DNV DNV-RP-G109 PDF

This document addresses the threat of corrosion under insulation in process plants.

Degradation mechanisms not involving CUI are not addressed by this document.

The document describes how to assess the probability of failure (PoF) due to CUI and how the different mitigation activities alter the probability. In this document, existing data should be used to assign a consequence of failure (CoF) to obtain the CUI risk.

The model combines individual probability assessments of the four CUI barriers, material barrier, coating barrier, water wetting barrier and design barrier, into a total probability of failure category, and combines this with the consequence of failure into a risk (CUI) category.

PoF_CUI = f(PoF_material' PoF_coating' PoF_{water wetting'} PoF_design)

Risk_CUI = f(PoF_CUI' CoF)