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HomeMy WebLinkAboutSection 15060 Conduit and Fittings    1 SECTION 15060 CONDUIT AND FITTINGS PART 1 GENERAL 1.01 RELATED DOCUMENTS A. All applicable provisions of Bidding and Contract Requirements including Division 1 - General Requirements, shall govern the work under this section. 1.02 WORK INCLUDED A. Provide all labor, materials, necessary equipment and services to complete the Conduits, Fittings and Supports work, as indicated on the drawings, as specified herein or both, except as for items specifically indicated as "NIC ITEMS". 1.03 RELATED WORK A. Section 02200 - Earthwork B. Section 15108-Handhole and Boxes 1.04 SUBMITTALS A. Submit shop drawings and product data in accordance with Section 01300 1.05 DESCRIPTION A. Provide conduit work to include excavating and backfilling as necessary for a complete duct bank in accordance with drawings and specifications. 1.06 QUALITY ASSURANCE A. The work shall be performed in accordance with the Section EXCAVATING, TRENCHING AND BACKFILLING FOR UTILITIES IN Division 2. 1.07 COORDINATION A. Do not excavate for conduit work until the work is ready to proceed without delay, so that the total time laps from exaction to completion of backfilling will be minimum. B. The surface disturbed during the installation of conduits shall be restored to its original elevation and condition. 1.08 LABELING: A. Materials to bear Underwriters' Laboratories Labels, where applicable.     2 PART 2 PRODUCTS 2.0l DUCTS A. Underground conduits of the size as indicated on drawings shall consist of a number of individual PVC schedule 80 shall be UL rated conduits installed in a common trench with a minimum depth as shown on the construction drawings between finished grade and top of the conduits. B. Plastic conduit shall be single bore, and shall be schedule 80 polyvinyl-chloride conduit. Conduit fittings shall conform to the applicable utility Standards, except that where utility standards for conduit fittings do not exist for the type of plastic installed, fittings shall be as recommended by the conduit manufacturer. C. Conduit and fittings shall be free, within commercial tolerances, of objectionable lines, striations, bubbles, welds, and other manufacturing defects that would impair the service of the conduit. The bore of the conduit shall be straight and circular in cross section with smooth interior surfaces free from obstructions and rough and flakey areas. The conduit and fittings shall be free from all substances that injuriously affect any wire or cable covering such as is used on rubber-covered wire, polyethylene or polyvinyl chloride sheathed cable. The conduit and fittings shall be corrosion-resistant and not adversely affected by acids, alkalies, salts, bacteria, and other organic matter that would normally be encountered in the ground. The conduit length for each size shall be the length that is standard with the manufacturer with a permissible tolerance of l/4 inch per l0-foot length. Bends, elbows, and other fittings shall be capable of freely passing a ball that is l/4 inch less in diameter that the nominal bore of the conduit..Conduit and fittings shall be capable of being joined, by means of a solvent welding cement so as to provide a watertight and rustproof joint.     3 PART 3 EXECUTION 3.01 INSPECTION A. Do not proceed with the work of this section until conditions detrimental to the proper and timely completion of the work have been corrected in an acceptable manner. 3.02 DUCT LINE INSTALLATION A. Duct lines shall be laid to a minimum grade of 4 inches per l00 feet. Grade from one manhole to the next or both ways from a high point between manholes, depending on the contour of the finished grade. Low points that may trap water are not acceptable. Conduits shall be installed so that the top of conduit to finished grade or finished paving at any point is not less than shown on the construction drawings..A 5 degree bend segmentmay be used to pass under obstruction.Changes in direction of run shall be accomplished by long sweep bends having a minimum radius of 36 inches., Conduit shall terminate in end bells where duct lines enter manholes. Conduit shall be thoroughly cleaned before using or laying. During construction and after the duct line is completed, the ends of the conduits shall be plugged to prevent water washing mud into the conduits or manholes. Particular care shall be taken to keep the conduit clean of concrete, dirt, and any other substance during the course of construction. 1. Excavate trench bottom to provide firm and uniform support for duct bank. Comply with requirements in Section 02220 for preparation of trench bottoms for pipes less than 6 inches in nominal diameter. 2. Support ducts on duct separators coordinated with duct size, duct spacing, and outdoor temperature. 3. Space separators close enough to prevent sagging and deforming of ducts, with not less than four spacers per 20 feet of duct. Secure separators to earth and to ducts to prevent displacement during backfill and yet permit linear duct movement due to expansion and contraction as temperature changes. Stagger spacers approximately 6 inches between tiers. 4. Depth: depth of cover from finished grade to the top of the duct bank shall be as shown on the construction drawings.. 5. Install conduits as shown on construction drawings. 6. Install manufactured rigid conduit elbows for stub-ups at poles and equipment, through floor, and at changes of direction in duct run. a. Conduits shall be extended a minimum of 6 inches into boxes. 7. After installing first tier of ducts, backfill and compact. Start at tie-in point and work toward end of duct run, leaving ducts at end of run free to move with expansion and contraction as temperature changes during this process. Repeat procedure after placing each tier. After placing last tier, hand place backfill over ducts and hand tamp. Firmly tamp backfill around ducts to provide     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.