Towards the development of a fitness for service tool for the inspection of corrosion under insulation

Yves Gunaltun, Merline J. Dyana, Ahmed Al Abri, Patrick Hivert, Gary Penney

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Corrosion under insulation (CUI) is a major problem for industry. Extensive removal and reinstatement of insulation for inspection is prohibitively costly. A non-destructive testing (NDT) tool which can characterise areas of CUI damage in insulated piping and pipelines with minimal removal of insulation is required. Sufficient data about the CUI is required to allow Fitness for Service to be assessed. Guided wave testing (LRUT) is a long range ultrasonic technique that was developed in the mid 1990's to provide the solution to CUI inspection of piping and pipelines. The technology, understanding and application of LRUT has been continuously developed over the last 15 years, but is still a screening technique which is currently unable to provide dimensions of CUI. Indications reported by LRUT must thus be followed up using a second NDT technique to confirm and quantify CUI damage. A project sponsored by the Petroleum Institute, Abu Dhabi, has been established to improve on commercially available LRUT and develop a Fitness for Service tool to allow integrity management decisions to be made from LRUT inspections. In the first phase of the project, an independent evaluation of the performance of LRUT was performed, in terms of probability of detection (POD) for the system and operators/analysts. A purpose built test loop was constructed to be representative of real-world conditions, including metal loss defects simulating CUI. Future phases will (i) evaluate and develop better understanding of key variables and factors affecting the performance of LRUT, aiming at developing best practice guidance, and (ii) develop a Fitness for Service tool based directly on LRUT data. The results of the first phase are presented in this paper, with a number of interesting observations and lessons learnt that can aid in improving the outcomes from LRUT for CUI and for piping and pipelines in general.

Original languageEnglish
Title of host publicationNACE International - Corrosion Conference and Expo 2016
PublisherNational Assoc. of Corrosion Engineers International
Number of pages15
ISBN (Electronic)9781510821354
Publication statusPublished - 2016
Externally publishedYes
EventCorrosion 2016 - Vancouver, Canada
Duration: Mar 6 2016Mar 10 2016

Publication series

NameNACE - International Corrosion Conference Series
ISSN (Print)0361-4409


ConferenceCorrosion 2016


  • CUI
  • Carbon steel
  • Corrosion defects
  • Corrosion under insulation
  • Fitness for service
  • Guided wave testing
  • Long range UT
  • POD
  • Pipelines
  • Piping
  • Probability of detection

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science


Dive into the research topics of 'Towards the development of a fitness for service tool for the inspection of corrosion under insulation'. Together they form a unique fingerprint.

Cite this