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
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
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
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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