(b) Before increasing the operating pressure above the previously established maximum allowable operating pressure, the operator shall comply with the following requirements:

1. (1) Review the design, operating, and maintenance history, and previous testing of the segment of pipeline and determine whether the proposed increase is safe and consistent with the requirements of this Part.
2. (2) Make any repairs, replacements, or alterations in the segment of pipeline that are necessary for safe operation at the increased pressure.
3. (3) Verify the condition of the pipe through the use of test excavations.
4. (4) Either prove compliance with the nondestructive testing requirements of sections 255.241(b) and 255.243(d) of this Part for the current class location or nondestructively test a sufficient number of welds to achieve compliance with the minimum percentages listed in section 255.243(d) of this Part for the current class location.
5. (5) Where nondestructive testing is required, the operator shall select welds within 150 feet (45.72 meters) of habitable structures until the minimum percentage is achieved.
6. (6) Establish adequate cathodic protection in compliance with section 255.463 of this Part.

(d) After complying with subdivision (b) of this section, an operator that does not qualify under subdivision (c) of this section may increase the previously established maximum allowable operating pressure if at least one of the following requirements are met:

1. (1) The segment of pipeline is successfully tested in accordance with the requirements of this Part for a new line of the same material in the same location.

2. (2) An increased maximum allowable operating pressure may be established for a segment of pipeline in a Class 1 location if the line has not previously been tested, and if:

   1. (i) it is impractical to test it in accordance with the requirements of this Part;
   2. (ii) the new maximum operating pressure does not exceed 80 percent of that allowed for a new line of the same design in the same location; and
   3. (iii) the operator determines that the new maximum allowable operating pressure is consistent with the condition of the segment of pipeline and the design requirements of this Part.

(e) Where a segment of pipeline is upgraded in accordance with subdivision (c) or paragraph (d)(2) of this section, the increase in pressure must be made in increments that are equal to:

1. (1) 10 percent of the pressure before the upgrading; or
2. (2) 25 percent of the total pressure increase, whichever produces the fewer number of increments.