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NII as replacement of IVI

Non Intrusive Inspection (NII) is being considered increasingly as an alternative to Internal Visual Inspection (IVI) as part of the integrity management of pressure equipment. The benefits of NII are significant and include the following.

  • Reduced production losses associated with shut-down
  • Reduced manpower requirements - this can lead to reduced shut-down cost and shorter overall shut-down times since greater capacity is available for other tasks
  • Removal of hazards associated with man entry of vessels
  • Removal of the need to clean vessels internally

It is widely recognised that NII is different in many respects to IVI hence a different approach to planning is needed. For example, while IVI has the capability to detect a range of different defect types without specific knowledge of what to expect, the capability of NII is very much technique driven. Hence an up-front knowledge of what degradation may be present takes on added significance when planning an inspection by NII.

This also means that successful NII is also very much dependent on knowledge of the capabilities and limitations of available inspection techniques so that the most appropriate is selected. Definition of the inspection requirements is also linked closely to what defects are of concern and what represents a threat to integrity. We offer a multi-disciplinary approach to NII, combining skills and knowledge in corrosion engineering, inspection technology and mechanical integrity.

Sonomatic is the world’s leading provider of NII for replacement for deferment of IVI of pressure vessels. Sonomatic’s Dr Mark Stone is the primary author of the HOIS guidance for NII, now published as DNVGL-RP-G103. Sonomatic’s Integrity Services group has a strong track record of delivery of NII projects, with experience covering assessment, planning and evaluation for more than 1000 process pressure vessels. We work worldwide and have completed projects in the Australia, UK, USA, South Africa, Malaysia and the Middle East.

Sonomatic’s knowledge and experience with NII ensures successful delivery of projects, with sound justifications for NII as an alternative or deferment of IVI and long term benefits to operators.

If you would like to know more about Sonomatic's approach to Non Intrusive Inspection, please download our brochure.


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