(a) Each imperfection or damage that impairs the serviceability of a segment of steel transmission line, or distribution main operating at 125 psig (860 kPa) or more in a Class 3 or 4 location, must be repaired according to the following requirements:

1. (1) If it is feasible to take the segment out of service, the imperfection or damage must be removed by cutting out a cylindrical piece of pipe and replacing it with pipe of similar or greater design strength.
2. (2) `If it is not feasible to take the segment out of service, the imperfection or damage must be repaired by a method that reliable engineering tests and analyses show can permanently restore the serviceability of the pipe.