(a) If you use direct assessment on an onshore pipeline to evaluate the effects of external corrosion, you must follow the requirements of this section for performing external corrosion direct assessment. This section does not apply to methods associated with direct assessment, such as close interval surveys, voltage gradient surveys, or examination of exposed pipelines, when used separately from the direct assessment process.
(b) The requirements for performing external corrosion direct assessment are as follows:
(1) General. You must follow the requirements of NACE SP0502 (incorporated by reference, see Sec. 195.3). Also, you must develop and implement a External Corrosion Direct Assessment (ECDA) plan that includes procedures addressing pre-assessment, indirect examination, direct examination, and post-assessment.
(2) Pre-assessment. In addition to the requirements in Section 3 of NACE SP0502 (incorporated by reference, see Sec. 195.3), the ECDA plan procedures for pre-assessment must include--
(i) Provisions for applying more restrictive criteria when conducting ECDA for the first time on a pipeline segment;
(ii) The basis on which you select at least two different, but complementary, indirect assessment tools to assess each ECDA region; and
(iii) If you utilize an indirect inspection method not described in Appendix A of NACE SP0502 (incorporated by reference, see Sec. 195.3), you must demonstrate the applicability, validation basis, equipment used, application procedure, and utilization of data for the inspection method.
(3) Indirect examination. In addition to the requirements in Section 4 of NACE SP0502 (incorporated by reference, see Sec. 195.3), the procedures for indirect examination of the ECDA regions must include--
(i) Provisions for applying more restrictive criteria when conducting ECDA for the first time on a pipeline segment;
(ii) Criteria for identifying and documenting those indications that must be considered for excavation and direct examination, including at least the following:
(A) The known sensitivities of assessment tools;
(B) The procedures for using each tool; and
(C) The approach to be used for decreasing the physical spacing of indirect assessment tool readings when the presence of a defect is suspected;
(iii) For each indication identified during the indirect examination, criteria for--
(A) Defining the urgency of excavation and direct examination of the indication; and
(B) Defining the excavation urgency as immediate, scheduled, or monitored; and
(iv) Criteria for scheduling excavations of indications in each urgency level.
(4) Direct examination. In addition to the requirements in Section 5 of NACE SP0502 (incorporated by reference, see Sec. 195.3), the procedures for direct examination of indications from the indirect examination must include--
(i) Provisions for applying more restrictive criteria when conducting ECDA for the first time on a pipeline segment;
(ii) Criteria for deciding what action should be taken if either:
(A) Corrosion defects are discovered that exceed allowable limits (Section 5.5.2.2 of NACE SP0502 (incorporated by reference, see Sec. 195.3) provides guidance for criteria); or
(B) Root cause analysis reveals conditions for which ECDA is not suitable (Section 5.6.2 of NACE SP0502 (incorporated by reference, see Sec. 195.3) provides guidance for criteria);
(iii) Criteria and notification procedures for any changes in the ECDA plan, including changes that affect the severity classification, the priority of direct examination, and the time frame for direct examination of indications; and
(iv) Criteria that describe how and on what basis you will reclassify and re-prioritize any of the provisions specified in Section 5.9 of NACE SP0502 (incorporated by reference, see Sec. 195.3).
(5) Post assessment and continuing evaluation. In addition to the requirements in Section 6 of NACE SP 0502 (incorporated by reference, see Sec. 195.3), the procedures for post assessment of the effectiveness of the ECDA process must include--
(i) Measures for evaluating the long-term effectiveness of ECDA in addressing external corrosion in pipeline segments; and
(ii) Criteria for evaluating whether conditions discovered by direct examination of indications in each ECDA region indicate a need for reassessment of the pipeline segment at an interval less than that specified in Sections 6.2 and 6.3 of NACE SP0502 (see appendix D of NACE SP0502) (incorporated by reference, see Sec. 195.3). [Amdt. 195-85, 70 FR 61576, Oct. 25, 2005, as amended by Amdt. 195-94, 75 FR 48607, Aug. 11, 2010]