What defines a perfect thermal insulation?
Microtherm® is the best high temperature insulation you can buy.
Microtherm® – we also believe that it is the best performing general thermal insulation at all temperatures right down to cryogenic temperatures that you can buy.
Let us explain why.
First, what is a thermal insulation?
In the simplest terms it is "Any material that offers resistance to heat transmission".
Even the very best thermal insulation will not block heat completely. Every material will transfer some heat if a temperature gradient exists across it i.e. it has a higher temperature on one side than the other. Heat will always move from a hot region to a region that is less hot. In the simplest situation, as the heat moves, the hotter region will cool and the cooler region will increase in temperature. This is simple physics.
Not all materials transfer heat equally and the thermal conductivity of a material is a physical property which describes its ability to transfer heat. The lower the value of the thermal conductivity, the more resistant the material is to the heat transfer. A thermal insulation has a low thermal conductivity. A good high temperature thermal insulation such as Microtherm® has a very low thermal conductivity at very high temperatures, up to 1000 °C (1832 °F) or even higher.
Examples of the thermal conductivity of some common materials at ambient temperatures
| Copper – an excellent conductor |
401 W/m.K |
| Carbon steel |
54 W/m.K |
| Glass |
1.05 W/m.K |
| Asbestos cement board |
0.744 W/m.K |
| Microtherm® |
0.021 W/m.K |
Microtherm® is the best microporous insulation available.
The reason why Microtherm® gives the best performance is once again due to simple physics.
A microporous insulation is defined in ASTM C168 as - "Material in the form of compacted powder or fibers with an average interconnecting pore size comparable to or below the mean free path of air molecules at standard atmospheric pressure. Microporous insulation may contain opacifiers to reduce the amount of radiant heat transmitted."
Heat transfer can occur through solid conduction, gaseous conduction, convection and radiation, usually the overall heat transfer comes from a combined effect of all of them.
The page Microporous Insulation elsewhere on this web site covers the physics in more detail and explains just why Microtherm® is so very good. Unlike other insulation materials, it is very good near its upper temperature limits because Infra Red radiation is the principal method of heat transfer at high temperatures and Microtherm® effectively blocks it. Because of the presence of a carefully selected opacifier in the form of fine particles which repeatedly refract the waves of IR radiation preventing it penetrating deeply into the insulation, the thermal conductivity of Microtherm® stays extremely low over its entire operating temperature range. With a TC of 0.021 W/m.K at ambient temperatures, it rises very little at high temperature – just 0.0343 W/m.K at a mean temperature of 800 °C (1470 °F).
This can be clearly seen on the Comparison TCs chart featured on our home page.
Microtherm® is also very stable at its maximum operating temperature and shows minimal long term shrinkage even after continuous exposure to 1000 °C (1832 °F). This is explained in more detail in Not all microporous insulations are the same – another technical page on this web site.
If even higher temperatures are encountered, Microtherm® Super A can handle up to 1200 °C (2192 °F).
However, what makes Microtherm® really exceptional as a thermal insulation is the fact that it will also give excellent protection right down to cryogenic temperatures. The thermal conductivity at a mean temperature of -170 °C drops to an impressive 0.015 W/m.K. It quite literally maintains its exceptional performance form the deep cold of cryogenic temperatures right up to the extreme heat of 1000 °C.
It is the single solution for all thermal protection problems irrespective of exposure temperature. That is why we believe that it is the best performing general thermal insulation at all temperatures that you can buy.
Microtherm® - cool answers to hot problems, but we’re hot on the cold side as well!