Anthony C. Yu, Hector Lopez Hernandez, Andrew H. Kim, Lyndsay M. Stapleton, Ruben J. Brand, Eric T. Mellor, Cameron P. Bauer, Gregory D. McCurdy, Albert J. Wolff, Doreen Chan, Craig S. Criddle, Jesse D. Acosta, Eric A. Appel
Proceedings of the National Academy of Sciences Sep 2019, 201907855; DOI: 10.1073/pnas.1907855116
Despite strong fire prevention efforts, every year wildfires destroy millions of acres of forest. While fires are necessary for a healthy forest ecology, the vast majority are human-caused and occur in high-risk areas such as roadsides and utilities infrastructure. Yet, retardant-based treatments to prevent ignitions at the source are currently impossible with existing technologies, which are only suited for reactive fire prevention approaches. Here we develop a viscoelastic carrier fluid for existing fire retardants to enhance retention on common wildfire-prone vegetation through environmental exposure and weathering. These materials enable a prophylactic wildfire prevention strategy, where areas at high risk of wildfire can be treated and protected from ignitions throughout the peak fire season.
Polyphosphate fire retardants are a critical tactical resource for fighting fires in the wildland and in the wildland–urban interface. Yet, application of these retardants is limited to emergency suppression strategies because current formulations cannot retain fire retardants on target vegetation for extended periods of time through environmental exposure and weathering. New retardant formulations with persistent retention to target vegetation throughout the peak fire season would enable methodical, prophylactic treatment strategies of landscapes at high risk of wildfires through prolonged prevention of ignition and continual impediment to active flaming fronts. Here we develop a sprayable, environmentally benign viscoelastic fluid comprising biopolymers and colloidal silica to enhance adherence and retention of polyphosphate retardants on common wildfire-prone vegetation. These viscoelastic fluids exhibit appropriate wetting and rheological responses to enable robust retardant adherence to vegetation following spray application. Further, laboratory and pilot-scale burn studies establish that these materials drastically reduce ignition probability before and after simulated weathering events. Overall, these studies demonstrate how these materials actualize opportunities to shift the approach of retardant-based wildfire management from reactive suppression to proactive prevention at the source of ignitions.