Johns Manville Industrial Insulation Group's (JM IIG's) Thermo-1200™ is the groundbreaking new water-resistant calcium silicate insulation that has just arrived on the industrial market. It is the first water-resistant calcium silicate to be manufactured in the U.S., and its ability to shed water is what makes it different from its predecessor, Thermo-12® Gold. While this is a major advancement in the product, there is a noteworthy similarity between Thermo-1200 and Thermo 12-Gold: Based on a widely accepted industry test method, both insulations are less corrosive than deionized water. This has led many to ask why both materials have the same exceptional corrosion-inhibiting performance despite the difference in their water resistivity.
In order to explain this, it's important to first understand the nuances between hydrophobic and water resistant. Most insulations labeled "hydrophobic" have been treated with a hydrophobic additive (typically silicone). This additive prevents the insulation from absorbing water. In contrast, a "water-resistant" insulation is designed to shed water; it is not impervious to water absorption.
In the case of Thermo-1200, it was designed to withstand a typical rainfall during the installation phase, allowing contractors time to cover or jacket the material if it begins to rain. Thus, "water resistant" pertaining to Thermo-1200 specifically means that tests have shown it can withstand up to 1.5 inches of rain over the course of 20 minutes without absorbing more than 15 percent of its weight in water (during testing, this number averaged closer to 8 percent). Bear in mind that once calcium silicate insulation absorbs more than 20 percent of its weight in water, it must be removed from the application and replaced with a new, dry piece of insulation (per its ASTM standard, ASTM C533). This is why the test parameters were set at less than 15 percent.
The common denominator between both insulations that influences their low corrosivity is the XOX Corrosion Inhibitor®. The XOX Corrosion Inhibitor is unique to JM IIG's calcium silicate and expanded perlite (Sproule WR-1200®) insulations. Rather than preventing water intrusion like a hydrophobic or water-resistant treatment, the XOX Corrosion Inhibitor has a two-pronged approach that protects the pipe once water has entered the system: 1. It neutralizes corrosive chemicals that enter the system through water ingress, and 2. It creates a passivation layer on the surface of the pipe that prevents water from contacting the pipe itself, effectively stopping the corrosive cycle.
The XOX Corrosion Inhibitor is why both JM IIG's new and legacy calcium silicate insulations show a lower corrosive potential than most other comparable insulations, including certain silica aerogels and mineral wools. Ultimately, the XOX Corrosion Inhibitor paired with the water resistance of Thermo-1200 offers a belt-and-suspenders approach to corrosion that makes Thermo-1200 one of the best in its class.
For more information on Thermo-1200 or the XOX Corrosion Inhibitor, visit www.jm.com/industrial or call (800) 654-3103.
