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Rug 04 07 07: 49a FYLE 'S 7632955422 p. 8 <br /> • University of Minnesota Pressure Distribution System Design - 10/25/04 <br /> AM boxed rectangles crust be entered,the rest MN be calculated. <br /> sZV..0C <br /> 1. Select number of perforated laterals: I 3 I Torsartp � <br /> 2. Select perforation spacing= 3 ft <br /> 3. Since perforations should not be placed closer that 1 foot to T,the edge of the rook layer(see diagram),subtract 2 feet from t_cz <br /> �nrn�.k <br /> the rock layer len! <br /> 1I 50 -2 ft- 48 ft <br /> i <br /> 4. Determine the number of spaces between perforations. <br /> Divide the length(3)by perforation spacing(2)and round down to nearest whole number. <br /> Perforation spacing= 48 ft/ 3 ft= 16 <br /> 5. Select perforation size 1/4 inch <br /> 6. Number of perforations is equal to one plus the number of perforation spaces(4). <br /> •Check figure E-4 to assure the number of perforations per lateral guarantees <br /> <10%discharge variation. <br /> 16 spaces+1 = 17 perforations/lateral <br /> E.4 Maxhuum Number of 1/4 inch perforations E-5 Maximum Number of 3/16 inch perforations <br /> per lateral to guarantee<10%discharge variation per lateral to guarantee<10%discharge variation <br /> Perforation Perforation <br /> Spacing Pipe Diameter Spacing Pipe Diameter <br /> ft 1 inch 1.25 inch 1.5 inch 2.0 inch feet 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> 2.5 8 14 18 28 2.5 12 19 25 39 <br /> 3.0 -:.1).. 37',. <br /> 13 : 1T :: 26. : 3 1118 --24..::: <br /> 3.3 7 12 16 25 3.3 10 17 23 36 <br /> -4.0 M :-33 <br /> �. • 11 15 .:: � 4 10,. ' r'1�' ,. •:� 21.� , <br /> 5.0 6 10 14 22 5 9 15 20 31 <br /> 7. A.Total number of perforations=perforations per lateral(5)times number of laterals(1). <br /> 17 perfs/tat x 3 laterals= 51 perforations <br /> B.Calculate the square footage per perforation. <br /> Recommended value is 6-10 sqft/perf.Does not apply to at-grades. <br /> 1. Rock bed area=rock width(ft)x rock length(ft) <br /> 10 ft x 50 ft= 500 ft2 <br /> 2. Square foot per perforation=Rock Bed Area/number of perfs(6) <br /> 500.0 ft2 / 51 perfs = 9.8 ft2/pert <br /> 8. Determine required flow rate by multiplying the total number <br /> of perforations(6A)by flow per perforations(see figure E-6) <br /> 51 perfs x I 0.74 jgpm/perfs= 37.7 gpm <br /> E-6 Perforation Discharge In GPM <br /> Head Perforations diameter <br /> (feet) (inches) <br /> 3/16 7/32 1/4 <br /> 1° 0.42 0.56 0.74 <br /> • :.1',':': 0.59 ' 0.80 1.04 .. <br /> 5 0.94 1.26 1.65 <br /> a. Use 1.0 foot for sing le-farnaly homes. 1 ---- -- - •-I <br /> b.Use 2.0 feet for arrylhng else . , 1 <br /> 9. Determine Minimum Pipe Size <br /> A. Manifold on End. If laterals are connected to header pipe • �, <br /> as shown in Figure E-1,to select minimum required lateral Fa.•E-1:MVMbd woad of Elva'Worn <br /> diameter,enter figure E-4 or E-5 with perforation spacing and <br /> number of perforations per lateral.Select minimum diameter <br /> for perforated laterals= 2.0 inches <br /> B. Center Manifold. If perforated lateral system is attached to In •c.nw.'°""ae."°'°'""d"°- - <br /> In m. .Mr. <br /> . <br /> manifold pipe near the center,like Figure E-2,perforated lateral length(3) , <br /> and number of perforations per lateral(5)will be approximately <br /> one half of that in step A. Using these values,select - <br /> minimum diameter for perforated lateral= L 1.5 inches - ` <br /> I hereby certify that I have completed this work in accordance with all applicable ordinances,rules and laws. <br /> A (signature) 810 (license#) 07/13/07 (date) <br />