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. � University of Minnesota Pressure Distribution System Design - 10/25/04 <br /> All boxed rectangVes musf be ente2d,the rest will be cakulated. <br /> OwsRe <br /> Sewwoe <br /> 1. Select number of perforated laterals: � T"""""'`T <br /> PawRww� <br /> 2. Select perforation spacing= �ft <br /> ,.�.-�..�,�, <br /> 3. Since perforations should not be placed Goser that 1 foot to ��.M__�}�.M,r,��p r-_�, "' <br /> the edge of the rock layer(see diagram),subtract 2 feet from y,.,,,_.k <br /> the rodc layer len h <br /> 75 -2ft= 73 ft ;;,r�;�^!�K/�IS_SI/4' <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= 73 ft/ 3 ft= 24 <br /> 5. Seled perforation size 7/32 inch <br /> 6. Number of perforations is equal to one plus the number of perforation spaces(4). <br /> 'Check figure E�to assure the number of perforations per lateral guarantees <br /> < 1096 discharge variation. <br /> 24 spaces+1= 25 perforations/lateral <br /> E-4 Maximum Number of 114 inch perforations E-5 Maximum Number of 3H6 inch perforations <br /> �lateral to uarantee<10•/.dischar e variation r lateral to uarantee<70°k dischar e 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 8 13 17 26 3 11 18 24 37 <br /> 3.3 7 12 16 25 3.3 10 17 23 36 <br /> 4A 7 11 15 23 4 10 16 21 33 <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 /> 25 perfs/lat x 3 laterals= 75 peAorations <br /> B.Calculate the square footage per perforation. <br /> Recommended value is 6-10 sqft/perf.Dces not apply to at�rades. <br /> 1. Rodc bed area=rock width(ft)x rodc length(ft) <br /> 10 ft x 75 ft= 750 ft� <br /> 2. Square foot per perforation=Rock Bed Arealnumber of perfs(6) <br /> 750.0 ft/ 75 perfs = 10.0 ft!perf <br /> 8. Detertnine required flow rate by multiplying the total number <br /> of perforations(6A)by flow per perforations see figure E-6) <br /> 75 perfs x 0.56 gpm/perfs= 42.0 gpm <br /> E-6 Perforation Dischar e 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 /> 2° 0.59 0.80 1.04 <br /> 5 0.94 1.26 1.65 <br /> a. Use 1.0 foot for single-family homes. <br /> b.Use 2.0 feet for anything else � <br /> '�� <br /> 9. Detertnine Minimum Pipe Size . <br /> A. Man'rfold on End. If laterals are connected to header pipe <br /> as shown in Figure E-1,to seled minimum required lateral Fa�--E-,:M�,+�w���aE^dda,�m <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 Manffold. If pertorated lateral system is attached to �.E-2."�°�°°�.° ' <br /> M n.unw ae ti sr.w,+ , <br /> man'rfold pipe near the center,like Figure E-2,perForated lateral length(3) .. <br /> and number of perforations per lateral(5)will be approximatey ' <br /> one half of that in step A. Using these values,select - <br /> minimum diameter for perforated lateral= 1.5 inches - ^Z-- <br /> I hereby rtify that I have completed this work in accordance with all applicab�e ordinances,rules and laws. <br /> /- <br /> (signature) 810 (license#) 9/1/2005 (date) <br />