The purpose of this article is to define the
general construction procedures, design and material standards and
specifications for new sanitary sewers and connections to the existing
Town sanitary sewer system.
All terms used in this article concerning the
construction of new sanitary sewers and connections to the existing
Town sanitary sewer system shall have the same meaning, and shall
otherwise be consistent with, the Town of Niagara Sewer Ordinance[1] and all amendments thereto.
A.
The developer shall comply with all federal, New York
State, Niagara County and Town of Niagara laws and ordinances, as
their jurisdictions apply, for all new sanitary sewer construction
and all connections made to the existing Town sanitary sewer system.
B.
It is recommended that the developer consult the following
sources and contact the following governmental agencies and any other
agency whose jurisdiction applies to construction of new sanitary
sewers in the Town:
C.
The developer shall obtain all permits and pay all
required fees to the various agencies prior to the start of any sanitary
sewer construction.
The design of all sanitary sewers and any connections
thereto shall comply with the New York State Department of Environmental
Conservation and the report by the Great Lakes Upper Mississippi River
Board of State Sanitary Engineers (latest edition) and the American
Society of Civil Engineers (A.S.C.E.) and the standards for materials
and construction in this article.
The minimum size of new sanitary sewers is eight
inches in diameter for trunk and lateral sewers. Direct connections
to existing sewers by tapping for house lateral connections shall
be six inches in diameter. Flows shall be determined using Kutter's
formula and n = 0.013.
A.
All new sewers shall be sized to accommodate peak
design flows at a minimum velocity 2.0 feet per second and not exceeding
the velocity of 10 feet per second for sewers not less than flowing
half full.
B.
Design maximum flows should be computed from the ratios
of peak to average daily flows from data contained in ASCE Manual
No. 37, Design and Construction of Sanitary and Storm Sewers.
A.
Manholes shall be provided for sanitary sewers at
all points of change in alignment grade, street intersections and
at the end of the sewer run. Manholes shall not be spaced farther
than 400 feet apart.
C.
All connections greater than six inches in diameter to existing sewers shall be made within a manhole. New manholes for this purpose shall be constructed over the existing sewer in accordance with the standards as outlined in § 135-54, Manholes, and the standard detail.[2]
[2]
Editor's Note: Standard detail drawings are
on file in the Town offices.
A.
The developer shall provide competent engineering
services for all phases of the project.
B.
As part of the sanitary sewer design plans, the developer shall submit the engineering report for sanitary sewers as stipulated in § 135-21 of these specifications.
C.
The developer shall provide for all construction layout by a registered professional engineer and shall establish and maintain the alignment and grades as shown on the approved drawings in accordance with Article II of these specifications for all work within public right-of-way or easement. The layout stakes for line and grade shall remain for the duration of the construction and be made available for checking purposes to the Town.
All new sanitary sewers and connections to the existing Town sanitary sewer system shall conform to the standards and specifications of this article and of Article III of these specifications.
All excavation and related work consisting of but not limited to clearing and grubbing, temporary sheeting, dewatering, excavation for pipe and structures, excavation of rock, bedding, backfill, concrete, disposal of materials, protection of existing facilities and maintenance and protection of traffic shall comply with the standards and specifications as outlined in Article III of these specifications and the Town of Niagara Building Code.
A.
All pipe sizing and materials for sanitary sewers
shall conform with the Town of Niagara Sewer Ordinance 1971[1] and amendments thereto, the Town of Niagara Building Code
and amendments thereto, the New York State Plumbing and Building Codes
and the specifications of this article. All materials used for the
manufacture of sewer pipe and pipe for casings shall conform with
the latest standards and specifications of the American National Standards
Institute (ANSI), and various manufacturer associations, as their
jurisdictions apply.
B.
All sewer mains and lateral connections in the public
right-of-way shall be constructed of approved pipe as specified below,
unless horizontal borings or other special crossings are required.
C.
Horizontal borings shall be constructed using steel casings and ductile iron-mechanical joint carrier pipe in accordance with § 135-71 of these specifications.
E.
Ductile iron.
(1)
The ductile iron pipe for special crossings shall
be centrifugally cast mechanical joint, Class 4, and shall conform
to ANSI Specification A 21.51. Pipe diameter and thickness shall be
factory stamped on each length of pipe. Fittings shall be cast iron
mechanical joint Class 150 ANSI Specification A 21.10. Pipe and fittings
shall be cement lined and bituminous-coated in accordance with ANSI
Specification A 21.4.
