(a) If an excavation is made parallel to any cast iron gas main, eight inches or less in nominal diameter, and said excavation is not adequately shored to protect the cast iron main against movement, the cast iron main must be replaced where more than half the pipe diameter lies above a line projected at an angle above the horizontal equal to the angle of repose for the soil conditions being encountered, starting from the bottom of the excavation at the side nearest the main.

(b) Replacement is to be completed prior to the third-party construction activity, if possible. Otherwise, replacement is to commence immediately after the contractor allows access to the excavation area for replacement and the area is to be maintained under daily leakage survey until replacement is complete.