What is Fitness for Service (FFS)?

Fitness for service assessment is multi-disciplinary engineering analysis of equipment to determine if it is safe and fit for continued service until the end of some desired period of operation (for example, until the next shutdown, until some specific future date, or until the end of its useful life).
Fitness for service assessment may be required, because the equipment may:
• Contain Flaws Such as Locally Thin Areas (LTAs) or Cracks
• Not Meet Current Design Standards
• Operate Under More Severe Conditions than Originally Expected
The main products of fitness for service assessment are (1) decisions to run, alter, repair, monitor, or replace equipment and (2) guidance on equipment inspection intervals.
Fitness for service assessment employs analytical methods, mainly stress analysis, to evaluate flaws such as locally thin areas and cracks as well as damage such as dents, bulges, and distortions.
Fitness for service assessment is multi-disciplinary engineering analysis of equipment to determine if it safe and fit for continued service until the end of some desire