Which insulation material is used for cold vessels?

• A. Cellular Glass
• B. Fiberglass
• C. Mineral Wool
• D. Perlite

Answer: (A)

When insulating a cold vessel, the goal is to minimize heat gain while keeping the insulation dry and stable at very low temperatures. A material with a closed-cell structure and very low moisture absorption does exactly that: it stays dry, maintains its insulating value, and remains dimensionally stable through cryogenic temperatures. Cellular glass fits this best because it is rigid, chemically inert, and highly resistant to water uptake. This means it won’t collapse or soak up moisture that could create frost or increase heat leak, which is crucial for maintaining low temperatures.

Fiberglass, while effective in many applications, can absorb moisture and lose insulation quality when wet, and its performance can degrade in cryogenic service. Mineral wool has better moisture resistance than fiberglass but still isn’t as impermeable as cellular glass and can be less reliable under extreme temperature cycling. Perlite is used in some cryogenic setups, often as loose-fill or within specific vacuum configurations, but it can be fragile, messy to handle, and not as robust for large or practical vessel insulation.

So, for cold vessels, cellular glass provides a dependable, moisture-resistant, and thermally stable insulation solution, which is why it is the preferred choice.