ESR completes assembly of test pipe assemblies for CUI NDT inspection performance trials

ESR Technology manages HOIS, a well-established (>30 years) joint industry project on good practice for non-destructive testing (NDT) in the oil and gas industry. HOIS has been collaborating with The Oil & Gas Technology Centre on an ambitious and strategic project for the inspection of external corrosion and corrosion under insulation.

CUI is an area of focus because of significant safety and cost implications to the oil and gas industry:

• CUI has caused ruptures and fires leading to damage costing 10s of millions of pounds on single assets in addition to the risk of loss of life and damage to the environment.
• It is estimated that 60% of piping failures are due to CUI
• CUI is unpredictable – and usually makes its presence known before it is found.
• Traditional methods of detection involve stripping and replacing insulation which is costly and time consuming

This HOIS/OGTC project seeks to demonstrate the potential of novel techniques to detect and size CUI and to highlight and assess the capabilities of existing non-destructive testing technologies.

ESR Technology staff have been working hard to design test samples using 3-D CAD modelling based on UT data maps from externally corroded specimens, commission the test pipe manufacture, accurately benchmark the areas of wall loss and then insulate and clad the components. There are many variables that can affect the performance of NDT methods and our test pieces have been designed to allow assessment of the effects on performance (probability of detection and sizing capability) of the following:

• Amount of wall loss
• Cladding and insulation thickness and type
• Pipe wall thickness
• Geometry changes: pipe elbow and support/hanger
• Other components – heat tracing and chicken wire (used to support insulation)

The next phase of the HOIS project is about to begin – we are inviting inspection service providers to participate in blind trials. The image shows two L assemblies fully insulated and clad. Additional straight test pieces are also available for trials. The first set of trials will be on 100mm of insulation, trial participants will be asked to report their results before completing a second trial on 50mm of insulation.

The results of these trials will inform the update the HOIS CUI Guidance document and the development of HOIS Guidance for Inspection through External Corrosion Scabs.