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� . <br /> PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> 1. Select number of perforated laterals_�_ 12� <br /> uarter inch erforations s aced�3' <br /> , .9"of,rock <br /> 2. Select perforation spacing= '�• D ft ' <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 ailowable number of 1/4-inch perforations <br /> perlcrteral to guarantee<l OX discharge variation <br /> ay�eng '2 ft = �n ft pertoraflon <br /> apac(ng <br /> 4. Determine the number of spaces between perforations. }eet 1 inch 1.25 inch 1.5 inch 2.o inch <br /> Divide the length(3)by perforation spacing(2) and round <br /> ��to nearest whole number. 2,5 8 14 18 28 <br /> Perforation spacing= �� 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 Q p � �� 15 23 <br /> perforation spaces(4). Check figure E-4 to assure the number of 5.0 6 10 14 22 <br /> perforations per lateral guarantees <10% discharge variation. <br /> � � spaces + 1 =��perforations/lateral E-6: Pertoration Dischorge in gpm <br /> 6. A. Total number of perforations = perforations per lateral (5) perforation diameter <br /> times number of laterals (1) head �nches <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 /> a s ft x_2'3.`ft= O�7 sqft ° 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 ni� Qise. <br /> _l�i�sqft+�_perfs = 1 K GI sqft/perf MANIFOLD IOCATEO AT END OF PRESSUNE DiSTRIBUT10N SYSTEM <br /> 7. Determule required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation(see figure E-6) �� <br /> °� SCs Qvm/ erfs = S3 m .�.�� <br /> � perfs x r„v p gp •. <br /> 8. If laterals are connected to header pipe as shown on upper ���,,,����d��„� <br /> example,to select rninimum required latera�diameter;enter \���,�d� <br /> figure E-4 with perforation spacing (2) and number of perforations <br /> per lateral (5) Select minimum diameter for ,,,,�,.„K1IIOMT[D►D[L�TCIU�S�ON <br /> perforated lateral= inches. .�Es�e o�s*��.�T�� W MWND <br /> n�ra..no RYTK�M[ <br /> 9. If perforated lateral system is attached to manifold pipe near �K_�,,,,,�,.,a,,,• „���` <br /> �N, ���y.:K"�»�4n t�°" �K''i°r <br /> the center,lower diagram,perforated lateral length (3) and t,,;.K o <br /> number of perforations per lateral (5)will be approximately one K�.�;s�.�;�p..�a <br /> half of that in step 8. Using these values, select minimum �°\ �" • •.,;���;�„�p, <br /> diameter for perforated lateral= a�D inches. �� �, <br /> . �/fl0 lu��It � �. ._n <br /> ` ���M <br /> d <br /> :� <br /> I hereby certify that I have comple ed this work in accordance with applicable ordinances, rules and laws. <br /> �� • � � (signature) 3"� � (license#) `� '� �'� (date) <br />