(2)
The pipe shall have mechanical joints wire brushed
from the inside to remove all loose rust and foreign matter. The surfaces
shall be cleaned and lubricated along with the rubber gasket by brushing
with soapy water just before assembly. Bolts shall be tightened evenly
so as to maintain approximately the same distance between the gland
and the face of the flange all around the socket. Bolt torque shall
be within the allowable torque range of 70 to 100 foot pounds. If
effective sealing is not attained at the allowable torque, the joint
shall be disassembled and reassembled after thorough cleaning.
F.
Steel pipe.
(1)
Steel casing pipe for special crossings shall conform
to ASTM Designation A 139. Inside and outside surfaces shall be bituminous-coated
at the shop before delivery and touched up in the field as required.
Sizes and wall thicknesses of casing pipe shall be as shown on the
drawings or specified herein.
(2)
Jointing of steel casing pipe shall have continuous
butt-welded joints made in strict accordance with the current applicable
code of the American Welding Society. Welding shall be performed only
by experienced persons classified as welders by union standards.
G.
Cast-iron soil pipe. Soil pipe shall be asphalt-coated,
extra heavy cast-iron soil pipe and fittings meeting ASTM Specifications
A-74 and CS-188-59. Joints shall be Cast Iron Soil Pipe Institute
molded neoprene compression gaskets. Lead-caulked joints shall be
used at terminals and where directed by the Town.
H.
Adapter and sleeve-type couplings.
(1)
Adapters. Where it is necessary to join pipe of different
types, pipe manufacturer approved adaptors with compatible joints
shall be used. Adaptors shall have ends, conforming to specifications
for the appropriate type of joint, to receive the adjoining pipe.
Adaptors joining two classes of pipe may be of the lighter class,
provided that the annular space in bell- and spigot-type joints will
be sufficient for proper jointing.
(2)
Sleeve-type couplings.
(a)
To ensure correct fitting of pipe and couplings,
all sleeve-type couplings and accessories shall be furnished by the
supplier of the pipe and shall be of a rating at least equal to that
of the pipeline in which they are to be installed. Sleeve-type couplings
shall be made by Dresser Mfg. Div., Bradford, PA; Smith-Blair, In.,
San Francisco, CA; R.H. Baker & Co., Inc., Huntington Park, CA;
or equal as permitted by the Town.
(b)
Couplings shall be cast iron and shall be Dresser
Style 53, Smith-Blair Style 431, Baker Allcast or equal products as
permitted by the Town. The couplings shall be furnished with the pipe
stop removed.
(c)
Couplings shall be provided with gaskets of
a composition suitable for sanitary sewer service requirements.
A.
Excavation and related work. Excavation and related work for the jacking pits and carrier pipe between the indicated manhole stations or house lateral locations shall be as specified in Article III of these specifications. Provisions shall be made for new permanent or temporary channels for rerouting the drainage ditches around the new construction as needed.
B.
Installation of casing pipe.
(1)
This method consists of pushing the casing pipe through
the ground with a boring auger rotating within the pipe to remove
the spoil. When augers, or similar devices, are used for casing pipe
emplacement, the front of the pipe shall be provided with mechanical
arrangements or devices that will positively prevent the auger and
cutting head from leading the pipe so that there will be no unsupported
excavation ahead of the pipe. The arrangement shall be removable from
within the pipe in the event that an obstruction is encountered. The
excavation by the cutting head shall not exceed the outside diameter
of the pipe by more than 1/2 inch. The face of the cutting head shall
be arranged to provide reasonable obstruction to the free flow of
soft or poor material.
(2)
The use of water or other liquids to facilitate casing
emplacement and spoil removal is prohibited.
(3)
Plans and descriptions of the equipment and procedures
to be used shall be submitted to the Town for review and permission
to proceed.
(4)
If an obstruction which stops the forward action of
the pipe is encountered during installation, and it becomes evident
that it is impossible to advance the pipe, operations shall cease
and the pipe shall be abandoned in place and filled completely with
grout.
(5)
Bored or jacked installations shall have a bored hole
essentially the same as the outside diameter of the pipe plus the
thickness of the protective coating. If voids should develop or if
the bored hole diameter is greater than the outside diameter of the
pipe plus the thickness of the protective coating by more than approximately
one inch, grouting or other methods permitted by the Town shall be
employed to fill such voids.
(6)
When water is known or expected to be encountered,
pumps of sufficient capacity to handle the flow shall be maintained
at the site. When dewatering, close observation shall be maintained
to detect any settlement or displacement of the roadway.
