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PRESSURE DISTRIBUTIONS STEM Geotextile fabric <br /> 1. Select number of perforated laterals Quarter inch Perforations soaced a 3' 12 <br /> X34)+-10 <br /> 9,7 of lock <br /> 2. Selecterforation g <br /> s acin 3 y <br /> P P = ft <br /> a).i>j$i=9 -( z 5 e Perf Sizing 3/16"-1/4" <br /> 3. Since perforations should not be placed closer than 1 Toot 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 /> per lateral to guarantee<10%discharge variation <br /> -2 ft t perforation <br /> 4. Determine the number of spaces between perforations. spacing <br /> 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= ft+ fl�= spaces 3.0 8 13 17 26 <br /> _ 2 16 25 <br /> 3.3 7 1 <br /> 5. Number of perforations is equal to one plus the number of 4 0 7 1 i 15 23 <br /> perforation spaces(4). Check figure E-4 to assure the number of <br /> perforations per lateral guarantees <10%discharge variation. 1 5.0 1 6 10 1 14 22 <br /> spaces +1 = perforati ns/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 /> perfs/lat x lat= .5 a perforations (feet) 3/16 7/32 114 <br /> 1.0a 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 dt-grades. <br /> Rock bed area= rock width (ft)x rock length(ft) 5.0 0.94 1.26 1.65 <br /> ft x ft= 90 0 sgft i 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 onythinq else. <br /> E'o 0 sqft+ 24 perfs= /(o sgft/perf MANIFOLD �TW 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(se figure E-6) „,X20 <br /> ►)y`lo)v4. <br /> IrIg perfs x i') m/perfs= 3 gpm <br /> 8. If laterals are connected to header pipe as shwn on upper `�,, <br /> example,to select minimum required lateral iameter;enter .d,�..''° " <br /> figure E-4 with perforation spacing(2) and number of perforations ��`"° <br /> per lateral(5) Select minimum diameter for <br /> perforated lateral= I rl-L inches. ""°° *p TON of M `°" <br /> 9. If perforated lateral system is attached to manifold pipe near <br /> the center,lower diagram,perforated lateral length (3) and Oji "K� <br /> tro <br /> number of perforations per lateral(5)will be approximately one <br /> half of that in step 8. Using these values,sele ft minimum b �- <br /> diameter for perforated lateral= inches. <br /> "".'00 <br /> OF . <br /> I hereby certify that I have completed this work in acco dance with applicable ordinances, rules and laws. <br /> 7 t--��• % (signature) 3�''l (license#) `)-a`-1-0 Z (date) <br />