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' 1. Thrust Blocks: <br /> ' a. All plugs, caps, tees, bends, reducers and other fittings shall <br /> be provided with adequate thrust blocks. Thrust blocks shall <br /> be constructed to the minimum dimensions shown on the <br /> ' drawings or as directed. Thrust blocks shall be made of <br /> concrete having a compressive strength of 28 days of 3000 <br /> psi and shall bear directly against the undisturbed trench wall. <br /> ' Where possible, the backing shall be so placed that the fitting <br /> joints will be accessible for repair. All bolts and pipe joints <br /> shall be protected against contact with thrust block concrete <br /> ' by the installation of a polyethylene film placed between the <br /> fittings and the poured concrete. Where any section of a <br /> main is provided with concrete thrust blocks, the hydrostatic <br /> pressure test shall not be made until three days after <br /> installation of the concrete thrust blocks unless otherwise <br /> approved by the Engineer. Where trench conditions are, in <br /> ' the opinion of the Engineer, unsuitable for thrust blocks, the <br /> Contractor shall provide steel tie rods and socket clamps to <br /> adequately anchor the piping. All tie rods and clamps shall be <br /> ' given a bituminous protective coating or shall be galvanized. <br /> b. Concrete for thrust blocks shall consist of a mix of Portland <br /> Cement, Fine Coarse aggregate and water to produce <br /> concrete with a minimum compressive strength at 28 days of <br /> not less than 3000 psi when tested in accordance with ASTM <br /> C39 or C42. Sakrete or any similar material will not be <br /> permitted under any circumstances. <br /> ' 2. Valves: Before setting each valve, the Contractor shall make sure <br /> the interior is clean and test opening and closing. Valves shall be <br /> set with stems plumb, unless horizontal installation is called for on <br /> ' the plans, and at the exact locations shown. Trench backfill shall be <br /> tamped thoroughly for a distance of S-0" on each side of valves <br /> boxes. <br /> ' 3. Valve Boxes: A valve box shall be installed over each underground <br /> ' valve. All boxes shall be set plumb with their top flush with finished <br /> grade. <br /> 4. Fire Hydrant: Fire hydrants shall be located as shown. Each hydrant <br /> shall be connected to the main with a 6" branch line having at least <br /> as much cover as the distribution main. Hydrants shall be set plumb <br /> with the pumper nozzle facing the roadway and with the center of the <br /> lowest outlet not less than 18" above the finished grade. Hydrants <br /> shall be thoroughly blocked with concrete or shall be rodded to the <br /> Rev. 10/22/01 PROJECT#13.01126 02640-Page 11 <br />