(7)
All operations shall be conducted so as not to interfere
with, interrupt or endanger the safe flow of traffic or to destroy
or endanger the integrity of the existing facilities.
C.
Installation of carrier pipe.
(1)
The carrier pipe shall be laid inside the casing pipe
on skids placed in pairs every six feet along the length of the pipe.
The size of the skids will be such as to provide a minimum of one-inch
clearance between the casing inside bottom and the joint coupling
of the pipe. Skids shall be sized so as to maintain the correct invert
levels of the carrier pipe.
(2)
If the illuminated interior of the pipe line shows
poor alignment, or any other defects, such defects designated by the
Town shall be immediately remedied by the developer at his or her
expense. Such lamping, however, shall not be construed as conclusive
for final acceptance of that portion of the sewer line nor as a substitute
for subsequent testing required herein.
(3)
Permissible tolerances for each length of sewer in
place will be plus or minus 0.02 feet vertically and plus or minus
0.20 feet horizontally.
A.
Sewers shall be hydrostatically tested for leaking
by filling the sewer with water to a height of at least two feet above
the highest section of the work being tested. No more than 400 feet
of sewer shall be tested at any one time unless otherwise directed
by the Town. Duration of each test shall be not less than two hours.
The developer shall furnish all necessary labor and appliances to
conduct the test.
B.
The allowable leakage or exfiltration shall not exceed
200 gallons per day per inch diameter per mile of pipe. Regardless
of whether or not the leakage allowance is met, should examination
of exposed pipe and joints disclose visible leaks, joints shall be
remade and defective pipe replaced so that there is no visible leakage.
The tests shall then be repeated until results satisfactory to the
Town are obtained.
C.
In areas where pipe is at least two feet below groundwater
level, leakage tests may be conducted, if acceptable to the Town,
by measuring infiltration into the sewer. The same test parameters
shall apply.
D.
Notwithstanding satisfactory test results, if at any
time during the tenure of the construction and the guaranty period
should a noticeable leak be discovered in the sewers, laterals or
manholes installed, the developer shall, upon written notice from
the Town, take the necessary steps to correct the leak. Such work
shall be accomplished within two weeks of the date of notification.
A.
When installing the building connection, the trenches
shall be dug in a careful manner and properly sheeted where required.
The excavated materials shall be placed so as to minimize possible
inconvenience to the public. Proper barricades and lights must be
maintained around the trench to guard against accidents. Extreme care
shall be taken to prevent any dirt, stones or other undesirable material
from entering the public sewer system through the house sewer lateral
during construction.
B.
Where the trench is excavated in rock, the rock must
be carefully excavated to a depth of six inches below the grade line
of the sewer and the trench brought to the proper elevation satisfactory
to the Superintendent. The remainder of the trench must be backfilled
with suitable material as shown on the detail sheet known as Appendix
A.[1]
[1]
Editor's Note: Appendix A is on file in the
Town offices.
C.
Nothing in this article shall be construed as abrogating
any of the existing requirements of the Town relating to the excavation
and backfilling of trenches. The requirements of this article are
in addition to all general requirements for excavation and backfilling
of trenches.
D.
Where in the opinion of the Superintendent of Sewer
and Water, subsurface conditions do not provide adequate support for
the pipe, a sufficient quantity of crushed stone shall be placed in
the trench bottom to obtain a firm bedding beneath the pipe.
A.
When installing a connection from any property to
the lateral sewer, the following pipe will be acceptable for use:
asbestos cement class 2400, extra heavy cast-iron soil pipe or polyvinyl
chloride (PVC) sewer pipe as specified in ASTM - D 3034. Rigid polyvinyl
chloride (PVC) and ABS (acryocowitrile, butadieng, snyrene), Schedule
40, DWV plastic pipe and fittings may be used underground in commercial
or residential applications. PVC and ABS pipe shall be installed according
to manufacturers' specifications and recommendations. When the total
fixture unit value, as designed in the New York State Plumbing Code,
does not exceed 50 fixture units, all PVC piping under floors shall
be a minimum of four inches.
B.
All existing installation of PVC Schedule 40 extending
through concrete walls or footers, may be continued in use if the
existing piping is not less than three inches Schedule 40 PVC piping.
Double hand hole traps shall be made from 1 - P TRAP U-bend and two
sanitary street tees only.
C.
All installation shall be tested pursuant to the requirement
of New York State Plumbing Code and the requirements of this article.
Each house lateral connection shall be constructed
in the following manner unless the Superintendent shall issue a written
variance:
