Level 3 based Fitness for Service (FFS) Assessment 

In this project, a metal spherical pressure vessel was investigated for Fitness for Service (FFS) level 3 assessment based on API 579. For modeling and numerical simulation of the vessel under the effect of pitting corrosion, using Abaqus finite element software and according to the provided coordinates, 11 different areas of the outer surface of the vessel were severely corroded, so, were simulated. In the simulation, the pressure load inside the vessel and weight load were applied.

Critical area thickness data were received from the inspection company and Fitness for Service (FFS) assessments were performed at Level 3. The Abaqus FEA results agreed with the results extracted from levels 1 and 2 of the inspection. We calculated the minimum thickness in different areas of the pressure vessel. As a result, with the performed analysis, the service status of the vessel was determined.

Fitness for Service (FFS)- Level 3 api 579 - ffs analysis by abaqus - bs 7910 standard

The figure shows the stress contour

Fitness for Service (FFS) - api 579 - abaqus - ansys - ffs analysis - signalffs

Sample of the main pressure vessel examined

FFS analysis - FFS assessment - fitness for service software


Contact us if you are an inspection company and need level 3 FFS assessments.