Technical study and comparative tests on thin insulators: initial thermal performance of Thin Reflective Products (PMR)
The BBRI as well as other organizations, including the public authorities, are today confronted with an increasing number of requests for information concerning products commonly known as “thin reflective products” (PMR). The public authorities, partners in this study, want clarifications as to the characteristics of this type of product, in particular with a view to the application of the thermal regulations in force in each region of the country.
One of the BBRI's missions being to carry out scientific and technological research making it possible to better inform the construction sector of the evolution of materials and installation techniques, the BBRI has been led to propose a study on the performance thermals of PRMs.
The study made it possible to determine the thermal performance of several thin insulation products, mainly on the basis of a measurement campaign carried out at the BBRI's experimental station.
A thin reflective product consists, in its central part, of a thin layer of material (plastic foam, polyethylene film trapping air bubbles or a fibrous material) covered on one or both sides with reflective sheets (sheets of aluminum or aluminized films). Some products are of the multilayer type, the layers being separated by intermediate reflective sheets. The total thickness is generally between 5 and 30 mm.
Only the thermal performances of the products in the winter period were studied.
The solar performance (including solar factor) of structures fitted with PMR were not considered, nor were other characteristics such as resistance to water vapor diffusion, sound insulation or reaction to fire.
The thermal performances were measured on the products in their initial state, that is to say as they were supplied by the manufacturers, and installed in an ideal way.
The influence of the conditions of use and implementation on the thermal performances of the products as well as the effect of the possible degradation of the thermal properties over time have not been studied.
The general methodology of the study as well as a proposal for a test procedure were presented to the various partners and were discussed before the start of the measurement campaign. Each partner (public authorities, scientific experts and manufacturers) had the opportunity to make their comments. These were incorporated into the work program when they were the subject of unanimous agreement between the scientific partners of the study (the two scientific experts and the BBRI).
The methodology adopted consisted in determining the thermal performance of PMRs, on the one hand, on the basis of laboratory measurements (under stationary boundary conditions) and, on the other hand, on the basis of measurements carried out in cells of test subjected to real external conditions (non-stationary petrol regime). The results of these two types of measurements were compared with each other as well as with the results of calculations carried out in accordance with the standards in force.
Appendix 2 (p. 35) provides a general outline of the study schedule (holding of the main meetings, test periods, etc.).