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OSTP Pressure Distribution <br /> UNIVERSITY -A"',' <br /> Minnesota Pollution Design Worksheet OF MINNESOTAibio! <br /> kft <br /> Control Agency <br /> Project ID: v 11.09.22 <br /> 1. Select Number of Perforated Laterals in system/zone: ------- <br /> (2 feet is minimum and 3 feet is maximum spacing) "n" "" <br /> 2. Select Perforation Spacing: 3.0 ft 12;- .. _ ._ 12:`5pi1 <br /> Mmfmum <br /> 12 <br /> 3. Select Perforation Diameter Size I 1 t'4 in pe,fara"�"s spa-ed 3-apa.t 1 -a of... <br /> 6-of tack <br /> 4. Length of Laterals =Media Bed Length-2 Feet. Ped-.O-slzinll Perfa.a,ian spaOnq:a•to 3• <br /> 38 - 2ft = 36 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 Spacing (Line 2)and <br /> round down to the nearest whole number. <br /> Number of Perforation Spaces = 36 ft ft = 12 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 = 12 Spaces + 1 = 13 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 /> V,inch Perforations 7/32 Inch Perforations <br /> Pipe Diameter(Inches) Perforation Sparing Pipe Diameter(Inches) <br /> Perforation Spacing(Feet) 1 1% 111 1 3 (Feet) 1 116 01 2 3 <br /> 2 10 13 18 30 60 2 11 16 21 34 68 <br /> 21't 8 12 16 28 54 A 10 14 20 32 64 <br /> 3 8 12 16 25 52 3 9 14 19 30 60 <br /> 3/16 Inch Perforations 118 Inch Perforations <br /> Perforation Spacing(Feet) Pipe Diameter(Inches) Perforation Spacing Pipe Diameter(Indies) <br /> 1 1% iv� 2 3 (Feet) 1 116 114 2 3 <br /> 2 12 18 26 46 87 2 21 33 44 74 149 <br /> 214 12 17 24 40 80 2�i 20 30 41 69 135 <br /> 3 12 16 22 37 75 3 20 29 38 64 1 128 <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 /> 13 Perf. Per Lateral X �3�Number of Perf. Laterals = 39 Total Number of Pert. <br /> 8. Calculate the Square Feet per Perforation. Recommended value is 4-10 ft2 per perforation. Perforation OHcheree(0P%) <br /> Perforation DMineoar <br /> Does not apply to At-Grades Head Oft) I/. ,/1. ,�„ 1% <br /> Bed Area = Bed Width(ft)X Bed Length(ft) <br /> t.o' 0.18 0.41 0.56 0.74 <br /> ��Z 1.5 0.22 0.71 0.69 0.9 <br /> 10 ft X 38 ft = 380 iL 20 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 0.98 1.28 <br /> Square Foot per Perforation =Bed Area divided by the Total Number of Perforations (Line 7). 4.0 0.37 o.0 1.13 1.47 <br /> 4.0 0.41 0:93 t36 1.K <br /> 1 foot 0weliinip with 3116 inch to 1/4 inch <br /> 380 ft2 39 perforations = 9.7 fe/perforations pe ioratiad <br /> Dwellings with 118 Inch perforations <br /> a feet Other establishments and MS1S with 3116 <br /> 9. Select Minimum Average Head: 1.0 ft inch to 114 inch perforation <br /> 5 feet Other establishments and MSTS with 1/0 Inch <br /> perforations <br /> 10. Select Perforation Discharge (GPM)based on Table 111: 0.74 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 />