Interest Heats Up Over Insulation Coating Systems
A detailed overview of the first thermal insulation coating to feature Enova ® aerogel from Cabot Corporation was presented to leading engineers, architects, applicators and contractors from the Northeast region during a recent technical seminar held at the company's headquarters in Boston.
The daylong seminar consisted of individual sessions where presenters demonstrated the thermal insulation properties of Enova aerogel additive contained in Series 971 Aerolon Acrylic, which is Tnemec's fluid-applied coating for pipes, valves, tanks and architectural applications.
Among the presenters at the seminar was Andy Hoffman, Tnemec market support manager, Industrial Market, who emphasized that Aerolon Acrylic is part of a complete coating system that includes specialty primers and topcoats. "Zinc-rich primers will be used for lower temperature and highly corrosive environments, while water-based epoxy primers are for use in higher temperature applications, and a novoloc epoxy primer is available for stainless steel," Hoffman shared. "The selection of topcoats includes a High Dispersion Pure (HDP) acrylic, water-based and high-solids epoxies and urethane coatings."
Once mixed, Aerolon Acrylic resembles a slurry, which can be applied with user-friendly spray equipment. The Enova aerogel imparts improved thermal efficiencies that result in energy savings, as well as condensation control, corrosion resistance and safe-touch performance.
"In terms of insulation value, Aerolon Acrylic is dramatically more efficient than other thermal coatings containing ceramic beads and are comparable to most conventional forms of industrial insulation," according to Hoffman. "Given the coating's exceptionally low K-value rating, which is a measure of thermal efficiency, energy savings of up to 50 percent can be realized."
The thermal efficiency of Aerolon Acrylic was demonstrated by Cabot in laboratory testing, which compared two tanks that were heated to a constant elevated temperature. One tank was coated with an Aerolon coating system except for a small square cutout, while the other tank was left uncoated. The heater on the coated tank operated 45 percent less than the unit on the uncoated tank to maintain the same constant temperature. Infrared photography revealed elevated color variations on the uncoated steel surfaces compared to areas coated with the Aerolon coating system.
An Aerolon Acrylic coating system has been specified for a new crude oil storage tank where the interior temperature is kept at 120 degrees F. "The coating system will reduce the amount of time the tank's bottom heaters will need to operate to maintain that temperature," Hoffman said.
Unlike foam, blankets or mineral wool where moisture can be trapped between layers causing damaging corrosion, Aerolon Acrylic coating systems use high-performance primers to create a tightly bonded seal that protects substrates and resists corrosion under insulation (CUI).
"Traditional insulation systems have issues with respect to condensation forming on the surface of a substrate," Hoffman observed. "These systems will absorb moisture from exposure to water from failed jacketing, or when water vapor comes into contact with colder surfaces, resulting in CUI. "
Hoffman cited the example of a water treatment plant in upstate New York where CUI was found to be a major issue on two 1,000-square-foot filter tanks where condensation formed on exterior steel. "During the summer, when it's 90 degrees outside, these tanks would sweat constantly," Hoffman explained. "During an inspection, black mold was discovered behind the insulation, which was totally saturated. They ended up hiring an abatement contractor and tearing off all the old insulation."
Both filter tanks in the water treatment plant are scheduled to be coated with an Aerolon Acrylic coating system that includes an advanced generation water-based epoxy primer, and a topcoat of a HDP acrylic polymer.
A similar Aerolon Acrylic coating system was used to replace traditional insulation on a section of steam pipe in the lower level of a water treatment plant in, Tennessee. When the insulation was removed following a flood, severe corrosion was discovered on the steam pipe. An Aerolon Acrylic coating system was applied on a section of the steam pipe to provide a safe-touch surface for employees who might accidently come in contact with its hot surface.
"Aerolon Acrylic meets safety standards for heated system surface conditions by providing a five second safe-touch barrier of protection at elevated temperatures," Hoffman noted. "Based on its safe-touch performance, the Aerolon Acrylic coating system is now included in the Nashville water plant's specifications."
In addition to covering the industrial applications of Aerolon Acrylic, the Cabot seminar also reported on its uses as a thermal break in architectural applications. Thermal breaks reduce heat loss through cold bridging and lower the risk of interstitial condensation or mold formation on structural steel and window frame systems.
Cabot developed a demonstration of thermal bridging using an aluminum framing system with a cooling loop on the exterior side to replicate cold weather conditions and room temperature on the interior side. Half of the frame was coated with Aerolon Acrylic applied at 80 mils dry film thickness (DFT) and a HDP acrylic polymer topcoat. The other half of the frame received only the topcoat.
"Condensation was dripping off the side of the frame where only a topcoat was applied," Hoffman observed. "The section of frame that was coated with the Aerolon Acrylic was dry, which demonstrates the coating system's effectiveness as a thermal break by preventing the moisture in the room from condensing off the surface."
In thermal modeling of several different building configurations, the Aerolon Acrylic coating system was evaluated for its effects on heat loss and condensation reduction. "A huge issue in architectural design is the condensation of moisture on structural steel that is conducted through the wall cavity," Hoffman acknowledged. "So the application of an Aerolon Acrylic coating system on that detail could make it more efficient."
Aerolon Acrylic achieves a higher, single-coat film build, resulting in shorter application times for a quicker return-to-service and lower labor costs compared to insulation coatings containing ceramic or glass beads. A single coat of Aerolon Acrylic can achieve up to 50 mils DFT, compared to 20 to 25 mils DFT for ceramic and glass-infused insulation coatings.
"There is no standard DFT for Aerolon Acrylic," Hoffman shared. "The thickness is dependent on temperatures, the type of job, environmental conditions and customer expectations, so the DFT will vary. Once we understand what the customer needs, we can model a couple different thicknesses and show them what the benefit will be at those thicknesses."
Hoffman added that NACE is recognizing the emergence of insulation coating technology. "Last year, NACE started a specific three-day seminar in Houston titled "Bring on the Heat,'" Hoffman reported. "Another seminar this year in New Orleans will dedicate roughly 10 presentations to insulation coatings, three of which are specifically on aerogel insulation coatings."
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