septic design for 3 br hse - not used

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, E-10 , Sand is defined as a soil texture composed by weight of at least 25 percent of very coarse, coarse, and medium sand varying in size from 2.0 to 0.25 mm, less than SO percent of fine or very fine sand ranging in size between 0. 25 and O.OS mm, and no more than 10 percent of particles smaller than 0.05 mm• A depth of at least 9 inches of filter material (rock) shall be placed on the sand layer prior to installing the distribution pipe. Filter material is defined as clean rock, crushed igneous rock or similar ' insoluble, durable and decay-resistant material free from dust, sand, silt, or clay. The size shall range from 3/4 inch diameter to 2 1/2 inch diameter. Pressure Distribution � Effluent shall be distributed over the filter material by 1-inch to 1 1/2-inch ' diameter perforated pipe under pressure. Perforation holes shall be 3/16 to 1/4 inch in diameter drilled in a straight line along the length of the pipe. ' Hole spacing shall be 30 or 36 inches. Holes shall be drilled straight into � the pipe and not at an angle. A sharp drill shall be used and any burrs in ' the inside of the pipe shall be removed. The perforated pipe laterals shall � be installed level with the perforations downward. i . The perforated pipe laterals shall be connected to a 2-inch diameter mani- I fold pipe and shall have their ends capped. The laterals shall be spaced no ' further than 40 inches on center and no further than 20 inches from the edge � of the filter material. Maximum lateral length shall be as specified on i 1I page E-13. � The manifold pipe shall be connected to the supply pipe from the pump. The ` manifold shall be sloped toward the supply pipe from the pump. I . , ' Gravity Distribution - � To provide distribuCion of effluent by gravity, 4-inch rigid plastic pipes ishould have three sets of two perforation holes per 10 foot length. The per- � foration size shall be at least one-half inch in• diameter. One row of holes ' shall be located in a straight line along the bottom axis of the pipe (6 o'clock � ; position) and one row shall be located at the 8 o'clock position. i � The 4-inch distribution pipes shall be connected to the outlets of a distribu- ition box and connected together on the far ends. The distribution pipes shall � be level or slope downward no more than 2 inches per 100 feet away from the ', ' distribution box. The distribution pipes shall be spaced no further than 60 i inches apart and no further than 30 inches from the edge of the filter material. � At least 2 inches of filter material shall be placed over the distribution pipes. i � Straw or marsh hay to an uncompacted depth of 3 to 4 inches shall be placed I over the filter material. A layer of untreated building paper (red rosin) � shall be placed over the hay or straw. � Construction vehicles shall not be allowed o�n the filter material until back- � � fill is placed. Sandy loam soil shall be placed on the filter material to a depth of 12 inches in the center of the mound and to a depth of 6 inches at the sides. ' • �