Microporous insulation is an inorganic, silica-based superinsulation—commonly supplied as boards or panels—for high-temperature applications. Its nano-sized pores and radiation-blocking additives reduce heat transfer by conduction, convection, and radiation, delivering exceptionally low thermal conductivity even at elevated temperatures.
It’s often selected when you need a bigger temperature drop with less thickness—especially where space, weight, or shell temperature limits are critical.
Heat travels in three main ways: conduction, convection, and radiation. Microporous insulation targets all three:
Convection is essentially “blocked”
The pore network is so fine that air can’t form meaningful convection currents through it.
Gas conduction is strongly reduced
In nano/micro-porous structures, pores can be comparable to or smaller than the mean free path of gas molecules, which reduces how effectively the gas transfers heat.
Radiation is reduced using opacifiers
Microporous cores often include opacifiers that reduce infrared (radiant) heat transmission at elevated temperatures.
Most industrial microporous boards/panels are built around:
Fumed/pyrogenic (amorphous) silica as the main low-k skeleton
Reinforcing fibers/filaments to improve handling strength
Infrared opacifiers to cut radiation at higher temperatures
Sometimes a aluminum foil cloth envelope/facing to reduce dusting and improve installation cleanliness
Optional hydrophobic / water-repellent treatments for condensation-risk situations
Example from a major product family: Promat notes a core that is an opacified blend of filament-reinforced pyrogenic silica (and alumina for higher grade) wrapped in a glass cloth envelope, with grades classified around 1100–1200°C.
Datasheets vary by formulation, but microporous boards commonly show very low k-values across 200–800°C. For example, a rigid microporous board datasheet reports thermal conductivity around 0.022 W/m·K at 200°C, rising to ~0.044 W/m·K at 800°C (test method ASTM C177).
Typical classification/continuous use depends on grade and system design—commonly ~1000°C for many rigid boards, with some panel systems offered at 1100–1200°C classification.
Microporous insulation is most often selected when you need maximum thermal resistance with minimum thickness and weight.
Many microporous products can be damaged by liquid water or wetting liquids because liquids may densify the pore structure and reduce insulation performance—so proper storage, protection, and jacketing/encapsulation matter. Hydrophobic grades help, but you still want good site discipline.
Microporous insulation is supplied in multiple formats depending on geometry and handling needs:
Rigid boards/blocks (flat sheets, high compressive strength)
Encapsulated panels (often aluminum foil cloth facing/envelope for clean handling)
Flexible panels (stitched/faced to wrap cylinders/contours)
Pipe sections (pre-formed half shells / curved segments)
Microporous insulation shows up wherever engineers need lower shell temperature, reduced heat loss, or thinner linings:
Used for energy savings and shell temperature reduction in melting and holding furnaces, launders, and related equipment—especially where thickness is limited and heat loss is costly.
Applied in hot zones and heat-loss bottlenecks (furnace structures, ducts, sensitive hot surfaces) where space and surface temperature control drive design.
Selected for high-temperature process units, exhausts, ducts, vessels where insulation thickness is constrained and safe-touch or lower outer skin temperature is required.
Commonly used where you want high thermal resistance with minimal diameter increase, plus better insulation performance at elevated temperature than many conventional materials.
Because many microporous cores are inorganic and non-combustible, they are also used in passive fire protection systems (always verify the specific product classification).
Microporous insulation is usually not the “default” insulation—it’s the “when it must be thinner / cooler / more efficient” option.
Vs. ceramic fiber board/blanket: often better insulation per mm at high temperature, but needs protection from wetting and mechanical abuse.
Vs. calcium silicate board: calcium silicate is robust and economical for many cases, but microporous is chosen when you need superinsulation performance in tight space.
Vs. insulating firebrick (IFB): IFB provides structure + insulation; microporous is typically a back-up layer or special insert where thickness is limited.
Vs. VIP (vacuum insulation panels): VIPs can be even lower-k, but they’re a different system concept (vacuum + barrier films). Microporous materials are often used as core materials in VIP designs.
Hot face temperature + max classification temperature (don’t guess—confirm grade)
Target cold-face / shell temperature (often the real KPI)
Wetting/condensation risk → choose hydrophobic/encapsulated options and define jobsite protection rules
Mechanical loads (compression, vibration, impact) → choose density/format accordingly
Dust control & cleanliness → favor faced/encapsulated panels (glass cloth envelope, etc.)
Cutting & installation constraints (curves? tight radii? complex shapes?) → flexible panels / pre-shaped parts
Not exactly. Both can be nano-porous and very low-k, but microporous insulation boards/panels are typically compressed silica-based solids often reinforced and opacified; aerogel products are frequently supplied as blankets/composites. (Selection depends on temperature, geometry, and durability needs.)
Because its pore structure and opacifiers reduce conduction/convection/radiation so effectively that you get more thermal resistance per millimeter.
It depends by grade and temperature. As one example, a rigid microporous board datasheet reports ~0.022 W/m·K at 200°C and ~0.044 W/m·K at 800°C (ASTM C177).
Many grades are permanently damaged by liquid water, so you must use jacketing/encapsulation and good storage/handling. Hydrophobic grades exist for condensation-risk applications, but protection is still recommended.
Common industrial boards are often around 1000°C classification, while some panel systems are offered at 1100–1200°C classification depending on grade.
High-temperature, energy-intensive industries like aluminum, glass, petrochemical/process heating, plus industrial piping/equipment and fire protection applications etc.
