perforations = perforations per lateral (5) <br /> times number of laterals(1) perforation diameter <br /> head (Inches) <br /> I perfs/lat x 3 lat= 5-41perforations (feet) 3/16 7/32 1/4 <br /> B. Calculate the square footage per perforation. 1.00 0.42 0.56 0.74 <br /> Should be 6-10 sqft/perf. Does not apply to at-grades. 2.0b 0.59 0.80 1.04 <br /> Rock bed area = rock width (ft)x rock length(ft) 5.0 <br /> lo ft x SS ft= SY° sqft <br /> 0.94 1.26 1.65 <br /> Square foot per perforation = Rock bed area +number ofperfs (6) b Use 1.0 foot for single-family homes. <br /> S�0 sqft+ Use 2.0 feet for anything else. <br /> q �`f perfs = /o.Z sqft/perf <br /> 7. Determine required flow rate by multi1 In MANIFOLD LOCATED AT END OF <br /> PRESSURE DISTRIBUTION SYSTEM <br /> perforations (6A) by flow per perforation(see figure E-6)unber of <br /> St•f- perfs x r')tf gpm/perfs= 4D gpm ....ao. <br /> 8. If laterals are connected to header pipe as shown on upper <br /> example,to select minimum required lateral diameter;enter „ ��`"` ...E <br /> figure E-4 with perforation spacing (2) and number of perforations \,..- two I <br /> - <br /> per lateral (5) Select minimum diameter for <br /> IAGPoosaRoYTANPION LaAT[R:Ns Operforated lateral= 2•0 inches. <br /> 9. If perforated lateral system is attached to manifold pipe near � ..E <br /> .ENIONo RAMC..E <br /> the center,lower diagram,perforated lateral length(3) and OO <br /> .fM, lw' .`"•-"fig" A��°""� � <br /> number of perforations per lateral (5)will be approximately one K. ,,,��,b„� « r""° <br /> half of that in step 8. Using these values, select minimum b fti:,•K."` �0- <br /> diameter for perforated lateral = inches. " �•+ s��.; <br /> - " <br /> Ea L OP <br /> rI <br /> I hereby certify that I ha e completed this work in accordance with applicable ordinances, rules and laws. <br /> si nature <br /> ( g ) 3°1 Li (license#) 4 -Zc1-O .7 (date) <br />