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PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals 3 uarter inch erforations s aced e�3� 12�� <br /> 2. Select perforation spacing =_�_ft s"of,rock <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: Maximum allowable number of 1/4•inch pertorations <br /> �`� -2 ft per lateral to guarantee<10%discharge variation <br /> oc ayer eng —�f t perforaiion <br /> spacing <br /> 4. Deternune the number of spaces between perforations. teet 1 inch 1.25 inch 1.S inch 2.o inch <br /> Divide the length (3)by perforation spacing (2) and round <br /> � down to nearest whole number. <br /> 2.5 8 14 18 28 <br /> Perforation spacing= lr c� ft+�ft=�_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 11 15 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 /> �Z- spaces + 1 = �'� perforations/lateral E-6: Perforotion Discharge fn gpm <br /> 6. A. Total number of perforations = perforations per lateral (5) perforat(on dfameter <br /> times number of laterals (1) head inches <br /> (feet) 3/16 7/32 1/4 <br /> �_perfs/lat x�_lat=�perforations 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= t��6 0 Sqft a 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 /> �a� sqft+ b / perfs = �. 4� sqft/perf MGNIf060 IOCATED AT ENO OF PRESSURE DISTFIBUTION SYS7EM <br /> 7. Determine required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation(see figure E-6) W�,.�,n <br /> � <br /> �perfs x � lo m�ei�s=��gpm "'�°" <br /> 8. If laterals are connected to header pipe as shown on upper �'� <br /> � K���.�,� <br /> example,to select mirumum required lateral diameter;enter ,,,��'`"`� .�'�''""�� <br /> figure E-4 with perforation spacing (2) and number of perforations ��``�TM <br /> per lateral (5) Select minimum diameter for <br /> LwYOUT OI►C�Id1�T[O�IIE l�T[��LS!OR <br /> PI1[33u11C C�ST��lV710N W MOUHO <br /> per orated atera = inches. <br /> KMpYT[p RtlTK�MC <br /> 9. If perforated lateral system is attached to manifold pipe near �nM�.,,�.WQ „• �,a,�`*` <br /> the center,lower diagram,perforated lateral length (3) and � �`�'"'``�`'�""g� ' """�� <br /> rr.�.�rao <br /> number of perforations per lateral (5)will be approximately one KM�iTOKMf M�WTTOY a ���` <br /> half of that in step 8. Using these values,select minimum '° a- <br /> •-����•:s,��:: <br /> diameter for perforated lateral = �) �z inches. _�,��� ,� <br /> ' �/fl0 t�1LR�� �=�r�rl � <br /> �rf n <br /> ����M <br /> I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. <br /> � ,� l:r���`�_____.-- (signature) �`��-I , (license#) 7-)-C�Z � (date) <br />