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OSTP Pressure Distribution <br /> UNIVERSITY <br /> Minnesota Pollution Design Worksheet OF MINNESOTA :__-__; <br /> Control Agency . <br /> 1. Select Number of Perforated Laterals in system/zone: I _3 I Geoteatile n1,',M a'V,:aeg rti m ice <br /> Minimu -'. • T <br /> i i-, <br /> (2 feet is minimum and 3 feet is maximum spacing) ;). '�+�Perforations spaced 3`apart ;u <br /> 2'of rock <br /> : Ty ;- <br /> 2. Select Perforation Spacing: 3.0 ft a;�� "' -4. _ _ <br /> 3. Select Perforation Diameter Size 1 1 inch `' r` om'` <br /> Perforation sizing:'/e'to Vi" <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 /> 38 - 2ft = 36 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 = 36 ft 3 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 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 /> 13 Perf. Per Lateral X 3 Number of Perf. Laterals = 39 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 /> Bed Area = Bed Width (ft)X Bed Length (ft) Head(ft) ,,,° r,,, •,• <br /> 10' 0.18 0.41 0.56 0.74 <br /> 10 ft X 38 ft = 380 ft2 1.5 0.22 0.51 0.69 0.9 <br /> 2.0° 0.26 0.59 0.80 1.04 <br /> 2.50.29 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 /> 4.0 0.37 0.83 1.13 1.47 <br /> 5.0' 0.41 0.93 1.26 t.65 <br /> 380 ft2 = 39 perforations = 9.7 ft2/perforations ,root 1/4 inch and 3/16 inch perforations on <br /> dwellings <br /> 1/8 inch perforations on dwellings and for <br /> 9. Select Minimum Average Head: 1.0 ft 2 feet other establishments <br /> 1/4 inch and 3/16 inch peforatlons 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 /> 39 Perforations X 0.74 GPM per Perfora_ion = 29 GPM <br /> 12. Select Type of Manifold Connection (End or Center): 2 End ❑Center <br />