Annex 65, Long-Term Performance of Super-Insulating-Materials in Building Components and Systems. Report of Subtask II: Scientific Information for Standardization Bodies dealing with Hygro-Thermo-Mechanical Properties and Ageing

Rapport, 2020

This subtask is divided in two actions:
Action 2A: Materials Assessment & Ageing Procedures (Experiments & Simulation)
Action 2B: Components & Systems Assessment (Experiments & Simulation)
As their structures and microstructures are completely different, Super-Insulating Materials (SIMs) cannot be compared directly to traditional insulating materials. Worldwide acceptance of these materials will be improved if the hygro-thermal and mechanical properties of SIM can be clearly articulated and reproduced. In particular, nano-structured materials used to manufacture a SIM are characterized by a high specific area (m²/g) and narrow pores (smaller than 1 μm) which make them very sensitive to gas adsorption and condensation, especially in contact with water molecules.
Therefore, methods of characterization must be adapted, or new methods developed to measure the microstructural, hygro-thermal and mechanical properties of these materials and their barrier films.
In parallel, modelling methods to describe heat, moisture and air transfer through nano-structured materials and films will have to be developed (adsorption and desorption models, diffusion models, freeze-thawing …).
Of course, a few methods will be common to all SIMs, but due to their structural differences some specific modelling methods have to be developed.
SIMs can offer considerable advantages (low thickness, low Uvalue) ; however potential drawback effects should be considered in the planning process in order to optimise the development of these extraordinary properties (very low thermal conductivity) and to prevent negative publicity which could be detrimental to this sector of emerging products. This is why ageing tests will be set according to realistic conditions (temperature, moisture, pressure, load …) as set out in SubTask 3A. One objective of artificial ageing is to understand potential degradation processes that could occur. The durability of hydrophobic treatment is one of these processes and will also be subject to discussion and investigation.
At the component scale, additional characterizations are needed as panels or rolls are sold by manufacturers. In particular, thermal bridges will be carefully investigated, as the extraordinary thermal performance of SIMs are sensitive to the influence of thermal bridges.