Plans, specifications, and methods of installation shall conform to the requirements of this article. Components and materials of wastewater facilities not covered in this chapter, such as pumping stations, lift stations, or force mains, shall be designed in accordance with Article
V and shall be clearly shown and detailed on the plans and specifications submitted for approval. Force main details are covered in Article
V. When requested, the applicant shall submit, to the Superintendent and/or the Orange County Health Department and/or NYSDEC, all design calculations and other pertinent data to supplement review of the plans and specifications. Results of manufacturer's tests on each lot of pipe delivered to the job site shall also be furnished, upon request.
All sanitary sewers or extensions to sanitary sewers, including manholes, shall satisfy requirements of a final infiltration test before they will be approved and wastewater flow permitted by the Town of Tuxedo. The infiltration rate shall not exceed 25 gallons per 24 hours per mile per nominal diameter in inches. An exfiltration test may be substituted for the infiltration test; the same rate shall not be exceeded. The exfiltration test shall be performed by the applicant, under the supervision of the Superintendent, who shall have the responsibility for verifying proper and accurate measurements required. The exfiltration 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 under test and then measuring the loss of water, from the pipe section under test, by the amount of water which must be added to maintain the original level. However, under no circumstances shall the head at the downstream manhole exceed 10 feet or fill to within six inches of the top of the downstream manhole. Should this condition prevail, the testing methods in §
80-41 and/or §
80-42 shall be utilized. In this test, the test section must remain filled with water for at least 24 hours prior to taking any 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 serving the test section. When a standpipe and plug arrangement is used in the upper manhole in the test section, there shall be some positive method for releasing entrapped air prior to taking any measurements.
The test section shall be as ordered or as approved but in no
event longer than 1,000 feet. In the case of sewers laid on steep
grades, the test length may be limited by the maximum allowable internal
pressure on the pipe and joints at the lower end of the test section.
For purposes of determining the leakage rate of the test section,
manholes shall be considered as sections of forty-eight-inch-diameter
pipe, five feet long. The maximum allowable leakage rate for such
a section is 1.1 gallons per 24 hours. If leakage exceeds the allowable
rate, then necessary repairs or replacements shall be made and the
section retested.
The test period during which the test measurements are taken
shall not be less than two hours.
Prior to testing, the section shall be lamped. Any length of
pipe out of straight alignment shall be realigned.
Also prior to testing, all plastic pipe in the test section
shall be tested for deflection. Deflection testing shall involve the
pulling of a rigid ball or mandrel, whose diameter is 95% of the pipe
inside diameter, through the pipe. Any length of pipe with a deflection
greater than 5% shall be replaced. The test section shall be flushed
just prior to deflection testing. The test shall not be performed
with a mechanical pulling device.
Force mains serving sewage lifting devices, such as grinder pumps and pump stations, shall be designed in accordance with Article
V. Additional design requirements are:
A. Force main pipe material shall be:
(1) Ductile iron pipe.
(a)
Pipe shall conform to ANSI A21.51. The minimum wall thickness
shall be Class 52 (ANSI A21.50). The pipe shall be clearly marked
with either "D" or "DUCTILE." Fittings shall conform to ANSI A21.10.
(b)
Pipe and fittings shall be furnished with push-on joints conforming
to ANSI A21.11.
(c)
Pipe and fittings shall be cement mortar lined and have an internal
and external bituminous seal coating.
(2) Polyvinyl chloride (PVC) plastic pipe.
(a)
Pipe shall conform to ASTM D2241. Materials used in the manufacture
of PVC pipe shall meet ASTM C1784. The minimum wall thickness shall
be SDR-21. Fittings shall conform to ASTM D2241. Joints and gaskets
shall conform to ASTM D2241, D1869, and F477.
(3) Other pipe materials.
(a)
Other pipe materials require prior written approval of the Superintendent
before being installed.
B. Trenching, bedding, and backfilling shall be in accordance with Article
V.
C. Joint preparation and assembly shall be in accordance with the manufacturer's
written instructions.
D. Anchorages, concrete blocking, and/or mechanical restraint shall
be provided when there is a change of direction of 7 1/2°
or whenever required by the Superintendent.
E. Drain valves shall be placed at low points.
F. Automatic air relief valves shall be placed at high points and at
maximum 400-foot intervals.
G. Air relief and drain valves shall be suitably protected from freezing.
H. When the daily average design detention time, in the force main,
exceeds 20 minutes, the manhole and sewer line receiving the force
main discharge or the sewage shall be treated so that corrosion of
the manhole and the exiting line are prevented. The corrosion is caused
by sulfuric acid biochemically produced from hydrogen sulfide anaerobically
produced in the force main.
I. The force main shall terminate, in the receiving manhole, at a PVC
plastic sewer pipe "T." The vertical arms of the "T" shall be twice
the diameter of the force main. The upper arm shall be at least four
feet long; the lower arm shall terminate in a PVC plastic sewer pipe
90° elbow in a flow channel directed to the manhole exit pipe.
The "T" and its arms shall be securely fastened to the inside surface
of the manhole wall using corrosion-resistant anchors.
All sanitary sewers and extensions to sanitary sewers constructed
at the applicant's expense, after final inspection by the Superintendent
and acceptance by the Town of Tuxedo Board, shall become the property
of the Town of Tuxedo and shall thereafter be operated and maintained
by the Town of Tuxedo. No sanitary sewer shall be accepted by the
Town of Tuxedo until four copies of as-built drawings have been so
filed with the Superintendent and the Superintendent has approved
the submitted drawings. Said sewers, after their acceptance by the
Town of Tuxedo, shall be guaranteed against defects in materials or
workmanship for one year by the applicant. The guarantee shall be
in such form and contain such provision as deemed necessary by the
Town of Tuxedo Board, secured by a surety bond or such other security
as the Town of Tuxedo Board may approve in an amount recommended by
the Superintendent.