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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> Za - <br /> 1. Select number of perforated laterals 3 Quarter inch perforations s aced Q3• 12 - <br /> 2. Select perforation spacing = 3 ft 1 <br /> 9"of rock <br /> Perf Sizing 3/16"-1/4" <br /> 3. Since perforations should not be placed closer than 1 foot to Perf Spacing 15-5' <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 perforatim, <br /> t.12per lateral to guarantee<10%discharge variation <br /> le <br /> Rock layer ngth -2 f t U ft Perforation <br /> 4. Determine the number of spaces between perforations. spacing <br /> Divide the length (3) by perforation spacing (2) and rotund feet 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> down to nearest whole number. 2.5 8 14 18 28 <br /> Perforation spacing= Lo ft_ ft= 94.>spaces 3.0 8 13 17 26 <br /> 5. Number of perforations is equal to one plus the number of 3.3 1 12 16 254 0 7 11 15 23 <br /> perforation spaces(4). Check figure E-4 to assure the number of 5.0 6 10 14 22 <br /> perforations per lateral guarantees <10% discharge variation. <br /> spaces+ 1 = _perforations/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 /> perforations (feet) 3/16 7/32 1/4 <br /> �_perfs/lat x_ _lat=-(,2�p 1.00 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-grades. <br /> Rock bed area = rock width (ft)x rock length(ft) 5.0 1 0.941 1.26 1 1.65 <br /> a ft x /U ft=--&k-c.---sgft a Use 1.0 foot for single-fornily homes. <br /> Square foot per perforation = Rock bed area =number of perfs (6) b Use 2.0 feet for anything else. <br /> 64ca sgft --CL?-perfs=--14;- sgft/perf MANIFOLD LOCATO AT END or PRESSURE o.sTRIBUTION SSTE. <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations(6A) by flow per perforation(see figure E-6) .. <br /> 3 perfs x .7'i gpm/perfs =_ Z gpm <br /> 8. If laterals are connected to header pipe as shown on upper <br /> example,to select minimum required lateral diameter;enter �,,r/°q <br /> figure E-4 with perforation spacing (2) and number of perforations /``l <br /> per lateral(5) Select minimum diameter for <br /> "TOUT Or I[R/'OP/1TtD MPF LgT[RglS Ipq <br /> MOU <br /> perforated lateral = inches. PRESSURE DISTAMUTIO W M <br /> M ro nnTa:.Pr <br /> 9. If perforated lateral system is attached to manifold pipe nearEM <br /> �M�R,.TR»s,..at,• „�, �` <br /> the center,lower diagram,perforated lateral length (3) and n��'"'r` "�"`� ; ,,, <br /> MM <br /> number of perforations per lateral (5) will be approximately one Kgs;:T ,,at.TTR W <br /> half of that in step 8. Using these values, select minimum ' <br /> diameter for perforated lateral = i.Xs inches. r� <br /> a <br /> ` rFgsM <br /> Of <br /> I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. <br /> 6/U (license# .��/a � <br /> (signature) ) (date) <br />