Thermal insulation at room temperature. Properties

The production and performance of thermal insulation materials have made great strides in recent decades, particularly since the 1970s. The number of insulating materials available on the market, and in particular lightweight insulating materials, has increased, and their thermal properties and suitability for use have been significantly improved.

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.

As of 1 ^er June 2001, a new document entitled "Réglementation thermique RT2000", drawn up by the CSTB, came into force in France, with the aim of contributing, on the one hand, to reducing energy consumption and, on the other, to optimizing comfort in the building sector. All the above-mentioned achievements in the field of thermal insulation, including the harmonization of working methods at European level (EN standardization), are taken into account. Thanks to these results, a home built in 2000 consumes half as much energy as one built in 1974.

Despite the progress mentioned, it cannot be said that research and development efforts in the field of thermal insulation have been weakened. In fact, current trends that are opening up new prospects include :

• extending the range of applications for super-insulators, in particular nanomaterials and vacuum insulation, in the field of room temperature and construction (high-insulating double glazing, transparent walls, etc.);

• the development of specific insulation applications, such as dynamic insulation, which combines the use of high-performance insulation materials, the thermal inertia of buildings and solar gain;

• the study of new interstitial gases with low thermal conductivity, not harmful to the atmospheric ozone layer;

• better control of the morphological...