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• SCREEN [Refer tb OAR 340-73-0055] • • • 1. • The pump shall be placed within a corrosion.resistant screen that extends above the maximum effluent level within the pump chamber.The use of a screen is.not required if the dosing assembly is preceded by a tank with an effluent filter. • 2. The screen shall have at least 12 square feet of surface area,with'1/8th inch openings. . 3.• .A screen is always required in a dosing septic tank. (See OAR 340-73-0030) VALVING .• . ' . . 1. A gate valve is installed in the pressure line set above the inlet pipe in a readily accessible location • -and position,within approximately 12 inches of the riser cover(see diagram). - • 2. A check valve is installed between the pump and the gate valve. _ 3. A union disconnect of noncorrosive material is installed between the check and gate valves above the inlet pipe in a'readily accessible location and position,within approximately 12 inches of the riser • . . • cover(see diagram). - . . . . . 4.- For the purposes of preventing pump air-lock, a 1/8" or larger orifice is recommended to be installed • (drilled)in the:pressure line•below the pump "ON'r;" level.This may be required by the pump . manufacturer's installation instructions.• . . PRESSURE PIPING • • - . . . - • • • 1.- .All pressure transport piping must meet or exceed standards for PVC 1120 as identified in ASTM . Specification D-2241. • • 2. For pipe diameters of one(1)inch or less,.the minimum pressure rating shall be 200 pounds per • square inch.For pipe diameters greater than one inch,the minimum pressure rating shall be 160 pounds per square inch. . • . 3. Piping shall be uniformly supported along the trench•bottom. 4•. Minimum depth of installation shall be 18" or below frost line whichever is greater. • •- • 5. Must be baffled at point of discharge: • • • • . a. Serial distribution:Enter the first drop box with pressure line elbowed down below I . the overflow header outlet.. . . . . - - b. -.Equal distribution:Enter the box with pressure line elbowed down below the header outlet. . . 6. An 18 gauge,green jacketed tracer wire or green color-coded metallic locate tape shall be placed . above piping when crossing property lines or entering public property or rights-of-way.A tracer wire.. l should also be installed from the dosing tank manhole lid to the first box of the disposal field. • • _ • • . SETBACKS [minimum setbacks from dosing tank,with exceptions for pressure transport piping] - • 1. 50' from creeks,ponds,streams, etc.;springs and wells. . • • . 2. . 10' from ground water interceptors,water lines and escarpments. • . 3. 5' from property lines,building foundations, septic tanks and disposal fields. • - • Mc:s-11 • • rev:8/00;8/04 . . . • • - PPOP.9.of4 . •