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I <br /> CITY OF EVERETT SPECIAL PROVISIONS <br /> Provide City approved double-check assembly for the purpose of testing and <br /> flushing. City will not charge for the water used in this operation. <br /> ISuccessfully complete hydrostatic pressure test prior to starting disinfecting new <br /> water mains. <br /> I 7-09.3(23)A Testing Extensions from Existing Mains <br /> Delete 7-09.3(23)A. <br /> 7-09.3(24) Disinfection of Water Mains <br /> I Delete 7-09.3(24), including subsections, and substitute the following: <br /> 7-09.3(24) Flushing and Disinfection of Water Mains <br /> (******) <br /> I Flush, disinfect with a chlorine solution and obtain passing coliform bacteria test reports <br /> before placing new water mains or extensions to existing mains in service. Submit <br /> flushing and disinfection procedures in accordance with this section. Provide submittal <br /> I containing, at a minimum: <br /> ❑ location of taps and other appurtenances used for chlorination and flushing <br /> purposes, <br /> I I . location of the sample collection taps, <br /> • disposal location and treatment procedure for chlorinated water discharged <br /> from the mains, and <br /> • procedure for disinfection including application method, point of application, <br /> 1 and target concentrations for the contact interval being used. <br /> 7-09.3(24)A Flushing <br /> Flush sections of pipe being disinfected to remove solids that may have become <br /> lodged in the pipe. Provide a tap sufficient to provide a flush velocity inside the main <br /> of at least 2.5 fps if no hydrant is installed at the end of the main. Flush as long as <br /> material or color is visible in the discharge. Flush at a minimum one full pipe volume <br /> I of water from the section of new main being tested. <br /> Guidelines for Required Flow and Openings to Flush Pipelines <br /> (assumes 40 psi residual pressure in water main) <br /> I <br /> Pipe Dia. Flow Required Size of Tap (in) Number of <br /> (in.) to Produce 2.5 2 1/2' Hydrant <br /> fps (approx) outlets <br /> I Velocity in Main(gpm) 1 1 1/2 2 <br /> (in) (in) (in) <br /> 4 100 1 1 <br /> 6 200 1 1 <br /> 8 400 2 1 1 <br /> 10 600 3 2 1 <br /> I 12 900 2 2 <br /> 16 1,600 4 2 <br /> I <br /> I <br /> Water Main Replacement"V" Division 7—STORM,SEWER,WATER April,2021 <br /> 1 WO No.—UP3730 SP—175 <br />