Wood can never achieve Euro class A1 or A2 because wood is an organic combustible material. There are operators who claim to be able to do so, but this is untrue.
The highest classification wood can achieve is euro class B with additional index -s1 and -d0 written as B-s1, d0. Product with performance C-s2, d0 is lower performance than Euroclass B, but higher than the wood's own performance, which is D-s2, d0 (CWFT). Certain wood processing processes for enhanced durability can cause deterioration of fire-resistant properties in the wood, which may result in the wood falling within the framework to Euroclass F.
EURO CLASS B is the highest performance wood can achieve, with additional index -s1, s2, s3 and -d0, d1, d2. The highest grade of wood is B-s1, d0. Index values -s, and -d are additions that indicate the production of a little or a lot of smoke as well as the presence of burning particles and droplets. In terms of s-values, s1 is the lowest smoke development and is always provided indoors. It is important to check whether the product's performance includes an air gap or just installation on the substrate.
EURO CLASS C: Building regulations provide for this mainly in smaller rooms, with a small number of people in the premises, private housing and in walls in combination with sprinklers.
EURO CLASS D: The wood's own natural performance i.e. reaction to fire according to CWFT.
EURO CLASS F: This performance is worse than natural wood, and in principle, it cannot be used where fire technology requirements are imposed. Certain processing processes against durability generate higher FIGRA than the wood itself generates, such as Euroclass D, and thus the performance of the product can deteriorate to be classified according to Euroclass F.