Thermal insulation - Classification and properties of insulating materials

Since the 1970s, all industrialized countries have been pursuing an energy-saving policy, which has led to considerable growth in the thermal insulation sector.

Thermal insulation can be associated with an insulating material, product or system. This article focuses on insulating materials, how they work and their thermo-physical characterization.

The vast majority of modern insulating materials are lightweight porous materials, within which heat is transferred by both conduction and radiation, thanks in particular to their semi-transparent nature.

Three factors that have played an important role in achieving this progress can be mentioned:

• the rapid evolution and improvement of insulation manufacturing technologies, with higher productivity and lower costs;

• in-depth knowledge of the physical bases of insulator operation;

• setting up a quality control system to guarantee the properties of manufactured products, on the one hand by drawing up standards to define and quantify insulation properties (specifications) and set measurement methods (development of reference equipment and materials, particularly for thermal conductivity measurements) and, on the other, by organizing a set of manufacturing control and product certification procedures, such as the ACERMI program in France, to ensure high-performance technical products.

This article takes a look at insulating materials used at room temperature, reviewing their classifications and properties.