[Ord. No. 1620 §1, 9-25-2006]
A. General. Proposed extensions of the water distribution system
shall, in general, follow the pattern established in the water facilities
plan as adopted by the City of Hermann. Deviations from this general
policy may be deemed necessary by the City's consulting engineer should
the provision of adequate service to prospective customer or fire
protection needs, existing or anticipated, in the area to be served
warrant said deviations. No public water line shall be constructed
less than size (6) inches in diameter (except for two (2) inch PVC
lines permitted on cul-de-sacs).
B. Location Of Water Mains And Appurtenances. Proposed water
mains shall be so located within street right-of-way to provide the
least interference with the location of other utility lines. Street
grades and elevations of proposed main shall be taken into consideration
so that once constructed they will not require regrading or relocation.
C. Depth. All water mains shall have a minimum cover of forty-two
(42) inches.
D. Material Of Construction. Ductile iron pipes, HDPE or PVC
shall be used for all mains constructed in the City of Hermann.
1. The ductile iron shall conform to ANSI A21.51; ASTM A536, Grade 60-42-10;
AWWA C151. The minimum nominal thickness class for ductile iron pipe
shall be fifty (50), unless otherwise designated by the City's consulting
engineer.
2. Joints, unless otherwise specified, shall be of the push-on type
conforming to ANSI A21.11/AWWA C111, except gaskets shall be synthetic
rubber. Natural rubber will not be acceptable. The pipe shall be cement
mortar lined, conforming to ANSI A21.4/AWWA C104 and shall be coated
inside and out with a bituminous coating.
3. Ductile-iron fittings shall be complete with all accessories and
shall be ASTM A536, Grade 7050-05 conforming to ANSI A21.10/AWWA C110,
350 PSI pressure rating. Joints shall be of the standard mechanical
joint type conforming to ANSI A21.10/AWWA C104 and shall be coated
inside and out with a bituminous coating.
4. PVC pressure pipe shall be designed to carry potable water at pressures
(including surge) up to the maximum class rating. Materials from which
the pipe, couplings and fittings are manufactured shall conform to
ASTM D1784, Type 1, Grade 1, two thousand (2,000) p.s.i design stress.
The minimum wall thickness for the pipe shall be C900 (Class 200).
Two (2) inch PVC pressure pipe shall have a minimum wall thickness
for the pipe shall be DR 17 (Class 250) or Schedule 40 (Class 270).
5. All PVC pipe shall conform to the latest revisions of ASTM D2241,
Department of Commerce PS22-70 (SDR-PR) pressure rated pipe and National
Sanitation Foundation Testing Laboratories (NSF). Pipe ends shall
be tapered to accept gasketed couplings. Flexible elastomeric gaskets,
meeting the requirements of ASTM F477, shall be synthetic rubber.
6. The couplings and fittings shall accommodate the pipe for which they
are used. The minimum pressure ratings shall be two hundred thirty-five
(235) psi for couplings and two hundred fifty (250) psi for the fittings.
E. Acceptance Testing.
1. All costs associated with acceptance testing of the water system
shall be the responsibility of the developer.
a. Pressure tests.
(1)
The contractor shall furnish all pumps, piping, labor and other
materials and services necessary to bring the piping up to the specified
test pressure.
(2)
All pipes shall be pressure tested. Pipes which will be pressurized
under normal operating conditions shall conform to the requirements
of the hydrostatic pressure test. All other piping shall meet the
requirements of the air leakage test.
(3)
Pipe in the sections to be tested shall be backfilled or center
loaded, with thrust blocks installed and completely backfilled. Interior
pipe supports and restraint systems shall be completely installed
prior to testing.
b. Hydrostatic pressure test.
(1)
Test connections shall be made and the pipe filled with water.
Unless otherwise specified, a pressure of not less than one and one-half
(1.5) times the normal operating pressure (for the lowest point on
the pipe line) but not less than one hundred fifty (150) pounds per
square inch (psi) or not more than the rated working pressure for
the pipe shall be used for testing.
(2)
After air removal, water shall be pumped in to bring the pipe
to the specified pressure. After two (2) hours, additional water shall
be drawn from a container of known volume. The amount of water required
to return the system to the specified pressure shall not exceed the
amount determined by the following formula:
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Q = SD(P)½/133000,
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Where
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Q
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=
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Total allowable leakage in two hours, gallons.
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S
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=
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Length of section tested, feet.
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D
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=
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Nominal pipe diameter, inches.
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P
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=
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Test pressure, psi.
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(3)
All exposed pipe, fittings, valves, hydrants and joints shall
be inspected and all evidence of moisture appearing on the surface
of the ground during the test shall be investigated by the contractor
by excavation where the pipe has been covered with backfill. Should
the leakage test results exceed allowable leakage, the test pressure
shall be maintained for an additional period of time as directed by
the engineer to facilitate location of leaks.
(4)
All pipe, fittings, valves, pipe joints, hydrants and other
materials which are found to be defective when the pipeline is tested
shall be removed from the line immediately and replaced with new and
acceptable material by and at the expense of the contractor. The pressure
test shall be repeated after repairing leaks and other defective work
until the pipeline installation conforms to specified requirements
and is accepted by the engineer.
F. Fire Hydrants.
1. Fire hydrants shall conform to AWWA C502 and shall be Mueller "Centurion"
A423.
2. Hydrants shall be traffic models with breakaway flanges and shall
have one (1) four and one-half (4½) inch pumper nozzle and
two (2) two and one-half (2½) inch nozzles. All hydrants shall
be furnished with auxiliary gate valves.
