We are excited to announce that the kiln has been installed and has already dried a few charges of thermally modified wood. After a long history of successful use in Europe, this closed-system pressure vessel is the FIRST to be installed in North America. This pressurized closed thermal modification system is important in maintaining a consistent high-quality product.
What Makes a Closed Thermal Modification Different?
Using a simple and accurate control strategy, this system is the only thermally modified system that keeps the wood near hygroscopic equilibrium during the entire treatment cycle. What is hygroscopic equilibrium? Also known in the lumber industry as “EMC”, equilibrium moisture content, is defined as the point where wood stops absorbing moisture from or releasing moisture into the surrounding air. At this point, the wood is said to have reached hygroscopic equilibrium.
For thermally modified wood from a closed system, the resulting wood is at a constant 5% moisture content.
Why is Equilibrium Moisture Content a Big Deal?
For anyone working with wood on a regular basis, EMC is important for a number of reasons. Wood expands and contracts with moisture content depending on the average moisture content of the region where the wood is located. In addition, when wood is exposed to a wet environment, such as exterior applications, wood will cup, warp, and degrade without specific exterior treatments.
How Is A Pressurized Closed System Better for Thermally Modified Wood?
Since the system is closed and pressurized, the system does not allow the wood to go below 5% moisture content. In some other system types the wood is dried to almost 0% and then reabsorbs moisture after the treatment is done. The pressurized system doesn’t allow that fluctuation which reduces the treatment stress on the wood. This allows for a more stable product as a result and reduces the potential for cracking, and splitting.
The pressurized closed system improves the wood’s properties, resulting in increased dimensional stability and increased decay resistance, while creating a chemical-free wood that repels moisture.
Learn more about thermally modified lumber.
Learn more about the history of thermally modified lumber.