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• til• i 40 water entering the pipe that the combined mixture shall contain 50 ppm of free available chlorine, but no more than 200 ppm of free available chlorine. Valves shall be manipulated so that the strong chlorine solution in the line being treated will not flow !rack into the line supplying the water. Backflow preventers shall be used if necessary. 3.2.5 Retention Period: Treated water shall be retained in the pipeline long enough to destroy all nonspore-forming bacteria. At the end of a twenty-four hour period, the disinfecting mixture shall have a strength of at least 10 ppm of free chlorine. Following disinfection, water shall be flushed from the line until the water through the line is equal chemically and bacteriologically to the permanent source of supply. Disinfecting water shall not be allowed to flow into a waterway without adequate dilution or other satisfactory method of reducing chlorine concentrations to a safe level. 3.2.6 The Contractor shall furnish all equipment and materials and perform the work necessary for the disinfecting procedures, including additional disinfection as required. PART 4 — EXECUTION: HYDROSTATIC TESTING 4.1 EXAMINATION 4.1.1 Verify all water mains/system has been cleaned, inspected and pressure tested prior to disinfection in accordance with AWWA C 601. 4.12. All tests shall be conducted in the presence of the Owner and/or his designated representative with, 24 hours advance written notice provided. 4.2 EXECUTION 4.2.1 Testing shall not proceed until all restraining devices have been installed and all concrete thrust blocks, if applicable, have been cured sufficiently to withstand static and dynamic t loads imposed. All piping shall be thoroughly cleaned and flushed prior to testing to clear the lines of all foreign matter. While the piping is being filled with water, care l shall be ex-,reised to permit the escape of air from extremities of the test section, with additional release cocks provided, if required. Filling of the main shall be witnessed under the observation of the Owner. Each valved section of the pipe shall be filled with water, slowly, and the specified test pressure shall be applied. The Contractor shall confirm that all valves in the area being tested are open. 4.2.2 Hydrostatic testing shall be performed at 150 pounds per square inch pressure, unless otherwise approved by the Utilities Engineer for a period of not less than two hourk Maximum distance to test shall not exceed 3000 feet. Testing, shall be in accordance with the applicable provisions as set forth in AW WA Standard C600. The allowable rate of leakage shall be less than the number of gallons per hour determined by the following formula: I L 133,200 02675-4 triamfecnon & Hydrotlstic iesting or Wavtt end Wssrsxsw Sytrem C %rigs t7oOt Priv* Pnotct - swckn* Si n - tirwfscbm aid thdwAc Incas