New Regulation EN 17619:2021

New Regulation EN 17619:2021

Classification of Wood-to-Wood Adhesives for External Use

The recent introduction of regulation EN 17619:2021 has brought significant changes to the classification of wood-to-wood adhesives for non-structural applications in external environments. This regulation defines three new durability classes for external use, known as XT5, XT6, and XT7, aimed at providing a more detailed classification for products that surpass the requirements of the previous standard D4.

The main objective of this new directive is to fill a regulatory gap in the sector of wood adhesives intended for external use. In fact, to ensure the long-term resistance of the bonded joint under specific environmental conditions, a wide range of application technologies is often employed. These include non-structural thermoplastic adhesives and various types of thermosetting adhesives.

The three durability classes defined by the regulation are as follows:

  • XT5: External applications with limited exposure to atmospheric agents, where the bonded wood is protected by coatings or shelters.
  • XT6: External applications with occasional but not persistent exposure to atmospheric agents.
  • XT7: External applications with frequent exposure to atmospheric agents but not in contact with the ground (terraces, playground equipment, etc.).

The new regulation imposes much more stringent conditioning cycles compared to the previous standard D4:

24h in boiling water 6h in boiling water
1h in water at 20°C 2h at 20°C
1h in an oven at 110°C 4 days in water at 20°C

At CATAS, an accredited laboratory specializing in testing and analysis, the test on the two-component product Nunivil 270 was successfully conducted, meeting the rigorous requirements of class XT6 according to the new regulation.

For more information on the new regulation and Nunivil 270, please contact us at