The assessment of LTAs is divided into two parts (sections) in API 579 General Metal Loss (Part 4; formerly Section 4) and Localized Metal Loss (Part 5; formerly Section 5). As of this writing, the second edition of the API 579 is being developed. In the first edition, the term "Section" is being replaced by "Part" to avoid confusion with the ASME BPV code names Section II, III, and so on. The exact distinction between uniform metal loss and local metal loss cannot be made without assessing the details of the metal loss profile. The Part 4 [Section 4] rules are structured to be consistent with the Part 5 [Section 5] rules. The inspection requirements for Part 4 are also consistent with Part 5, with the exception of groove-like flaws. Generally it is recommended to perform a general metal loss assessment before proceeding to a localized metal loss assessment. Each section gives acceptance criteria, but it is difficult to find the remaining life using these criteria without countless iterations. That is why we derived Eq. 3-18 to determine the MAWP This equation was developed from both parts (sections) on general and localized metal loss. Each part (section) is divided into three assessment levels, as mentioned earlier. We will get into the details for each part, but the vast majority of cases can be handled at Level 1 or Level 2. Level 3 nonlinear elastic-plastic analysis is reserved for critical applications where a major impact in...