Leading Edge Technology for
Insulation & Composite Foam Cores

28Oct

New Technical Bulletin: Insulation Performance at Cryogenic/Cold Temperatures (Part 1)

Dylast Leading Edge InsulationComposites3

With this blog, Dyplast is beginning a three-part series of Technical Bulletins on “INSULATION PERFORMANCE AT CRYOGENIC/COLD TEMPERATURES: Logical Thinking.”

Facility

We use the term Logical Thinking to describe the logical examination of the complex issues that surround insulant performance at very low or cryogenic temperatures - a different approach than simply examining and comparing numbers advertised in datasheets, which are often measured at ambient conditions. In this 3-part series, we will also offer some lessons learned that can help a buyer or engineer improve the likelihood of an apples-to-apples comparison, otherwise made difficult by:

  • Different ASTM standards and test protocols for different insulants.
    • For instance, how do you compare water absorption data when some require 2-hour immersion and some 96?
  • Lack of physical property data at cryogenic/cold temperatures.
    • For instance, what is the water vapor transmission rate at -265°F (-165°C), considering the physics of the ASTM test at 75°F versus in-situ conditions?
  • The real implications of “aged” thermal conductivities.
    • Aging per ASTM is intended to facilitate an apples-to-apples comparison.
    • An improved understanding may give you an edge.
  • Suppliers that offer data with stated or unstated caveats.

In this first installment, we focus primarily on the complexities surrounding comparisons of insulant thermal conductivities (k-factor or λ). The major conclusion is that simply comparing the datasheets of alternative suppliers can lead to inaccurate decisions, since some datasheets may not fully disclose data, and others have caveats such as utilizing EN standards rather than ASTM - calling into question whether there is requisite ASTM compliance.

The second installment will continue the discussion on some of the more interesting aspects of thermal conductivity such as across radial geometries, reasons for and impact of discontinuities in λ gradients, and we may begin touching on other physical properties such as water absorption at very low temperatures. The final installment will delve deeper into physical properties as cryogenic temperatures are approached.

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Don’t forget to view INSULATION PERFORMANCE AT CRYOGENIC/COLD TEMPERATURES: Logical Thinking.