A.
Right-of-way or easement acquisition. The developer
shall be responsible for acquisition of necessary right-of-way or
easements required for a project including service to adjoining properties.
The County may provide assistance for obtaining adequate right-of-way
or easements. The width of the right-of-way or easement will be approved
by the Public Works Director.
B.
Reference points. The location of the reference points
of a project shall be identified to the contractor in the field, together
with a location map by the design engineer.
C.
Project layout. The contractor will be responsible
for the layout of the work and will protect and preserve the established
reference points and will make no changes or relocations without the
prior written approval of the Public Works Director.
D.
Sewer layout. Sewer pipe will be laid to grade as
specified on the approved construction drawings. The stakeout level
surveying can be made by qualified persons with three years' experience,
and pipe center line transit surveying should be performed by a licensed
surveyor in the State of Delaware. The spacing of the cut stakes and
the placement of batterboards or other grade control devices should
be subject to the approval of the inspector of the County. Cut sheets
should be supplied to the County for all stakeouts.
A.
Construction materials shall conform to the HUD Minimum
Design Standards for Community Sewage System.
B.
The Public Works Director may require a specific material,
permit material not specified, or require special reinforcement, extra
weight pipe or special interior or exterior coatings or encasements
where, in his opinion, conditions warrant these special requirements.
These requirements will be stated in contract document as special
provision.
A.
Construction contract. The latest edition of the Standard
General Conditions of the Construction Contract, prepared by the National
Society of Professional Engineers, shall be used as a guide for contract
documentation.
B.
Construction inspection. The County will maintain the responsibility of construction inspection, either through County personnel or one or more contracted third parties at the discretion of the Director of the Department of Public Works. The cost of the construction inspection is detailed in Chapter 128 of the Kent County Code. An inspector shall be on site during all construction and shall record as-built information, including but not limited to as-built lengths of pipe, inverts, rims, lateral ties, etc., and during TV inspections. For facilities located in the public road right-of-way, the inspector shall make sure that the material and compaction of backfill meet state highway specifications. A minimum of one density test shall be made each day that backfilling occurs in the public road right-of-way. The developer shall be responsible for the project being built in accordance with the approved construction plans and specifications.
C.
Public safety. All excavations shall be adequately
guarded with barricades and lights in order to protect the public
from hazard. The contractor is responsible for the setup of these
public safety devices. All work in the public road right-of-way shall
conform to the conditions outlined in the latest edition of the Division
of Highway's Highway Safety Manual. All public property disturbed
in the course of the work shall be restored in a manner satisfactory
to the County.
D.
Other utilities. Other existing and proposed utilities
shall be accurately and clearly shown in plans and profiles in accordance
with the best available information. It shall be the contractor's
responsibility to call Miss Utility prior to excavating and to field
verify the location of existing utilities.
E.
Pumping station construction. Technical plans and
specifications for sewage facilities shall be prepared by a professional
engineer for each pumping station construction. Plans and specifications
for small grinder pump stations with pumps of two horsepower or less
may be prepared by a professional surveyor. The pumping facilities
will be constructed accordingly after the specifications are given
approval by the Public Works Director and except for small grinder
pump stations after a DNREC sewer construction permit is obtained.
A DNREC sewer construction permit is required for other infrastructure
components (i.e., collection lines), based upon DNREC's current flow
criteria.
F.
Construction revision. Any change from the construction
plan should not be made without a written approval from the Public
Works Director.
A.
Exfiltration test. All sewers shall satisfy requirements
of a final exfiltration test before they will be approved and sewage
flow accepted from them by the County. This test consists of filling
the pipe with water to provide a head of at least five feet above
the top of the pipe or five feet above groundwater, whichever is higher
at the highest point of the pipeline under test, and then measuring
the loss of water from the line by the amount which must be added
to maintain the original level. In this test, the line must remain
filled with water for at least 24 hours prior to the taking of measurements.
Exfiltration shall be measured by the drop of water level in a standpipe
with a closed bottom end, or in one of the sewer manholes available
for convenient measuring. When a standpipe and plug arrangement is
used in the upper manhole of a line under test, there must be some
positive method of releasing entrapped air in the sewer prior to taking
measurements. The test length intervals for either type of test shall
be as ordered or approved but in no event shall they exceed 1,000
feet. In the case of sewers laid on steep grades, the length of line
to be tested by exfiltration at any time may be limited by the maximum
allowable internal pressure on the pipe and joints at the lower end
of the line. The test period, wherein the measurements are taken,
shall not be less than two hours in either type of test. The total
leakage of any section tested shall not exceed the rate of 100 gallons
per mile of pipe per 24 hours per inch of nominal pipe diameter. For
purposes of determining the maximum allowable leakage, manholes shall
be considered as section of forty-eight-inch diameter pipe, five feet
long. The equivalent leakage allowance shall be 4.5 gallons per manhole
per 24 hours, for forty-eight-inch diameter manholes. If leakage exceeds
the specified amount, the necessary repairs or replacements required
shall be made to permanently reduce the leakage to within the specified
limit, and the test shall be repeated until the leakage requirement
is met.
