Plans, specifications and methods of installation shall conform to the requirements of this article. Components and materials of wastewater facilities not covered in this Part
2, such as pumping stations, lift stations or force mains, shall be designed in accordance with §
174-30 and shall be clearly shown and detailed on the plans and specifications submitted for approval. Force main details are covered in §§
174-45 and
174-46. When requested, the applicant shall submit to the Superintendent 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.
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 §
174-30. Additional design requirements are:
A. Force main pipe material shall be:
(1) Ductile iron pipe. 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. Pipe and fittings shall be furnished with
push-on joints conforming to ANSI A21.11. Pipe and fittings shall
be cement mortar lined and have an internal and external bituminous
seal coating.
(2) Polyvinyl chloride (PVC) plastic pipe. 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. Other pipe materials require
prior written approval of the Superintendent before being installed.
B. Trenching, bedding and backfilling shall be in accordance with §
174-35.
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 greater.
E. Drain valves shall be placed at low points.
F. Automatic air-relief valves shall be placed at high
points and at 400 feet intervals on level force main runs.
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 stainless steel anchors.
All force mains shall be subjected to hydrostatic
pressure of 150% of the normal operating pressure. The duration of
the test, at pressure, shall be at least two hours. Before conducting
the test, the pipe shall be filled with water and all air shall be
expelled. During the test, water shall be added, as needed, to maintain
the test pressure. The amount of water added shall be recorded so
as to calculate leakage. Leakage shall not exceed 200 gallons per
day per mile per inch nominal pipe diameter. During the test, the
owner and the Superintendent shall walk the route of the force main
and examine the exposed pipe and the ground covering any backfilled
pipe to discover leaks. Leakage in excess of that specified above
shall be corrected with new material at the owner's expense and the
test repeated. Any observed leaks shall be repaired at the owner's
expense. Each test section length shall be as approved by the Superintendent,
but in no event longer than 1,000 feet.
All sanitary sewers and extensions to sanitary
sewers constructed at the applicant's expense, after final approval
and acceptance by the Superintendent and concurrence by the City Council,
shall become the property of the City and shall thereafter be operated
and maintained by the City. No sanitary sewer shall be accepted by
the City 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 City, 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 City Council, secured by
a surety bond or such other security as the City Council may approve.