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, <br /> , , Unlevel Pressure Distribution System Design <br /> 1. Lay out system in order of highest to lowest elevation <br /> Line 1 Elevation 1018.7 ft Length 111 ft <br /> Line 2 Elevation 1018.0 ft Length 111 ft <br /> ; Line 3 Elevation ft Le�gth ft , <br /> i Line 4 Eleva6on ft Le�gth ft <br /> Line 5 Elevation ft Length ft � <br /> 2. Change in Elevation over the Trenches <br /> Highest elevation-lowest elevation: 1018.7 - 1018.0 = 0.7 feet <br /> 3. Total Head=head at orifices(Zft)+change in elevation(2) 2 ft + 0.7 ft = 2.7 feet <br /> ('�f gr+eater than 5 feet modify design) <br /> 4. Cakulate pressure head for each system <br /> 1. Highest Trench Elevation the Head=2 feet <br /> 2. Po+(E1 -Ex)=eEx <br /> Line 1 Elevation 1018.7 2+[E1 -E1]=2 + [ 1018_7 - 1018.7 j= 2.0 feet <br /> Line 2 Elevation 1018.0 2+[E1 -E2j=2+ [ 1018.7 - 1018.0 ]= 2.7 feet <br /> Line 3 Elevation 0.0 2+[E1 -E3]=2+ [ 1018.7 - 0.0 ]= 0.0 feet <br /> Line 4 Elevation 0.0 2+[E1 -E4]=2+[ 1018.7 - 0.0 j= 0.0 feet <br /> Line 5 Elevation 0.0 2+[E1 -E5]=2+( 1018.7 - 0.0 ]= 0.0 feet <br /> 5. Determine flow rate per hole(See Ngure E-6) <br /> Line 1 Pres 2.0 Perf Diameter 3N6 = 0.59 gpm <br /> Line 2 Pres 2.7 Perf Diameter 3/16 = 0.69 gpm <br /> Line 3 Pres 0.0 Perf Diameter = gpm <br /> Line 4 Pres 0.0 Perf Diameter = gpm <br /> Line 5 Pres 0.0 Perf Diameter = gpm <br /> 6. Calculate flow for Line 1 <br /> Number of perforations- len th of pipe-2)/spacing]+1 <br /> [( 111 ft-2ft) / 3 � ft]+1 = 37 perforations(Check figure E-4 to make sure it is ok) <br /> Flow= number of perforations x flow rate <br /> 37 perf x 0.59 gpm = 21.8 gpm <br /> 7. Calculate the gallons per foot for Line 1 <br /> Gallons/length= 21.8 gpm / 111 ft= 0.20 gpm/ft <br /> E�Perforation Dischar e in GPM E�Maximum Number of 1/4 inch perforations <br /> Pressure r lateral to uarantee<10°k discha e variation <br /> Head PerForation Diameter in inches PerForation <br /> feet 1/8 3/16 7/32 1/4 Spacing <br /> 1 0.18 0.42 0.56 0.74 feet 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> 1.5 0.22 0.51 0.68 0.90 2.5 8 14 18 28 <br /> 2 0.26 0.59 0.80 1.04 3.0 8 13 17 26 <br /> 2.5 0.29 0.65 0.88 1.17 3.3 7 12 16 25 <br /> 3 0.32 0.72 0.98 1.28 4.0 7 11 15 23 <br /> 4 0.37 0.83 1.13 1.47 5.0 6 10 14 22 <br /> Page 1 of 2 <br />