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END PERFORATION OF A PERFORATED LATER,- <br /> 44 ' ' ' PRESSURE DISTRIBUTION SYSTEM <br /> ,..---Grass Cover <br /> • <br /> ,l Topwll a r' <br /> ?;.�.--L <br /> 1. Select number of perforated laterals _ <br /> • Loamy Sand Loyd ILnocy,rtooer Goaore Faw r <br /> with red rosin paper) <br /> 2. Selectperforation spacing = 3 feet fi <br /> 4( ,Y7i• -Pinrt,o loCralpionNoGr illTeodp ton. <br /> I <br /> /i Plus AI Laost 12'tc <br /> 3. Since perforations should not be placed closer than 1 ft. to .aW°th Held Rock. ` ,;;;,''-ol RxN Layer <br /> Located .1 <br /> the edge of the rock layer (see diagram), subtract 2 ft. from • Clean Sand Layer Bottom <br /> Lateral Bottom of Lateral <br /> the rock layer length. . <br /> ` �`Original Soil Properly Scar Iliad <br /> V Before Placing Sand Layer <br /> Rock layer length - 2 ft. _ r6)_ feet <br /> TABLE OF PERFORATION DISCHARGES IN GI <br /> 4. Determine the number of spaces between perforations. Head Perforation diameter(inches) <br /> Divide the length above by perforation spacing and round <br /> down to nearest whole number. v32 '/, <br /> 1.0a 0.56 0.74 <br /> Length pert. spacing = 3 ft. _ 'n..) ft. = lc- spaces 1.5 0.69 0.90 <br /> (#3) (#2) 2.Ob 0.80 1.04 <br /> 2.5 0.89 1.17 <br /> 5. Number of perforations is equal to one plus the number of 3.0 0.98 1.28 <br /> 4.0 1.13 1.4747 <br /> perforation spaces . 5.0 1.26 1.65 <br /> aUse 1.0 foot of head for residential systems. <br /> /6 spaces + 1 = /7 perforations per lateral bUse 2.0 feet of head for other establishments <br /> 6. Multiply perforations per lateral by number of laterals to <br /> get total number of perforations. <br /> _ Table 2 <br /> lateral s x rfs/Kral C�/ p <br /> erf ora ti ons Maximum allowable number of quater inch perforations per <br /> 1R lateral to guarantee<10%Discharge variation <br /> Perfor.Ii"n'pacis 1.25 inch 1.5 inch 2.0 in(' <br /> 7. Determine required flow rate by multiplying <br /> 2.5 <br /> 14 18 28 <br /> number of perforations by flow per perforation 3.0 13 17 26 <br /> 3.3 12 16 25 <br /> 4.0 11 15 23 <br /> _ ,7Z _ 5.0 10 14 22 <br /> perfs x gpm/perlgplll. • <br /> . 8. If laterals are connected to header 1 e as shown on u """ `°""°at """'"`� `�'"'" �'711,0.P P upper <br /> example,select minimum required lateral diameter from <br /> table 2; enter table with perforation spacing and number _ --�'�� <br /> of perforations per lateral. Select minimum diameter for <br /> perforated lateral = 7" inches �� ..- ,,, i n - <br /> .--___...-.--'..„.,-e" <br /> ' -- . <br /> 9. If perforated lateral system is attached to manifold pipe near <br /> the center, as in lower example, perforated lateral length and l. -w1r0"e 10. <br /> number of perforations per lateral will be approximately one cf <br /> half of that in # 6. Using these values, select minimum201.7.1 "7=<,,. ' � <br /> iy <br /> diameter for perforated lateral from table 2 -..--r.,�.,.. ��..--''� <br /> lateral = --~'' ....,------ <br /> perforated <br /> inches ,� „W,i.r. <br /> err w M\ /•-' <br />