There are several types of heat-insulating materials in use in a variety of commercial and residential applications. Some of these heat-insulating materials include asbestos, fiberglass insulation and mineral wool. Less-conventional materials include multi-layer insulation (MLI) used on spacecrafts and satellites, ceramic-based paints and chemical films that are often wrapped around pipes and laid on flat surfaces.
While the typical use of insulation is to prevent cold air from entering an area, many heat-insulating materials are designed to keep heat away from an object. The materials can also be used inside of a component so as not to damage other components within an assembly. Heat is a common enemy of many devices and, as such, requires special heat-insulating materials to prevent a wide array of damage from minor malfunction to complete thermal meltdown and destruction.
One of the first widely-used insulating materials found to protect against heat was asbestos. A fiber-like material, asbestos has been used in buildings, ships and various types of machinery to safeguard against heat damage. Dust particles from asbestos have been linked to health concerns, including cancer, and the material is beginning to be used in very limited applications.
Fiberglass insulation is a versatile material that has found many uses, including use as heat-insulating materials. The amount of heat protection is often attributed to the thickness of the fiberglass material. The air trapped inside the many strands and fibers of the insulation prevent the transfer of heat from one particle to another, thus creating a successful thermal-barrier. For extreme heat conditions, mineral wool in the form of slag wool and rock wool is commonly used in areas that may come into direct contact with humans. Slag wool is a byproduct of iron ore blast furnace slag, while rock wool is a byproduct of natural rock and stone.
Some of the less conventional and more exotic heat-insulating materials can be found in outer space or under the hood of the family automobile. Ceramic-based paints and coatings are often applied to space vehicles and automobile exhaust components in order to protect against heat damage. By covering a component in this liquid coating, the cured coating has the ability to both contain any heat inside the component as well as protect external heat from entering the component. Other heat-insulating materials known as MLI consist of several layers of materials bonded together and make up the gold-colored material often seen on spacecraft.