From August 2024, all treated wood panels, cladding and other timber products on sale must meet at least the same fire classification as untreated wood. The change follows a revision of an EU regulation adopted in November 2023, which came into force in autumn 2024. The regulation aims to enhance fire-safety in buildings by tightening requirements on the ignition and fire spread of treated timber.
The EU regulation on fire safety requirements for construction products is not new in itself, but its interpretation has been clarified to cover all wood panels and cladding, as well as timber framing. This means that a large proportion of wood products will need to be tested to verify the required fire classification and possibly treated with a fire retardant to meet the new requirements.
The thermal treatment, impregnation or surface treatment of wood by painting, varnishing or coating can affect the fire performance of wood. This is evident if the wood has been treated with oil or acrylic-based coatings in particular, but thermal or other modification of the wood material can also change the fire performance of the wood.
In the past, some wood products could be used without a specific fire classification, but now building projects must ensure that all exposed wooden surfaces meet at least the D-s2, d0 classification (corresponds to untreated wood). This particularly affects exterior and interior cladding, ceiling structures and trim in public and private buildings.
Reijo Ravila, Product Manager at Kiwa Certification Finland, believes that the revised interpretation of the law may change the products on sale.
"Not all combinations of treatments and wood will meet the new requirements. It is possible that manufacturers will have to change either the wood materials, the surface treatment or its layer thickness," he says.
Ensuring safer wooden structures
For construction projects, the change means that more attention will have to be paid to the fire performance of wood materials at the design stage. Architects, structural designers and contractors will have to ensure that the timber products they use meet the requirements and, if necessary, look for prefabricated fire-retardant alternatives.
Nordtreat's technical advisor Pekka Hurri sees the new interpretation of the EU regulation as making timber structures safer.
"I believe that fire safety will become an important criterion for creating value in buildings in the future, alongside energy efficiency and a low carbon footprint."
A large proportion of treated wood products on the market do not meet the D-s2, d0 requirement, so companies will either have to test their products or implement fire-retardant treatments. This is particularly the case for thermally modified, impregnated or surface-treated wood products, for which fire safety must be verified by testing.
Nordtreat's team of experts actively monitors changes in legislation and helps the construction and wood industry to adapt to the new requirements.
Nordtreat offers a wide range of solutions to certify the fire classification of wood products from class D-s2, d0 to the highest Euroclass B-s1, d0. Our flame retardant solutions enable wood products to meet the more stringent requirements while maintaining the natural appearance and properties of wood. Our products are suitable for a wide range of wood products, including exterior cladding, interior panels, CLT and glulam structures and slatted cladding.
NORFLAM® W313 Flame retardant offers an easy and secure solution to meet D-class on thermally modified wood and selected solid wood with a beautiful translucent finish.
