A. Backfilling up to the first eighteen inches (18") above the top of utility pipes or similar installations shall be done with thin layers, each layer is to be tamped by manual or mechanical means. Layers that are hand-tamped shall not exceed four inches (4") in thickness. Layers that are power-tamped shall not exceed six inches (6") in thickness. These same requirements shall apply to the remainder of the backfilling if tamping is the method used for backfilling.
B. Backfilling of all pipes over twenty four inches (24") in diameter shall be carried up to the spring line of the pipe in three inch (3") layers with each layer moistened and thoroughly tamped with suitable mechanical equipment. The backfill around all pipes twenty four inches (24") or less is diameter shall be flooded or tamped, as specified in subsection A of this section, to a depth of eighteen inches (18") above the top of the pipe before any additional backfilling is placed thereon. (Ord. 157 § 460, 1961)