By Dave Russell
Chimney fires have increased in Jackson County in recent years, and an even more recent spate of the blazes has fire officials concerned.
A chimney is “a vertical channel or pipe that conducts smoke and combustion gases up from a fire or furnace and typically through the roof of a building.”
Sometimes, though, a chimney can ignite and lead to a house fire.
Jackson County has seen an uptick in chimney fires recently, according to Jackson County Fire Marshal Michael Forbis.
“We see an increase anytime we have a cold snap, of course, but lately we have had a rash of them,” he said.
The fires are the result of creosote buildup in the chimney, he said.
When wood is burned, byproducts of that combustion, including creosote and soot, are released up the chimney and can build up.
Creosote is black or brown, can be crusty and flaky, tar-like, drippy and sticky, or shiny and hardened. With each fire creosote can build up, thicken and glaze.
Creosote is corrosive and can damage the flue liner over time, but the danger of fire is the biggest problem.
“Creosote is highly flammable,” Forbis said. “It can ignite with temperatures as low as 451 degrees. Think about the temperature of a fire within a fireplace compared to your stove and what 450 degrees feels like in your stove – it doesn’t take long for a fireplace to reach that temperature when you’ve been burning it for hours and you’re adding fuel to it during the cold winter months.”
“Creosote starts to degrade all the structural components of the chimney,” said Zeb Holland of the Fire Marshal’s office. “And that’s what causes the fires. They get outside of the chimney into the structure of the building.”
“The higher the heat, the quicker it can degrade any of those materials,” Forbis said. “Plus you have to think that, especially in old structures, buildings settle. You add that with the heat and time and mortar moves and cracks and it gets loose because it starts to shrink. And then you have these little spots that filled up with creosote. And when that creosote burns, you know, it’s going to go in the direction where it’s getting oxygen.”
It can also be challenging for firefighters trying to put out chimney fires.
“We make a 360 around the outside of the house,” Holland said. “That’s common practice for any fire. And then if it’s available or we have the opportunity to go inside, we do that and we use what we call a tic, a thermal imaging camera. We can actually use that camera to detect heat within the walls or if we need to in the attic as well.
“We’re not going to spray water on it because that water could crack the chimney, the block or the rock, whatever the chimney is made out of,” Holland said. “So we actually use a dry chemical that we call dry chem. It’s similar to the substance in a fire extinguisher. Often we put it in a plastic bag, like a Ziploc bag, and then we drop that down the chimney.”
“You’re not adding cold water to a hot, hot, hot environment and cracking and cool and everything,” Forbis said. “So basically what happens is that our plastic bag melts and the dry chem goes down the chimney.”
According to the Chimney Safety Institute Of America, blockages caused by birds’ nests and other debris can also cause a chimney fire. An uncapped chimney is a welcoming place for birds, raccoons, squirrels and other critters and their nesting materials, fur, feathers and feces, all of which can cause a chimney blockage and dirty the flue.
Routine inspections and cleanings by a chimney sweep can prevent chimney fires.
A chimney sweeping and inspection cost around $150-$450, the institute said.
A google search on “chimney sweeps near me” revealed five in the immediate area and many more around Asheville.
