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Building safetyNew materials to make buildings better, safer

Published 15 June 2017

A new type of construction material, called cross-laminated timber, is currently approved for buildings with up to six stories. Designers would like to use it in taller buildings because it is environmentally sustainable and can speed the construction process. To use it for those taller buildings, the industry needs to understand how the timber would perform during a fire. NIST experiments are measuring the material’s structural performance and the amount of energy the timber contributes to the fire.

When the voice over the intercom announces, “We are clear for ignition,” instead of the deafening roar of a rocket engine, here at the National Fire Research Laboratory (NFRL) in Gaithersburg, Maryland, things stay pretty quiet. 

Inside a 9.1- by 4.6-meter (30- by 15-foot) wood structure furnished like a studio apartment, a firefighter crouches in the corner. He uses a propane torch to light a small gas pilot flame, then leaves to join his colleagues outside, where they will wait…and watch.

The structure sits beside an identical one in the middle of the lab’s massive high-bay. The bay’s precisely engineered floor measures 18 by 27 meters (60 by 90 feet), and its ceiling disappears into shadow more than 12 meters (41 feet) above. What appears to be a giant canvas tent suspended from the ceiling is actually an exhaust hood, ready to guide smoke and gases from the fire into an environmental control system that will scrub toxins from the air before it’s released outside.

“Once the data and video start recording and everyone is in place, I get calm,” says fire scientist Matt Bundy, the NFRL’s director of operations. “All the preparation is done; all the decisions have been made. I am certainly more nervous, more stressed about the whole thing, the day before and the hours leading up.”

The lead-up to a test like this can take years. NIST says that the NFRL, which is part of the National Institute of Standards and Technology (NIST), got involved in this project in 2016, but the National Research Council Canada (link is external)and its partners at the Fire Protection Research Foundation (link is external)had spent the preceding two years preparing for it. The entire experiment—which involves the construction and burning of six identically furnished rooms over the course of eight weeks—focuses on determining how a new type of construction behaves in a fire. 

Called cross-laminated timber, this type of construction material is currently approved for buildings with up to six stories. Designers would like to use it in taller buildings because it is environmentally sustainable and can speed the construction process. To use it for those taller buildings, the industry needs to understand how the timber would perform during a fire, so these experiments are measuring its structural performance and the amount of energy the timber contributes to the fire.