B.
Alternate acceptance leakage test. Other than exfiltration
test, air test may be used as an alternative for the sewer leakage
test for pipe with a diameter of 30 inches or less. The test should
be conducted in accordance with the following procedure:
(1)
All branch fittings and ends of lateral stubs shall
be securely plugged to withstand the internal test pressures. The
section of line being tested shall also be securely plugged at each
manhole. All stoppers shall be adequately braced when required.
(2)
Air shall be slowly supplied to the plugged pipe line
until the internal air pressure reaches 4.0 pounds per square inch
greater than the average back pressure of any groundwater that may
submerge the pipe. At least two minutes shall be allowed for temperature
stabilization before proceeding further.
(3)
The rate of air loss shall then be determined by measuring
the time interval required for the internal pressure to decrease from
3.5 to 2.5 pounds per square inch.
(4)
The line shall be considered acceptable if the time,
T, in seconds, required for the 1.0 psi pressure drop is not less
than the following:
|
T = 0.0850 DK/Q = 28.33 DK
| ||
|
Where:
| ||
|
K = 0.000419DL, but not less than 1.0
| ||
|
Q = rate of loss of 0.003 cu. ft/min/sq ft.
on internal surface
| ||
|
D = pipe diameter, in.
| ||
|
L = length of line being tested, ft.
| ||
(5)
No connection shall be made until the final inspection
and County TV inspection tests have been performed.
C.
Pumping test. After the completion of the construction
of a pumping station, a pumping test and a report of the test will
be required to determine the relationship of total developed head
and efficiency to capacity at various operational speeds. The test
equipment, test procedure and test results and related data should
be given in a report. A graphical summary of data will be needed.
Each graph should be identified by specifying pertinent data such
as the pump type, impeller diameter and speed, and specific speed,
and test data. Certified pump performance curves prepared at the factory
will be acceptable only with the approval of the Public Works Director.
D.
As-built drawings submission. Three sets of as-built
drawings in digital format should be submitted to the Kent County
Department of Public Works, Engineering Division, in accordance with
the red-lined documents provided by the County inspection staff for
project acceptance. No certificates of occupancy will be issued until
as-built drawings are submitted.
E.
Pumping station recordation. A deed of the pumping
station should be recorded at the County's Deeds and Records Office
prior to the operation.
F.
Projection authorization. The Public Works Director
will provide a written statement to the project engineer or the developer
indicating the acceptance of the project or a phase of a project,
if the project or phase of a project construction meets the County's
standards.
(1)
The County shall require from the developer a one-year
maintenance bond on all new sanitary sewer infrastructure (within
sanitary sewer districts), including but not limited to pumping stations,
lift stations, force mains, collection lines, laterals and all related
appurtenances. The effective date of the maintenance bond shall commence
after final inspection/testing of the sewer infrastructure, installation
of all other utilities and project (or phase/s thereof) acceptance
by the Kent County Department of Public Works, Engineering Division,
via a written letter. This written letter shall be provided within
30 days after the County's field acceptance. The maintenance bond's
amount shall be equal to 25% of the total costs of the sanitary sewer
infrastructure for the specific project under consideration or 100%
of the costs of mechanical equipment, whichever is larger.
(2)
If defective work is encountered within the effective
dates of the maintenance bond, then the developer shall be responsible
for all aspects of repair. If the developer is not able to repair
the defective work in what the Kent County Department of Public Works,
Engineering Division, deems a timely fashion, then the County may
repair as it seems appropriate and cite the maintenance bond as a
guaranty of the developer's maintenance obligations.
G.
Building lateral construction. A permit shall be obtained in accordance with § 180-9 of this chapter. If work is required in the public road right-of-way, the sewer lateral connection permit shall be invalid unless accompanied by a Division of Highways utility construction permit. A DelDOT franchise agreement will be required for new construction located within the state's right-of-way. Laterals shall be laid between 1/8 inch and 1/4 inch of fall per foot unless prior permission is obtained to utilize a different slope from the Kent County Department of Public Works, Engineering Division. Laterals shall have a minimum of one foot of cover. A cleanout shall be placed on a lateral within the first three feet after exiting the building. Cleanouts shall be placed immediately downstream of each ninety-degree bend. Cleanouts shall be placed every 50 feet on four-inch laterals and every 100 feet on six-inch laterals. Laterals shall be laid on firm undisturbed earth or dry granular bedding material. The property owner, developer, plumber or contractor which obtained the sewer lateral connection permit shall be responsible for adjusting all cleanouts located in yards, grass areas, sidewalks or driveways to final grade after final grading, paving or concrete work has been completed. Cleanouts located in gardens or landscaped areas, such as shrubbery adjacent to the building, may be left above final grade. All cleanouts will be required to have brass/cast-iron caps installed on them.
