Treatability of different wood types

The treatability of the various wood types has an important role to play, particularly for the impregnation of timbers in the vacuum pressure process or the double vacuum process. Depending on the treatability of the particular wood type, the treatment parameters are selected to ensure the wood receives optimum protection from the process.
In the EN 350-2 standard "Natural Durability of Solid Wood", the treatability of the various wood types is also listed. There are altogether 4 treatability classes:

In the vacuum pressure process, mainly coniferous wood types are treated, some of which have very different treatability levels.