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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric M- , 1. ' Select number of perforated laterals 3 1 Quarter inch perforations spaced Q 3 } 1� 9 of rock 2. Select perforation spacing = 3•0 ft - Perf Sizing 3/16"- 1/4" 3. Since perforations should not be placed closer than 1 foot to Perf Spacing 1.5'-5' the edge of the rock layer (see diagram),subtract 2 feet from the rock layer length. E-4: Maximum allowable number of 1/4-inch perforations l _ per lateral to guarantee<10%discharge variation Rock layer length -2 ft `? ft perforation spacing 4. Determine the number of spaces between perforations. Divide the length (3)by perforation spacing (2) and round (feet) 1 inch 1.25 inch 1.5 inch 2.0 inch down to nearest whole number. 2.5 8 14 18 28 Perforation spacing= 3'1 ft_ 3 ft= 1 spaces 3.0 _____8, _ 13 _ _17 26 5. Number of perforations is equal to one plus the number of 3.3 7 12 16 25 perforation spaces(4). Check figure E-4 to assure the number of 4,0 7 11 15 23 perforations per lateral guarantees <10% discharge variation. 5.0 b 10 14 22 1". spaces + 1 = l if 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) y head (inches) 11Ii F"11- (feet) 1/8 3/16 7/32 1/4 H y perfs/lat x 3 lat= 47- perforations 1.00 0.18 0.42 0.56 (0.74., B. Calculate the square footage per perforation. Should be 6-10 sqft/perf. Does not apply to at-grades. 2.0b 0.26 0.59 0.80 1.04 Rock bed area = rock width (ft) x rock length (ft) 5.0 0.41 0.94 1.26 1.65 /0 ft x 4/ ft= i4 l0 sqft w ° Use 1.0 foot for single-family homes. h Square foot per perforation=Rock bed area-number of perfs (6) b Use 2.0 feet for anything else. 4)0 sqft- HI- perfs = c').') sqft/perf 7. Determine required flow rate by multiplying the total number of • manifpldpipe perforations (6A) by flow per perforation (see figure E-6) `✓ pipe frompass i14 a, 9' - perfs x ,17`-1 gpm/perfs = 3I gpm end cop `O 8. If laterals are connected to header pipe as shown on upper %.,• example,to select minimum required lateral diameter;enter oa(plpeefpbcoton 1pe from pump figure E-4 with perforation spacing (2) and number of perforations Figure E-1:Manifold Located at End of System per lateral (5) Select minimum diameter for perforated lateral= 1ill- inches. Figure E-2:Manifold Located end cop in the Center of the System 9. If perforated lateral system is attached to manifold pipe near the center,lower diagram,perforated lateral length (3) and . morifoldpipe number of perforations per lateral (5) will be approximately one half of that in step 8. Using these values,select minimum diameter for perforated lateral = inches. leo" ollerralelo o(pipe tom pump pipe tom pump • I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. 1 g... ,,z-," „a. (signature) 7,9 4 (license#) }'a") P` (date)