A study conducted by DNV for the Petroleum Safety Authority Norway (PSA) provides an overview of establish practice with and knowledge of managing risk related to corrosion under insulation (CUI) in corrosion-resistant alloys (CRA).
The PSA is working consciously to achieve continuous improvement in its risk-based supervision of activities, where follow-up of CUI in design and operation of offshore facilities and land-based plants represents a priority issue.
CUI ranks as a serious contributor to major accident risk, and the PSA has previously investigated a series of leaks associated with the condition – including a steam leak in 2012, a hydrogen escape in 2016 and naphtha leaks in 2017 and 2020. In addition comes cracking in a stainless-steel gas cooler in 2021.
The PSA commissioned a CUI project in 2021, with the emphasis on such incidents in normal steel. Attention has now been turned to rust-free materials in the study by DNV.
In its report, the classification society sheds light on relevant CUI-related activities for materials characterised as corrosion-resistant, with the emphasis on the standards applied.
National and international standards have been reviewed and compared, and information has been gathered from the petroleum industry. Learning points and improvement areas have also been identified.
The goal of the project is to identify CUI challenges for corrosion-resistant materials and suitable maintenance programmes. An anticipated effect is that a shared approach and lessons learnt across the industry can reduce the accident risk.