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OSTP Pressure Distribution <br /> UNIVERSITY f ` <br /> Minnesota Pollution Design Worksheet OF MINNESOTA <br /> Control Agency 4L�•.. <br /> Project ID: v 11 <br /> 1. Select Number of Perforated Laterals in system/zone: 3 --_ <br /> (2 feet is minimum and 3 feet is maximum spacing) <br /> insulated.o:o s o. <br /> :: �r 7 <br /> 2. Select Perforation Spadng: 3.0 ft '2 12'Soil rover '` ; I <br /> GPot...We t <br /> ini /� <br /> V."pertorati°rn spared 3'span I 1M"•2"mowf n rock J 11' • <br /> 3. Select Perforation Diameter Size 7/32 in _ <br /> 16 of rock <br /> 4. Length of Laterals =Media Bed Length-2 Feet. perforation sizing:•f."to V1." perforation spacing:2'to 3' <br /> 63 - 2ft = 61 ft Perforation can not be closer then 1 foot from edge. <br /> 5. Determine the Number of Perforation Spaces. Divide the Length of Laterals (Line 4)by the Perforation Spadng (Line 2)and <br /> round down to the nearest whole number. <br /> Number of Perforation Spaces = 61 ft 3 ft = 20 Spaces <br /> 6. Number of Perforations per Lateral is equal to 1.0 plus the Number of Perforation Spaces (Line 5). <br /> Perforations Per Lateral = 20 Spaces + 1 = 21 Perfs. Per Lateral <br /> Check table below to verify the number of perforations per lateral guarantees less than a 10%discharge variation. The value is <br /> double if the a center manifold is used. <br /> Maximum Number of Perforations Per Lateral to Guarantee<10%Discharge Variation <br /> '/,Inch Perforations 7/32 Inch Perforations <br /> Perforation Spacing(Feet) PipeDiameter(Inches) Perforation Spacing Pipe Diameter(Inches) <br /> 1 114 111 2 3 (Feet) 1 134 131 2 3 <br /> 2 10 13 18 30 60 2 11 ' 16 21 34 68 <br /> 211 8 12 16 28 54 261 10 14 20 32 64 <br /> 3 8 12 16 25 52 3 9 14 19 30 60 <br /> 3/16 Inch Perforations 1/8 Inch Perforations <br /> Perforation Spacing(Feet) PipeDiameter(Inches) Perforation Spacing Pipe Diameter(Inches) <br /> 1 164 lit 2 3 (Feet) 1 136 111 2 3 <br /> 2 12 18 26 46 87 2 21 33 44 74 149 <br /> 211 12 17 24 40 80 211 20 30 41 69 135 <br /> 3 12 16 22 37 75 3 20 29 38 64 128 <br /> 7. Total Number of Perforations equals the Number of Perforations per Lateral (Line 6)multiplied by the Number of <br /> Perforated Laterals (Line 1). <br /> 21 Perf. Per Lateral X 3 Number of Perf. Laterals = 63 Total Number of Perf. <br /> 8. Calculate the Square Feet per Perforation. Recommended value is 4-10 ft 2 per perforation. Perforation DhGw0e(6111) <br /> Does not apply to At-Grades ,d thr Perforation Diameter <br /> Bed Area = Bed Width(ft)X Bed Length(ft) <br /> 1.w o.1e o.a os6 0.2� <br /> 1.5 0.22 0.51 0.69 0.9 <br /> 10 ft X 63 ft = 630 ft2 2.0• 0.26 0.59 0.80 1.04 <br /> 2.5 0.29 0.65 0.89 1.17 <br /> 3.0 0.32 0.72 <br /> Square Foot per Perforation =Bed Area divided by the Total Number of Perforations (Line 7). 4.0 0.22 0.83 ,.1133 1.47 <br /> 5.0 0.41 0.93 1.26 1.65 <br /> Dwellings wi <br /> 630 ft' .r. 63 perforations = 10.0 ft2/perforations "wt perforations 3/16 inch to l/41Kh <br /> Disellfngr with Ill inch perforetlws <br /> 2 feet Other establishments end MSTS with 3116 <br /> 9. Select Minimum Average Head: 1.0 ft Inch to 114 inch perforations <br /> s feet Other establishments and MST'with Minch <br /> perforations <br /> 10. Select Perforation Discharge (GPM)based on Table III: 0.56 GPM per Perforation <br /> 11. Determine required Flow Rate by multiplying the Total Number of Perforations (Line 7)by the Perforation Discharge (Line 10). <br />