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and other appurtenances. Where piping passes through concrete or masonry walls, <br /> take-down fittings shall be employed within 3 feet of the wall. <br /> All exposed pipelines shall accommodate expansion and contraction forces by the use of <br /> expansion joints, anchors, and pipe guides. Where pipes cross structure expansion <br /> joints, rubber spherical molded type pipe expansion joints with restraining rods shall be <br /> installed whether specifically shown or not. <br /> All unrestrained joints in pressure pipelines, including bell and spigot, flexible couplings, <br /> expansion joints and flange adapters shall have tension bars (tie rods) provided in <br /> accordance with AWWA M11 Design Manual, Figures 19.15 and 19.16, and Tables 19.7 <br /> and 19.8. Thrust protection shall be for 1'/2 times the specified test pressure for the pipe. <br /> C. Buried Pipe <br /> All buried pipe shall be prepared as herein before specified and shall be laid on the <br /> prepared granular base and bedded to ensure uniform bearing. No pipe shall be laid in <br /> water or when, in the opinion of the Engineer, trench conditions are unsuitable. Joints shall <br /> be made as herein specified for the respective types. Take all precautions necessary to <br /> prevent uplift and floating of the pipe prior to backfilling. <br /> Piping under slabs and structures shall be encased in concrete unless otherwise directed <br /> by the Engineer. <br /> D. Gravity Lines <br /> Laying of gravity pipelines shall proceed upgrade with the spigot ends pointing in the <br /> direction of flow. Each piece shall be laid true to line and grade and in such manner as to <br /> form a close concentric joint with the adjoining pipe and to prevent sudden offsets in the <br /> flow line. As the work progresses, the pipe interior shall be cleared of all dirt and debris of <br /> every description. Where clearing after laying is difficult because of small pipe size, a <br /> suitable swab or squeegee shall be kept in the pipe and pulled forward past each joint <br /> immediately after jointing has been completed. Pipe shall not be laid when the condition of <br /> the trench or the weather is unsuitable. At times when work is not in progress, open ends <br /> of pipe and fittings shall be closed. <br /> E. Corrosion Protection <br /> All buried metal parts such as valves and bolt-ups not cement mortar coated shall be <br /> coated with two coats of bitumastic in accordance with Section 09900 Coating Systems, <br /> and encased with two sheets of 8-mil minimum thickness polyethylene to form a <br /> continuous and all-encompassing double layer of polyethylene between the protected <br /> metal and surrounding earth. All polyethylene shall be secured in place with 10-mil <br /> polyethylene tape. <br /> F. Dielectric Connections <br /> Where pipes of dissimilar metals are connected, a dielectric insulator shall be provided <br /> in accordance with Section 13100. Dielectric insulators shall be installed on the first <br /> exposed flanges or couplings of pipes which are connected to buried piping. Where <br /> July 2007 Division III-158 NEI Phase II Water and Sewer <br /> CIP Nos. 7468, 7589, 7590 <br />