Understanding wildfire spread
With a wall of fans six-stories high creating winds in a huge, one-of-a-kind laboratory, researchers from UNC Charlotte’s Fire Safety Engineering Technology program and the Insurance Institute for Business and Home Safety (IBHS) are burning building materials and wildland vegetation to study wind-driven wildfire embers. These large-scale tests are part of three-year study to understand, and in the long run mitigate, the risks involved when embers from wildfires spread.
Sponsored by the Joint Fire Science Program (JFSP), the $420,000 “Fire Ember Production from Wildland and Structural Fuels” project brings together researchers from seven institutions. Aixi Zhou, an associate professor in the Fire Safety Engineering Technology Department in the Lee College of Engineering, is the principal investigator on the project.
“The project addresses the emerging problems we face as a nation with wildfire,” Zhou said. “Human safety and property damage risks are increasing as development continues to get closer and closer to wildland areas. The number of wildfires is also increasing, as warmer temperatures and drought conditions are leading to more fires such as those in the North Carolina and Tennessee mountains in fall 2016.”
The JFSP project aims to gain a better understanding of the embers produced during a wildfire and to characterize them based on size and mass. The research includes small-scale laboratory ignition tests and large-scale tests where vegetative and structural materials are burned in a wind tunnel.
Partnering researchers on this project include IBHS, the Pacific Southwest Research Station of the U.S. Forest Service, the University of Texas, the University of Maryland, the Fire Protection Research Foundation at the National Fire Protection Association and the JFSP Southern Fire Exchange at the University of Florida.
The project involves testing building materials and vegetation that are native to the participating members’ regions. These include common construction materials used for siding, roofing and fencing. Vegetation includes native trees, shrubs and grasses.
In early 2016, UNC Charlotte researchers did small-scale laboratory tests using a cone calorimeter to determine combustion characteristics and thermogravimetric analysis (TGA) equipment to study the pyrolysis properties of samples. In late 2016, the team began large-scale tests at IBHS’s Research Center in Richburg, South Carolina. “They have the only facility in the U.S. that can do this scale of tests,” Zhou said.
The IBHS Research Center includes a specially designed wind tunnel that is six-stories tall, 145 feet wide and 145 feet long. The test chamber contains a wall of 105 fans, each nearly six feet in diameter and driven by a 350 HP engine.
Steve Quarles, chief scientist for wildfire and durability with IBHS, is a co-investigator on the JFSP project. He has been working with UNC Charlotte fire safety researchers on several projects during the past three years.
“Working at our facility lets the students apply what they are learning in school into a large laboratory situation,” Quarles said. “These tests involve a lot of steps and details, and the students have gotten very comfortable with their tasks. Overall it’s been a good experience for both of us.”
As a nonprofit, member-based organization, IBHS performs research on behalf of its insurance industry members. “This project will ultimately provide members with information that helps them better manage their risks,” Quarles said. The end goal is to learn how to prevent or reduce property damage from wildfires. IBHS issues public safety tips and guidelines on a number of natural-disaster risks, including wildfires, to help people understand the steps they can take to protect their homes and businesses.
To perform the research that generates this information, UNC Charlotte has two Ph.D. and one master’s student involved in the project as part of their theses work. Three undergraduates are working as research assistants.
“This type of experience gets the students out in the field to learn,” Zhou said. “Experiential learning is a key to all of our academic programs.”