API 579 
Fitness‑for‑Service (FFS) Assessment

A Fitness‑for‑Service (FFS) assessment is a multidisciplinary engineering evaluation used to determine whether equipment is suitable for continued operation—typically until the next scheduled shutdown, repair, or maintenance window. API 579 provides a structured methodology for evaluating existing flaws, damage mechanisms, and degradation to support sound, defensible integrity decisions.

FFS assessments are used to:

• Support run, repair, or replace decisions
• Establish appropriate inspection intervals by determining remaining life

Types of FFS assessments:

• Reactive assessments: initiated when damage is discovered during inspection
• Proactive assessments: performed to justify continued operation under defined conditions (e.g., hydrostatic test exemptions)

An FFS evaluation addresses:

• The current integrity of the component based on its existing damage state
• The projected remaining life using defined or calculated damage‑rate assumptions

Through the application of API 579 methodologies, Vertix Reliability & Asset Management ensures that equipment remains safe, compliant, and reliable throughout its operational lifecycle.