Impregnation and field of application are crucial for the fire properties of wooden panels

It is significant whether wood is fire-impregnated before or after it is cut into panels. Additionally, the material onto which the panels are mounted is of crucial importance for the fire properties of the panels. This was demonstrated by four comparative SBI fire tests conducted by DBI in collaboration with Burnblock.

B-s1,d0! This is the reaction-to-fire classification typically required to meet fire safety standards for interior and exterior surfaces within the pre-approved solutions – and is often the ticket to market access for building materials.

Wood products, however, are often classified as D-s2,d0 according to EU Commission decisions (CWFT). This means that the wood requires post-treatment, such as fire impregnation, to achieve the B-s1,d0 classification.

Whether the wood is cut into panels before or after fire impregnation is crucial for the fire properties of the panels. Another factor that can significantly affect the test results is the fire properties of the underlying material – for example, an acoustic fabric. Therefore, it is important also to focus on the fire properties of the remaining materials in the construction, in addition to the panels themselves.

The importance of fire impregnation and the fire properties of the underlying material are confirmed by four SBI fire tests (Single Burning Item) conducted by DBI in collaboration with the company Burnblock. The four tests were carried out with identical geometry but with varying fire impregnation and different underlying materials.

The four SBI tests are as follows:

1. B-product: Each wooden panel is impregnated separately, and there is a focus on the fire properties of the underlying material.
2. C-product: Each wooden panel is impregnated separately, but there is no focus on the fire properties of the underlying material.
3. D-product: The wood is impregnated as whole panels and then cut into slats, with a focus on the fire properties of the underlying material.
4. E/F-product: The wood is impregnated as whole panels and then cut into slats, but there is no focus on the fire properties of the underlying material.

The tests show that the best-performing construction is the one where the panels are impregnated individually, with attention to the fire properties of the underlying material (no. 1). Conversely, the worst-performing construction is where the wood is impregnated as whole panels, and the fire properties of the underlying material are arbitrary (no. 4).

Watch a video of four comparative SBI tests

Are you unsure how a B-s1,d0 cladding burns compared to, for example, a D-s1,d0 cladding? Then watch the video showing four SBI tests and the difference between classifications B-E/F:

Read also the article DBI streamlines standard for fire testing of wooden panels