New Guideline for Corrosion Under Insulation

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.