PIR (polyisocyanuate) rigid foam panels have a remarkable U-value of 0.023 W/(m2K), making them one of the most effective thermal insulations available.
It is a very complex compound of plastics that cure under appropriate heat treatment to form the rigid foam sheets. The finished PIR panels are usually covered with an aluminium foil. This protects against moisture and mechanical stress. Despite their high stability, these panels can be easily and unproblematically processed on the construction site.
The PIR rigid foam panels comply with DIN EN 13165, which applies to thermal insulation materials for buildings.