What it is
API 579 (published as API 579-1/ASME FFS-1) is the fitness-for-service standard. It is a structured, code-based way to assess whether in-service equipment that has degraded or contains a flaw is still safe to keep operating, and under what limits.
When you need it
Fitness-for-service is usually triggered when an inspection finds something on pressure equipment, piping or storage tanks and you need to decide what to do about it. Common cases include wall thinning or corrosion, cracking, dents or gouges, blistering, creep damage, and fire damage. The question it answers is whether to keep running, repair, re-rate or replace, ideally without unnecessary downtime.
What it gives you
A defensible answer on remaining life and safe operating limits, backed by a recognised standard. Done well, it often avoids replacing equipment that is actually still fit to operate, which can save significant cost and outage time.
The three assessment levels
API 579 works in levels of increasing detail. Level 1 is a conservative screening check using simple criteria. Level 2 is a more detailed assessment using more data. Level 3 is advanced analysis, often using finite element analysis, for complex or borderline cases. Higher levels need more data and expertise, but can justify keeping equipment in service where a simpler check would not.
How it fits with other codes
Fitness-for-service is used alongside the in-service inspection codes (for example API 510 for vessels, API 570 for piping, API 653 for tanks) and the original design code the equipment was built to (for example ASME VIII or AS 1210).
Who does it
A mechanical or pressure-equipment engineer with fitness-for-service experience, and often finite element analysis capability for Level 3 work. Where the equipment is in Queensland and the work needs sign-off, the engineer should be RPEQ-registered for the relevant field.
If you have equipment with a flaw and need a fitness-for-service assessment, describe your project and Edelvor will match you with a specialist.