By K. Sophie Will
LONDON - As the U.S. state of California struggles through a wildfire season that has forced hundreds of thousands of people to flee and burned hundreds of homes, researchers are seeking ways to protect buildings including by wrapping them in "fire blankets".
Last month, Fumiaki Takahashi, a professor at Case Western Reserve University in Ohio, published the findings of 10 years of research on the potential for sheets of fire-resistant material to preserve homes.
The blankets work but only in certain conditions, he said. "Each fire is different and each house is different," he noted.
The blankets can withstand intensive fire exposure for little more than 10 minutes and take hours or days to apply.
"It's quite the lengthy process and they're very expensive," said Jessica Gardetto, chief of external affairs at the U.S. Bureau of Land Management (BLM). "With what the average homeowner can pick up and do, it would be impractical."
The U.S. Forest Service and the BLM have used fire blankets to protect historic cabins and important buildings for years.
California's fires are being exacerbated by climate change, which is making the fire season longer, drying out forests and increasing the strength of winds, forest experts say.
Dan Hirning, CEO of California-based FireZat Inc, which supplies fire "shields" made from one of the materials tested by Takahashi, said people could wrap their homes in the blankets independent of fire officials.
"It's very practical if they have not been evacuated and do have time to protect their structure, or have any doubt in their mind that the fire crews could protect their structure," he said.
Applying a fire blanket to an average home would take four to five hours, with four people working on it, he noted. One reusable roll of FireZat's material can cover 1,500 square feet (about 140 square metres) and costs close to $900.
The shields are made of a flexible aluminium sheet and a fiberglass backing held together by an acrylic adhesive to form a fire barrier built to withstand heat of up to 550 degrees Celsius (1,022 degrees Fahrenheit).
FireZat said it has supplied fire blankets to the U.S. Forest Service and the BLM, as well as hundreds of homeowners.
The blankets work by deflecting heat away from buildings, preventing flammable materials from combusting and acting as a barrier to keep out airborne embers and windswept flames.
But any gaps in the covering could let in fire and hot gas, which may ignite, Takahashi warned.
"Unless you install it properly, it may fail," he added.
There are other ways to prevent buildings catching fire, such as applying foams and gels.
Communities also can adopt the National Fire Protection Association's programme "Firewise", which helps people stop fire from spreading to their homes by encouraging them to clear flammable materials from around the structure.
Removing leaves and other plant debris from roofs, spacing out surrounding trees, and clearing overhanging vegetation are some of the recommended methods.
But the association advises that Firewise is most effective when an entire neighbourhood participates.
Guillermo Rein, a professor of fire science at Imperial College London, welcomed Takahashi's results but said those seeking to use fire blankets "should have exhausted all other possibilities".
"Not many people are adopting Firewise which is very simple," he noted. "Everyone should be thinking about being fire-safe."