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1:%^.I®irte <br />iSgs"Mi’v <br />''■’\;v*u. <br />t*' * I . \ <br />8tvJ-’m-s.i* i ■m'r <br />. . :/ <br />£-19 <br />»fe>. •..■ <br />MOUira DESIGN PROCEDU?>£ <br />(For Flovs up to 1200 gpd) <br />A. Sewage Flow Rate <br />See D-7 or 1-3, A, or 5, or ase <br />metered value; Flow Rate - <br />/2O0 gpd /T/or. <br />B. Septic Tank Liquid Volume <br />(see C-3 or gallons <br />C» Soil Characteristics <br />1. Depth to restricting layer <br />such as seasonally saturated <br />soil, bedrock, coarse scil, <br />etc. ; So Inches <br />2. Depth of percolation tests; <br />/S inches <br />Number of percolation test <br />holes; ^ holes <br />Ave. percolation rate; <br />y. /_____rapi <br />5. Landslope » S ^ 7, <br />D. Rock Laver Dinensicr.s' <br />1. Multiply gpd by 0.33 to <br />obtain required area of <br />rock layer; <br />/2 gpd X 0.83 " fc <br />2. Select width of rock Icyer <br />(10 feec or less) “ fO feet <br />3. Length of rock layer ■ Area <br />- Width/_^^sq ft - JO_tt ' <br />» fOO fc <br />E. Rock Volume <br />1. Multiply rock area by rock depth <br />to get cubic feec of rock; <br />sq ft 7S ft = 7^(7 CM ft <br />2. Divide cu ft by 27 c ft/cu yd <br />CO get cubic yards; 2 7. S <br />3. Multiply cubic yards by 1.4 to <br />get weight of rock in tons; <br />2 7. cv yds X 1.4 - SS. ‘^tons <br />ressure Distribution System <br />Select number of perforared <br />laterals ^ <br />Select pertorotion <br />= 3 ft <br />sp'.cing <br />3. Select perforated lateral <br />length; Note if manifold is <br />at > ad of rocU layer, lateral <br />if ch is roci. laytr length <br />less half c p ;rf ora cion <br />spacing. If -'.an if old is in <br />•'.enter of rock layer, lateral <br />length is one-half rock layer <br />leng_h less half a perforation <br />spacing. Perforated lateral <br />’ ength = y/, C ft. <br />Divide lateral length by perfor­ <br />ation spacing to get number of <br />perforations per lacar^l <br />So feet r S feeC = / 7 perfs <br />Note: last perforation must be <br />in end cap, (see page E-14) <br />Multiply perforations per <br />lateral by number of laterals <br />Co get cctal number of <br />perforations; <br />/7 perfs/lat x ^ lacs = /^Z. <br />6. Determine required flow race <br />by multiplying number of <br />perforations by flow per <br />perforation (see page E-17) <br />/{P Z perfs X ,7Vgpro/perf ° /jT.Sgpm <br />7. Select minimum rcauired lateral <br />diameter from table on Page E-i7; <br />enter table with perforation <br />spacing, perforation diameter, <br />and number of perforations per <br />lateral. Select minimum <br />diameter for perforated lateral <br />*■ / inches ^ t4S^ 2 <br />G. Basal Width <br />1. Percolation rate in top 12 <br />inches of soil is 7. / mpi , /6 j <br />2. Select allowable soil loading <br />rate from table on page E—16; <br />0.60 gpd/f