Laserfiche WebLink
Tom <br />'Y <br />MOUND DESIGN PROCEDURE <br />(For Flows up to 1200 gpd) <br />A. Sewage Flow Rate <br />See D-7 or I-3, 4, or 5, or use <br />metered value; Flow Rate = <br />grD O gpd <br />B. Septic Tank Liquid Volume <br />(see C-3 or C-5) /g gallons <br />C. Soil Characteristics <br />1. Depth to restricting layer <br />such as seasonally saturated <br />soil, bedrock, coarse soil, <br />etc.; -76 inches <br />2. Depth of percolation tests; <br />_ /flinches <br />3. Number of percolation test <br />holes; 2 holes <br />4. Ave. percolation rate; <br />S. a mp i <br />5. Landslope - Z/ _% <br />D. Rock Layer Dimensions' <br />1. Multiply gpd by 0.83 to <br />obtain required area of <br />rock layer; <br />COO gpd x 0. 83 - J?V sq f t <br />2. Select width of rock layer . <br />(10 feet or less) = L-feet <br />3. Length of rock layer - Area <br />Width Soo sq f t L /o f t <br />So f t <br />E. Rock Volume <br />1. Multiply ruck area by rock depth <br />to get cubic feet of rock; <br />Soo sq f t x 0.75 f t= _77.Scu f t <br />2. Divide cu ft by 27 cu ft/cu yd <br />to get cubic yards; /_?,9 <br />3. Multiply cubic yards by 1.4 to <br />get weight of rock in tons; <br />/1.9 cu yds x 1.4 - /9 Ytons <br />E-19 <br />F. Pressure Distribution System <br />1. Select number of perforated <br />laterals 6 <br />2. Select perforation spacing <br />3 ft <br />3. Select perforated lateral <br />length; Note if manifold is <br />at end of rock layer, lateral <br />length is rock layer length <br />less half a perforation <br />spacing. If manifold is in <br />center of rock layer, lateral <br />length is one-half rock layer <br />length less half a perforation <br />spacing. Perforated lateral <br />length - Z , S f t. <br />4. Divide lateral length by perfor- <br />ation spacing to get number of <br />perforations per lateral <br />23.5 feet _ _?feet - 8 perfs <br />Note: last perforation must be <br />in end cap, (see page E-14) <br />5. Multiply perforations per <br />lateral by number of laterals <br />to get total number of <br />perforations; <br />-ff_perfs/]at x 6 lats = yJP <br />6. Determine required flow rate <br />by multiplying number of „.A <br />perforations by flow per V`1 rxFS, <br />perforation (see page E-17) <br />_ —perfs x,7Zigpm/perf=j?S.Sgpm <br />7. Select minimum required lateral <br />diameter from table on Page E-17; <br />enter table witli perforation <br />spacing, perforation diameter, <br />and number of perforations per <br />lateral. Select minimum <br />diameter for perforated lateral <br />= / Yy inches a rf / 91' " <br />G. Basal Width <br />1. Percolation rate in top 12 <br />inches of soil is 'mpi <br />2. Select allowable soil loading <br />rate from table on page E-16; <br />��'. 0, 60 gpd/ft2 <br />