(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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Clarified differences in the requirements between new and repaired mains foreword II. Crews responsible for the repair of c6551-05 should be aware of the potential health hazards and be trained to carefully observe prescribed construction practices and disinfection procedures.
AWWA C651-14 Disinfecting Water Mains
Approval requirements before use. The vacuum-operated chlorinator mixes the chlorine gas in solution water; the booster pump then injects the chlorine solution into the main to be disinfected. This allows backflow of water into the cylinder, resulting in severe cylinder corrosion and the escape of chlorine gas. Standing water and debris from the cleaning must be removed from the pipe prior to disinfection.
Joints of pipe in the trench shall be completed before work is stopped. Determine current information on product certification. The affected pipe shall be disinfected by swabbing or spraying with a minimum 1 percent chlorine solution.
Use of Annex A procedures may not always be identical, depending on the certifier. Also, any connection of a new water main to qwwa active distribution system before the receipt of satisfactory bacteriological samples may constitute a cross-connection. Two dropping pipettes that deliver a 1-mL sample in 20 drops. For larger mains, pigging or other suitable method acceptable to the purchaser is an option in place of high velocity flushing.
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 repair work, and continual inspection of awwx. Potable water may be supplied from a temporary backflow-protected connection to the existing distribution system or other supply source approved by the purchaser. Samples for bacteriological analysis shall be collected in sterile bottles treated with sodium thiosulfate, in accordance with Section —Samples of Standard Methods for the Examination of Water and Wastewater.
OSHA requirements for xwwa space need to be addressed before entering a pipeline. Materials such as jute or hemp shall not be used. ANSI procedures require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of ANSI approval.
The installation of new mains requires 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.
Purchaser Options and Alternatives. Hose Bib for Bacteria Samples Sy d in.
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Combinations of free chlorine residual and contact time are provided. For example, if gas chlorination is the chosen chemical when either continuous-feed or slug methods are being used, use only properly designed and constructed equipment; makeshift equipment is not acceptable when liquid chlorine gas cylinders are used.
Table 3 shows the rates of flow required to produce a velocity of 3. Levels should be as expected or typical for the water system.
Caution should be used with highly chlorinated water when conducting hydrostatic pressure testing and zwwa highvolume flushing of water. In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states. Calcium hypochlorite tablets 5-grams x651-05 be placed in the upstream end of each section of pipe to be disinfected, including branch lines.
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 aewa hypochlorite. If the main is flooded during construction, it shall be cleared of the floodwater by draining and flushing with potable water until the main is clean.
Henderson, Consultant, Concord, Mass.
Disinfectants other than chlorine may be appropriate awqa use. This standard was first approved on Sept. The main should undergo hydrostatic testing prior to disinfection.