The most destructive fire in Colorado's history began burning through the tinder-dry brush west of Boulder earlier this month and ultimately destroyed more than 170 homes over at least 6,000 acres. Closing my windows tight on the smoke permeating the city, I started asking: What kind of advanced technology do we have to fight fire? And what exactly is in that slurry they douse on fires from airplanes or helicopters?
To be clear, I wasn't in any immediate danger being on the eastern side of town. Those in the Fourmile Canyon wildfire's path, however, suffered terrible loss and heartbreak. Fortunately no one died, but several homes that burned belonged to firefighters, including the home of the volunteer firefighter accused of starting it when embers from the fire pit he had doused repeatedly with water reignited.
With local firefighters converging at the fire, I reached Mike Simons, a firefighter with Metro West Fire in a suburb of Denver. He explained that a key difference between fighting an urban fire and a wildfire is that the approach is not so much about fighting it, but containing it. So when you see water and retardant being dropped during a wildfire, it's not to put out the flames but to make a line where the fire can't pass through.
"There’s certainly technology involved, but bottom line is that it’s a lot of hard work. The basis is taking the fuel away," he told me.
I'll admit that I've always wondered just what's in the slurry doused on wilderness. The exact contents of fire retardants that are either sprayed on trees or dropped from planes are known to the manufacturers, but the USDA has stringent rules for what retardants can contain, and how much testing they have to undergo prior to approval. Foams are mostly water mixed with surfectant, foaming agents and dispersants. Among the unacceptable ingredients for USDA approved foams: polychlorinated biphenols (PCBs), sodium ferrocyanide, and polybrominated diphenyl ethers (PBDEs).
Long-term retardants are mostly water with fertilizer, some other ingredients and an added red that comes from iron oxide. That's the red stuff you'll see being dropped from planes -- the red is so firefighters can see where it went, and the color fades with exposure to light. Gels are sometimes sprayed onto structures, and they mostly contain water with some thickener.
But even the best retardant might not be able to hold the line. "The problem is you get these really high winds and the high heat that evaporates the retardant they’re trying to put down," Simons said. "You might have a four lane highway, but the winds will just push the fire right across it."
In looking for sustainable fire tech, I came across relatively new fire retardant coating that releases water when fire hits it. The patented barrier is called Pyrotite and it's made by the Minnesota-based company International Barrier Technology, Inc., which specializes in fire-resistant building materials. According to CEO Mike Huddy, Pyrotite is a molecule with a crystalline structure that "binds" hydrogen and oxygen molecules in the lumber, releasing water once the wood reaches 475 degrees F. He says that the coating is made entirely of inert, inorganic materials and doesn't contain any hazardous compounds.
Residents in the Fourmile Canyon area are planning on rebuilding, which creates an opportunity to do so in a more sustainable, fire-resistant way. The Boulder Green Building Guild is going to hold an open house in early October so local architects and builders can share their expertise with those who lost homes.
Now when I smell smoke or hear fire engines roaring down the street, I do get a pang. Wildfires have a new meaning. "It’s an unbelievable force," Simons said. "It’s like trying to stop a tornado."
Photo: The Fourmile Canyon wildfire looms above Boulder on September 5. Credit: Zach Dischner.
Tags: Conservation, Emergency Response, Fire Safety, Green Tech, Materials
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