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MO ISTD 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 of <br /> Estimated Lo o gpd (see figure A-1) bedrooms class I Clan II Class III class Iv <br /> 2 300 225 180 6096 <br /> or measured — x 1:5 (safety factor) _ — gpd 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 /> gallons(see re C-1) 7 1050 600 370 o or m <br /> 1;k_1000 <br /> g figs 8 1200- 675 . 408 columns. <br /> C. SOILS (refer to site evaluation) a1: SeptIcTiallCopcides On tallow) <br /> Liquid capacity <br /> Number of Itfinimum liquid Liquid capacity with with di al& <br /> 1. Depth to restricting layer= /,z g t.3• feet Bedrooms Capacity, image disposal lift inside <br /> 2. Depth of percolation tests= /-D feet 2orless 750 1125 1500 <br /> 3. Texture L!:, �,o+4rvt_ s a 6 15500 1 500 2000 <br /> =0 <br /> 3000 <br /> Percolation rateIt . fil _mpi 7,8 or9 2000 300° <br /> 4. Soil loading rate .4-C gpd/sgft(see figure D-33) <br /> 5. Percent land slope 6 <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A)by 0.83 to obtain required rock layer area. <br /> Lam--gpd x 0.83 sqft/gpd =�—sgft+tem=Sys <br /> 2. Determine rock layer width= 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> 0.83 sqft/gpd x )-I- gpd/sgft= /o ft Mound LLR <br /> 3. Length of rock layer= area+width <br /> I sgft(Dl)+ 10 ft(D2) _ ft < 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 /> �sgft x 1 ft=Si2_cult <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> _�_cuft +27 cuyd/cult=�o _cuyd <br /> 3. Multiply cubic yards by 1.4 to get wei ht of rock in tons <br /> go cuyd x 1.4 ton/cuyd = R tons <br /> 0.33: AbooMdon Width Sizing Table <br /> ftvoletion RISM <br /> lmdgna Rote <br /> F. SEWAGE ABSORPTION WIDTH inMi�tedp �c,�n "R bion <br /> Faster than 1.20 1.00 <br /> Absorption width equals absorption ratio (See Figure D-33) 2.00 <br /> times rock layer width (D2) � LAM 2.40 <br /> x/_ft- .C�ft Sill <br /> 46 to 60 Sandy any 0.45 2.67 <br /> Qay lam <br /> 61 to 120 Silty aeY 0.24 S.00 <br /> Sud pay <br /> ower than 120* _4 <br /> esymoladedgmd far dwr adb rem W odWwP0ffflnneea <br />