New exterior coatings for wood with permanent flame retardancy

30. November 2020

Thanks to its characteristics, wood can principally be used in almost all areas of construction.

However, there are still obstacles that prevent the increased use of wood in the building industry. For buildings higher than seven metres, low flammability is one of the minimum requirements for façade claddings. There are currently no processing technologies or approaches for wooden façades to make cladding material permanently fire retardant. In outdoor applications, such as façades, it must by all means be taken into consideration that the effectiveness of treatment is quite drastically reduced by weather exposure. But as façade systems remain in buildings for decades, the robustness of fire protection measures with regard to outdoor impacts, such as weather and damage, is of high importance.

Hence, the aim of a new research project at the IHD is to develop defined Fire Retardant Treatment (FRT) procedures, for enhancing wood products to become permanently low flammable construction materials in weather-exposed applications in civil engineering.

Thereby, reaction to fire is always influenced by the total setup, i.e. the complete system arrangement, and needs to be duly and compulsorily tested as a building product in its new state.

Therefore, proof of durability of behaviour when exposed to fire acc. to DIN EN 16755:2017 needs to be newly taken into account for FRT wood-based products after applying weathering procedures. Based on investigations on the surface-stable, washout-resistance combination of the required system components (wood substrates, FR impregnations, FR coatings, protective coatings), in application-related variants, functional systems of permanent low flammability shall be found.

The project results shall substantially contribute to satisfying the rising material requirements, especially those of safety relevance. Surface materials made from the renewable source material wood shall be made fit in a multistep development process as cladding material in outdoor civil engineering applications of permanent flame retardancy, expressly for façades of buildings.

The project, with the funding code F719001, is co-financed by the German Federal Ministry of Food and Agriculture (BMEL) based on a resolution taken by the Deutscher  Bundestag, via the project support agency Fachagentur Nachwachsende Rohstoffe e. V. (FNR) (expert agency for renewable resources, non-profit).

Contact person at the IHD:
Daniel Hafner