Volume 12, Issue 6 - July/August 2011


Advances in Wood
University Research Helps Fenestration Industry Stay Strong
by June Kallestad

A unique research institute at the University of Minnesota Duluth has a group of scientists focused on one thing: supporting the competiveness and success of the wood products industry. And they have a couple of winner ideas on the burner—quite literally—for the fenestration industry.

Cooking Wood
One project is focused on laying the foundation for a thermally modified wood industry—basically “cooking” wood at high temperatures, from 365 degrees Fahrenheit (185 degrees Celsius) to 419 degrees Fahrenheit (215 degrees Celsius), while being protected by steam, making it more stable, durable and rot-resistant, according to researchers. This treatment allows any wood (for example, aspen, red pine or birch) to be used for door and window manufacturing. A grant from the USDA Forest Service’s Wood Education Resource Center is funding their research on the mechanical, physical and chemical properties of the thermally modified wood.

“We conducted a pretty elaborate experiment and got a lot of really, really good data,” says Pat Donahue, director of the Market Oriented Wood Technology program at the Natural Resources Research Institute (NRRI). “We’re not quite done yet.

We still have to do the biological degradation testing.”

Donahue and his team think the thermally modified wood technology, which has been used for decades in Finland, can offer door and window manufacturers new sources of local wood supply, and can positive
ly impact their bottom lines. In fact, international door and window manufacturers (including Timba Windows in Australia and Thermo Wood Windows and Doors in Poland) have used the technology with great success.

Researchers point to the fact that Finnish saunas often are made of thermally modified aspen and that this works for doors and windows as well. Extensive research in Finland by VTT Technical Research Centre and the Institute of Environmental Technology resulted in an industrial-scale heat-treatment process called ThermoWood®. NRRI is helping two regional businesses get started with this technology. Wolf Wood Inc. in Spooner, Wis., is going to treat the wood and make door and window components. Superior ThermoWood® in Palisade, Minn., is going to make thermally modified lumber for a variety of uses.

“I believe this is a really great technology strategy to utilize more regional woods,” says Donahue. “We can use hardwoods or softwoods, and there’s a lot of potential in ash because of the wood available from the Emerald Ash Borer infestation.”

Donahue is also working with Mathew Leitch, a wood products professor at Lakehead University in Ontario, Canada, to develop a North American Thermally Modified Wood Standard Protocol. The two researchers are seeking funding from both countries.

“Right now there are a number of different manufacturers who make the ovens, with a number of different processes and ‘recipes’ for using the wood for different purposes,” Donahue says. “At this point, it’s not well-documented what that means to the manufacturer or its end-use. We’re trying to address that need.”

NRRI’s second fenestration industry project is focused on using two readily available industrial waste resources to make fire-resistant door cores, stiles and rails.

Researcher Matt Aro began working in 2004 to find a large-scale, practical application for paper mill waste residue that would fill a real need. Today, Aro has a concept ready for commercial partnership to move the idea from bench-scale testing to commercialization.

The mill residue is mixed with fly ash, a byproduct of coal-burning power plants, held together with a magnesium-based, inorganic binder that produces a very stable, chemical bond that’s very rigid and solid. The composite material has been fire-tested and found to exhibit very good fire-resistant properties. At this point, Aro is searching for a company with whom he can partner so the recycled materials can be manufactured to door industry standards. Door companies that are near paper mills would have an obvious advantage: close access to the residue. Depending on the size, a paper mill can produce as much as 150 tons of waste per day and they have to pay to get rid of it. Fly ash also is an abundant resource. NRRI is working in partnership with the Wisconsin Business Innovation Corporation on this research, funded by the EPA.

“We believe this can be cost-effective and, of course, could be marketed as a green product,” says Aro. “It wouldn’t take a lot of capital expenditure to get started—some mixers, molds and an oven. We just need someone from the industry to help us target the product more specifically to their needs.”

Both the fire door cores and the thermally modified wood projects help the Natural Resources Research Institute meet their mission to foster the economic development of Minnesota’s natural resources in an environmentally sound manner to promote private sector employment.

June Kallestad is public relations manager for UMD Natural Resources Research Institute in Duluth, Minn.


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