5 Key Takeaways from Webinar - CUI Test Results: Understanding the Corrosive Mechanism

Last week, we hosted CUI Test Results: Understanding the Corrosive Mechanism, a live webinar detailing the latest test results from the most recent long-term corrosion under insulation (CUI) testing. Our webinar covered the various types of corrosion, the science behind the thermodynamics of corrosion, and the latest findings from long-term corrosion research on Thermo-1200™ calcium silicate, and Sproule WR-1200® expanded perlite, and a silica aerogel blanket specimen.

If you missed the webinar, don’t worry. Below, we’ve outlined 5 takeaways from the webinar, and you can watch a recording of it here on the Webinars tab.

  1. There is a growing trend in the industrial industry to develop and incorporate “real-world” test methods. The industrial industry is moving toward a “whole-systems” approach to material testing. This approach strives to account for the interaction of multiple variables in complete systems, rather than isolating each variable and testing it independently. This approach is designed to give researchers a better idea of how systems will perform in an actual industrial application. The latest long-term CUI testing was initiated and conducted by insulation end-users, a third-party research laboratory for unbiased research and assessment, and an insulation manufacturer. It utilized the proposed NACE TG516 test protocol to explore the corrosive potential of the three insulations listed above.

  2. Not all corrosion is created equal. The samples exhibited two types of corrosion byproducts: magnetite and hematite. Magnetite is a more stable type of iron oxide that researchers hypothesized can actually impede further corrosion on the pipe surface when it is thick and strongly adhered. By contrast, hematite is a much more fragile byproduct that results in pits in the metal surface of the pipe. Pitting corrosion creates deep pits that if left unchecked, can ultimately result in holes in the pipe surface. These deep pits can threaten the integrity of the entire system as they weaken, and in extreme cases rupture, the surface of the pipe. Notably, the Thermo-1200™ calcium silicate and Sproule WR-1200® expanded perlite exhibited a magnetite layer that was substantially thicker and more strongly adhered than it was on the silica aerogel specimen.

  3. Researchers attribute the thick, strongly adhered magnetite layer to the XOX Corrosion Inhibitor®. Both Thermo-1200™ and Sproule WR-1200® have the XOX Corrosion Inhibitor® as a key component to their chemical makeup. This is not an additive or a coating, but rather an ingredient that goes into the material during manufacturing. Researchers found that the presence of the XOX Corrosion Inhibitor® actually allowed the pipe samples to form the thick layers of magnetite and helped prevent deep pits from forming on the pipe surface. By comparison, the tested silica aerogel specimen has no corrosion-inhibiting technology and resulted in pits that were up to 196% deeper than the pits in the other two material samples.

  4. Insulation material selection is critical to designing systems with a robust defense against CUI. Given that this is the second series of the proposed NACE TG516 test protocol (the first series tested InsulThin™ HT, a microporous blanket, and a silica aerogel blanket specimen), science has demonstrated that the insulation material selection is a critical step to inhibiting CUI. As clearly shown in the results, different materials have substantially different corrosive potentials that need to be considered when designing to inhibit CUI.

  5. There is no “one size fits all” solution to corrosion. Corrosion is a result of a number of variables, some of which cannot be controlled. A well-designed system will take these variables into account and address them in the design phase. That said, there is no “magic bullet” that will prevent CUI in all cases. This is why it’s important to have multiple stop-gaps in place to help inhibit CUI. These stop-gaps can range from properly installing jacketing, to applying coatings, to selecting insulating materials with low corrosive potential. All this comes down to the fact that a well-thought out system will have a much stronger chance at preventing CUI than one that fails to account for the numerous variables that are at play in a real-world system.

If you would like more information on the latest CUI testing, we encourage you to download our free e-Book,The Comprehensive Results from “Real-World” Corrosion Under Insulation Test Protocols. We go through the test procedure and results in fine detail to help you better understand the corrosive potential of insulation and how you can use it to your advantage to design more robust systems.