Laserfiche WebLink
' ' PRESSURE DISTRIBUTION SYSTEM Geotextile fabric <br /> � 12 �. <br /> 1. Select number of perforated laterals v Uarter inch erforations s aced�3' <br /> 9"of rock <br /> 2. Select perforation spacing = � ft <br /> Perf Sizing 3/16"- 1/4" <br /> 3. Since perforations should not be placed closer than 1 foot to Perf Spacing 1.5�-s� <br /> the edge of the rock layer (see diagram), subtract 2 feet from <br /> the rock layer length. E-4: Maximum allowable number of 1/4-inch perforations <br /> �� per lateral to guarantee<10�discharge vanation <br /> Rock la er len th � <br /> Y g -2 ft =�_ft pertoration <br /> spacing <br /> 4. Determizie the number of spaces between perforations. teet 1 inch 1.25 inch 1.5 inch 2.0 inch <br /> Divide the length (3)by perforation spacing (2) and round <br /> �iown to nearest whole ntunber. <br /> 2.5 8 14 18 28 <br /> Perforation spacing= c�� ft- � ft=�_spaces 3.0 8 13 17 26 <br /> 5. Number of perforations is equal to one plus the number of 3.3 � �2 �6 25 <br /> 4.0 1 11 15 23 <br /> perforation spaces(4). Check figure E-4 to assure the number of 5.0 6 10 14 22 <br /> perforations per lateral guarantees <10% discharge variation. <br /> / SPaces + 1 = L�5" PerforaHons/lateral E-6: Perforation Discharge in gpm <br /> 6. A. Total number of perforations = perforations per lateral (5) perforation diameter <br /> times number of laterals (1) head inches <br /> (feet) 3/16 7/32 1/4 <br /> �_perfs/latx ? lat= r; �--i perforations <br /> 1.Oa 0.42 0.56 0.74 <br /> B. Calculate the square footage per perforation. b <br /> Should be 6-10 sqft/perf. Does not apply to at-grades. 2•0 0.59 0.80 1.04 <br /> Rock bed area = rock width (tt) x rock length (ft) 5.0 0.94 1.26 1.65 <br /> '� ft x �� ft = ��'� sqft a Use 1.0 foot for single-famity homes. <br /> Square foot per perforation = Rock bed area =number of perfs (6) b Use 2.0 feet for an �� ei�. <br /> a 5� sqft= �� perfs =1�sqft/perf <br /> MANIfOLO IOCATED AT ENO OF PRESSURE qSTPIBUTION SYSTEM <br /> 7. Determuze required flow rate by multiplying the total number of <br /> perforations (6A) by flow per perforation (see figure E-6) �K <br /> .� <br /> �_perfs x � ?'� gpm/perfs = � gpm � <br /> 8. If laterals are connected to header pipe as shown on upper ,,�,��'" � <br /> �,� �,.^��, <br /> example, to select minimum required lateral diameter;enter �M,�""" <br /> figure E-4 with perforation spacing (2) and number of perforations ��` <br /> per lateral (5) Select minimum diameter for <br /> UrOUT 0� K�IOnnTEO�iPf LaTEn��S!OR <br /> perforated lateral -_j_ inches. ""`5=,�`o�s�a�e���o« w�a�.o <br /> a�u .� <br /> 9. If perforated lateral system is attached to manifold pipe near �.�.,�.,,.�„p��o,.. ^` <br /> EM S�n�wt[� �wrh.!� �- AK��r� � <br /> the center, lower diagram, perforated lateral length (3) and °"w °����"" � <br /> r W.;,,ao <br /> n <br /> number of perforations per lateral (5) will be approximately one K��;,«�,«.�.�.,�� <br /> half of that in step 8. Using these values, select minirnum '° '�" - ._,�.��;��„�,�, <br /> diameter for perforated lateral = �_ inches. � � <br /> b. ,a„` <br /> �„irto Y�Mn . <br /> \ `�M d � .� <br /> ��� <br /> I hereby certify that I have completed this work in accordance with applicable ordinances, rules and laws. <br /> � . �___ �-� ;: " <br /> _ (signattue) -- �� _(license �) __(date) <br />