Section 15060 Conduit and Fittings

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4 maximum supporting strength. Use hand tamper only. After placing controlled backfill over final tier, make final duct connections at end of run and complete backfilling with normal compaction. Comply with requirements in Section 02220 for installation of backfill materials. Place minimum 3 inches of sand as a bed for duct bank. Warning Tape: Bury warning tape approximately 12 inches above all direct buried ducts and duct banks. Align tape parallel to and within 3 inches of centerline of duct bank. Provide an additional warning tape for each 12-inch increment of duct-bank width over a nominal 18 inches. Space additional tapes 12 inches apart. B. After the duct line has been completed, a standard flexible mandrel not less than 12 inches long, having a diameter approximately 1/4 inch less than the inside diameter of the conduit, shall be pulled through each conduit in the presence of the engineer after which a brush with stiff bristles shall be pulled through each conduit to make certain that no particles of earth, sand, or gravel have been left in the line. If the mandrel fails to pass through the conduit being tested, defective conduits must be exposed and the defect corrected. Provide pull line with a minimum tensile strength of 1800 lbs at both ends of conduit to facilitate conductor pulling. Where connection is made to an existing duct that is of different material and shape that the duct line being installed, a suitable coupling of a type recommended by the duct manufacturer shall be used. Conduits shall be stored to avoid warping or deterioration. Plastic conduit shall be stored on a flat surface and protected from the direct rays of the sun, unless otherwise shown on the construction plans. D. Installation of couplings: Joints in all types of conduit shall be made up in accordance with the manufacturer's recommendations for the particular conduit and coupling selected. Conduit joint couplings shall be made watertight. E. Plastic conduit joints shall be made up by brushing a plastic solvent cement on the inside of the plastic coupling fitting and on the outside of the conduit ends. The conduit and fitting shall then be slipped together, until seated, with a slight twist to set the joint tightly, and the conduit then rotated one-half turn to distribute the cement evenly. Excess cement built up on the inside surface of the conduit shall then be removed. F. Ends of conduits shall be adequately sealed against water entry. Provide end bells on conduit entries into manholes and walls.