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Researchers are developing a gel-like fluid to prevent wildfires



Stanford researchers have developed a gel-like fluid to prevent wildfires

Under CalFire's supervision, the researchers performed test burns on a grassy roadside area near San Luis Obispo, California, to gauge the effect of a fire-retarding hydrogel. The images above show untreated (left) and treated (right) plots shortly after fire ignition. Credit: Eric Appel

A preventive treatment developed by Stanford researchers could greatly reduce the incidence and severity of wildfires. The approach, outlined Sept. 30 in Proceedings of the National Academy of Sciences, involving an environmentally benign gel-like fluid that helps common wildland fire retardants last longer on vegetation.


Applied to ignition-prone areas, these materials retain their ability to prevent fires during peak fire season, even after weathering that would sweep away conventional fire retardants. By stopping fires from starting, such treatments can be more effective and less expensive than current firefighting methods.

"This has the potential to make wildland firefighting much more proactive, rather than reactive," said Eric Appel, a senior study author and an assistant professor of materials science and engineering. "What we do now is monitor wildfire-prone areas and wait with bated breath for fires to start, then rush to put them out."

A century of fire suppression plus hotter, drier weather has intensified the destructive power of wildfires and lengthened the threatening season. While the 2019 season has been relatively calm in the West so far, the past two years have brought four of the 20 largest and eight of the 20 most destructive wildfires in California's history. Across the country, federal firefighting costs in 2018 came to more than $ 3 billion — the highest total ever.

Long lasting, environmentally benign

Wildfires are a critical part of some ecosystems, but the vast majority in the U.S. are human-caused. Many of them originate in the same hotspots, such as roadsides, campgrounds and remote electrical lines, time after time. Treating these areas prophylactically could provide a highly targeted approach to wildfire prevention, but until now, long-lasting and environmentally benign materials have not been available.

Aside from clearing and burning potential fuels, wildfire management generally revolves around fire suppressants and retardants, with many suppressants used as short-term retardants. To combat active fires, crews use suppressants, such as gels that carry water and superabsorbent polymers found in diapers. These gels are often used as short-term retardants on buildings in the encroaching way, but they lose their effectiveness once the water enters them evaporates — something that often occurs in less than an hour during normal wildland fire conditions.

The most widely used commercial wildland fire retardant formulations use ammonium phosphate or its derivatives as the active fire-retarding component. However, these formulations only hold retardants on vegetation for short periods of time, so they cannot be used preventively. By contrast, the Stanford-developed technology — a cellulose-based gel-like fluid — stays on target vegetation through wind, rain and other environmental exposure.

"You can put 20,000 gallons of this on an area to prevent, or 1 million gallons of traditional formulation after a fire starts," said study lead author Anthony Yu, a Ph.D. student in materials science and engineering at Stanford.

Complete fire prevention

Researchers have worked with the California Department of Forestry and Fire Protection (CalFire) to test the retardant materials on grass and chamber — two vegetation types where fire often begins. They find the treatment provides complete fire protection even after half an inch of rainfall. Under the same conditions, a typical commercial retardant formulation provides little or no fire protection. The researchers are now working with the California Department of Transportation and CalFire to test the material on high-risk roadside areas that are the origin of dozens of wildfires each year.

"We don't have a tool that's comparable to this," said Alan Peters, a CalFire division chief in San Luis Obispo who monitors some of the test burns. "It has the potential to definitely reduce the number of fires."

The Stanford-developed treatment contains only nontoxic starting materials widely used in food, drug, cosmetic and agricultural products. The unique properties of these gel-like retardant fluids allow them to be applied using standard agricultural spraying equipment or from aircraft. While it washes away slowly, providing the ability to protect treated areas against fire for months, the materials eventually degrade.

"We hope these new materials can open the door to identifying and treating high-risk areas to protect people's lives and livelihoods," said Appel.


Most California wildfire is in the wildland-urban interface area with less fuel, more people


More information:
Anthony C. Yu el al., "Wildfire prevention through prophylactic treatment of high-risk landscapes using viscoelastic retardant fluids," PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1907855116

Provided by
Stanford University

Citation:
                                                 Researchers develop gel-like fluid to prevent wildfires (2019, September 30)
                                                 retrieved 30 September 2019
                                                 from https://phys.org/news/2019-09-gel-like-fluid-wildfires.html

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