(Revision of ANSI/AWWA C). Copyright © This document is an American Water Works Association (AWWA) standard. It is not a. 1, , AWWA issued the updated ANSI/AWWA C 14 standard, Disinfecting Water Mains, a result of the review that AWWA standards must go through. AWWA Standard for Disinfecting Water Mains – Jun 1, – Ansi/AWWA C DS60 Water Supply Distribution Standard – Pipelines Other.
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Organochlorine compounds can form when chlorine reacts with organic substances. Joints of pipe in the trench shall be completed before work is stopped. Specific situations not captured below need to be evaluated and the appropriate disinfection and sampling methods followed. This method may be used only if the pipes and appurtenances are kept clean and aawa during construction.
Adequate drainage must be provided during flushing.
AWWA C Disinfecting Water Mains
The number of 5-g tablets required for each pipe section shall be 0. After satisfactory bacteriological sample results have been received for the predisinfected pipe, the pipe can be used in connecting the new main to the active distribution c651-0.
Purchaser Options and Alternatives. What is that symbol.
c651–05 The tablet method is convenient to use in mains having diameters up to 24 in. The chlorinated water may then be drained or flushed from the main.
AWWA C651-14 Disinfecting Water Mains
Major revisions made to the standard in this edition include the following: Dechlorination equipment may not be capable of wwwa high flows with high levels of chlorine. If the initial disinfection fails to produce satisfactory bacteriological results, or if other results indicate unacceptable water quality, the main may be reflushed and shall be resampled.
Flushing the chlorinated water from the main. It should be recognized that the primary means of ensuring the sanitary integrity of a main are the sanitary handling of materials, the practices during construction, and continual inspection of work. Certain contaminants, such as caked deposits, resist flushing at any awwwa velocity, and pigging of the main, or other suitable method acceptable to the purchaser, may be required.
Rodent-proof plugs may be used when watertight plugs are not practicable and when thorough cleaning will be performed by flushing or other means. For very-large-diameter pipe where personnel may safely enter the pipein lieu of flushing following disinfection, the interior of the pipe at the repair site may be cleaned by sweeping or high pressure wash using potable water before disinfection.
The party that provides the work and materials for placement or installation. The tablet method cannot be used unless the main can be kept clean and dry.
The purpose of all four chlorination methods awaa to disinfect water lines, c615-05 in an absence of coliforms as confirmed by laboratory analysis. While the contact times of the methods may not aawa identical, the end result, absence of coliforms, is the same for all four methods.
It should be noted if the line is depressurized or opened to the environment prior to or during repair, the sanitary integrity of the pipe is compromised and it is critical to follow sanitary procedures throughout the repair—not just as it is being returned to service. The tablet method consists of placing calcium hypochlorite granules or tablets in the water main during installation and then filling the main with potable water to create a chlorine solution.
Where such flow rates are not possible, flushing at the maximum expected flow rate for the line for 2—3 volumes may be acceptable. In the case of new mains, high velocities in the adjacent existing system, resulting from flushing the new main, may disturb sediment that has accumulated in the existing mains.
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Sanitary construction practices must be followed during installation of the final connection so that there is no contamination of the new or awwz water main with foreign material or groundwater. This procedure must not be used on solvent-welded plastic or on screwed-joint steel pipe because of the danger of fire or explosion from the reaction of the joint compounds with the calcium hypochlorite.
Gordhamer, Measurement Technologies C651-0. Test results should confirm that the water quality is appropriate for distribution. The chlorine concentration is uniform throughout the main.
In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states. The installation of new mains c651-0 that two sets of samples for coliform analysis are collected at least 16 hr apart, or two sets collected 15 min apart after at least a hr rest period.
This American National Standard may be revised or withdrawn at any time. When the existing pipe has to be opened and the interior surfaces of the water system exposed to the environment, additional procedures need to be followed. This allows backflow of water into the cylinder, resulting in severe cylinder corrosion and the escape of chlorine gas. It must be remembered that the final water quality test is not the primary means for certifying the sanitary condition of a main.
As chlorinated water flows past fittings and valves, related valves and hydrants shall be operated so as to disinfect appurtenances and pipe branches.
Since this is a threshold velocity, 3. Individual states or local agencies have authority to accept or accredit certification organizations within their jurisdictions.
Containers of 30 gal After the applicable retention period, heavily chlorinated water should not remain in prolonged contact with pipe.