Development of guidance for the inspection of external corroded components both with insulation (CUI) and uninsulated corrosion scabs

Burch, Steve; ESR Technology; United Kingdom

Burch, S.F.; ESR Technology Ltd; United Kingdom
Peramatzis, H.R.; ESR Technology Ltd; United Kingdom

ID: ECNDT-0135-2018
Session: Oil & Gas 4
Room: H2
Date: 2018-06-12
Time: 11:30 - 11:50

External corrosion of carbon steel pipework can, and does, cause loss of containment in pressurised process equipment. On uninsulated components, as external corrosion occurs, corrosion product or scale often builds up. This is hazardous to remove on live process pipework and complicates the measurement of remaining wall thickness. For inspection of insulated components there is a requirement to detect economically the presence of corrosion (CUI) as well as determining its severity, as an alternative to removal of the existing insulation.

The HOIS joint industry project for improved NDT in the oil and gas industry has performed independent blind trials to assess the effectiveness of several different NDT methods to detect and size external corrosion, both under insulation and un-insulated corrosion scabs. The HOIS trial based projects have been running for several years and have developed a significant body of results. There are many parameters that can affect a component’s inspectability which include the corrosion morphology, wall thickness, diameter, insulation material, thickness and cladding/weather proofing type. A range of NDT methods are available, but all have their own advantages and limitations and their effectiveness is generally restricted in terms of these component inspection parameters. The results from the HOIS blind trials are being used to develop and update guidance documents for these challenging applications for NDT which, when finalised, will be publicly available.

This paper describes the status of the HOIS project on these major inspection challenges in the oil and gas and other industries.