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University of Minnesota Pressure Distribution System Design - 10/25/04
<br /> All boxed redanpfes must be entered,the rest wiN be cakulated.
<br /> OwsRs
<br /> se.v..e
<br /> 1. Select number of perforated laterals: � T""""�"'
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<br /> 2. Select perforation spacing= �3 ]R
<br /> c•.... .,:i.r.a.�
<br /> 3. Si�ce perforations shouVd not be plaoed doser that 1 foot to �_���Q�� �� ,
<br /> tt�edge of the rodc layer(see diagram),subtract 2 feet from ,,,,,,�,�k
<br /> the rodc I�yer len ; ��,'„�,.,r--,..-
<br /> � 38 -2 ft 7 36 R ��a,�.-,..;,�.R•_s• '
<br /> I
<br /> 4. Detertnine the number of spaces between perforations.
<br /> Oivide the length(3)by perforation spaang(2)and round down to nearest whole number.
<br /> Parforation spacing= 36 ft/ 3 R= 12
<br /> 5. Seled perforation size 1/4 inch
<br /> 6. Number of perforations is equal to one plus the number of perforation spaces(4).
<br /> 'Chedc Bgure E-4 to assure the number of pe►forations per lateral guarantees
<br /> <1096 discharge variation.
<br /> 12 spaoes+1 = 13 perforationsAateral
<br /> E-4 Maximum Number of 1/4 inch ratlo� E-5 Maxlmum Number of 3/16 inch perforatlons
<br /> labral to uarantee<10°/.discha variation r lateral to uaraMee<10%discha e variation
<br /> Perforatlon Perforation
<br /> gpacing 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 /> . "`.' `',,�r' `13 � "a,. .,� �.t.�',.�, . rg :;�.' ..���,�..,�. 48 '�a J�����:�
<br /> K ,:
<br /> 3 3 7 � 12 16 25 3.3 10 17 23 36
<br /> _,.��: . .Z ; 11 ,.:i L''�.u,.S.` :�, 4.'. .;tQ. 16, , i ,2���:!4 ,�,� .`R:
<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 /> 13 perfs!lat x 3 laterals= 39 perforetions
<br /> B.Calculate the square footage per perforatio�.
<br /> Recommended value is 6-10 sqtt/perf.Does not apply to at�rades.
<br /> 1. Rodc bed area=rock width(ft)x rodc length(ft)
<br /> 10 ft x 38 ft= 380 ft
<br /> 2. Square foot per perForation=Rodc Bed Area/number of perFs(6)
<br /> 380.0 ft/ 39 perfs = 9.7 ft/perf
<br /> 8. Determine required flow rate by mu�iplying the total number
<br /> of perforations(6A)by flow per perforations see figure E-6)
<br /> 39 perfs x 0.74 gpm/perfs= 28.9 gpm
<br /> E-8 Petforation Discha in GPM
<br /> Head Perforabons diameter
<br /> feet inches
<br /> 3/16 7/32 1l4
<br /> 1 a.42 0.56 0.74
<br /> 2°:; 0`59 :�i4;. _ 1..04
<br /> 5 0.94 1.26 , 1.65
<br /> a. Use 1.0 foot far single-famiy homes.
<br /> b.Use 2.0 teet fw a hin else
<br /> .��.� .,.
<br /> 9. Detertnine Minimum Pipe Size ' ,
<br /> A. Manifold on End. If laterals are conneded to header pipe ,, .
<br /> as shown in Figure E-1,to select minimum required lateral Fquro E-1:MonlbW looa�eO a�Fnd m 6ysNm
<br /> diameter;enter figure E-4�r E-5 with perforation spacing and
<br /> number of perforations per lateral.Seled minimum diameter
<br /> for perforated laterals= 1.5 inches
<br /> ------.__._.._._.__________.... ..__.,
<br /> B. Cerrte�Mlanffold. If perforated lateral system is attached to ��;��;�� '" ``.
<br /> ma�ifold pipe nearthe center,like Figure E-2,perforated lateral length(3) . _ ,,.
<br /> and number of perforations per lateral(5)will be appro�mately � �
<br /> y', 1
<br /> one half of that in step A. Using these values,select � . . •-
<br /> minimum diameter for perforated lateral= 1.5 inches • ' 1-- ,,�� �
<br /> I hereby certify that I have com leted this work in accordance with all applicable ordinances,rules and laws.
<br /> (signature) 810 (license#) 08/15/O6 (date)
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