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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric 1. Select number of perforated laterals 3 Quarter inch perforations space 12 2. Select perforation spacing= 5 ft s'of:.rock 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 (o ceper laterd to guarantee d 0%discharge variation Rock ayer lenger, -2 ft - ft perforation 4. Determine the number of spaces between perforations. spacing feet 1 Inch 1.25 inch 1.5 inch 2.0 inch Divide the length(3)by perforation spacing(2)and round down to nearest whole number. 2.5 8 14 18 28 Perforation spacing= (o(,e ft+ _,S ft=ate_spaces 3.0 8 13 17 26 5. Number of perforations is equal to one plus the number of 3.3 7 12 16 254.0 7 11 15 23 perforation spaces(4). Check figure E-4 to assure the number of perforations per lateral guarantees <10%discharge variation. 1 5.0 6 10 14 22 spaces+ 1 = 2.7--, 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 Inches (feet) 3/16 7132 1/4 11 a�perfs/lat x _lat= �L_perforations 1.Oa 0.42 0.56 0.74 B. Calculate the square footage per perforation. 2.0b 0.59 0.80 1.04 Should be 6-10 sqft/perf. Does not apply to at-grades. Rock bed area = rock width (ft) x rock length(ft) 5.0 0.94 1.26 1.65 /ft x (ou ft= taus Sgft a 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 anythina else. La q U sgft+_21-perfs = '.Z sgft/perf M"IFOLO 10CATED AT END OF PRESSURE DISTRIBUTION SYSTEM 7. Determine required flow rate by multiplying the total number of perforations (6A) by flow per perforation(see figure E-6) perfs x g m/perfs= �� gpm 8. If laterals are connected to header pipe as shown on upper ' example,to select minimum required lateral diameter;enter figure E-4 with perforation spacing (2) and number of perforations per lateral(5) Select minimum diameter for urour OF rERroR.rro vlvE I..rER.Is FOR perforated lateral= inches. PRESSURE D STRIOUTION IN MWW KRNNYTSp R.STK PK 9. If perforated lateral system is attached to manifold pipe near CE,�„�,m "coo the center,lower diagram,perforated lateral length(3) and VIEW 7aN ,Ta+ truPxrcoo number of perforations per lateral (5)will be approximately one KIr�sI�aP ��orTw o, half of that in step 8. Using these values,select minimum �- diameter for perforated lateral = IL-1_inches. If too I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. (signature) 3 c)L4 (license#) z--)g-b Z (date)