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END PERFORATION OF A PERFORATED LATERAL <br /> PRESSURE DISTRIBUTION SYSTEM <br /> Grow cover <br /> ,c ,_ r <br /> w <br /> .1 ` ToDsoll <br /> .vv <br /> 1. Select number of perforated laterals <br /> Layer of Geote:rile Fabric (or four- <br /> ... Loamy Sand Layer inch toyer of hay or straw covered <br /> with red rosin paper) <br /> 2. Select perforation spacing = 2 r'D feet R . 'a I Perforation Grilled Horizontally <br /> t •• c.I Into COD Near Top <br /> a ,` At Least 12�to Edge <br /> v r Plus <br /> Oroln Field Rocko .7.4.'4. of Rock Layer <br /> 3. Since perforations should not be placed closer than 1 ft. to • • �'_P�rIarallon,Located at <br /> the edge of the rock layer (see diagram), subtract 2 ft. from Clean Sand Layer Bottom of Lateral <br /> the rock layer length. <br /> 4.Original Soil Properly Scarified <br /> 5C <br /> /� Before Placing Sand Layer <br /> Rock layer length - 2 ft. = �i S 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. y/n t/' . <br /> 1.0a 0.56 0.74 <br /> Length perf. spacing = `)c ft. - 25 ft. = ri spaces 1.5 0.69 0.90 <br /> 2.0b 0.80 1.04 <br /> (#3) (#2) 2.5 0.89 1.17 <br /> 5. Number ofperforations is equal to oneplus the number of 3.0 0.98 1.28 <br /> q 4.0 1.13 1.47 <br /> perforation spaces . 5.0 1.26 1.65 <br /> aUse 1.0 foot of head for residential systems. <br /> 1S spaces + 1 = 20 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 /> 3 �.eJ _ Maximum allowable number of quater inch perforations per <br /> laterals x perfs/lateral �� perforations lateral to guarantee<10%Discharge variation <br /> arfer•(��;)"ch4I 1.25 inch 1.5 inch I 2.0 inch <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 /> rte, O _ 5.0 10 I 14 22 <br /> perfs x gpm/pert - gpm. <br /> sY+✓0.o LOWED at•CNr or Memwe MT.efl TTX. <br /> 8. If laterals are connected to header pipe as shown on upper <br /> example, select minimum required lateral diameter from -m. <br /> table 2; enter table with perforation spacing and number _____ <br /> of perforations per lateral. Select minimum diameter for �. "f ,�.. <br /> perforated lateral = inches ✓,,..--- u- <br /> \/ <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 9, """"' <br /> ~� <br /> half of that in #6. Using these values, select minimum 3z.r.,r 1• " <br /> diameter for perforated lateral from table 2 R--- <br /> perforated lateral = 2. inches <br /> l\w\ � ,mer, . <br /> yam', <br />