Corrosion under insulation, or CUI, is a condition that plagues high-temperature chemical processing plants across the province. It is a form of localized corrosion that typically occurs in insulated carbon and low alloy steel equipment. CUI can be disastrous, creating literal holes in pipes and machinery alike. Mitigating this problem requires careful planning, regular maintenance, and knowledgeable installation professionals.
Types of Corrosion
To properly combat CUI, you must know what type of corrosion you are dealing with, or are more likely to have to deal with in the future. The three most common types of corrosion are:
- Galvanic. This occurs when a current flows between different metals, typically caused by wet insulation. Even if one of the metals is more noble, meaning resistant to corrosion, the other will experience a gradual breakdown.
- Alkaline / Acidic. When certain fibrous or granular insulations get wet, the drying process can actually cause alkali or acid in the material to condense at the edges and begin to eat away at the insulation jacketing.
- Chloride. This type of corrosion can happen when insulation that contains chlorides is exposed to water and high temperatures. Like alkaline/acidic corrosion, chloride damage results from evaporated moisture.
Preventing CUI
Repairing the damage caused by corrosion is much more costly than taking preventative measures. As is evident by the types of corrosion, the most effective method of preventing CUI is to keep the space between equipment and insulation free from water and electrolytes. In this way, protective coatings, weather barriers, and regular maintenance ensure that the damage caused by CUI is minimized and mitigated.
Corrosion within insulation can be detrimental. Enlist a team of insulation experts to ensure that your insulation isn’t causing more harm than good. For facilities in the Calgary area, we can help you create a strategy to keep your equipment safe. Contact us today to get started.
