Resource efficient technology improves performance and appearance of wood.
Cambia by NFP® is a venture formed by Northland Forest Products to manufacture and market thermally modified (TM) lumber as an environmentally responsible choice to tropical hardwoods or petrochemical-based wood alternatives. The thermal modification treatment, which uses high heat in a controlled atmosphere to remove naturally occurring organic compounds in wood that provide a food source for insects or fungi, can be applied to just about any wood, and so exact characteristics will tend to vary by species. Nonetheless, thermal modification is a clean and efficient technology that modifies the cellular structure of the wood, limiting the amount of water that can be absorbed by the wood cells, which significantly increases the dimensional stability of wood.
Founded in 1970, Northland Forest Products is a family-owned, wholesale processor and distributor of quality hardwood lumber, and an industry leader in advocating the use of sustainably-managed forest products. In 1996, Northland Forest Products became the 22nd company in North America to be chain-of-custody certified by the Forest Stewardship Council (FSC). Today, Northland Forest Products is one of the leading suppliers of wood from FSC-certified forests. The company operates two lumber concentration and distribution yards located in Kingston, NH and Troy, VA, and a retail outlet warehouse in Manassas, VA. The Cambia production facilities are located in Kingston, NH.
Wood Made Better: Thermal Modification
Northland Forest Products operates one of the first ovens in the United States to produce thermally modified lumber. The thermal modification process, a clean and energy efficient technology, uses high heat in a controlled atmosphere to improve both the dimensional stability and the decay resistance of wood by permanently altering its chemical and physical properties. By processing wood produced from America's well-managed hardwood forests, Cambia provides an affordable, domestically-sourced, environmentally- friendly alternative to imported hardwoods that often are illegally harvested from endangered tropical rainforests.
The thermal modification process limits the ability of wood to absorb moisture, so Cambia products are more dimensionally stable and less prone to cup, warp and twist with changes in relative humidity. This increase in dimensional stability significantly extends the service life of applied finishes, thereby reducing maintenance costs. The thermal modification process also removes those nutrients in wood that would otherwise provide a food source for insects and wood-destroying fungi. As a result, Cambia products do not contain any toxic chemicals to improve longevity and performance. The thermal modification process also sequesters carbon within the wood, giving Cambia products a rich brown color and appearance; and the uniform coloration of Cambia products rival that of many imported tropical hardwood species.
Thermally modified wood was introduced in Europe in the early 1990's and has since become widely accepted and utilized for both interior and exterior applications. Cambia accepts stains and finishes that have been formulated for non-modified hardwoods as the thermal modification minimizes the difference in early and late wood densities, actually allowing paints and stains to last longer. Thermally modified wood is also extremely durable; the wood is rot and insect resistant, and as there are no toxic chemicals involved, special handling precautions and scrap waste disposal are not issues.
Testing by an independent testing lab placed CambiaTM Yellow Poplar in the highest durability rating class achievable for rot and decay resistance. Currently available in a selection of domestic hardwoods and prefabricated components,Cambia hardwoods are most commonly used for siding, decking, lumber and site furniture.
Main uses
• Exterior Trim, Siding, and Decking
• Window frames, Sashes, Sills
• Interior Flooring
• Interior/Exterior Doors and Cabinetry • Outdoor Furniture
• Docks and Floats
• Hot tub and Spa surrounds • Bench Slats
• Playgrounds
The Green Choice
Cambia wood may be the first truly green lumber resource that performs better and costs less than alternative wood species and substitute products developed to replace wood. A significant percentage (up to 80 percent) of the energy required to thermally transform wood using the Cambia process comes from the wood itself, making the process not only energy-efficient, but also environmentally friendly as no chemicals are used to preserve the wood and no pollutants are emitted to the environment, thereby enabling it to have a low carbon footprint.
Cambia adds value and utility to wood harvested from sustainably managed temperate forests, thereby promoting responsible and sustainable forestry practices. The enhanced performance of Cambia thermally modified wood makes it an environmentally responsible alternative to wood produced from tropical rainforests. Further, Cambia wood scrap is easily disposed of as it can be burned or landfilled without adverse environmental impact. As a testament to its environmental credentials, Cambia products are available with a FSC certification and can qualify for 100 percent valuation under the LEED 'certified wood credit' (MRc7). Cambia is currently available in red oak, poplar, white ash and soft maple lumber.
Working with Cambia
Despite the thermal modification, Cambia wood is still wood. The mechanical and chemical properties unique to each species modified remain roughly the same as before the thermal modification process. As such, Cambia wood can still be worked with all standard woodworking tools, though the use of carbides will definitely extend the life of cutting edges. Sawdust produced from sawing and planing operations is generally finer than that of non-modified wood, possibly requiring better quality dust masks and more frequent cleaning of dust collection systems. In addition, material safety data information for kiln-dried wood remains unchanged by the thermal modification process.
PROPERTIES
Color: The color of thermally modified wood is determined by treatment time and temperature. Color may vary from light brown to a deep roasted brown.
Dimensional Stability: Thermally modified wood significantly reduces the ability of the modified wood to absorb water. This limits the amount of swelling or shrinking associated with non-thermally modified kiln-dried wood.
Density: Thermally modified wood has a slightly lower density than non-thermally modified kiln- dried wood. This is mainly due to the removal of sugars and other non-essential organic compounds during the treatment process.
Permeability: Thermally modified wood is 20-30 percent lower in permeability than that of normal kiln-dried samples.
Thermal Conductivity: Thermally modified wood has a thermal conductivity that is 20-25 percent lower compared to untreated wood.
Resistance to insect attack: Thermally modified wood has no food source for wood- destroying insects. Insects may bore into a piece of thermally modified wood, but will not infest the piece due to the lack of a food source.
Fire Resistance: Thermal modification does not significantly alter resistance to fire.
Biological Durability: Thermally modified wood demonstrates a remarkable ability to resist decay by brown rot. Test results do indicate that thermally modified wood should not be used in ground contact applications where structural performance is required.
Weather Resistance: Thermally modified wood will change color over a period of time from the original brown to a grayish weathered color and may also develop light surface checking when exposed to direct sunlight. The original color and surface integrity may be preserved with pigmented or UV-protective non-toxic coatings.
Leachate: Thermally modified wood is not subject to chemical leaching issues.
Surface Hardness: Thermal modification does not significantly change the surface hardness of wood of the same species.
Bending Strength: Thermally modified wood has a slightly reduced modulus of rupture, though no significant reduction in modulus of elasticity when compared to kiln-dried wood of the same species.
Compression Strength: The thermal modification process has no significant effect on the compression strength values.
Splitting Strength: The thermal modification process can cause some reduction in the splitting strength.
Screw Extraction: The thermal modification process has no significant effect on screw extraction resistance.
© Timber Design & Technology 2012
