3.8
DISINFECTION
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NOTE: For modification of existing systems, provide
specific procedures for disinfection of new
equipment. If sprinkler piping is isolated from the
domestic water piping systems by means of a reduced
pressure backflow prevention assembly or if
sprinkler piping in not connected to the domestic
water piping, this paragraph should be deleted.
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After all system components are installed and hydrostatic test(s) are
successfully completed, each portion of the sprinkler system to be
disinfected shall be thoroughly flushed with potable water until all
entrained dirt and other foreign materials have been removed before
introducing chlorinating material. Flushing shall be conducted by removing
the flushing fitting of the cross mains and of the grid branch lines, and
then back-flushing through the sprinkler main drains. The chlorinating
material shall be hypochlorites or liquid chlorine. Water chlorination
procedure shall be in accordance with AWWA C651 and AWWA C652. The
chlorinating material shall be fed into the sprinkler piping at a constant
rate of 50 parts per million (ppm). A properly adjusted hypochlorite
solution injected into the system with a hypochlorinator, or liquid
chlorine injected into the system through a solution-fed chlorinator and
booster pump shall be used. Chlorination application shall continue until
the entire system if filled. The water shall remain in the system for a
minimum of 24 hours. Each valve in the system shall be opened and closed
several times to ensure its proper disinfection. Following the 24-hour
period, no less than 25 ppm chlorine residual shall remain in the system.
The system shall then be flushed with clean water until the residual
chlorine is reduced to less than one part per million. Samples of water in
disinfected containers for bacterial examination will be taken from several
system locations which are approved by the Contracting Officer. Samples
shall be tested for total coliform organisms (coliform bacteria, fecal
coliform, streptococcal, and other bacteria) in accordance with AWWA EWW.
The testing method shall be either the multiple-tube fermentation technique
or the membrane-filter technique. The disinfection shall be repeated until
tests indicate the absence of coliform organisms (zero mean coliform
density per 100 milliliters) in the samples for at least 2 full days. The
system will not be accepted until satisfactory bacteriological results have
been obtained. After the successful completion, all sprinklers or plugs
and gravity flush all drops or trapped piping.
3.9
PIPE COLOR CODE MARKING
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NOTE: Designer will coordinate color code marking
with UFGS-09900 PAINTS AND COATINGS. Color code
marking for piping which are not listed in Table I
of Paragraph 3.5 Pipe Color Code Marking of
UFGS-09900 will be added to the table.
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Color code marking of piping shall be as specified in Section 09900 PAINTS
AND COATINGS.
SECTION 13935A
Page 27
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