Quest Reliability assists clients in minimizing loss of production incidents by improving the information to support decisions about pressure vessels containing flaws, defects and damage. Quest Reliability provides expert FFS engineering assessments of pressure vessels in order to establish whether the vessel is fit for service or requires repair.
Quest Reliability’s staff of mechanical and structural integrity engineers is experienced in the three levels of assessment of pressure vessels called for in API 579-1/ASME FFS-1/2007:
- Level 1: Conservative assessment considering material classification and detailed design
- Level 2: Mid-level assessment extending the Level 1 results to include design/operating stresses, fabrication quality and prior damage
- Level 3: Advanced fracture mechanics assessment considering the fundamental driving factors, material properties, finite element stress analysis and known defect information
When the vessels fail to pass assessment Levels 1 and 2 or when problems are found during plant outage or routine inspection, a decision whether to re-rate or repair arises. Not only is it common for repairs to be undertaken unnecessarily at potentially great direct expense and indirect expense through lost production, but the weld repairs often undertaken can also lead to more severe damage with complex residual stresses than were originally present. Quest Reliability can help provide a clear direction about which path is best to take.
The assessment is carried out in accordance with relevant standards and codes; API 579-1, BS7910:2005 “Guide on methods for assessing the acceptability of flaws in metallic structures”, British Energy, R6 "Assessment of the integrity of structures containing defects” and other ISO and ASTM codes.
These assessments require a number of skilled technical operations, including:
- Fracture assessments in accordance with standard procedure
- Time-dependent crack growth assessment (fatigue and/or creep)
- Advanced finite element stress analysis
- Determination of damage evolution
- Remaining life assessment
- Recommendations with regard to future inspection intervals
For further information about Pressure Vessels, please contact us.