Available information based on field data falls short of providing conclusive evidence in support of the practice of curvilinear alignment for sewers that are twenty-four inches or less in diameter. Where local governments elect to permit the construction of curvilinear sewers, it is mandatory that available maintenance equipment be evaluated and proper equipment acquired.
When permitted by the local government, construction of sewers that are twenty-four inches or less in diameter on curvilinear alignment shall be subject to the following criteria:
(a) Alignment. Alignment shall follow the general alignment of the street. Curvilinear sewer alignment shall be limited to curved street areas.
(b) Curvature. Only simple curves may be used.
(c) Radius. Minimum radius shall be not less than 200 feet.
(d) Minimum Slope. The minimum slope shall be that which produces a minimum velocity of 2.0 fps. (Hydraulics of curvilinear alignment shall be taken into account.)
(e) Manhole Location. Manholes are required at the point of beginning and at the end of the curve and at the point of inflection (PC, PT and PR C).
(f) Deflection. Deflection of pipe shall not exceed the maximum deflection recommended by the joint manufacturer. The deflection shall be uniform and the finished installation shall follow a smooth curve.
(Ord. 1975-15. Passed 11-10-75.)