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' <br /> � Pressure Distribution Design }3i5i1<<-`�" ���_ � <br /> SEWAGE �p.� <br /> Minnesota Pollution Worksheet ��� nTr�� ��� � <br /> Control A enc ,~ �"�..``�.�� <br /> , 1. Select Number o Per orated Latera(s : �3 Geotextile <br /> f f �q�°�°�Q°��°�°��O�o�� Minimum�q°�'O b'° 1 <br /> L perfaations spaced 3'apan 2"ot rock o o <br /> (2-3 foot spacing) � <br /> ' 2. Select Perforotion Spacing: 3.0 ft � oc��o���o�q���c� o 0 0 �� <br /> �o`=tiSo�ao`"':dc���'cS� cS 3�'o`�o°nd'o��t'o� <br /> Note:Must use 2 feet for media filters �oS`�q��o��s��o��o�Db��oc�Z 9�o(rak yDO�DoD°�o�oq����do��o <br /> �o`=Ko�o�o'r�''oo�o� kYd o�d o��So° dGco <br /> 3. Select Perforation Diameter Size 1/4 1f1Ch Perlcraiion sitiag'h"to 7�" <br /> � Perforation s aci :1'to 3' <br /> 4. Length of Laterals =Media Bed Length -2 Feet. Perforation can not be c(oser then 1 foot from edge. <br /> � 50 - 2ft = 48 ft <br /> 5• Determine the Number of Perforation Spaces. Divide the Length of Lnterols (Line 4)by the Perforntion Spacing (Line 2)and <br /> � round down to the nearest whole number. _ _ <br /> Number of Perforation Spoces = 48 ft . �ft 16 Spaces <br /> � 6. Number of Perforations per Latera( is equal to 1.0 plus the Number of Perforation Spaces (Line 5). <br /> Perforations Per Loteral = 16 Spaces + 1 = �� Perfs. Per Lateral <br /> , Check Table 1 to ensure that the number of perforations per lateral guarantees less thnn a f0%discharge variation. <br /> �• Totol Number of Perforotions equals the Number of Perforations per Lateral (Line 6)multiplied by the Number of <br /> ' Perforated Latero(s (Line 1). - <br /> 17 Perf. Per Lateral X �Number of Perf. Laterals - 51 Total Number of Perf. <br /> � 8. Calculate the Square Feet per Perforation. Recommended value is 4-10 ftz per perforation. Tablelll <br /> Does not appl y to At-Grades Pertoration Dixh+rge(c� <br /> Bed Area = Bed Width (ft)X Bed Length (ft) �����"��"� <br /> Head(ft) ��� '/,. '/� '/. <br /> ' 10 ft x 50 ft = 500 tt2 <br /> 1.0' 0.18 0.41 0.56 O.TI <br /> Z,p" 0.2b 0.59 0.80 1.04 <br /> Square Foot per Perforation =Bed Area divided by the Total Number of Perforations (Line 7). 5• o.�� 0.93 t.tb 1.65 <br /> ' - a:Use 1.0(or dwellings uzing i/4 inch or 3/16 inch <br /> hdes. <br /> 500 ft = 51 perforations _ 9.80 ft /perforations b:Use 2.0 fa dwellfngs ustng t/S fnch hdes;Q.ra <br /> z z <br /> • otber estabUshments using 1/4 inth or 3/16 inch <br /> ' hdes. <br /> 9. Select Minimum Average Head: 1.0 ft c use 5.0 f«other estaWistvnenu ust��IS Inch <br /> perforatian and media filters. <br /> 10. Select Perforation Dischorge (GPM)based on Table III: 0.74 GPM per Perforation <br /> ' >>• 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): �End ❑Center <br /> , <br /> , <br /> � <br />