A. Trenches shall not be excavated more than three hundred feet (300') in advance of pipelaying, nor left unfilled for more than seven feet (7') where pipe has been laid, except by special permission from the Water Commissioner. The length of the trench that may be opened at any time shall not be greater than the length of pipe and the necessary accessories which are available to the site and ready to put in place.
B. Trenches shall be excavated and braced according to "Safety Standards for Construction Work".
C. The completed trench shall be kept not less than three hundred feet (300') ahead of the pipelayers. Trenches shall be at least six inches (6") wider on each side, or a total width of twelve inches (12") more than the exterior diameter of the pipe, except where pipes are four inches (4") or less in diameter. If rock is excavated, it shall be removed to a depth of six inches (6") below the bottom of the pipe and the trench refilled to cover the pipe with six inches (6") of sand or noncorrosive soil of one and one-quarter inches (11/4") minus gravel and well-tamped.
D. Excavation for manholes and other structures shall be sufficient to leave at least twelve inches (12") between their outer surfaces and the sides of the excavation. (Ord. 157 § 320, 1961)