Coupled Processes of Structure Ignition, Burning, Collapse, and Fire Spread in Wildland–Urban Interface Fires
Dr. Shuna Ni is an Assistant Professor of Fire Protection Engineering at the University of Maryland, College Park.
Abstract: Wildland–urban interface (WUI) fires increasingly threaten communities, yet the coupled processes governing structure ignition, burning, collapse, and subsequent fire spread remain insufficiently understood. This study integrates numerical simulation and experimental investigation to elucidate these interactions. Using the NIST Fire Dynamics Simulator (FDS), the burning of a two-story source structure and the ignition of an adjacent target structure during the 2023 Lahaina fire were simulated. The results demonstrate that wind direction and vegetation have a strong influence on inter-structure fire spread and ignition timing. Complementary fire tests on small-scale timber structures examined how external fire exposure, structure configurations, and compartment openings affect fire development and spread, structure collapse behavior, and its feedback on fire dynamics. Different collapse modes were observed, and structure collapse was found to intensify burning and generate large quantities of embers, promoting further fire spread in WUI environments. Collectively, the modeling and experimental results highlight the interconnected processes of structure ignition, burning, collapse, collapse-induced fire intensification, and structure-to-structure fire spread, providing essential insights for performance-based design and fire resilience in WUI communities.
About: Dr. Shuna Ni is an Assistant Professor of Fire Protection Engineering at the University of Maryland, College Park. Ni’s research focuses on fire forensics, fire resilience of wildland-urban interface communities, structural fire engineering, impact of fire on civil infrastructure, and fire safety of tall mass- timber buildings. Her research has been funded by the National Science Foundation, National Institute of Justice, Fire Protection Research Foundation, University Transportation Centers, BLM-National Interagency Fire Center, Grand Challenges Grants Program at the University of Maryland, and industrial partners such as FM.