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OSTP Pressure Distribution <br /> UNIVERSITY . r. <br /> ,te <br /> Minnesota Polluln Desgn Worksheet OF MINNESOTA -, ; <br /> Control Agency <br /> 1. Select Number of Perforated Laterals in system/zone: 3 Geoteatile n <br /> ��pi� §�gglapO D�pBCjr g }Minimum G-i if 1pg <br /> (2 feet is minimum and 3 feet is maximum spacing) l^"„Perforations spaced 3yapart° q it z'of rocks s ter`i'asze � <br /> 2. Select Perforation Spacing: '` '` '`�' <br /> f P g' 3.0 ft :ta 1 '+ . 1,` `, roc , iz ' <br /> + � + , 9 of rock ti;":+ •+ _�} i!1 l�+�4 <br /> + + + <br /> 3. Select Perforation Diameter Size 1/4 inch Perforation sizing' l+ <br /> 1."to' ' <br /> Perforation spacing:2'to 3' <br /> 4. Length of Laterals =Media Bed Length-2 Feet. Perforation can not be closer then 1 foot from edge. <br /> 50 - 2ft = 48 ft <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 = 48 ft 3 ft = 16 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 = 16 Spaces + 1 = 17 Perfs. Per Lateral <br /> Check Table I to verify the number of perforations per lateral guarantees less than a 10%discharge variation. The value is double if <br /> the a center manifold is used. <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 /> 17 Perf. Per Lateral X 3 Number of Perf. Laterals = 51 Total Number of Perf. <br /> 8. Calculate the Square Feet per Perforation. Recommended value is 4-10 ft 2 per perforation. <br /> Perforation Discharge(GPM) <br /> Does not apply to At-Grades Perforation Diameter <br /> Head(ft) <br /> Bed Area = Bed Width(ft)X Bed Length (ft) v. ',,, ri„ v. <br /> 1.0' 0.18 0.41 0.56 0.74 <br /> 10 ft X 50 ft = 500 ft2 1.5 0.22 0.51 0.69 0.9 <br /> 2.0° 0.26 0.59 0.80 1.04 <br /> 25 0.29 0.65 0.89 1.17 <br /> Square Foot per Perforation =Bed Area divided by the Total Number of Perforations (Line 7). 3.0 0.32 0.72 0.98 1.28 <br /> $. 0.37 0.83 1.13 1.47 <br /> 3 <br /> 500 ft2 = 51 perforations = 9.8 ft2/perforations 15 foot 0.41 llh i f.r6 ,.65 <br /> 1/a Inch and 3/76 inch perforations on <br /> dwellings <br /> 1fe. <br /> 9. Select Minimum Average Head: 1.0 ftestablishmentsInch <br /> perforations <br /> 2 feet ootheerrestablishmmon dwellings and for <br /> lzhents <br /> 1/4 inch and 3/16 Inch peforations on MSTS <br /> 5 feet 1/8 inch perforations on MSTS <br /> 10. Select Perforation Discharge (GPM) based on Table III: 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 /> 51 Perforations X 0.74 GPM per Perforation = 38 GPM <br /> 12. Select Type of Manifold Connection (End or Center): ID End ❑Center <br />