Classifications of Thermowood®

Classifications

SWM-WOOD is the only Finnish manufacturer of the Thermowood® able to offer both Thermowood® and Stellac®Wood trademarks to you.

Stellac®Wood product classification is based on the results of process and equipment development carried out at Stellac Oy. Thermowood product classification is based on the research work carried out at VTT Technical Research Centre of Finland. This provides the basis for the introduction of the Thermowood® product classification in 2002 by Lämpöpuuyhdistys ry / Finnish Thermowood Association. Its product classifications are Thermo-D and Thermo-S.

In addition to general product classifications, SWM-WOOD offers its customers customer-specifically tailored thermal modification service matched to meet the requirements of the end-use purpose.

General Thermowood® product categories

Thermo-D

The letter D in Thermo-D comes from the word ‘durability’. In addition to the outward appearance, biological durability is an essential property in regard to the end-use of products belonging to this product category. The average moisture-related dimensional changes of wood belonging to Thermo-D category are 5% – 6% in the tangential direction. ThermoWood® wood belonging to Thermo-D category is classified to be durable in accordance with the standard EN 113, i.e. it belongs to Category 2 in terms of its natural decay resistance.

Thermo-S

The letter S in Thermo-S comes from the word ‘stability’. In addition to the outward appearance, stability is an essential property in regard to the end-use of products belonging to this product category. The average moisture-related dimensional changes of wood belonging to Thermo-S category are 6% – 8 % in the tangential direction. ThermoWood® wood belonging to Thermo-S category is classified to be fairly durable in accordance with the standard EN 113, i.e. it belongs to Category 3 in terms of its natural decay resistance.

Stellac®Wood product classification is based on the results of process and equipment development carried out at Stellac Oy.

Stellac^®wood product categories

Stellac^®Wood D1

This is the most intense treatment category. Wood belonging to this category is classified to be very durable in accordance with the standard EN 113, i.e. it belongs to Category 1 in terms of its natural decay resistance. It should be noted that the treatment applied has affected the strength properties of the wood in such a way that working the wood is more difficult.

Stellac^®Wood D2

Treated with the objective of achieving Category 2 (‘durable’) in decay resistance in accordance with the standard EN 113. This treatment ensures the strength properties required for the wood to be workable. This category of treatment is recommended for applications in which the wood is destined for outdoor use. Spruce wood belonging to the Stellac®Wood Category D2 has been awarded the international KOMO product certificate.

Stellac^®Wood D3

Recommended for applications in which biological durability is not the sole selection criterion.

Stellac^®Wood T4

The foremost property of wood belonging to this category is its reduced moisture-related dimensional changes. Also the colour of wood is distinctly darker than that of untreated wood.

Stellac^®Wood T5

Treatment category in which the objective is to change the colour of the wood. Moisture-related dimensional changes are slightly diminished.

Classifications of Thermowood®