While you are enjoying the warmth of your fireplace, something far more dangerous may be occurring in the flue: a chimney fire. Chimney fires are more prevalent than many homeowners realize because most happen unbeknownst to them. A chimney fire typically occurs when the high temperature or a hot ember ignites creosote buildup in the flue.
While most chimney fires are relatively small and may go unnoticed, temperatures can reach 2,000°F resulting in damage to the flue liner, masonry, and other components. Also, a fire that starts in the chimney could quickly spread to nearby combustible objects and engulf the entire house in flames in less than three minutes. There are more than 50,000 residential fires annually, and excessive creosote in the flue is cited as the primary cause in the majority of incidents, according to the National Fire Protection Association (NFPA) statistics. Moreover, chimney fires result in over $1B in property damage, nearly 1,500 injuries, and over 400 deaths each year.
It is often difficult for homeowners to spot signs of a previous chimney fire, so annual chimney inspections are vital for fire prevention. During an annual inspection, the chimney sweep will look for these signs of a chimney fire and any related damage:
Flue tile cracks: When a fire breaks out in the chimney, interior temperatures can quickly soar and cause the clay flue tiles to crack or burst. The cracked tiles reduce the flue liner’s integrity, risking fire spreading to other areas of the home. It can also increase exposure to carbon monoxide fumes.
Masonry cracks: A chimney fire can also cause cracks in bricks and mortar. Depending on where it occurs, you may notice burnt brick pieces on the ground. Masonry cracks will also allow water to seep inside, where it will cause even more damage to the chimney. It can weaken the structure and increase the risk of fire and exposure to carbon monoxide.
Puffy creosote: Creosote is a by-product of combustion that becomes increasingly flammable with age. It typically has a dark, tarry, and charcoal-like texture, but when exposed to extremely high temperatures, it has a puffy or honeycomb appearance indicating that a chimney fire most likely had previously occurred.
Chimney cap damage: The smoke and soot pouring out of the chimney during a fire can cause warping, discoloration, and other heat-related damage to the chimney cap. There may also be smoke or heat damage to the roof or other mounted accessories like a satellite dish, t.v. antenna, or security camera.
Sometimes a chimney fire is mistaken for the sounds of the crackling wood burning in the fireplace. Whenever you are using the fireplace, watch, listen, and smell for these signs that there may be a fire in your chimney:
Watch: for thick, puffy smoke coming out of the chimney.
Listen: for loud popping, whistling, or rumbling noises in the flue.
Smell: a sharp burning smell
If you believe there is a chimney fire in progress, get everyone out of the house safely. Keep your distance from the house and call 9-1-1.
The best way to prevent a chimney fire is to have a Certified Chimney Sweep® inspect and clean your chimney annually. Also, only burn “seasoned” firewood. Its low moisture content will create less creosote.