Each permanent field repair of a leak on a transmission line, or distribution main operating at 125 psig (862 kPa) or more in a Class 3 or 4 location, must be made according to the following requirements.
(a) If feasible, the segment must be taken out of service and repaired by cutting out a cylindrical piece of pipe and replacing it with pipe of similar or greater design strength.
(b) If it is not feasible to take the segment out of service, repairs must be made by one of the following methods:
(1) install a full encirclement welded split sleeve of appropriate design;
(2) if the leak is due to a corrosion pit, the repair may be made by installing a properly designed bolt-on-leak clamp;
(3) if the leak is due to a corrosion pit and is on pipe with a SMYS of not more than 40,000 psi (267 Mpa), the repair may be made by fillet welding a steel plate patch with rounded corners, of the same or greater thickness than the pipe, and not more than one-half of the diameter of the pipe in size;
(4) apply a method that reliable engineering tests and analyses show can permanently restore the serviceability of the pipe.