Fitness for Service

Image thanks to Woodside Petroleum Ltd.

Equipment owners can face a dilemma when a flaw is detected either during service or scheduled shutdown.

Repair may not be an option due to lack of resources, access within the original shutdown window, lack of immediate spares or the risk of further damage during the repair itself.

Fitness-for-Service (FFS) can manage this situation by assessment of the damage and the application of quantitative engineering to help determine whether the equipment can continue to operate safely, typically until the next shutdown.

Typical Problem Areas

  • Crack-like flaws or brittle fractures in thick-walled pressure vessels
  • Corrosion damage in pipelines, pressure vessels and above ground tanks
  • Boiler and heat recovery headers sustaining creep and creep-fatigue damage
  • Weld misalignment in pressure piping
  • Shell distortion of tanks, distillations and pressure vessels
  • Oil and gas pipelines and headers sustaining hydrogen induced damage

Our Expertise

SVT conduct FFS analysis to API 579-1/ASME FFS-1. The standard can be used for assessment and/or re-rating of pressure equipment designed and constructed to ASME B&PV Code (Sect. VIII div 1 & 2 and Sect. I), ASME B31.1 and B31.3 Piping Code, as well as above ground storage tanks to API 650 and API 620.

SVT engineers are also familiar with other flaw acceptability assessment methods, such as BS 7910 which covers both pressure equipment and general structures.

SVT also have experience in non-destructively evaluating the micro-structure around and at the flaw. Such assessment minimises the number of unknowns in conducting FFS by enabling better estimation of material property, verification of the damage mechanism, assessment of the level of damage in micro scale (which can't be revealed by standard NDE techniques), as well as revealing whether or not a crack-like flaw is active.

In addition to substantial capability in fracture mechanics and mechanical testing, SVT has expertise in computational stress analysis (elastic-plastic), strain gauging, and practical knowledge for coordination of non-destructive examinations.