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MOUND DESIGN WORK SHEET(For Flows up to 1200 d) <br /> A. Average Design FLOW <br /> A-1: Estimated Sewage Flows in Gallons per pay . <br /> numbe <br /> Estimated bo U gpd(see figure A-1) bedrooms class 1 class II 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 /> B. SEPTIC TANK Capacity 4 600 375 256 values <br /> P 5 750 450 294 in the <br /> 6 900 525 332 Gass I, <br /> a-1000 gallons (see figure C-1) 7 1050 600 370 0, or In <br /> 8 1200 1 675 1 408 1 columns. <br /> C. SOILS (refer to site evaluation) C-1:SepikkTaACa esft as <br /> Uquid 1. Depth to restricting layer= :R AA 40 -4.$ feet <br /> Number <br /> M��t i� capacity <br /> life ituide <br /> 2. Depth of percolation tests= /.0 feet 2orless 750 1125 <br /> 3. Texture CL'Aq LOA 3or4 1000 1500 1500 <br /> 2000 <br /> Percolation rate 9-to mpi 7,8 a 9 � 2250 3000 <br /> 4. Soil loading rate 1%I gpd/sgft(see figure D-33) <br /> 5. Percent land slope 7 % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A)by 0.83 to obtain required rock layer area: <br /> 1000 gpd x 0.83 sgft/gpd = 4'14sgft-rxor,)d:Sy,)" <br /> 2. Determine rock layer width= 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> _ <br /> 0.83 sqft/gpd x 12 bpd/sgft= 10 ft Mound LLR <br /> 3. Length of rock layer= area=-width = <br /> S4 -) sgft(Dl)- o ft(D2) _ _S ft 5U 10,,( � < 120 MPI <121 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> La <br /> 1. Multiply rock area (Dl)by rock depth of 1 ft to get cubic feet of rock <br /> IN 0 _sgft x 1 ft= 54 rf cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> A-40 cuft =27 cuyd/cuft= a g cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> ao cuyd x 1.4 ton/cuyd = tons <br /> D-33: Absorption Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Iercolafinnwu ta.aingiwe <br /> in Mi�per Soil Texton Gallon: Absorption <br /> Inch par day per Ratio <br /> stare foot <br /> Faster than 5 coarse sud 1.20 1.00 <br /> Absorption width equals absorption ratio (See Figure D-33) Medico Sudmesad <br /> times rock layer width (D2) <br /> 16 to 30 L.oa,n 2.00 <br /> 1 to 4s ill t.wm 2, <br /> Sill <br /> • x ft= to. ft 46 to 60 SO%Sancly Clay <br /> Loam Lain 0.45 2.67 <br /> C�y61 to 120 Silty osy0.24 5.00 <br /> s- oar <br /> Slowathur 1z0+ <br /> •syswa aedv d(o.*K rails orw ba ober ar perfwm <br />