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. PRESSURE DISTRIBUTION SYSTEM Geotextue fabric 1. Select number of perforated laterals 3 f Quarter inch perforations spaced et 3" U 1 9..of rock 2. Select perforation spacing= 3 ft Perf Sizing 3/16"-1/4" 3. Since perforations should not be placed closer than 1. foot to Perf Spacing 15 the edge of the rock layer(see diagram),subtract 2 feet from the rock layer length. E-4: f1 riMUM allowable neer of 1/4-inch perforations per lateral to guarantee<10%discharge variation 41 -2 ft = 3/ ft Rock layer length perforation spacing 4. Determine the number of spaces between perforations. (feet) 1 inch 1.25 inch 1.5 inch 20 inch Divide the length(3)by perforation spacing(2)and round down to nearest whole number. 25 8 14 1 28 Perforation spacing= 3 ft=3c/ ft= / 3 spaces 3.0 8 13 26 3.3 7 12 16 25 5. Number of perforations is equal to one plus the number of 4.0 7 11 15 23 perforation spaces(4). Check figure E-4 to assure the number of 5.0 6 10 14 22 perforations per lateral guarantees <10%discharge variation. 13 spaces+ 1 = /4 perforations/lateral E-6: Perforation Discharge in gpm 6. A. Total number of perforations= perforations per lateral(5) perforation diameter times number of laterals (1) head (nches)(feet) 1/8 3/16 7/32 1/4 /7 perfs/tat x -3 lat. 112. perforations 1.00 0.18 0.42 0.56 0.74 B. Calculate the square footage per perforation. 2.0b 0.26 0.59 0.80 1.04 Should be 6-10 sqft/perf.Does not apply to at-grades. 5.0 0.41 0.94 1.26 l.b5 Rock bed area= rock width(ft)x rock length(ft) /8 ft x 41 1 ft= 1-11 0 sqft O Use 1.0 foot for single-family homes. Square foot per perforation=Rock bed area=number of perfs(6) b use 2.0 feet for anything else. 41 f 0 sqft_ 42 perfs= '-7( sqft/perf SWOFOLD LOCATED AT OM OF DISTRIBUTION SYSTEM 7. Determine required flow rate by multiplying the total number of perforations(6A) by flow per perforation(see figure E-6) Z perfs x r 74 gpm/perfs= 3) gPm A 8. If laterals are connected to header pipe as shown on upper / l"""'rr: -� example,to select minimum required lateral diameter;enter - cam" figure E-4 with perforation spacing(2)and number of perforations \,-- -- per ,--/per lateral(5) Select minimum diameter for l..r";,,ES �,� FOR perforated lateral= inches. ,O�,,,IO 11.6,4..0 9. If perforated lateral system is attached to manifold pipe nearv� x,�, ° the center,lower diagram,perforated lateral length(3)and r . number of perforations per lateral(5)will be approximately one `--urt,.:�.e.,d- - half of that in step 8. Using these values,select minimum m-2.0-4 diameter for perforated lateral= inches. `��. ..,rte I hereby certify t I have completed this work in accordance with applicable ordinances, rules and laws. & y 4- (signature) (license#) -5--3--/e) (date)