Mineral Wool with Corrosion Inhibitor Durability for CUI Applications

Abstract Corrosion Under Insulation (CUI) is a multi-factorial problem, meaning there are many causes and no one obvious solution. Regardless of cause, one thing is apparent: reducing the amount and exposure time that water is in contact with metal will have tangible benefits to mitigating CUI. Keeping water out of an insulation system is an ongoing challenge, as cracks in the cladding and gaps in the insulation can form over time. Relying on just one line of defense (such as water repellency) can leave your system vulnerable when water eventually finds its way under the insulation. Using a corrosion inhibitor provides another means of defense against the dangers of CUI. This paper looks at the durability of a corrosion inhibitor integrated within mineral wool at a high temperature using the ASTM C1617 standard corrosion test method. Also, a full-scale insulated and jacketed heated pipe CUI test was performed per the ASTM G189 standard guide to document the corrosion mitigation performance of mineral wool with corrosion inhibitor, when exposed to a water volume equivalent to 15 times the annual rain water for Houston, Texas, USA at a 1% infiltration rate. Corrosion-inhibiting mechanisms will be discussed, and how they can modify the environment around steel substrates to influence corrosion rates will be discussed.