Turning Up the Heat: Fires Test Performance of Tall Wood Buildings

Wood buildings provide an array of economic and environmental benefits. Interest in capitalizing on those benefits by constructing mid- to high-rise buildings using cross-laminated timber (CLT) is growing. CLT is made from layers of dried lumber boards stacked in alternating direction at 90-degree angles, glued and pressed to form solid panels. These panels have exceptional strength and stability and can be used as walls, roofs, and floors. Additionally, calculations have shown that a seven-inch floor made of CLT has a fire resistance of two hours.

In order for wood structures to rise above six stories without special building official permission, changes to the International Building Code are needed. It’s a tall order, but researchers from the Forest Service’s Forest Products Laboratory (FPL) recently completed a series of fire tests that will address concerns about fire performance of wood buildings and help take them to new heights. Continue reading

Technology Helps Turn Salvaged Trees into Moneymakers

When insect scourges run rampant through forested ecosystems they can leave behind entire stands of dead and dying trees – especially if that scourge is the spruce budworm. In the Upper Midwest, where the spruce budworm infests forests on a cyclic 30-50 year pattern, forest managers oftentimes use salvaged logs from the dead and dying trees to produce low-value wood products, such as wood pulp, or merely count the dead trees as a loss and leave them standing.

Spruce budworm mortality,
Chequamegon–Nicolet
National Forest, Summer
2014 (Steven Katovich, USDA
Forest Service, Bugwood.org).

But Forest Products Laboratory (FPL) researchers developed ways to evaluate the quality of salvaged wood and sort out the higher-quality wood for production of cross-laminated timber (CLT) – a high-value wood product that can increase forest revenues. “We’re at the point of demonstrating commercially available technologies,” said FPL engineer Robert Ross, “and the idea that we can take high-grade material out [of dead tree stands].” Continue reading

CLT and ‘America’s Forests’: Television Program Highlights Benefits of Sustainable Building

A new public television series focused on maintaining and sustaining healthy forests in America kicked off by exploring cross-laminated timber (CLT) and the future of green building.

In the premiere episode of America’s Forests with Chuck Leavell, music industry giant and tree conservationist Chuck Leavell steps into the world of sustainable construction, as he investigates the innovative possibilities of building with CLT. Continue reading

“Timber Innovation Act” Resurfaces in Congress

A bill promoting the construction of tall wood buildings has been reintroduced to Congress.

CLT offers outstanding structural, thermal, and acoustic performance.

Cross laminated timber makes tall wood buildings possible.

The bipartisan Timber Innovation Act is an effort to spur economic development with new and innovative uses for wood as a building material. The legislation will accelerate the research and development of wood for use in construction projects, focusing on the construction of buildings more than 85 feet tall.

Reaching such great heights requires the use of mass timber products, such as cross laminated timber, or CLT. Researchers here at the Forest Products Laboratory (FPL) have been studying CLT from all angles, including engineering properties, fire and moisture performance, and how they hold up during earthquakes. A quick search of this blog turns up a great reading list on CLT if you’d like to learn more.

U.S. Senator Debbie Stabenow (D-MI), ranking member of the Senate Committee on Agriculture, Nutrition and Forestry, joined Senator Mike Crapo (R-ID) and U.S. Representatives Suzan DelBene (WA-01) and Glenn Thompson (PA-05) to reintroduce the bill.

“Advancing tall wood building construction through the Timber Innovation Act is a win for working families and our environment,” DelBene said. “Technological advancements in cross-laminated timber have made it easier for us to support healthy forests, wildlife habitats and rural economies dependent on forest products. Encouraging the use of green building materials instead of building materials dependent on fossil fuels reduces greenhouse gases creating a cleaner, healthier environment for future generations.”

Blast Testing Shows CLT Can Take the Heat

Here at the Forest Products Laboratory (FPL), we sometimes get a little destructive. We bend and break wood samples of all sizes, and we even shoot lumber out of a cannon at 100 miles per hour.

But explosions? That’s a bit out of our wheelhouse. Not that wood can’t handle it. Particularly when it’s used in engineered products like cross-laminated timber (CLT), which FPL researchers have studied from many angles, including fire performance, use in earthquake-prone regions, and the effects of moisture on CLT.

Recent tests of CLT structures show just how tough this material can be. A series of live blast tests were conducted at Tyndall Air Force Base by WoodWorks in cooperation with the U.S. Forest Service and Softwood Lumber Board.

The specifics of the tests are outlined in this great Woodworking Network article, but if you’re looking for a spoiler, the results were promising, and they “will be used to further expand the use of wood solutions for Department of Defense applications and other blast-resistant construction.”

You can view all the tests at http://bit.ly/2hwVE1g and we posted our favorite below. While not a dramatic view of the explosion itself, this high-speed shot shows the wood panels moving with the force of the blast without being destroyed.

WoodWorks will publish the complete results in 2017.