Researchers Study Fire Behavior to Better Understand Mass Timber Buildings

The Bureau of Alcohol, Tobacco, and Firearms (ATF) Fire Research Laboratory in Beltsville, Maryland, tested mass timber fire behavior in October.

The test was the third in the series of four experimental burns that researchers from the USDA Forest Service Forest Products Laboratory, Oregon State University, US Environmental Protection Agency, and ARUP, an engineering consulting firm, designed to study fire behavior in mass timber structures. The results from their project could inform building codes and fire models for multistory buildings made from wood and add to the understanding of smoke, emissions, and char formation.

At the ATF Fire Research Laboratory, the research team designed experiments to see how fire would behave in a building without sprinkler systems, a response from the fire department and other safety checks that exist in real-life scenarios. Testing to failure is important because “if you don’t know the order in which things fail, you don’t know [what] to design for,” said Erica Fischer, a professor at Oregon State University.

Another unique aspect of this experiment is the fuel load, or the combustible materials that are available to burn. Researchers filled three of the compartments with items that you might find in an overcrowded dorm room—furniture, appliances, household chemicals, and stuffed animals. By comparing smoke and emissions from a fully stocked room to one filled with precisely arranged stacks of 2x4s called wood cribs, researchers can get a better idea of what kinds of chemical compounds enter the air when structures burn and any potential public health implications.

Burning full-scale structures in a large fire lab isn’t possible for every study. More frequently, researchers measure emissions, temperature, and other data from much smaller samples of material. Next year, this project will continue with smaller-scale testing at the fire lab at the Forest Products Laboratory. The goal is to better understand the strengths and limitations of scaling fire tests, especially in terms of emissions and fire behavior with different materials.

“What’s really special about this project is you’ve got all these different fields coming together. Each separate analysis that we’re talking about is then going to be combined into [a bigger picture]” said Kara Yedinak, a scientist with the USDA Forest Service Northern Research Station.