New Guideline for Corrosion Under Insulation

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Corrosion Under Insulation (CUI) is considered one of the major threats to integrity of process facilities. The Net Zero Technology Centre (UK) estimates that CUI now contribute to over 20% of the major oil and gas accidents reported within the EU since 1984 /1/ and regulators in the North Sea report that 50% of the reported hydrocarbon leaks is caused by CUI /2/. Earlier industry publications /3/ suggest that CUI accounts for more than 40% of a plant's piping maintenance expenditure and 10% of the total maintenance budget. A Joint Industry Project (JIP) consisting of oil & gas operators in the North Sea and DNV resulted in 2019 in a new recommended practice, DNV-RP-G109 "Risk Based Management of Corrosion Under Insulation" ©/4/ where a new qualitative risk methodology was introduced to the industry. This methodology is based on assessment of 4 barriers, the material barrier, the coating barrier, the water wetting barrier and the design barrier/5/. The methodology is now referred to as a preferred methodology to manage CUI by legislators in Norway /6/ and are taken into use in several other countries as well. This paper will address the forthcoming update of DNV-RP-G109 related to CUI in corrosion resistant alloys and the use of humidity sensors to assess probability of water wetting in the insulation.