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MOUND DESIGN WORK SHEET (For Flows up to 1200 gpd) <br /> A. Average Design FLOW <br /> A-1: Estimated Sewage Flows in Gallons per Day <br /> number of <br /> Estimated TE:.)0 1 gpd (see figure A-1) bedrooms Class I Class li Class Iii Class IV <br /> or measured x 1.5 (safety factor) = -- gpd 2 300 225 180 60% <br /> 3 450 300 218 of the <br /> 4 600 375 256 values <br /> B. SEPTIC TANK Capacity 5 750 450 294 in the <br /> 6 900 525 332 Class I, <br /> q--I 00 p gallons (see figure C-1) 7 t 050 600 370 II.or m <br /> /000,,,...1 Vo vti'T c-rhbrovl S.; � , 8 1200 675 408 columns. <br /> C. SOILS (refer to site evaluation) C-1: Septic Tank Capacities lin,zallonsl <br /> Number of Minimum Liquid Liquid capacity with wth Liquid capacity <br /> 1. Depth to restricting layer= a.a 'S0 ;l,e, feet Bedrooms Capacity garbage disposal "'thtinsidel& <br /> lift inside <br /> 2. Depth of percolation tests = !. 0 feet 2orless 750 1125 1500 <br /> 3. Texture G1.1�� 'LO>t4�rv1 3«4 1000 1500 2000 <br /> 5 or 6 1500 2250 3000 <br /> Percolation rate 14,3 mpi 7,8 or 9 2000 3000 <br /> 4000 <br /> 4. Soil loading rate 14 S gpd/sqft(see figure D-33) <br /> 5. Percent land slope /0 % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A)by 0.83 to obtain required rock layer area. <br /> '-►ao gpd x 0.83 sqft/gpd = ')2'5 sqft <br /> 2. Determine rock layer width = 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> 0.83 sqft/gpd x 1-7.--- gpd/sqft= -10 ft Mound LLR <br /> 3. Length of rock layer = area=width= <br /> 3') Z sqft (D1) T 10 ft (D2) = 39 ft < 120 MPI <12 <br /> E. ROCK VOLUME > 120 MPI < b <br /> 1. Multiply rock area (D1) by rock depth of 1 ft to get cubic feet of rock <br /> 3') "3 sqft x 1 ft = 30 C, cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> "..,?/7'7,, cuft -=27 cuyd/cuft= I L-f cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> I L} cuydx 1.4 ton/cuyd = 20 tons <br /> i <br /> 13-33: Absorption Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Percolation Rate Loading Rate <br /> in Moulin per Soil Texture Gallons Absorption <br /> Inch per day per Ratio <br /> (MPI) square fax <br /> Faster than 5 Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) Loamy Sand <br /> Fitimes rock layer width (D2) 6 to 15 Sandy <br /> Loam 0 79 <br /> 10 <br /> y164030 Loam 0.60 2.00 <br /> 0 <br /> 31tn45 Silt Loam 0.50 2.40 <br /> . .to 9 X ' 1 ft = 2,14p E'.//� ft Silt <br /> 46 to 60 Sandy Clay Loam 0.45 2.67 <br /> Siltyy Clay Loam <br /> rmaloam <br /> 61 to 120 Silty Clay 0.24 5.00 <br /> Sandy Clay <br /> Clay <br /> Slower than 120* <br /> •Sysiom doaisonl for them soils num he other or perlomrnce <br />