3. Hydrants should be placed at or near street intersections and at
intermediate points when block lengths become long. Under no circumstances
shall the spacing of fire hydrants exceed five hundred (500) feet
in residential areas or three hundred (300) feet in commercial areas.
4. Fire hydrant installations shall conform to the standard drawings.
a. Clean and disinfect potable water distribution piping as follows:
(1)
Purge all new water distribution piping systems and parts of
existing systems that have been altered, extended or repaired prior
to use.
(2)
Use the purging and disinfecting procedure prescribed by the
authority having jurisdiction or, in case a method is not prescribed
by that authority, use the procedure described in AWWA C651 or as
described below:
(a)
Fill the system or part thereof with a water/chlorine solution
containing at least fifty (50) parts per million of chlorine. Isolate
(valve off) the system or part thereof and allow to stand for twenty-four
(24) hours.
(b)
Drain the system or part thereof of the previous solution and
refill with a water/chlorine solution containing at least two hundred
(200) parts per million of chlorine and isolate and allow to stand
for three (3) hours.
(c)
Following the allowed standing time, flush the system with clean,
potable water until chlorine does not remain in the water coming from
the system.
(d)
Submit water samples in sterile bottles to the authority having
jurisdiction. Repeat the procedure if the biological examination made
by the authority shows evidence of contamination.
G. Line Valves. Gate valves shall be of the resilient-seated
configuration and shall conform to the applicable requirements of
AWWA C509.
1. Resilient-seat gate valves shall be American-80 "CRS" or Mueller
A-2370-20 or approved equal.
2. Gate valves shall be used in all water mains twelve (12) inches in
diameter and smaller.
3. Butterfly valves shall conform to AWWA C504 and shall be American
(Class 150B), Mueller "Line Seal III" or approved equal. Butterfly
valves shall be used in mains larger than twelve (12) inches in diameter
or where otherwise approved by the City's consulting engineer.
4. Valves shall be placed in all straight runs of pipe at intervals
not to exceed eight hundred (800) feet. Where two (2) lines intersect,
a valve should be placed in each pipe on each side of the intersection.
Valves should be so placed that any pipe two (2) blocks long can be
cut out of the general circulation without interrupting service in
the rest of the system.
5. Extension stems shall be provided for buried valves when the operating
nut is more than three (3) feet below finished grade. Each extension
stem for a buried valve shall extend to within three (3) feet of the
ground surface, shall be provided with spacers that will center the
stem in the valve box and shall be equipped with a wrench nut.
H. Tapping Sleeves And Valves. Tapping sleeves and valves shall
be used where required to connect to existing in-service mains.
1. The valves shall be two hundred (200) p.s.i, resilient-seated, cast
iron body, non-rising stem gate valves conforming with all applicable
requirements of AWWA C509 and shall be Mueller "No. A2307-16" or an
approved equal. Each tapping valve shall be provided with a flanged
inlet end designed, faced and drilled for connection to the outlet
end of the tapping sleeve. The outlet end of the tapping valve shall
be provided with a tapping flange for attachment of a standard drilling
machine and also with a mechanical joint-type bell end for connection
of the branch main.
2. Tapping sleeves shall be of the flanged-outlet type designed for
attachment to the flanged inlet end of the tapping valve and shall
be provided with mechanical joint ends at each end of the run and
shall be Mueller "No. H-615" for ductile iron pipe or approved equal.
I. Connections To Existing Water Mains. Connections to existing
water mains shall be made in such a manner as to provide the least
amount of interruption to water service. In the event closing of valves
to make a connection will affect a customer who cannot be without
service, provisions shall be made on the plans for a temporary service.
J. Provisions For Future Extensions Of Water Maims.
1. At the termination of all water mains or at locations as specified
by the City's consulting engineer, a dead-end assembly in accordance
with the specifications of the City of Hermann shall be provided to
allow for future water main extensions.
2. Flushing assemblies shall be used at locations as required to provide
for thorough flushing of all water mains in the project area. Whenever
practical, water mains five hundred (500) feet and longer shall be
provided with a fire hydrant for flushing.
K. Thrust Blocking. Reaction blocking of adequate size shall
be provided at all tees, elbows and bends to resist all resultant
thrusts due to hydrostatic pressure. All blocking shall conform to
the standard drawings.
L. Highway And Railroad Crossings. All crossings of highways
or railroads shall be made by boring or tunneling. The work shall
be in conformity with all requirements and regulations and be under
the control of the authority owning or having jurisdiction over and
control of the right-of-way in each case.
M. Street Crossings. Open cutting of streets shall be allowed
only where permitted by the City's consulting engineer. At locations
where open cutting is not permitted, the crossing shall be made by
boring or tunneling. Crossings made by boring or tunneling shall require
a casing pipe unless otherwise approved by the City's consulting engineer.
All work and materials shall be in conformity with all requirements
of the technical specifications of the City of Hermann. The diameter
and length of the casing pipe to be used shall be as determined by
the City's consulting engineer.
N. Fire Flow Requirements. Public improvement plans for water
line projects serving development sites other than single-family or
duplex subdivisions shall be reviewed for fire protection sufficiency.
The City Fire Chief shall determine the amount of water that is required
for fire protection based on I.S.O. guidelines for the proposed type
of structures to be built within the development. The design engineer
shall obtain the flow requirement and then determine if the existing
operating conditions will allow for the plan improvement. Calculations
verifying that the required flows can be met shall accompany the drawings
when submitted for approval.