Laboratory fire behavior measurements of chaparral crown fire

Abstract

In 2013, there was an estimated 9,900 wildland fires that claimed more than 577,000 acres of land. That same year, about 542 prescribed fires were used to treat 48,554 acres by several agencies in California. Being able to understand fires using laboratory models can better prepare individuals to combat or use fires. Our research focused on chaparral crown fires. Chaparral is a shrub community that blankets 5% of California land. As a result, it becomes key fuel sources for wildfires. By using chaparral to model crown fires, our goal is to develop a model that can be deployed for evacuation planning or firefighting in the event of these fires. Laboratory experiments were conducted at the USDA Forest Service Pacific Southwest Research Station. We utilized a wind tunnel equipped with cameras for visualization, arrays of thermocouples, and an in-house developed MATLAB script to analyze experiments. By controlling wind tunnel velocity, fuel moisture content and fuel geometry, we have quantified the fires by their flame heights, flame velocities and fuel consumption rates. Experiments were conducted inside the wind tunnel, with a raised platform for modeling crown fires. Results showed that wind velocity significantly enhances fire intensity and creates a far more destructive flame relative to one without wind. Also, depending on other variables, torching, incomplete burns, or spotting were observed in our experiments. Finally, results were used to validate a Computational Fluid Dynamics program that simulates fires.

Citation

Sanpakit, C.; Omodan, S.; Weise, D.; Princevac, M. 2015. Laboratory fire behavior measurements of chaparral crown fire. University of California Riverside Undergraduate Research Journal. 9: 123-129