Fire testing completed on full-scale mass timber building

Jul 13, 2017
Mass Timber Fire TestLEESBURG, VA. – Five full-scale mass timber fire tests in a multi-story apartment building have been completed with promising results.

The International Code Council Ad-hoc Committee on Tall Wood Buildings provided the five fire scenarios that were tested in each of the two one-bedroom apartments constructed using mass timber. The test scenarios included various arrangements of exposed and unexposed cross-laminated timber (CLT) with open doors between living and sleeping areas. Additionally, automatic sprinkler systems effectiveness was evaluated.

  • Test 1: a mass timber structure fully protected with gypsum wall board was subjected to a large furnishings and contents fire. The test was terminated after three hours without significant charring on the protected wood surfaces of the structure.
  • Test 2: approximately 30 percent of the CLT ceiling area in the living room and bedroom were left exposed. The test was terminated after four hours, providing additional time to determine if there would be any significant fire contribution from the exposed CLT. Notably, once the furnishings and contents had been consumed by the fire, the exposed CLT essentially self-extinguished due to the formation of char that protected the underlying wood.
  • Test 3: parallel CLT walls were left exposed, one in the living room and one in the bedroom. Similar to Test 2, once the apartment furnishings and contents had been consumed by the fire, during which a protective surface of char formed on the CLT, the mass timber surfaces essentially self-extinguished).
  • Test 4 and 5: examined the effects of sprinkler protection. For both tests, all mass timber surfaces in the living room and bedroom were left exposed. Test 4 demonstrated that under normal operating conditions, a single sprinkler easily contained the fire. For Test 5, the fire was allowed to grow in the compartment for 23 minutes before water was supplied to the sprinklers which quickly controlled the fire.

“The results of these fire tests will continue to be studied and will help inform code change recommendations from the Ad-hoc Committee later this year,” said Stephen J. DiGiovanni, P.E., Ad-hoc Committee Chair and Fire Protection Engineer for the Clark County (NV) Department of Building and Fire Protection. “These tests are an important part of the extensive research data the Committee has reviewed to validate the performance of tall wood buildings.”

The tests were funded in partnership with the U.S. Forest Service’s State and Private Forestry Wood Innovations division and Forest Products Laboratory and the American Wood Council, and were conducted at the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives Fire Research Laboratory. A General Technical Report FPL-GTR-247 on the fire tests will be available from the Forest Products Laboratory in the near future.


The American Wood Council (AWC) is the voice of North American wood products manufacturing, representing over 75 percent of an industry that provides approximately 400,000 men and women in the United States with family-wage jobs. AWC members make products that are essential to everyday life from a renewable resource that absorbs and sequesters carbon. Staff experts develop state-of-the-art engineering data, technology, and standards for wood products to assure their safe and efficient design, as well as provide information on wood design, green building, and environmental regulations. AWC also advocates for balanced government policies that affect wood products. | @woodcouncil

The mission of the U.S. Forest Service, an agency of the U.S. Department of Agriculture, is to sustain the health, diversity and productivity of the nation’s forests and grasslands to meet the needs of present and future generations. The agency manages 193 million acres of public land, provides assistance to state and private landowners and maintains the largest forestry research organization in the world. Public lands the Forest Service manages contribute more than $13 billion to the economy each year through visitor spending alone. Those same lands provide 30 percent of the nation’s surface drinking water to cities and rural communities and approximately 66 million Americans rely on drinking water that originated from the National Forest System. The agency also has either a direct or indirect role in stewardship of about 900 million forested acres within the U.S., of which over 130 million acres are urban forests where most Americans live.

The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) Fire Research Laboratory (FRL) opened in 2003. FRL engineers utilize its unique capabilities and sophisticated instrumentation to assist ATF Special Agent Certified Fire Investigators (SA/CFI) with fire investigations. In addition, FRL engineers work closely with other federal agencies to provide testing services to assist with their research programs or investigations. This one-of-a-kind facility includes state-of-the-art scientific instruments that allow researchers to measure data significant to fire behavior, including heat release rate, burning rate, and smoke production. The facility offers a range of capabilities, from bench-scale fire measurement instruments to a 16,900-square-foot burn room that can accommodate a three-story structure. The Data Acquisition System (DAQ) is capable of collecting over 2,300 channels of data every second. A 16-channel video collection system allows for video to be captured in both Standard Definition (SD) and High Definition (HD). Additional video capabilities include high speed and FLIR thermal imaging cameras.  The facility also features an on-site air and water pollution treatment facilities.