Thermo-Treatment of Wood
State-of-Art Value-Added Technology
The Art of Thermo Modification
Thermo modification of wood is a modern 100% “Green” alternative to pressure treatment of lumber. Thermo treatment uses extremely high temperatures (400 degrees F) and water steam with no chemicals added. The thermo modification cycle includes preliminary drying under water-saturated conditions to reach residual stress relief, heating up to the temperatures of wood treatment (in an oxygen-free environment) exposure to the given temperatures, cooling down with condensation, and moisture saturation of the treated wood. Steam is used to prevent the wood from burning or cracking and creates chemical changes which result in a durable, weather-resistant, and stable wood product. The equilibrium moisture content (EMC) of thermally modified wood products is reduced to 4-6% even outdoors. This process changes the color of lumber to a gold-brown tint that is consistent beyond the surface and creates an exotic wood look. The thermal modification also significantly improves various characteristics of wood such as dimensional stabilization and protection against rot and decay. As a result, this new generation of wood material has a lot of applications indoors and outdoors: decking, siding, fences, landscape design, flooring (especially for high humidity areas), sound barriers for autostradas, outdoor wood furniture, musical instruments, doors, windows, docks areas, boardwalks, and much more.
Several thermo-treating technologies were first used in the mid-1990s in Finland and France. Presently, thermo treatment technology is conquering the world. In the European Union, chemical additives usage in wood protection was prohibited in 2004. In the USA and Canada, no chemical wood protection additives are allowed in such sectors as children's playground production, decks for waterfront homes, and pallets for transportation of foods since 2005. The "Green" alternative to chemically-treated wood is thermally modified wood. The thermo-treatment market has continuously grown in Europe in the last 20 years.
Westwood Thermo Plant in Macon, GA
Our thermo treatment plant in Macon, GA is the biggest in the USA with three thermo modification chambers and a total capacity of about 15 TLs of thermally modified lumber a month. We use our own patented thermo-treatment process, which we developed more than 20 years ago. We own one of five world's patents for wood modification. Westwood technology was specially developed for the treatment of hardwoods (hardwoods create thermochemical reactions at high temperatures and it is more complicated to control them than for treatment of softwoods). The industry of thermo-modification started in Europe in the 1990th. In 2007 Westwood was the first starting production of thermally-modified lumber in the USA.
There are more than 30 thermo treatment plants all around the world and new plants are launched every year. Some of them belong to the Finland Thermowood Association. The diagram shows a consistent growth of Thermo Wood production of plants belonging to the Thermowood Association in the last two decades.
There are 5 thermo-treatment wood production plants currently in the USA and Canada. The Westwood thermo-modification plant in Macon is the biggest on the North American market.