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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals Quarter inch perf,orations spaced a 3' 12 � <br /> 2. Select perforation spacing= 10 ft <br /> Perf Sizing 3/16"-1/4" <br /> 3. Since perforations should not be placed closer than 1 f lot 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 agowable number of 1/4-Inch pedordons <br /> per'iaterd to guarantee<10%discharge variation <br /> -2 ft =�ft pedoratton <br /> .spacing . <br /> 4. Determine the number of spaces between perforatio f� 1 inch 1.251nch. .1.5inch 2.0 Inch <br /> Divide the length(3)by perforation spacing(2)and <br /> dower to nearest whole number. 2b 8 14 18 28 <br /> Perforation spacing= Lew ft+ 3 ft= 2:t aces 3.0 8 13 17 26 <br /> 3.3 7 12 16 25 <br /> 5. Number of perforations is equal to one plus the er of 4.0 7 11 15 23 <br /> perforation spaces(4)..Check figure E-4 to assure the n mber of 5.0 6 10 14 22 <br /> perforations per lateral guarantees<10%discharge varia on. <br /> ate. _spaces+1 = a 3 perforations/late al E-6: Perforation Discharge in gpm <br /> 6. A. Total number of perforations= perforations per teral(5) perforation diameter <br /> times number of laterals(1) Inches <br /> 7) ' (feet) 3/16 7/32 1/4 11 <br /> perfs/lat x_ _lat=�e1_perfor tions 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 sgft/perf.Does not apply to at grade . <br /> Rock bed area= rock width(ft)x rock length(ft) 5.0 0.94 1.26 1 1.65 <br /> = VO sgft a use.1.0 toot for single-family homes. <br /> Square foot per perforation=Rock bed area+n er of perfs (6) b Use 2.0 feet for an in else. <br /> _ (g_5O sgft+_LLk _perfs= 41.4. .sgft/perf MAW= IMIM AT END OF PMMM DISTRIBUTION SYSTEM <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations (6A) .by flow per perforation f see figure E4) � <br /> perfs x . 5 L g m/perfs= 3 gpm <br /> 8. If laterals are connected to header.pipe as shown upper , '-� <br /> example,to select minimum required lateral " eter;enter ,,,d► �� <br /> figure E-4 with perforation spacing(2)and number of perforations \� <br /> per lateral(5) Select minimum diameter for „ ,,,,,a,„��,nR,�, <br /> erforated lateral= inches. '"`WfTRilYTION <br /> MR <br /> 1? <br /> 9. If perforated lateral system is attached to manifold pipe near <br /> the center,lower diagram,perforated lateral len (3) and <br /> number of perforations per lateral(5)will be ap roximately one iu , .mTa <br /> half of that in step 8. Using these values,select <br /> diameter for perforated lateral= Il l'� in �,w <br /> ."now ice"" <br /> ' �d <br /> I hereby certify that I have ompleted this work in accord ce with applicable ordinances, rules and laws. <br /> P. (signature) 3®' (license#) (date) <br />