API 579
Definition
The American Petroleum Institute's Fitness-For-Service standard, which provides assessment methods for determining whether a damaged or corroded pressure vessel or piping component can continue in safe service, and when repair or replacement is required.
- Issuing body
- American Petroleum Institute
- Subject
- Fitness-For-Service assessment
- Applies to
- Damaged or corroded pressure vessels and piping
- Purpose
- Determines whether continued service, repair, or replacement is needed
Common questions
How does API 579 get used in a forensic explosion investigation?+
Investigators reconstructing a pressure-vessel failure use its assessment methods to judge whether pre-existing damage such as corrosion or a crack had reduced the vessel below a safe fitness-for-service level, helping establish whether the failure was foreseeable rather than a sudden, unpredictable event.
Is API 579 a design code or an in-service assessment standard?+
It is an in-service assessment standard applied to equipment already installed and showing damage, distinct from design codes that govern how a new vessel or pipe is built and rated before it enters service.
Related terms
- BLEVE
- Boiling liquid expanding vapour explosion. Catastrophic failure of a vessel containing a superheated liquid, producing an expanding pressure wave and, if the...
- Corrosion Under Insulation (CUI)
- External corrosion of a pipe or vessel surface that occurs beneath thermal insulation, hidden from visual inspection, driven by moisture infiltrating the...
- Deflagration
- A subsonic combustion front propagating through an explosive by thermal conduction. Characteristic of low explosives such as black powder and smokeless powder;...
- Detonation
- A supersonic shock wave coupled to a chemical reaction front, propagating through a high explosive at velocities between approximately 4,500 and 9,100...
- Overpressure
- Pressure above ambient atmospheric pressure produced by an explosion. The peak overpressure and its duration (impulse) together determine structural damage and injury...