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END PERFORATION OF A PERFORATED LATERAL <br /> PRESSURE DISTRIBUTION SYSTEM <br /> -Grass Cover <br /> i i C C: <br /> Topsoil y �, <br /> 3 „, <br /> 1. Select number of perforated laterals `' •'-°Layer of Geote=rile Fabric (or lour- <br /> Loamy Sand Layer t Inch layer of hoy or was covered <br /> t . .. itn red rosin poper) <br /> 2. Select perforation spacing = 2 r-D feet ' R■ ��___I Per forat on Oril led Nar;:anf ally <br /> rYrr t r,Ante Cop Naar Top <br /> • /i Plus �` At Least 12e to Edge <br /> 3. Since perforations should not be placed closer than 1 ft. to �Oraln Field Rock ._.:', of Rock Layer <br /> the edge of the rock layer (see diagram), subtract 2 ft. from y Bottom l Ions LateraLocoll d al <br /> Clean Sond Lo er Bottom of Lateral <br /> the rock layer length. „- .. r <br /> ` <br /> ' Original Soil Properly Scarified <br /> 5 Before Placing Sand Layer <br /> Rock layer length - 2 ft. = 4S feet <br /> TABLE OF PERFORATION DISCHARGES IN GPM <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. yin '/4 <br /> 1.0a 0.56 0.74 <br /> � 1.5 0.69 0.90Length perf. spacing = ft. _ 2ft. = spaces <br /> 2.0b 0.80 1.04 <br /> (#3) (#2) 2.5 0.89 1.17 <br /> 1.25. Number of perforations is equal to one plus the number of 3.00 0.9843 1.47 <br /> perforation spaces . 5.0 1.26 1.65 <br /> aUse 1.0 foot of head for residential systems. <br /> 19 spaces + 1 = 20 perforations per lateral bU'sc 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 /> 3 x -2.A.) _ )(- erforations Maximum allowable number of quater inch perforations per <br /> laterals perfs/lateral P lateral to guarantee<10%Discharge variation <br /> pe(ostion•pacing 1.25 inch 1 1.5 inch 2.0 inch <br /> (feet) <br /> 7. Determine required flow rate by multiplying 2.5 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 /> ()%'' 017 5.0 10 t 14 22 <br /> pis X gpm/perf - gpm. <br /> 8. If laterals are connected to header pipe as shown on upper "'""°`°`°""° "'°`"`SS"`US.e.°ta.,'K <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 /> .---,,/ j, <br /> perforated lateral = inches �,'er <br /> 9. If perforated lateral system is attached to manifold pipe near <br /> the center, as in lower example, perforated lateral length and <br /> number of perforations per lateral will be approximately one c." "'R""••" <br /> half of that in # 6. Using these values, select minimum -��r=. >• �...."'"."-‘....'- <br /> i. diameter for perforated lateral from table 2 tires:..-�-- - <br /> • <br /> perforated lateral = 2. inches .- N. -.=,,.1,-,..m <br /> /:- <br />