Could this gel protect against wildfires?

The sprayable, silica gel could keep flames at bay for hours

Spotted: The threat of wildfires is increasing as climate change creates hotter, drier conditions, with the global economic damages caused by wildfires last year reaching around $4 billion. Coating gels are one way to protect buildings from fire damage, but existing solutions don’t last long. Researchers at Stanford University want to change that.

At the moment, once a wildfire has taken hold, protective gel layers are sprayed onto buildings to create a gelatinous shell made up of super-absorbent polymers and water, offering a last line of defence against the flames. However, conditions near a wildfire are often so hot and windy that the water in these gels evaporates quickly, causing current gels to lose their protective properties in 45 minutes.
 
The new gel created by a team at Stanford University, including Changxin “Lyla” Dong and Eric Appel, is much longer lasting. Water within their gel offers the first layer of protection (as with current gels), but in addition to a cellulose-based polymer, the new gel also contains silica particles. Even when the water and polymer are burnt away, the silica particles remain and form a robust, insulating silica aerogel.

During tests, the new aerogel protected plywood against fire damage from a blowtorch (which is much hotter than a typical wildfire) for over seven minutes, around five times longer than a commercially available gel that was tested in the same way. Because of its longevity, the new gel could be sprayed onto buildings much further in advance of a wildfire.

The novel gel is stable in storage and is easily applied using existing equipment. It also sticks well to surfaces while required, but can be easily washed off once a fire has passed, with the non-toxic components being safely broken down by soil microbes after use.

Written By: Jessica Wallis