255.506 - Transmission lines: Spike hydrostatic pressure test

 

(a) Spike test requirements. Whenever a segment of steel transmission pipeline that is operated at a hoop stress level of 30 percent or more of SMYS is spike tested under this Part, the spike hydrostatic pressure test must be conducted in accordance with this Section.

(1) The test must use water as the test medium.

(2) The baseline test pressure must be as specified in Section 255.619(a)(2) of this Part.

(3) The test must be conducted by maintaining a pressure at or above the baseline test pressure for at least 12 hours as specified in Section 255.505 of this Part.

(4) After the test pressure stabilizes at the baseline pressure and within the first 2 hours of the 12-hour test interval, the hydrostatic pressure must be raised (spiked) to a minimum of the lesser of 1.5 times MAOP or 100 percent SMYS. This spike hydrostatic pressure test must be held for at least 15 minutes after the spike test pressure stabilizes.

(b) Other technology or other technical evaluation process. Operators may use other technology or another process supported by a documented engineering analysis for establishing a spike hydrostatic pressure test or equivalent. Operators must notify the Department 90 days in advance of the assessment or reassessment requirements of this subchapter. The notification must be made in accordance with Section 255.18 of this Part and must include the following information:

(1) Descriptions of the technology or technologies to be used for all tests, examinations, and assessments;

(2) Procedures and processes to conduct tests, examinations, assessments, perform evaluations, analyze defects, and remediate defects discovered;

(3) Data requirements, including original design, maintenance and operating history, anomaly or flaw characterization;

(4) Assessment techniques and acceptance criteria;

(5) Remediation methods for assessment findings;

(6) Spike hydrostatic pressure test monitoring and acceptance procedures, if used;

(7) Procedures for remaining crack growth analysis and pipeline segment life analysis for the time interval for additional assessments, as required; and

(8) Evidence of a review of all procedures and assessments by a qualified technical subject matter expert.