Section 02666 WATER PIPELINE TESTING AND DISINFECTION

Section 02666

WATER PIPELINE TESTING AND DISINFECTION

PART 1 - GENERAL

1.1 THE REQUIREMENT

A. The CONTRACTOR shall furnish all tools, equipment, materials, and supplies and shall perform all labor required to complete the Work, as indicated in the Contract Documents.

B. The CONTRACTOR shall flush and test all pipelines and appurtenant piping and disinfection of all pipelines and appurtenant piping for city or potable water, including conveyance of test water from OCSD-designated source to point of use and all disposals thereof, in accordance with the requirements of the Contract Documents.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. The requirements of the following sections and divisions apply to the Work of this section. Other sections and divisions of the Specifications, not referenced below, shall also apply to the extent required for proper performance of this Work.

1. Section 02200, Earthwork

2. Division 15, Mechanical

1.3 REFERENCE SPECIFICATIONS, CODES AND STANDARDS

A. All Work specified herein shall conform to or exceed the applicable requirements of the referenced portions of the following publications to the extent that the provisions thereof are not in conflict with other provisions of these Specifications.

B. Comply with the current provisions of the following Codes and Standards.

ANSI/AWWA B300 Hypochlorites ANSI/AWWA B301 Liquid Chlorine ANSI/AWWA C651 Disinfecting Water Mains

1.4 CONTRACTOR SUBMITTALS

A. General: Submittals shall be made in accordance with the General Requirements, Additional General Requirements, and as specified herein.

B. The following submittals and specific information shall be provided.

1. A testing schedule, including proposed plans for water conveyance, control, disposal, and disinfection, shall be submitted in writing for acceptance a minimum of

48 hours before testing is to start.

1.5 QUALITY ASSURANCE

A. Comply with the applicable reference Specifications of the General Requirements and Additional General Requirements.

PART 2 - PRODUCTS

2.1 MATERIALS REQUIREMENTS

A. All test equipment, chemicals for disinfection, temporary valves, bulkheads, or other water control equipment and materials shall be determined and furnished by the CONTRACTOR subject to the ENGINEER’s acceptance. No materials shall be used which would be injurious to the construction or its future function.

B. Chlorine for disinfection shall be in the form of liquid chlorine, sodium hypochlorite solution, or calcium hypochlorite granules or tablets.

C. Liquid chlorine shall be in accordance with the requirements of ANSI/AWWA B301. Liquid chlorine shall be used only:

1. In combination with appropriate gas flow chlorinators and ejectors;

2. Under the direct supervision of a certified testing laboratory;

3. When appropriate safety practices are observed.

D. Sodium hypochlorite and calcium hypochlorite shall be in accordance with the requirements of ANSI/AWWA B300.

PART 3 - EXECUTION

3.1 GENERAL

A. Unless otherwise provided herein, water for testing and disinfecting water pipelines inside the treatment plants will be furnished by OCSD; however, the CONTRACTOR shall make all necessary provisions for conveying the water from OCSD-designated source to the points of use.

B. All pipeline trenches shall be backfilled and compacted per Section 02200, Earthwork, prior hydrostatic testing of pipe.

C. All pressure pipelines shall be tested. Disinfection shall be accomplished by chlorination. All chlorinating and testing operations shall be performed by a certified laboratory in the presence of the ENGINEER.

D. Disinfection operations shall be scheduled by the CONTRACTOR as late as possible during the contract time period so as to assure the maximum degree of sterility of the facilities at the time the Work is accepted by the ENGINEER. Bacteriological testing shall be performed by a certified testing laboratory approved by the ENGINEER and at the expense of the CONTRACTOR. Results of the bacteriological testing shall comply with the requirements of the Orange County Health Care Agency or other appropriate regulatory agency.

3.2 HYDROSTATIC TESTING OF PIPELINES

A. Prior to hydrostatic testing, all pipelines shall be flushed or blown out at 6-8 feet per second or as approved by the ENGINEER. The CONTRACTOR shall test all pipelines either in sections or as a unit. No section of the pipeline shall be tested until all field- placed concrete or mortar has attained an age of 14 days. The test shall be made by closing valves when available, or by placing temporary bulkheads in the pipe and filling the line slowly with water. The CONTRACTOR shall be responsible for ascertaining that all test bulkheads are suitably restrained to resist the thrust of the test pressure without damage to, or movement of, the adjacent pipe. Care shall be taken to see that all air vents are open during filling.

