Wood can never achieve Euroclass A1 or A2 due to being an organic combustible material. There are producers who like to make such claims, but they are mistaken.
The highest classification that wood can achieve is Euroclass B with supplementary indices -s1 and -d0, and it is then registered as B-s1, d0. Euroclass C-s2, d0 (formerly called surface layer class 2) has a lower performance rating than Euroclass B, but higher than the wood's own performance rating, which is D-s2, d0 (CWFT). Certain wood refinement processes for better durability can cause the wood to have deteriorated fireproofing properties, which can result in the product being degraded to Euroclass E.
EUROCLASS B: The highest performance rating for wood. The additional indexes are –s1, s2, s3 and –d0, d1, d2. The highest rating for wood is B-s1, d0. Index values - s, -and - d are additions that indicate smoke development and the presence of burning particles and droplets. When it comes to s-values, - s1 indicates the lowest smoke output and is therefore always prescribed for indoor use.
Note: The smoke class has less significance for outdoor installation; this is reflected in the B-s3, d0 requirements of Norway compared to those of Denmark (B-s1, d0).
EUROCLASS C: Prescribed in building regulations for mainly smaller premises with a small number of people, private housing and for walls that are in some way connected to a sprinkler system.
EUROCLASS D: The natural performance of the wood, i.e. its reaction to fire according to the CWFT.
EUROCLASS F: This performance is inferior to the natural wood, and must not be used when setting reaction to fire requirements. Certain refinement processes aimed at increasing durability generate a higher FIGRA (fire growth rate) than the wood itself, in accordance with Euroclass D, and thus the product's performance can be degraded to Euroclass F.
REMEMBER that each individual tree species must have its own classified performance rating and must be included in a CE approval. A spruce wood product with the performance rating B-s1, d0 cannot be used to verify other types of wood such as pine or birch etc.
- Each individual type of wood must have its own verified performance rating.
- Be sure to check that said performance level is achieved when installing spaced boarding.
- The performance rating(eg B-s1, d0) should include color settings, e.g. coatings, varnishes, etc. This also applies to wood panels painted with fireproofing paint.
- Industrially fire-painted wood is subject to the same requirements as fire-impregnated wood, i.e. CE marking and DoP requirements.
- On-site painted wood cannot be CE marked. Procedural controls are executed through control systems designed by the Nordic Association for Fire retardant treated wood (NBT). Click here.