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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals 3 . -I Quarter inch perforations spaced a 3' <br /> 2. Select perforation spacing= 3, 0 ft <br /> g"aro <br /> ck <br /> Perf Sizing 3/1e-1/4" <br /> 3. Since perforations should not be placed closer than 1 foot to Perf Spang, 1.5'-5' <br /> the edge of the rock layer(see diagram),subtract 2 feet from <br /> the rock layer length. E-4: Maximum a1Iowable number of 1/4-inch perforations <br /> per lateral to guarantee<10%discharge variation <br /> 3'7Rock layer iength -2 ft = 3 ft perforation <br /> spacing ' <br /> 4. Determine the number of spaces between perforations. (feet) 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> Divide the length(3)by perforation spacing(2)and round <br /> down to nearest whole number. 2:5 8 14 18 28 <br /> Perforation spacing= -3,S ft+ 3 ft= )z spaces X3.0 8 13 17 26 <br /> 3.3 7 12 16 25 <br /> 5. Number of perforations is equal to one plus the number of 4.0 7 11 15 23 <br /> perforation spaces(4)..Check figure E-4 to assure the number of 5.0 6 10 14 22 <br /> perforations per lateral guarantees<10%discharge variation. - <br /> 1-z.- spaces+1 = 13 perforations/lateral E-6: Perforation Discharge in gpm <br /> 6. A. Total number of perforations= perforations per lateral(5) perforation diameter <br /> times number of laterals(1) head inches) <br /> (feet) 3/16 7/32 1/4 <br /> l3 perfs/lat x 3 lat= 3'1 perforations 1.00 0.42 0.56 0.74 <br /> B. Calculate the square footage per perforation. 2.0b 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)x rock length(ft) 5.0 0.94 1.26 1.65 <br /> JO ft x 3 7 ft= 3 00 sqft a Use 1.0 foot fpr single-family homes. <br /> Square foot per perforation=Rock bed area+number of perfs (6) b Use 2.0 feet for am/hino else. <br /> 3')C) sqft+ 3 q perfs= 9,Li sgft/perf MANIFOLD LOCATED AT c►a or PRESSURE aSTRPBUTION SYSTEM <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation(see figure E-6) x. <br /> 1 N <br /> 3 9 perfs x .1%-% gpm/perfs= aq gpm .-‘ <br /> 8. If laterals are connected to header pipe as shown on upper ,, :� <br /> example,to select minimum required lateral diameter;enter ir,,,,gy°""D r"r�. <br /> figure E-4 with perforation spacing(2)and number of perforations \, <br /> per lateral(5) Selectminimum diameter for or,ten,,,,E„TENALS„p <br /> perforated lateral= 1112- inches. c 01TIMUTION w MOUND <br /> MC <br /> 9. If perforated lateral system is attached to manifold pipe near <br /> the center,lower diagram,perforated lateral length(3)and ' `` 's''„" <br /> -tire. <br /> number of perforations per lateral(5)will be approximately one : awra..Ta- <br /> half of that in step 8. Using these values,select minimum `` •- .wa.iu k,M;, <br /> diameter for perforated lateral= inches. ... a <br /> ►,,l,, <br /> I hereby certify that I ve completed this work in accordance with applicable ordinances, rules and laws. <br /> l&---tg, <br /> (signature) 3° (4 (license#) :)-1'-i--O? (date) <br />