327 IAC 3-6-16 Manholes

Sec. 16. (a) Manholes must: (1) be constructed of: (A) precast concrete that has lift holes; or (B) poured-in-place concrete; and (2) have grade adjustment rings sealed with nonshrinking mortar in conformance with ASTM C478-96*, Standard Specification for Precast Reinforced Concrete Manhole Sections. (b) Inlet or outlet pipes must be joined to the manhole with a gasketed, flexible, and watertight connection. (c) Manholes must have a minimum diameter of forty-eight (48) inches and a minimum access diameter of twenty-two (22) inches. (d) Watertight manhole covers must be used in any area where the manhole tops are: (1) subject to flooding by street run-off or high water; (2) in a floodway; or (3) in a floodplain. (e) Manholes must be located as follows: (1) At all end points of sanitary sewers. (2) Wherever changes occur in grade, size, or alignment of the sanitary sewer. (3) At all intersections of sanitary sewers. (4) With separation distances between any two (2) manholes not to be greater than the following: (A) Four hundred (400) feet for sanitary sewers less than fifteen (15) inches in diameter. (B) Five hundred (500) feet for sanitary sewers equal to or greater than fifteen (15) inches and less than thirty (30) inches in diameter. (C) Six hundred (600) feet for sanitary sewers equal to or greater than thirty (30) inches in diameter. (f) All upstream sanitary sewers less than twenty-four (24) inches from the manhole invert must be filleted to prevent solids deposition. Drop pipes must be provided for incoming sanitary sewers entering a manhole at an elevation of twenty-four (24) inches or more above the manhole invert and must be in accordance with the following: (1) Drop pipe connections on the inside of manholes must be secured to the interior wall of the manhole and provide access for cleaning. (2) Drop pipe connections on the outside of manholes must be encased in concrete. (g) A flow channel that conforms to the shape of the connecting sanitary sewer must be made through the bottom surface of the manhole. The channel walls must be formed or shaped to the full height of the crown of the outlet sewer. (h) A bench must: (1) be provided on each side of any flow channel if the pipe diameter is less than the manhole diameter; (2) have a surface slope of no less than four percent (4%); and (3) receive no discharge onto the surface of the bench from a: (A) lateral; (B) service connection; or (C) drop manhole pipe. (i) The inlet to a manhole from a force main must enter the manhole at an elevation less than twenty-four (24) inches above the flow line of the receiving manhole. (j) Manholes must be air tested in accordance with ASTM C1244-93*, Standard Test Method for Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test. *These documents are incorporated by reference. Copies may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428, www.astm.org, or are available for review at the Indiana Department of Environmental Management, Office of Legal Counsel, Indiana Government Center North, 100 North Senate Avenue, Thirteenth Floor, Indianapolis, Indiana 46204.