B. The pipeline shall be filled at a rate, which will not cause any surges or exceed the rate at which the air can be released through the air valves at a reasonable velocity and all the air within the pipeline shall be properly purged. After the pipeline or section thereof has been filled, it shall be allowed to stand under a slight pressure for at least 24 hours to allow the concrete or mortar lining, as applicable, to absorb what water it will and to allow the escape of air from any air pockets. During this period, bulkheads, valves, and connections shall be examined for leaks. If leaks are found, corrective measures satisfactory to the ENGINEER shall be taken.

C. The hydrostatic test shall consist of holding the test pressure on the pipeline for a continuous period of 4 hours. The test pressure for pipelines shall be 150 percent of the pipe pressure class shown or specified, measured at the lowest point of the pipeline section being tested. Potable water piping shall be tested at a minimum pressure of 200 pounds per inch. The test pressure for yard piping shall be as shown or specified on the Pipe Schedule, measured at the lowest point of the pipeline section being tested. No pressure test will be required for a reservoir overflow line. All visible leaks shall be repaired in a manner acceptable to the ENGINEER.

D. The maximum allowable leakage for pipelines shall be 10 U.S. gallons per inch of diameter per mile of pipe per 24 hours for pipe with 40-ft or greater joint lengths and with rubber-gasketed joints, and 20 U.S. gallons per inch of diameter per mile of pipe per 24 hours for pipe with 20-ft or less joint lengths and with rubber-gasketed joints. Pipe with welded joints shall have no leakage. In the case of pipelines that fail to pass the prescribed leakage test, the CONTRACTOR shall determine the cause of the leakage, shall take corrective measures necessary to repair the leaks, and shall again test the pipelines.

3.3 DISINFECTING PIPELINES

A. General: All water pipelines except those appurtenant to hydraulic structures shall be disinfected in accordance with the requirements of ANSI/AWWA C651 disinfection of water mains using the Continuous-Feed Method as modified herein.

B. Chlorination: A chlorine-water mixture shall be uniformly introduced into the pipeline by means of a solution-feed chlorinating device. The chlorine solution shall be introduced at one end of the pipeline through a tap in such a manner that as the pipeline is filled with water, the dosage applied to the water entering the pipe shall be approximately 50 mg/l. Care shall be taken to prevent the strong chlorine solution in the line being disinfected from flowing back into the line supplying the water.

C. Retention Period: Chlorinated water shall be retained in the pipeline long enough to destroy all non-spore-forming bacteria. This period shall be at least 24 hours. After the chlorine-treated water has been retained for the required time, the free chlorine residual at the pipeline extremities and at other representative points shall be at least 25 mg/l.

D. Chlorinating Valves: During the process of chlorinating the pipelines, all valves and other appurtenances shall be operated while the pipeline is filled with the heavily- chlorinated water.

E. Final Flushing: After the applicable retention period, the heavily chlorinated water shall be flushed from the pipeline until chlorine measurements show that the concentration in the water leaving the pipeline is no higher than that generally prevailing in the system or is acceptable for domestic use. If there is any question that the chlorinated discharge will cause damage to the environment, a reducing agent shall be applied to the water to neutralize thoroughly the chlorine residual remaining in the water.

F. Bacteriological Testing: After final flushing and before the pipeline is placed in service, a sample, or samples shall be collected from the end of the line, and shall be tested for bacteriological quality in accordance with the requirements of the Los Angeles County Department of Health Services or other appropriate regulatory agency. For this purpose, the pipe shall be re-filled with fresh potable water and left for a period of 24 hours before any sample is collected. Should the initial disinfection treatment fail to produce satisfactory bacteriological test results, the disinfection procedure shall be repeated until acceptable results are obtained.

3.4 CONNECTIONS TO EXISTING SYSTEM

A. Where connections are to be made to an existing potable water system, the interior surfaces of all pipe and fittings used in making the connections shall be swabbed or sprayed with a one percent hypochlorite solution before they are installed. Thorough flushing shall be started as soon as the connection is completed and shall be continued until discolored water is eliminated.