A. Storm sewers may be constructed of either concrete or PVC pipe with the following specifications:
1. Concrete:
a. Reinforced concrete shall meet AASHTO M17OM specification and/or IDOT specification #550.
b. A minimum class 3 concrete pipe is required under all pavement areas.
2. PVC:
a. Straight walled PVC pipe with smooth interior:
(1) PVC pipe shall have a minimum standard dimension ratio (SDR) of 35.
(2) The pipe shall conform to ASTM D1784 and ASTM D3034.
(3) The joints shall be bell and spigot with rubber gaskets conforming to ASTM D3212.
b. Corrugated PVC pipe with smooth interior:
(1) PVC pipe shall have a minimum stiffness of forty six (46) pounds/in./in.
(2) The pipe shall conform to ASTM D1784 and ASTM F949 (or ASTM F794).
(3) The joints shall be bell and spigot with rubber gaskets conforming to ASTM D3212. (Ord. 658, 6-9-2003)
B. Storm sewer capacity shall be adequate to carry the surface water falling or coming on the streets in a 2-year storm as that term is used by the Illinois state water survey. (Ord. 530, 3-23-1998)
C. Storm sewer inlets shall be provided at a spacing not greater than two hundred fifty feet (250'). Storm laterals connecting inlets or manholes shall be a minimum diameter of twelve inches (12"). Inlets shall be located as near to intersections as possible, but shall not conflict with ramps as described in subsection 6-4-2-2J of this chapter. Inlets shall not be installed in front of any residential driveway area. Storm flows shall be intercepted such that cross crown flow on the streets is not required. (Ord. 530, 3-23-1998; amd. Ord. 687, 12-28-2004)
D. Inlet drop boxes shall be cast in place concrete or precast concrete. Inlet frame and grates shall be provided with an open style curb box and a minimum, nominal grate area of six (6) square feet. The frames and grates shall be Neenah model R-3246-A, East Jordan Iron Works, model 7510, or approved equal. Grates shall be diagonally slotted. Vane type grates may be utilized on pavement slopes greater than two percent (2%). Grates utilized shall be safe to bicycle riders.
Where possible, the inlet frame and grate shall be recessed into the curb line so that the edge of the grate nearest the pavement is located one foot (1') from the edge of pavement. The curb line transition, or the edge of pavement transition when the inlet cannot be recessed, shall occur over a distance of six feet (6') either side of the inlet. The concrete gutter shall be widened to encase the inlet frame from the edge of pavement to the face of the curb.
E. Storm sewer outlets to natural drainageways shall be provided end sections, headwalls or appurtenances designed to control erosion and energy dissipation. Storm sewer outlet pipes shall discharge at or within one foot (1') of elevation to the flow line of the drainageway. (Ord. 530, 3-23-1998)