Laserfiche WebLink
MOUND DESIGN WORK SHEET (For Flows up to 1200 gpd) <br /> A. Average Design FLOW A-1: Estimated Sewage Flows in Gallons per Day <br /> number of <br /> Estimated 5/SZ) gpd (see figure A-1) bedrooms Class I Class II Class Ill Class IV <br /> or measured x 1.5 (safety factor) = gpd 2 300 225 180 of <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 /> e?- /coUgallons (see 7 1050 600 370or Ill <br /> figure C-1) 8 1200 675 4088 columns. <br /> C. SOILS (refer to site evaluation) C-1: Septic Tank Capacities(in Ralbns) <br /> Liquid capacity <br /> Number of Minimum Liquid Liquid capacity with with disposal& <br /> 1. Depth to restricting layer = /.0 feet Bedrooms Capacity garbage disposal lift inside <br /> 2. Depth of percolation tests = 1, 0 feet 2 or less 750 1125 1500 <br /> 3. Texture C�A Y 1.0/4w' 3 or 4 1000 1500 2000 <br /> 5 or 6 1500 2250 3000 <br /> Percolation rate ?.0 mpi 7,8 or 9 2000 3000 4000 <br /> 4. Soil loading rate . y.s' gpd/sqft (see figure D-33) <br /> 5. Percent land slope 6 Cavil stOPei % <br /> II%Of striae, - <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A)by 0.83 to obtain required rock layer area. <br /> Y.57.) gpd x 0.83 sqft/gpd = 36 o sqft <br /> } 2. Determine rock layer width = 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> 0.83 sqft/gpd x a gpd/sqft = id ft Mound LLR <br /> 3. Length of rock layer = area_width = <br /> 38r) sqft(D1) _ /0 ft (D2) = 3 r ft < 120 MPI <12 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> 1. Multiply rock area (D1) by rock depth of 1 ft to get cubic feet of rock <br /> 387.) sqft x 1 ft = 3ao cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> .;6'0 cuft _ 27 cuyd/cuft = /y cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> /9 cuyd x 1.4 ton/cuyd = 020 tons <br /> D-33: Absorption Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Percolation Rate Loading Rate <br /> in Minutes per Soil Texture Gallons Absorption <br /> Inch per day per Ratio <br /> (MPI) square foot <br /> Faster than 5 Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) S LoamS:dal <br /> times rock layer width (D2) t 6 t �s Sandy l.nam o 60 1.50 <br /> 16 to 30 Loam 0.60 2.00 <br /> 31 to 45 Silt Loam 0.50 2.40 <br /> Silt <br /> /o x a.4-7 ft = a ft 46 to 60 Sandy Clay Loam 0.45 2.67 <br /> Silly Clay Loam <br /> Clay Loam <br /> 61 to 120 Silty Clay 0.24 5.00 <br /> Sandy Clay <br /> Clay <br /> Slower than 120' <br /> •system designed for we.e wits Bail be oilier or perfumroce <br />