Saving money on energy costs is everyone’s goal. Increasing capacity might also be your objective. Using microporous insulation in your furnace can accomplish either or both of these goals and/or improve the safety of your facility by reducing the temperature of the furnace cold face.

Improving efficiency, making equipment smaller or using the same equipment to produce more product is becoming more important for businesses everywhere. By improving the efficiency of the insulation in industrial heating equipment – from small lab furnaces to large aluminum holding furnaces – businesses can reduce the amount of fuel needed to run the equipment and the amount of toxins released from the equipment. One way to do this is to use microporous insulation for equipment running up to 1200°C (2192°F) or using a microporous liner behind refractory materials for equipment running at higher temperatures.

Fig. 1. Without microporous insulation – surface temperature: 163°F; heat loss: 181 BTU/SF-Hr

All About Microporous Insulation

The original microporous theory was developed in the 1940s. The microporous product was originally developed for the nuclear industry in the 1950s and was quickly applied in aerospace and military applications. The product was further developed and commercialized for industrial uses and became popular in the storage heater and ceramic cooktop industries

Microporous insulation is based on nanostructured submicron synthetic amorphous silica (SAS) and other environmentally safe materials. Long “chains” of SAS particles help to keep solid heat conduction to a minimum. Spaces in the structure are smaller than the mean free path of an air molecule, eliminating most of the gaseous heat conduction. Mineral-oxide opacifiers effectively block infrared radiation.

Basically, microporous insulation is a collection of fine compacted powders and fibers. It is manufactured in boards, panels, flexible panels and preformed shapes. Microporous insulation is usually completely inorganic and non-combustible, though some manufacturers add organic content to improve the machineability of the product. While this improves handling and makes machining the product easier, it is important for the end customer to understand that the organics will burn out, leaving a less sturdy product than typically desired.

Microporous insulation is totally non-combustible, and some grades can withstand continuous exposure to temperatures as high as 1200°C (2192°F). Typical grades can withstand continuous exposure to temperatures as high as 1000°C (1832°F). Within its temperature limits, it is the most effective insulation. It is fireproof, flame retardant, the lightest and most compact solution available, completely inorganic and non-combustible, load bearing and environmentally friendly. Microporous is three to four times more efficient compared to conventional insulations and 10 times more efficient than refractory materials. It also has excellent load-bearing capabilities. Typical densities are 250-500 Kg/m3(15-30 Lbs/ft3), with compression resistance of 615 kPa (89 PSI) at 10% deflection.

Most businesses deciding to use a microporous solution are trying to achieve one of three goals.
1. Save energy
2. Save space (decrease footprint of equipment)
3. Improve capacity/safety

Examples follow illustrating how the end user could achieve these goals.

Fig. 2. With microporous insulation – surface temperature: 127°F; heat loss: 95 BTU/SF-Hr

Example 1: Save Energy

Typical Application – Furnace Industry
  • Heat-treating furnace (Fig. 1)
  • Process temperature – 1650°F
  • Goal – save energy
By adding a 1-inch layer of microporous insulation, the owner of the equipment would be able to reduce the cold-face temperature by 36°F and achieve a heat-loss reduction of 48% (Fig. 2). The large reduction in heat loss will provide a shorter payback period.

Fig. 3. Without microporous insulation – outside diameter: 169 inches; height: 50 feet

Example 2: Save Space (Decrease Footprint of Equipment)

Typical Application – General Industry
  • Hydrogen reformer (Fig. 3)
  • Operating temperature – 1900°F
  • Goal – reduce diameter and length
  • Save on reformer tubes and shipping

Fig. 4. With microporous insulation – outside diameter: 160 inches; height: 49 feet

The end user saved $40,000 in shipping costs due to special permits required. Due to the increased efficiency, 50 feet of costly reformer tubes could also be eliminated (Fig. 4).

Fig. 5. Without microporous insulation – surface temperature: 648°F; diameter: 45.75 inches

Example 3: Improve Safety/Capacity

Typical Application – Burner (Fig. 5)
  • Process temperature – 2300°F
  • Tubular design
  • Reduce surface temperature for safety without changing size.
The external surface temperature would be reduced by >200°F with no change in space requirement (Fig. 6). It would also improve worker safety and maintenance access.

Fig. 6. With microporous insulation – surface temperature: 443°F; diameter: 45.75 inches

Benefits of Microporous Insulation

Microporous insulation has been around for many years, but its use in the furnace industry has only recently begun to grow. With ever-increasing energy costs, the drive is on for better efficiencies. New product forms and improved manufacturing methods have made microporous insulation a better option for furnace applications. Microporous insulations can be used in a variety of furnace applications to save energy, increase capacity, save space or a combination of the three (Fig. 7).

By using microporous insulation alone or in combination with other materials, equipment manufacturers and owners can achieve their desired results, whether it be to save energy, save space or increase safety/capacity. With the ever-growing emphasis on “green” materials and improving our environment, microporous insulation also offers advantages for industrial heating equipment. Manufacturers of the material can provide more information on how to use this extremely efficient material to reduce greenhouse emissions by keeping the heat where it belongs.IH

Fig. 7. Illustration of Microtherm benefits vs. conventional insulation

For more information:Contact Alyssia K. Flynn, application engineer, Microtherm Inc., 269 Cusick Rd. Suite C-4, Alcoa, TN 37701; tel: 865-681-0155; fax: 865-681-0016; e-mail:; web:

Additional related information may be found by searching for these (and other) key words/terms via BNP Media SEARCH at www. microporous insulation, efficiency, refractory, heat loss