ASTM C552

Covers — cellular glass thermal insulation for piping, vessels, and equipment across hot, cold, and cryogenic temperatures, defining composition, dimensions, thermal conductivity, and physical properties (compressive strength, water absorption, combustibility).

Does NOT cover (exclusions) — the following are governed elsewhere:

• Hot-only mineral fiber insulation → ASTM C547.
• Rigid PIR foam for cold service → ASTM C591.
• Chloride limits on austenitic stainless → ASTM C795; calculation → ISO 12241.

Cellular glass excels where moisture resistance matters (cold/cryogenic); fibrous insulation is cheaper for dry hot service.

C552 sets minimum requirements for cellular glass:

• Composition & Structure — closed-cell glass foam, essentially non-absorbent.
• Thermal Conductivity — k-value across the wide service temperature range.
• Physical Properties — compressive strength, water vapor/liquid absorption, and non-combustibility.
• Dimensions & Marking — sizes and product identification.

ASTM C552 specifies cellular glass thermal insulation — a rigid, closed-cell, non-combustible glass foam usable from cryogenic to elevated temperatures. Its defining property is that it does not absorb moisture, which makes it the material of choice for cold and cryogenic lines where wet fibrous insulation would ice, lose performance, and promote corrosion under insulation.

The trade-offs are brittleness and higher cost than mineral fiber. On cold service, careful support, joint sealing, and vapor-barrier detailing are essential to preserve the moisture advantage. Thickness follows ISO 12241.

Engineering Note: On cryogenic lines, cellular glass only performs if the vapor barrier and joint sealing are intact — a breached vapor barrier lets moisture in and defeats the reason cellular glass was chosen.