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Windows (and doors) of opportunity

NRRI research helps fenestration industry stay strong

Smoke escapes the top edges of a fire door during testing.

NRRI forest products scientists are focused on one thing: helping the regional wood products industry be competitive and successful. Researchers Pat Donahue and Matt Aro have a couple of winner ideas on the burner — quite literally — for the fenestration industry.

Cooking wood

Donahue’s project is focused on laying the foundation for a thermally-modified wood industry — basically "cooking" wood at high temperatures to make it more stable and durable. This treatment makes any wood — aspen, red pine, birch — useable for window and door manufacturing. A grant from the USDA Forest Service’s Wood Education Resource Center is funding research on the mechanical, physical and chemical properties of the thermally-modified wood.

"This is my opportunity to replace out-of-state species with in-state species," said Pat Donahue, director of the Market Oriented Wood Technology program at the Natural Resources Research Institute (NRRI). "Minnesota’s red pine does not work for the fenestration industry. It has too much pitch. But this process eliminates the pitch and makes the wood decay resistant."

Donahue and his team think the thermally-modified wood technology — used for decades in Finland — can offer window and door manufacturers new sources of local wood supply.

Finnish saunas are often made of thermally modified aspen. 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, Wisc., 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 think thermally modified wood will add to the regional economy more than anything I’ve done at NRRI," said Donahue. "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 Dr. 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 explained. "It’s not well-documented what that means to the manufacturer or it’s end-use."

Fire doors go green

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

Starting in 2004, Aro focused on finding a large-scale, practical application for paper mill waste residue that would fill a real need. Today, he has a concept ready for commercial partnership to move the idea from bench-scale testing to pilot-scale and eventually commercialization.

The residue is mixed with fly ash, a by-product 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 work very well. At this point, Aro needs to find a company partner so that the recycled materials can be manufactured to door industry standards. He thinks there is potential for a door component business to set up shop near a paper mill and be a cost-effective, green product supplier to the door industry.

Door companies that are near paper mills would have an obvious advantage — close access to the residue. Depending on the size of the mill, they can produce as much as 150 tons of waste per day and they have to pay to get rid of it — usually in landfills. Finding an effective use for the residue is in everyone’s best interest. Fly ash is also an abundant resource. NRRI is working in partnership with the Wisconsin Business Innovation Corporation on this research, funded by the Environmental Protection Agency.

"We believe this can be cost-effective and, of course, could be marketed as a ‘green’ product," said 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.