Aluminum wrap used to protect homes in California wildfires
RENO, NEV.
Martin Diky said he panicked as a huge wildfire started racing down a slope toward his wooden house near Lake Tahoe.
The contractor had enough time to do some quick research and decided to wrap his mountain home with an aluminum protective covering. The material that can withstand intensive heat for short periods resembles tin foil from the kitchen drawer but is modeled after the tent-like shelters that wildland firefighters use as a last resort to protect themselves when trapped by flames.
Diky, who lives most of the time in the San Francisco Bay Area, bought $6,000 worth of wrapping from Firezat Inc. in San Diego, enough to cover his 1,400-square-foot second home on the edge of the small California community of Meyers.
“It’s pretty expensive, and you’d feel stupid if they stopped the fire before it got close,” he said. “But I’m really glad we did it. It was pretty nerve-wracking when the flames came down the slope.”
The flexible aluminum sheets that Diky affixed to his $700,000 home are not widely used because they are pricey and difficult to install, though they have saved some properties, including historic cabins managed by the U.S. government.
Fire crews even wrapped the base of the world’s largest tree this week to protect it from wildfires burning near a famous grove of gigantic oldgrowth sequoias in California’s Sequoia National Park. The colossal General Sherman Tree, some of the other sequoias in the Giant Forest, a museum and some other buildings also were wrapped amid the possibility of intense flames.
It comes after another aluminum-wrapped home near Lake Tahoe survived the Caldor Fire, about 20 miles (32 kilometers) west of Diky’s home, while neighboring houses were destroyed.
The wrapping deflects heat away from buildings, helping prevent flammable materials from combusting. It also keeps airborne embers — a major contributor to spreading wildfires — from slipping through vents and other openings in a home. With a fiberglass backing and acrylic adhesive, the wraps can withstand heat of up to 1,022 degrees Fahrenheit.
Until about a decade ago, most wildfire damage was blamed on homes catching fire as flames burned nearby vegetation. Recent studies suggest a bigger role is structure-to-structure fires that spread in a domino effect because of tremendous heat that causes manufactured materials to burst into flames.
The company where
Diky bought his wraps gets about 95% of its sales from the U.S. Forest Service and National Park Service. Firezat Inc. founding president Dan Hirning estimates the Forest Service has wrapped 600 to 700 buildings, bridges, communication towers and other structures in national forests this year alone.
Firefighters on social media liken the wraps to a “big baked potato.” One who helped install some said he felt like he was “wrapping Christmas presents.”
Forest Service officials say they have been using the wraps for several years throughout the American West to protect sensitive structures. At Lake Tahoe, they have wrapped the Angora Ridge Lookout, a nationally registered historic fire lookout tower, said Phil Heitzke, an agency battalion chief.
“Many times, Forest Service structures are wrapped well in advance of the fire,” he said in a statement. Crews often can then focus on protecting other buildings or other work.
Firezat sells fire shield rolls that are 5 feet (1.5 meters) wide by 200 feet (61 meters) long for about $700 each. Installation by a contractor typically costs thousands of dollars.
“People think we should be selling tons of these things, but it’s not as much as everybody thinks,” Hirning said. Despite the cost, he said a building won’t burn unless “fire falls right on it.”
A mechanical engineering professor at Ohio’s
Case Western Reserve University published 10 years of research about protective wraps in the Frontiers in Mechanical Engineering journal in 2019, saying they “demonstrated both remarkable performance and technical limitations.”
The aluminized surface blocked up to 92% of convective heat and up to 96% of radiation, Fumiaki Takahashi said.
The wrapping is most effective if a wildfire burns past with exposure of less than 10 minutes, he said. It’s less effective in areas with high-density housing, where spreading infernos can burn for hours without being stopped by firefighters.