Fitness-For-Service (FFS) Assessments are quantitative engineering evaluations that are performed to demonstrate the structural integrity of an in-service component that may contain a flaw or damage, or that may be operating under a specific condition that might cause a failure. This Standard provides guidance for conducting FFS Assessments using methodologies specifically prepared for pressurized equipment. The guidelines provided in this Standard can be used to make run-repair-replace decisions to help determine if components in pressurized equipment containing flaws that have been identified by inspection can continue to operate safely for some period of time.
The methods and procedures in this Standard are intended to supplement and augment the requirements in API 510, API 570, API 653, and other post construction codes that reference FFS evaluations such as NB-23. The assessment procedures in this Standard can be used for FFS Assessments and/or rerating of equipment designed and constructed to the following codes: ASME BPV Codes – Section I, Section VIII Division 1, & Section VIII Division 2; ASME Piping Codes – B31.1, B31.3, B31.4, B31.8, & B31.12; API Standards 530, 620, & 650. The assessment procedures in this Standard may also be applied to pressure containing equipment constructed to other recognized codes and standards, including international and internal corporate standards. This Standard has broad applications since the assessment procedures are based on allowable stress methods and plastic collapse loads for non-crack like flaws, and the Failure Assessment Diagram (FAD) Approach for crack-like flaws.