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MOtJND DESIGN WORKSHEET <br />(For Flows up to 1200 gpd) <br />A. FLOW Estimated Sewage Flow in Gallons per Day (gpd) <br />Estimated ')_~() gpd Number <br />of Type! 1ypc II 1ypc III or measured X 1.5 = ~ gpd. Bedroonu <br />2 300 225 180 <br />3 450 300 218 B. SEPTIC TANK UQUID VOLUMES 4 600 375 256 <br />5 150 450 294 /-!d--.5'0 s1-1oc0gallons 6 900 525 332 <br />7 1050 600 370 -y-u--f~~ 8 1200 675 408 ,1 •I I/ <br />C. SOII.5 (refer to site evaluation) 11 <br />;;loJ?.l,J.l-.'-1 <br />Number ---11 I( s.e,1w c:.;,.:,,ywuh <br />1. Depth to restricting layer = ;;.(_,, ,1 ;J... <d ~ ;;i_ 'I{ inches of G~ <br />Bedrooms c.p.c;,y ll--i-1 <br />2. Depth of percolation tests = / ~ ,; inches {plJooo) (plla,,) <br />3. Percolation rate C). '-6 mpi 2 or less 750 1,125 <br />3 or4 1,000 1.500 <br />4. Land slope :i_ ";lo -ro L, % 5 or6 1.500 2,250 <br />7 or 8 2,000 3,000 <br />over9 See fig. C-6 (x 1.5) <br />D. ROCK LA YER DIMENSIONS <br />1. Multiply flow rate by 0.83 to obtain required area of rock <br />layer: A x 0.83 = , <br />'] {D gpd x 0.83 sq. ft./ gpd = l,,~:Z sq. ft.+1e':::6 -:::.1.,1s4° <br />2. <br />3. <br />Select width of rock layer (10 feet or less) = 10 ft. <br />Length of rock layer = area + width = <br />1,,:, V'-1 sq. ft.+ Jo ft. = 1,, ~ ft. <br />Rock Bed <br />E. ROCK VOLUME Leng th <br />1. Multiply rock area by rock depth to get cubic feet of rock; <br />I&_ sq. ft. x J,o,< ft. = '7 1 '"ls" cu. ft. <br />2. Divide cu. ft. by 27 cu. ft./cu. yd. to get cubic yards; <br />'J 1 ic' cu. ft. + 27 =_]!]__cu. yd. <br />3. Multiply cubic yards by 1.4 to get weight of rock in tons; <br />_&cu.yd. x 1.4 ton/ cu. yd. =~tons. <br />F. ADSORPTION WIDTII c..L.A'--1'. L-.cl 4-~ Absorption Width Si2in11: Table <br />1. Percolation rate in top 12 inches of soil is ---1:.:i._ mpi <br />2. Select allowable soil loading rate from table; <br />'L/ ( gpd/ft2 <br />3. Calculate adsorption width ratio by dividing rock layer <br />loading rate of 1.20 gpd/ ft2 by allowable soil loading rate; <br />1.20 gpd/ft2+ ,y.{" gpd/ft2 = ?, l>() <br />Pen:olation Rate <br />Minut.,, per inch <br />(mpi) <br />Faster than 0.1 <br />0.1 to5 <br />0.1 to5 <br />6 to 15 <br />16 to 30 <br />31 to 45 <br />46 to 60 <br />61 tO 120 <br />Slower than 120 <br />C&I]..,. <br />Soil Texture !""clay <br />per "l"'"' <br />1- <br />K:oarseSand 1.20 <br />Sand 1.20 <br />Fine Sand-0.60 <br />$3.ndy Loam 0.79 <br />Loam 0.60 <br />Silt Loam 050 <br />ClatLoam 0.45 <br />lay 0.24 <br />Clav -- <br />1ypc JV <br />60'i, <br />of <br />L'>c ,,1..,. <br />in <br />L'>c <br />olher <br />col=r.1 <br />latiom <br />rock bed <br />wick.h tD <br />&~CZ\ <br />1.00 <br />1.00 <br />2.00 <br />1.52 <br />2.00 <br />2.40 <br />2.67 <br />5.00 - <br />-Soil luving ~ or more of fine or very fine sand. <br />4. Multiply adsorption width ratio by rock layer width to get <br />required adsorption width; <br />J,V7 x _l,Q_ ft=~ ft <br />'--------------------------------------------1 <br />I <br />') <br />--~~)