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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals ? uarter inch erforaHons s aced Q 3� 12�� <br /> 2. Select perforation spacing = �? ft 9'•of ro�k <br /> Perf Sizing 3/16"- 1/4" <br /> 3. Since perforations should not be placed closer than 1 foot to Perf Spacing 1.5�-s' <br /> the edge of the rock layer (see diagram),subtract 2 feet from <br /> the rock layer length. E-4: Moximum ailowable number ot 1/4-inch perforations <br /> /J per lateral to guarantee<10%discharge variation <br /> Rock ayer eng �2 ft —�ft perforation <br /> 4. Determuze the number of spaces between perforations. spacing <br /> feet 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> Divide the length (3)by perforation spacing (2) and�'ound <br /> down to nearest whole number. 2,5 8 14 18 28 <br /> Perforation spacing= `� ft=�ft= 1 So spaces 3.0 8 13 17 26 <br /> 3.3 7 12 16 25 <br /> 5. Number of perforations is equal to one plus the number of 4,0 7 �i �5 23 <br /> perforation spaces(4). Check figure E-4 to assure the number of <br /> perforations per lateral guarantees <10% discharge variation. 5.0 6 10 14 22 <br /> ��spaces + 1 =��perforations/lateral E-6: Perforation Dischorge in gpm <br /> 6. A. Total number of perforations = perforations per lateral (5) perforation diameter <br /> times number of laterals (1) head inches <br /> .� (feet) 3/16 7/32 1/4 <br /> �_perfs/lat x ,.� lat= 5,1_perforations <br /> 1.Oa 0.42 0.56 0.74 <br /> B. Calculate the square footage per perforation. 2,Ob 0.59 0.80 1,04 <br /> Should be 6-10 sqft/perf. Does not apply to at-grades. <br /> Rock bed area = rock width (ft) x rock length (ft) 5,0 0.94 1 .26 1.65 <br /> �ft x�ft= 0 0 SClf t ° Use 1.0 foot for single-family homes. <br /> Square foot per perforation = Rock bed area +number of perfs (6) b Use 2.0 feet for an hin else. <br /> UV sqft=_�►_perfs = �.4� sqft/perf MqNIFOLD LOCATED AT END OF PRESSURE DISTRIBUTION SYSTEM <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation(see figure E-6) w;,;� <br /> � � �ly"�,��A . <br /> perfs x ��� gpm/perfs =_,�_gpm ��' <br /> 8. If laterals are connected to header pipe as shown on upper ���'E':� <br /> �LV�N �i,wa� <br /> example, to select minunum required lateral diameter;enter ,,��"` <br /> figure E-4 with perforation spacing (2) and number of perforations �`�``�M <br /> per lateral (5) Select minimum diameter for <br /> I.�YWT pi►ERfORATED PIPE LOTEHRL$fDR <br /> PAESSURE DiSTPIBUTION W/nOUHO <br /> per orated atera = inches. <br /> �[IIIdUT[D R�STIC hK <br /> 9. If perforated lateral system is attached to manifold pipe near �n„�.,,,.�,,.Q,x• u•�~` <br /> �Np o�^[c[w:�x�.r4'rion \ ^K�oNrroN <br /> the center,lower diagram,perforated lateral length (3) and �� Y„�,,�a, <br /> number of perforations per lateral (5) will be approximately one K,.�;S;��,;,�w�r�,a <br /> half of that in step 8. Using these values, select minimum '°• '-- <br /> I ���a�nrc�no�°�'�.i0o: <br /> diameter for perforated lateral = �) 1 z inches. <br /> _��o<.. b, <br /> ��,ra�� <br /> � �yn•rt� x�.�.r- <br /> �� �, <br /> ���*N <br /> I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. <br /> / <br /> ,.� v �' � ��- (signature) 3� �-} (license#) Z -')I �bZ (date) <br />