All extensions to the sanitary sewer system owned and maintained
by the City shall be properly designed in accordance with the Recommended
Standards of Sewer Works, as adopted by the Great Lakes-Upper Mississippi
River Board of State Sanitary Engineers and in strict conformance
with all requirements of the New York State Department of Environmental
Conservation (NYSDEC). Plans and specifications for sewer extensions
shall be submitted to, and approval obtained from, the Director of
Public Works and NYSDEC before construction may proceed. The design
of sewers must anticipate and allow for flows from all possible future
extensions or developments within the immediate drainage area.
Sewer extensions may be constructed by the City under public
contract, by City forces, if, in the opinion of City Council, the
number of properties to be served by such extension warrants its costs.
Property owners will be assessed the full costs of constructing an
eight-inch sanitary sewer for the width of their property. Property
owners may propose sewer extensions within City limits by drafting
a written petition, signed by a majority of the benefiting property
owners, and filing it with the City Clerk. The City Council has the
right to order sewer extensions where deemed necessary for the health
of the community and assess charges against property owners.
Sewer design shall be in accordance with §
277-28 and the following provisions:
A. Pipe shall be ductile iron conforming to ASTM C151 and/or polyvinyl
chloride (PVC) conforming to ASTM D3034 with a minimum pipe stiffness
of 46 psi at a maximum deflection of 5% and a standard dimension ratio
(SDR) of 35 or less.
B. Ductile iron pipe joints shall be push-on or mechanical conforming
to ASTM C111.
C. Polyvinyl chloride pipe shall be joined with push-on or mechanical
joints conforming to ASTM C111.
D. Joints of any of these types of pipe shall be made in accordance
with the manufacturer's published recommendations.
E. Ductile iron and PVC pipe shall be installed and backfilled in accordance
with ASTM 2321. Polyvinyl chloride pipe deflection shall be checked
by pulling a deflection gauge through completed pipelines by hand.
F. Manholes shall be constructed with a poured three-thousand-psi concrete
base, steel-troweled concrete or mortar inverts and precast four-foot
diameter concrete manhole barrel sections and a tapered top section
as specified by ASTM C0478, or cement brick or block solid. The manhole
frame and cover shall be the standard design of the City and shall
be set with no less than two courses of brick underneath to allow
for later adjustment in elevation.
Pipe Diameter
(inches)
|
Trench Width
|
---|
8
|
3' - 3"
|
10
|
3' - 6"
|
12
|
3' - 9"
|
G. If the trench widths are found, during field inspection, to exceed
the limits in the above table, the sewer pipe shall be encased with
a minimum of six inches of concrete. Pipe shall be firmly and evenly
bedded on a minimum of three inches of No. 2 crushed stone (NYSDOT
Specification). Pipe thickness and field strength shall be calculated
on the following criteria:
Safety factor
|
1.5
|
Load factor
|
1.7
|
Weight of soil
|
120 lbs. cu. ft.
|
All sewers shall be tested for leakage prior to being placed
in service. The leakage shall be determined by exfiltration, infiltration
or low-pressure air. The testing method shall be as directed by the
Engineer or Director of Public Works. If the line fails the test,
the contractor shall explore for and repair the cause of the excessive
leakage. After repairs have been made, the line shall be retested.
This procedure shall be repeated until the pipe complies.
A. Exfiltration testing. Exfiltration tests shall be made by filling
a section of pipeline with water and measuring the quantity of leakage.
The head of water at the beginning of the test shall be at least two
feet above the highest pipe within the section being tested. Should
groundwater be present within the section being tested, the head of
water for the test shall be two feet above the level of the groundwater.
Should the requirement of two feet of water above the highest pipe
subject any joint at the lower end of the test section to a differential
head greater than 11.5 feet, another method of testing shall be employed.
B. Infiltration testing. Infiltration tests will be allowed only when
the groundwater level is two feet or more above the highest pipe of
the section being tested. The quantity of water leaking into each
section of pipeline shall be measured by a calibrated weir constructed
at the outlet of the section being tested.
C. Allowable leakage.
(1) The allowable leakage (exfiltration or infiltration) shall not exceed
the following in gallons per 24 hours per inch of diameter per 1,000
feet of pipe.
Type of Pipe
|
Leakage
|
---|
Ductile iron, mechanical or push-on joints
|
10
|
Polyvinyl chloride, thermal plastic or fiberglass with rubber
joints
|
10
|
Polyvinyl chloride, thermal plastic or fiberglass with solvent-cemented
joints
|
0
|
(2) Regardless of the above allowable leakage, any spurting leaks detected
shall be completely and permanently stopped.
D. Manhole testing. Each manhole shall be tested by either exfiltration
or infiltration. A manhole will be acceptable if the leakage does
not exceed an allowable of one gallon per vertical foot of depth for
24 hours. Regardless of the allowable leakage, any leaks detected
shall be permanently stopped. An exfiltration test may be performed
prior to or after backfilling. The test shall be made by filling the
manhole with water and observing the level for a minimum of eight
hours. Infiltration tests shall be performed when the groundwater
level is above the joint of the top section of a precast manhole.
E. Air testing.
(1) Air testing shall not be performed until the backfilling has been
completed. Low-pressure air tests shall conform to ASTM C828 except
as specified herein and shall not be limited to type or size of pipe.
All sections of pipelines shall be cleaned and flushed prior to testing.
(2) The air test shall be based on the average holding pressure of three-psi
gauge, a drop from 3.5 to 2.5 psi, within the period of time allowed
for the size of pipe and the length of the test section. The time
allowed for the one-psi drop in pressure, measured in seconds, will
be computed by the Engineer/Director of Public Works and will be based
on the limits of ASTM C828. When groundwater is present, the average
test pressure of three psig shall be above any back pressure due to
the groundwater level. The maximum pressure allowed under any condition
in air testing shall be 10 psig. The maximum groundwater level for
air testing is 13 feet above the top of the pipe.
(3) The equipment required for air testing shall be furnished by the
contractor and shall include the necessary compressor, valves and
gauges to allow for the monitoring of the pressure, release of pressure
and a separable test gauge. The test gauge shall be sized to allow
for the measuring of the one-psig loss allowed during the test period
and shall be on a separate line to the test section.
All sewer extensions constructed at the property owner's,
builder's or developer's expense, after final approval and
acceptance by the City Engineer or Director of Public Works, shall
become the property of the City and shall thereafter be maintained
by the City.
No builder or developer shall be issued a building permit for
a new dwelling or structure requiring sanitary facilities within the
City until a sewer permit has been received from the Department of
Public Works, and all new developments shall be provided with an approved
system of sanitary sewers.