Laserfiche WebLink
� � University of Minnesota Pressure Distribution System Design - 10/25/04 <br /> ,4N boxed rectanyks musi De entered,the rest wfp be cakulateQ. <br /> ONs�Ts <br /> Eewase <br /> 1. Seled number of perforated laterals: �� T�'�'TM�T <br /> P�eoowwr <br /> 2. Select perforation spacing= 03 ft <br /> c...a�..�l.�(.n�.� <br /> 3. Since perforations should not be placed doser that 1 foot to <br /> the edge of the rodc layer(see diagram),subtract 2 feet from ��� „,,,.,,,,.k <br /> the rodc layer len h � <br /> 55 -2 ft= 53 ; ft �.�..-:�.,,,�.�K--��.- <br /> rti.�r sr...�..,x�.s._z. <br /> �- � <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= 53 ft/ 3 ft= 17 <br /> 5_ Se1ed perforation size 1/4 inch , <br /> 6. Number of perforations is equal to o�e plus the number of perforation spaces(4). <br /> •ChBdc figure E-4 to assure the namber of perforafions per lateral guarantees <br /> <1096 discharge vana6on. <br /> 17 spaces+1 = 18 perforations/lateral <br /> E�d Maximum Number of 1!4 inch perforetions E�Maximum Number of 3116 inch perforations <br /> r laterel to uarantee<10�.discha variation r lateral to uarantee<10%dischar variation <br /> Perforation Perforation <br /> Spaang Pipe Diameter Spaang 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 /> �$°< �.�1 � . �6�"x�' .��.: �� ���� '��$�'. ��.��t+,�'��`' <br /> 3.3 7 12 16 2b 3.3 10 17 23 36 <br /> ��A�� �� ��.��: �:���� ��,�;: `.��d���s� �.. `�;;`: <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 /> 18 perfs/lat x 5 laterals= 90 perforations <br /> B.Calculate the square footage per perforation. <br /> Recommended value is 6-10 sqft/perf.Does not appfy to at-grades. <br /> 1. Rodc bed area=rock width(ft)x rock length(ft) <br /> 15 ft x 55 ft= 825 ft2 <br /> 2. Square foot per perforation=Rodc Bed Area/number of perfs(6) <br /> 825.0 ft� / 90 perfs = 9.2 ft/perf <br /> 8. Determine required flow rate by muftiplying the total number <br /> of perforations(6A)by flow per pertorations see figure E-6) <br /> 90 pe�fs x 0.74 gpm/perfs= 66.6 gpm <br /> E-6 Perforation Discha e in GPM <br /> Head Perforations diameter <br /> feet inches <br /> 3/16 7/32 1/4 <br /> 1 0.�4�ww2 .�pf0�V�.w56s. 0.74 <br /> S..�1�a( -�`T,C..� xT.h.�T�.�'' vd �`i:..'[�:£. <br /> 5 0.94 126 1.65 <br /> a. Use 1.0 toot for single-famly homes. <br /> b.Use 2A feet for a else " , <br /> �/ � . <br /> 9. Determine Minimum Pipe Size �" " . <br /> A. Manifold on End. If laterals are conneded to header pipe . ,.�� ,,, <br /> as shown in Figure E-1,to seled minimum required lateral fqu�E 1:MaMb1O lxaF�a al ErW ot iY��� <br /> diameter;enter figure E-4 or E-5 wlth perforation spacing and <br /> number of perforations per lateral.Select minimum diameter <br /> for perforated laterals= 2.0 inches <br /> 6. Center Manifold. If pertorated lateral system is attached to ^�.-E-=:M�°�»° •- <br /> ti n.c..�r a.»p.r.� � <br /> manffold pipe near the center,like Figure E-2,perforated lateral fength(3) __.,.,,. <br /> and number of perforations per lateral(5)will be approximately . ' <br /> one half of that in step A. Using these values,seled , . <br /> minimum diameter for perforated lateral= 1.5 inches • ''L-',"'' ' <br /> I hereby certify that I have completed this work in accordance with all applicable ordinances,rules and laws. <br /> jsignature) 810 (license#) 05/16/06 (date) <br />