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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals Quarter inch perforations s aced®3' 12 <br /> 2. Select perforation spacing= .�:? ft of`.ro`k <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 /> JD per lateral to guarantee d0%discharge variation <br /> Rock layer lenigeir -2 ft --j_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. <br /> 2.5 8 14 18 28 <br /> Perforation spacing= 4 V: ft+3--ft= spaces 3.0 8 13 _17 26 <br /> 2 16 25 <br /> .3 7 1 <br /> 5. Number of perforations is equal to one plus the number of 3 3.0 7 1 t 1 <br /> perforation spaces(4). Check figure E-4 to assure the number of 23 <br /> 5.0 6 10 15 5 22 <br /> perforations per lateral guarantees <10% discharge variation. <br /> )t _spaces + 1 = I� 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) 11 head Inches <br /> 11) -j \J I r)' (feet) 3/16 7/32 114 <br /> perfs/lat x at=-�perforations 1.Oa 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 /> jft X l) ft= O 0 sgft a 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 /> U sgft+ _perfs = 'D.'l sqft/perf <br /> MANIFOLD LOCATED AT END 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) MYWO,D <br /> I)Li Lb <br /> _perfs x 1 g m/perfs = gpm <br /> 8. If laterals are connected to header pipe as shown on upper <br /> example,to select minimum required lateral diameter;enter <br /> figure E-4 with perforation spacing (2) and number of perforations <br /> per lateral (5) Select minimum diameter for YOUT Of <br /> 1 i 4 PRESSURE DISTRIBUTWN N MOUND TED PIPE LATERALS FOR <br /> perforated lateral= Z inches. <br /> ��{{RMWMTED RKTK PIP[ <br /> 9. If perforated lateral system is attached to manifold pipe near `LR DR.tNM voD y y�"A <br /> the center,lower diagram,perforated lateral length (3) and w ` ''`�' ' <br /> YrwlDlD <br /> number of perforations per lateral (5)will be approximately one RMpYyp{".pTTW„ R <br /> half of that in step 8. Using these values, select minimum <br /> IND CAP %01 <br /> - ITTM(IRMI <br /> diameter for perforated lateral = inches. AW <br /> d " <br /> I hereby certify that I havmpleted this work in accordance with applicable ordinances, rules and laws. <br /> (signature) 3 n/ y (license#) ' Z 0 Z(date) <br />