(A) Installation.
(1) Pipe depth. Water mains shall be installed with a minimum cover of 42 inches.
(2) Relation to sanitary sewers.
(a) Unless specifically allowed otherwise by the town, water mains shall be installed a minimum of ten feet horizontally from any existing or proposed sanitary sewer. Where such a requirement is not possible, the sanitary sewer material shall meet the material requirements for water mains as specified herein for the entire length where the minimum separation cannot be met.
(b) Where water mains cross sanitary sewer lines, a minimum vertical clearance of 18 inches shall be provided, whether the main is above or below the sewer. Conformance with this requirement shall not waive the minimum cover requirements.
(3) Plastic pipe locating tape.
(a) Locating tape shall be installed over all PVC water lines. This tape shall be of a type which can be used with electronic pipe locating devices.
(b) Locating tape shall be continuous and in a three-inch width. Tape shall be a sandwich type of a metallic strip between polyethylene film. Tape shall be printed “Caution, Water Line Buried Below”.
(c) Tape shall be spliced together for continuity and shall be brought into mainline valve boxes for connection to a locating device.
(d) Tape shall be laid in the trench along the pipe centerline two inches below finish grade.
(4) Valves.
(a) Butterfly and gate valves shall be set vertically and bedded solidly on trench bottom. Flanged valves shall be securely bolted utilizing red rubber or asbestos gaskets and high strength cast iron bolts and nuts.
(b) Valve boxes shall be set squarely over tee wrench nut and vertical. Leave valve box flush with finish grade and readjust as necessary to reconform with surface until final settlement or paving is complete.
(c) All valves shall be buried and have road boxes unless otherwise specified.
(5) Fire hydrants.
(a) Fire hydrants shall be rigidly blocked and braced against thrust. Contractor shall back up hydrant base with concrete and support base all as detailed on the plans.
(b) An envelope of washed, coarse gravel shall be provided around the drain ports of the hydrants to assure barrel drainage of the hydrants. Gravel shall be a minimum two feet diameter and to six inches above ports.
(c) Ground line marks on hydrants shall be set two inches above finish grade. All hydrants shall have one prime coat and two field coats of a suitable exterior machinery enamel or color used in this system. Prime coat shall be touched-up prior to application of finish coat.
(6) Tapping valves. Tapping valves shall be installed and the tap made in accordance with the manufacturer’s recommended procedures and good practice. Valves shall be securely supported in vertical position during tapping operations. Tamp fill thoroughly around and under valve after installation. Installation shall be checked for leaks before backfilling.
(7) Service connections. At locations shown on the plans or where designated by the town, the contractor shall furnish all materials and labor to connect water services to mains. Any piping or fittings required to make the connection and provide service shall be furnished by the contractor. Meter pits and settings shall be installed plumb and true according to good construction practices.
(B) Hydrostatic testing.
(1) The contractor shall perform a combination pressure and leakage test on the new mains after they have been filled with water as previously specified. This work shall be done after all of the main is backfilled.
(2) The test procedure shall be as herein specified and in accordance with applicable provisions of AWWA Standard C-600.
(3) The mains shall be subjected to a minimum test pressure of 150% of the maximum system operating pressure of the main being tested; provided that, the maximum pressure does not exceed the ratings of the valves, restraints and other materials. The duration of each test shall be at least two hours. Each valved section of pipe shall be so tested.
(4) The test pressure shall be accomplished by means of a pump connected to the pipe. Such pump, including all meters, connections, fittings, gauges and the like shall be supplied by the contractor. Leakage shall be defined as the quantity of water required to refill the main in order to maintain pressure within five psi of the specified test pressure after the pipe has been filled with water and expelled of air. Leakage shall not be measured by a drop in pressure over a period of time. No pipe installation shall be accepted if the leakage is greater than that determined by the following formula:
L = SD (P)1/2
133,200
where: L = allowable leakage, in gallons per hour
S = length of pipe tested, in fee
D = nominal pipe diameter, in inches; and
P = average test pressure, in pounds per square inch (gauge)
(C) Disinfection of mains.
(1) General. The contractor shall be required to disinfect all new water mains, services, leads and appurtenances in accordance with AIWA C-651 “Standards for Disinfecting Water Mains”. The work shall consist of filling the mains, disinfection, testing and flashing as specified herein.
(2) Filling the mains.
(a) The new piping system shall be slowly filled with water from the utility distribution system. Where pressure is insufficient to raise water into mains at higher elevations, the contractor shall furnish booster pumping equipment to complete the filling and flushing.
(b) All air shall be expelled from the mains as they are filled. Air valves and hydrants at high points in the main shall be utilized for this purpose. Where permanent vents are not provided, the contractor shall install corporation cocks at high points to assure removal of air. Such cocks shall be left in place and location noted by dimension ties on the field record set of drawings.
(3) Disinfection.
(a) Before being placed in service, all new mains and repaired portions of, or extensions to, existing mains shall be chlorinated with a chlorine solution so that a chlorine residual of not less than 25 PPM remains in the water after 24 hours standing in the pipe.
(b) A chlorine gas-water or hypochlorite mixture shall be applied by means of a solution-feed chlorinating device. Chlorinating devices for feeding solutions of chlorine gas must provide means for preventing the backflow of water into the chlorine cylinder.
(c) The preferred point of application of chlorinating agent is ahead of the beginning of the pipeline extension or any valve section of it and through a corporation stop inserted by the contractor, in the top of the pipe. The water injector for delivering the chlorine-bearing water into the pipe should be supplied from a tap on the pressure side of the gate valve controlling the flow into the pipeline extension.
(d) Water from the existing distribution system or other source of supply shall be controlled so as to flow slowly into the newly laid pipeline during the application of chlorine. The rate of chlorine mixture flow shall be in such proportion to the rate of water entering the pipe that the chlorine dose applied to the water entering the newly laid pipe shall produce at least a 25 P.M. residual after 24 hours.
(e) If the circumstances are such that a shorter retention period must be used, the chlorine concentration shall be increased accordingly.
(f) In the process of chlorinating newly laid pipe, all valves or other appurtenances shall be operated while the pipeline is filled with the chlorinating agent.
(4) Testing and flushing.
(a) Following chlorination, all treated water shall be thoroughly flushed from the newly laid pipeline at its extremities until the replacement water throughout its length shall, upon testing, be proven comparable in quality to the water served the public from the existing water supply system and approved by the state’s Board of Health. This satisfactory quality of water delivered by the new main should continue for a period of at least two full days as demonstrated by laboratory examination of samples taken from a tap located and installed in such a way as to prevent outside contamination.
(b) Before the system is placed into use, the contractor shall obtain from the new mains two successive water samples 48 hours apart, and have them tested for bacteria content by the state’s Board of Health. Samples shall be drawn in accordance with the Board’s procedure.
(c) If samples do not prove satisfactory, the system shall be rechlorinated and resampled until safe water is approved.
(2004 Code, Art. III, § A, part 3)