Considerations for Thin Blanket Insulations
As the industrial industry evolves, new insulation technology has emerged to meet the changing needs of the industry. One of the latest introductions has been thin, blanket insulation. Thin blankets typically range between 5mm and 10mm thick, and can be used in high-temperature or cryogenic applications. Two popular thin blanket insulations are Johns Manville’s InsulThin™ HT, a hydrophobic, microporous, thin blanket insulation, and silica aerogel, a hydrophobic, aerogel, thin blanket insulation. While these materials may seem similar, they each have unique properties that make them useful in varying applications.
With that in mind, what should you be considering when selecting a thin blanket insulation?
Hydrophobicity: Both of these materials are hydrophobic. As a result, they can help system designers battle corrosion by preventing water from reaching the pipe surface. However, hydrophobic treatments oxidize at higher temperatures. Thus, hydrophobicity should not be the sole method used to combat corrosion under insulation (CUI).
Corrosion: Each insulation has a unique corrosive potential that can influence CUI. Numerous studies, including both long-term corrosion tests and ASTM laboratory tests, have shown that the tested silica aerogel blankets have a much higher corrosive potential than InsulThin™ HT.
Operating Temperatures: Accounting for the system operating temperatures is key to selecting the right material for the application. While InsulThin™ HT offers better thermal performance in high-temperature applications than silica aerogel blankets, it should not be used in cryogenic applications. In contrast, silica aerogel blankets, with certain design modifications like a facing, can be used for both cryogenic and high-temperature applications, but the insulation does not perform as well at higher temperatures and undergoes thermal shift.
Thermal Shift: Thermal shift is the permanent degradation in thermal performance due to exposure to high temperatures. It only impacts silica aerogel blanket insulations, and the degradation is not indefinite. The thermal performance will decrease to a certain point, at which it will begin to maintain a consistent thermal conductivity.
Safety: Safe-to-touch standards suggest insulation systems maintain a surface temperature of 140°F. In any system designed for safe-to-touch temperatures, system designers need to consider thermal shift as a potential influencer in the system and account for the decrease in thermal performance in the design phase by adding additional layers of insulation if necessary.
Ease of Fabrication: Many installers prefer working with blanket materials as they take up less storage on the jobsite. That said silica aerogel products produce a substantial amount of dust that has led some owners and contractors to require installers to wear full body suits to protect against the dust during installation. InsulThin™ HT produces less dust, and subsequently does not require such extensive PPE coverage during installation.
These variables and more come into play when we look at what makes a successful insulation system design. To learn more about thin blanket insulation, please keep an eye out for information on our upcoming webinar on Thin Blanket Insulation Considerations.