49 CFR § 192.931 - How may Confirmatory Direct Assessment (CDA) be used?
(1) The procedures for indirect examination may allow use of only one indirect examination tool suitable for the application.
(2) The procedures for direct examination and remediation must provide that -
(i) All immediate action indications must be excavated for each ECDA region; and
(ii) At least one high risk indication that meets the criteria of scheduled action must be excavated in each ECDA region.
(c) Internal corrosion plan. An operator's CDA plan for identifying internal corrosion must comply with § 192.927 except that the plan's procedures for identifying locations for excavation may require excavation of only one high risk location in each ICDA region.
(d) Defects requiring near-term remediation. If an assessment carried out under paragraph (b) or (c) of this section reveals any defect requiring remediation prior to the next scheduled assessment, the operator must schedule the next assessment in accordance with NACE SP0502 (incorporated by reference, see § 192.7), section 6.2 and 6.3. If the defect requires immediate remediation, then the operator must reduce pressure consistent with § 192.933 until the operator has completed reassessment using one of the assessment techniques allowed in § 192.937.