255.715 - Transmission lines: Permanent field repair of welds

 

Each weld that is unacceptable under section 255.241(c) of this Part must be repaired according to the following requirements:

(a) If it is feasible to take the segment of transmission line, or distribution main operating at 125 psig (862 kPa) or more in a Class 3 or 4 location, out of service, the weld must be repaired in accordance with the applicable requirements of section 255.245 of this Part.

(b) A weld may be repaired in accordance with section 255.245 of this Part while the segment is in service if:

(1) the weld is not leaking;

(2) the pressure in the segment is reduced so that it does not produce a stress that is more than 20 percent of SMYS; and

(3) grinding of the defective area can be limited so that at least 1/8-inch thickness in the pipe weld remains.

(c) A defective weld which cannot be repaired in accordance with subdivision (a) or (b) of this section must be repaired by installing a full encirclement welded split sleeve of appropriate design.