Laserfiche WebLink
MOUND DESIGN WORK SHEET(For Flows up-to 1200 d) <br /> A. Average Design FLOW A-1: Estimated Sewage Flows in Gallons per Day <br /> number o <br /> Estimated to oy gpd (see figure A-1) bedrooms class I 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 /> 4 600 375 256 values <br /> B. SEPTIC TANK Capacity 5 750 450 294 in the <br /> 6 900 525 332 Class I, <br /> a"10o0 gallons (see figure C-1) 7 1050 600 370 11,or III <br /> 8 1200 1 675 1 408 1 columns. <br /> C. SOILS (refer to site evaluation) C-1: Septic Tank Capacities(in allons <br /> aci <br /> Number of Minimum liquid Uquid capacity with with disuid posal& <br /> 1. Depth to restricting layer = a.-s -to 3,i feet Bedrooms Capacity garbage disposal lift i aside <br /> 2. Depth of percolation tests = /10 feet 2orless 7s0 1125 1500 <br /> 3. Texture CA.,4q \-V Ay✓1 3 or4 1000 1500 2000 <br /> Percolation rate `d.(o mpi 758 or 9 or 6 1200 3� 3000 <br /> 4. Soil loading rate_ Iii t4 gpd/sgft(see figure D-33) <br /> 5. Percent land slope '� % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A) by 0.83 to obtain required rock layer area. <br /> (000 gpd x 0.83 sqft/gpd = a2q sgft-ool)f,=Sy)" <br /> 2. Determine rock layer width = 0.83 sqft/gpd x linear Loading Rate (LLR <br /> 0.83 sqft/gpd x 12, gpd/sqft = 1c7 ft Mound LLR <br /> 3. Length of rock layer = area _width = <br /> ar y Q sgft (D1) = 10 ft (D2) = �5,5 _ft 10"(L'a' < 120 MPI <12 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> 1. Multiply rock area (Dl) by rock depth of 1 ft to get cubic feet of rock <br /> S40 sqft x 1 ft = Z cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> S4') cuft -27 cuyd/cuft = a o 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 /> Pereol°tion Rate Loading Rale <br /> F. SEWAGE ABSORPTION WIDTH <br /> in Minutes per Soil Texture Gallons Absorption <br /> Inch per day per Ratio <br /> MPI uare foot <br /> Faster than 5 Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) Remy Sand <br /> times rock layer width (D2) ,61030 r S,ndyLosun <br /> Loam 0.60 2.in <br /> 31 to 45 Silt Loam 0.50 2.40 <br /> ll <br /> 4• x j 0_ft = �p ft 46 to 60 Sandy Clay Lo 0.45 2.67 <br /> Silty Clay Loam <br /> 61 to 120 Silty Clay 0.24 5.00 <br /> Sandy Clay <br /> Clay <br /> Slower than 120' <br /> .61 <br /> 'System designed for these Boils=9 Ee other or perfomunce <br />