(a) Sewers which receive discharge from a building sanitary sewer and convey sewage to the sanitary curb connection or disposal plant shall be four inches or larger, as required, in diameter for cast iron pipe, Type "L" or heavier copper or Schedule 35 polyvinylchloride (PVC) or heavier pipe. Other approved pipe, such as vitrified clay, shall be six inches or larger in diameter.
(b) Storm sewer pipe receiving drainage from the subsoil, building storm drain or downspouts shall be six inches or larger for Schedule 35 or heavier polyvinylchloride (PVC) plastic, vitrified clay or other approved pipe.
(c) Sewer piping shall be installed as follows:
(1) The minimum slope shall be not less than one-fourth of an inch per foot, except when the computed fluid velocity is not less than two feet per second, based upon Manning's or Kutter's Formula, with the value of "n" equal to 0.013.
(2) Where ferrous soil or waste pipe, other than a horizontal branch, connects to an underground nonmetallic building drain, the section of building drain at the connection shall be cast iron for a length of not less than eighteen inches.
(3) The minimum cover shall be three feet (where possible) for underground sewers or drains installed outdoors, or where they are subject to frost conditions.
(4) Bedding and initial backfill to six inches above the pipe shall be clean sand.
A. Within the boundaries of a street, the balance of backfill shall be course interlocking aggregate and puddled as directed by the Building Inspector.
B. When not within the boundaries of a street, backfill shall be clean earth free from rocks and debris.
C. Backfill shall be thoroughly compacted.
(Ord. 1992-101. Passed 1-14-92.)