Classes of use for robinia wood
When choosing a wood species, several criteria must be considered according to the according usage. The first criteria is the class of employment. The class of employment or risk class is established by the European standard EN 335-2013. This European Standard defines five risk classes that correspond to the different situations in which wood may be exposed. These classes are summarized in the table below:
According to the European standard, robinia wood is the only European species suitable for uses in risk class 4, "Outdoor use in contact with soil and fresh water, exposed permanently to moisture," just as the tropical species such as iroko and ipe. However, these tropical woods arrive in Europe after traveling thousands of kilometers, which has a harsh impact on the carbon footprint. In addition, the management of some of these forests is not always respected. At the European level, two species try to compete with robinia wood: oak and chestnut. However, these two species are classified in risk class 3; they can be used outside but without contact with soil and permanent humidity.
In terms of natural durability, robinia is rated class 1-2 (very durable to durable) under European standard EN 350:2016, like moabi, teak or ipe (see the table below). In our experience: up to 30 years in the ground without treatment, depending on the soil, and up to 60 years above ground.
Oak and chestnut are rated class 2 (durable); in the ground, our experience gives 10 to 15 years for oak and 15 to 20 years for sweet chestnut.
Wood durability classes (© DIN EN 350-2)
