Sanitary sewer facilities shall be furnished and installed to
adequately service the developments and shall conform to the town’s
sanitary sewer plan. The adequacy of the sewer facilities provided
by the subdivider shall be determined by the town.
(1998 Code, sec. 51.60)
(a)
Sanitary sewer mains may be vitrified clay sewer pipe (extra strength),
conforming to ASTM C700, latest revision, or cement-lined bituminous
coated ductile iron pipe or polyethylene-lined ductile iron pipe.
(b)
As approved by the town, sanitary sewer mains may also be constructed
of polyvinyl chloride (PVC) pipe conforming to the specifications
of ASTM D 3034, SDR 35, or equal. Joints for the PVC pipe and fittings
shall be compression rubber gasket joints. The bell shall consist
of an integral wall section with a factory-installed ring securely
locked in a bell groove to provide a positive seal under all installation
conditions. Fittings and accessories shall be manufactured and furnished
by the pipe supplier, or approved equal, and shall have a bell and/or
spigot configuration identical to that of the pipe.
(c)
Connections shall be made with a fabricated fitting. Field-glued
connections are not allowed. When PVC pipe passes through a manhole
wall, asbestos cement sleeves with a rubber ring joint shall be used
to provide a positive watertight connection.
(d)
The PVC pipe shall be placed on a four-inch layer of crushed rock
or rounded gravel bedding material. The trench shall be backfilled
with a minimum of six inches of sand over the sides and 12 inches
loose sand over the top of the pipe and consolidated to a minimum
of 90% standard proctor density. This is basic class B embedment as
defined by ASCE Manual No. 37 and AWWA C900-75 and ASTM D2321, with
5% maximum Mandrell test to be performed. Final backfill is to conform
to section S.4.17. The class B embedment material is further defined
as follows:
(e)
PVC pipe shall be encased in concrete. PVC pipe, vitrified clay pipe,
and ductile iron pipe shall be embedded in four inches of crushed
stone and covered with one foot of free-flowing sand.
(1998 Code, sec. 51.61)
The minimum diameter of sewer mains shall be eight inches. Six-inch
diameter sewer mains may be acceptable only for short distances (not
to exceed 400 feet) and only in locations approved by the town.
(1998 Code, sec. 51.62)
All vitrified clay sanitary sewer pipe joints shall be of the
premolded type conforming to ASTM designation C425.
(1998 Code, sec. 51.63)
Wherever possible, sewers shall be located in the alleys or
easements and shall be a minimum of five feet to six and one-half
feet deep to the invert.
(1998 Code, sec. 51.64)
All sewers shall be laid in straight alignment where possible,
with a uniform grade between the manhole. In those cases where horizontal
curvature must be utilized to serve a particular area, the minimum
radius of curvature shall be 100 feet. Grades and appurtenances of
sanitary sewers shall conform to the requirements of the department
of state health services, and the following are the minimum slopes
which should be provided for a velocity of at least 2.0 feet per second;
however, slopes greater than these are desirable:
|
Sanitary Sewer
(Diameter)
|
Minimum Slope in Feet Per 100 Feet
|
|---|---|
|
4-inch (service mains)
|
1.000
|
|
6-inch
|
0.500
|
|
8-inch
|
0.330
|
|
10-inch
|
0.250
|
|
12-inch
|
0.200
|
|
15-inch
|
0.150
|
|
18-inch
|
0.110
|
|
21-inch
|
0.090
|
|
24-inch
|
0.080
|
|
27-inch
|
0.060
|
|
30-inch
|
0.055
|
|
36-inch
|
0.045
|
(1998 Code, sec. 51.65)
Prior to acceptance, the sanitary sewers shall be subject to
leakage tests. The leakage outward or inward (exfiltration or infiltration)
shall not exceed 200 gallons per inch of the pipe diameter per mile
per 24 hours for any section of the system. Other testing procedures
(exfiltration, air, and the like) may be used subject to the approval
of the town.
(1998 Code, sec. 51.66)
All lift stations shall be designed and constructed with two
or more sewage pumps, and the stations shall be capable of pumping
the design maximum flow with the largest pump-out of service. Detailed
design data, plans, and specifications of the pumps shall be submitted
to the town engineer prior to the purchase and installation of the
lift station unit.
(1998 Code, sec. 51.67)
(a)
All force mains shall be ductile cast iron pipe, minimum class 50,
with rubber gasket joint, and shall have a cement mortar lining with
a seal cast of bituminous material, or may have a polyethylene lining.
(b)
Force mains constructed of polyvinyl chloride (PVC) pipe, as required
for water mains, may be used where adequate provisions are made for
the embedment of the pipe.
(c)
At design for average flows, a cleansing velocity of at least two
feet per second shall be maintained. Where necessary, automatic air
relief valves shall be placed at high points in the force main to
prevent air locking.
(1998 Code, sec. 51.68)
(a)
Manholes shall be placed at points of change in alignment, grade,
or size of the sewer, the intersection of sewers, and the end of all
sanitary sewer mains that will be extended at a later date.
(b)
Maximum manhole spacing for sewers with straight alignment and uniform
grades should be determined so as to assure continuous operation based
on available cleaning equipment. The maximum manhole spacing shall
be as follows:
|
MINIMUM DESIGN STANDARDS
| ||
|---|---|---|
|
Sewer Pipe Size
|
Manhole Diameters
|
Maximum Distance Between Manholes
|
|
6"
|
4'-0"
|
400 ft.
|
|
8"
|
4'-0"
|
600 ft.
|
|
10"
|
4'-0"
|
800 ft.
|
|
12"
|
4'-6"
|
900 ft.
|
|
15"
|
4'-6"
|
1,000 ft.
|
|
18"
|
5'-0"
|
1,100 ft.
|
|
21"
|
5'-0"
|
1,200 ft.
|
|
24"
|
5'-0"
|
1,300 ft.
|
|
30"
|
6'-0"
|
1,500 ft.
|
|
36"
|
6'-0"
|
1,500 ft.
|
(c)
All sewer and storm sewer manhole lids shall include the words “Town
of Fairview” and shall be submitted to the director of public
works or town engineer for approval.
(1998 Code, sec. 51.69)
Standard cleanouts shall be constructed at the ends of all sanitary
sewers where no further extensions will ever be made to the main.
(1998 Code, sec. 51.70)
