Batteries and Pyrolysis: Two Stealthy Causes of Structure Fires
A few weeks ago a large home burned beyond repair in a highly preventable fire. The homeowners had changed the batteries in their smoke detectors and placed the old batteries in a recycling bag in their garage. At some point two of the 9-volt batteries in the bag shifted so that the battery terminals touched; as a result, a fire started and engulfed the home. The homeowners had been unaware of the dangers posed by the batteries. A simple way to diffuse the potential danger of discarded 9-volt batteries is to place duct tape over the terminals. Another danger that causes many structural fires every year that many people are completely unaware of is pyrolysis. Anyone with a solid-fuel burning appliance, such as a fireplace or wood stove, should especially understand the potential threat of pyrolysis.
When combustible objects are placed too close to a heat source at temperatures of 212°F or more for a long period of time, a chemical breakdown called pyrolysis can occur. Pyrolysis is a major cause of fires throughout North America. Every year many tragedies and fires are caused by pyrolysis and yet most people don’t know what it is or the importance of preventing it. Understanding the potential presence of the threat is where prevention of this little-known danger begins.
Materials break down chemically as they dry out due to exposure to extreme heat. Eventually they will ignite, and a direct flame is not required for the fire to start. All that is required for pyrolysis to occur is heat and oxygen.
Genevieve Bures is a former chimney sweep and fire investigator in Rocky River, Ohio, who has studied and sifted through ashes of many fire-damaged buildings. She says that of all the solid fuel-related fires she has investigated are caused by pyrolysis over 85% of the time. About 10% of the fires she has investigated were caused by improper maintenance of the connector, appliance, pipe, or chimney. Another 5% of the fires have been caused by careless or improper maintenance of heating systems.
What Causes Pyrolysis?
Pyrolysis is practically an inevitable event when fireplaces, fireplace inserts, solid-fuel stoves and furnaces are installed improperly. The tragedies resulting from pyrolysis are completely preventable. All that needs to be done is to ensure that the amount of space between a wood-burning stove, stovepipe, and other heating appliances is at least the minimum recommended by the manufacturer.
It is common for unprotected furnishings, walls, and other combustible structural components to be placed too closely to heat sources. Because everything seems fine for months or even years, homeowners fail to realize that the process of pyrolysis is occurring and could unexpectedly result in a fire at any time.
Pyrolysis is also caused by a damaged chimney liner. Even the smallest amount of deterioration in the chimney liner can cause nearby combustibles to catch fire.
How is Pyrolysis Prevented?
The best way to protect your home from pyrolysis is to have a professional chimney sweep install heating appliances. Certified sweeps understand the dangers of pyrolysis and are careful to install appliances according to manufacturer’s instructions.
Identifying damage in the chimney liner typically requires the help of a professional chimney technician. Without an expert eye or the equipment which provides a close view of the chimney lining, a damaged liner can go undetected, which can lead to a chimney fire and ultimately a deadly house fire.
Contact our chimney sweeps today to schedule a chimney inspection and cleaning and for help determining whether pyrolysis may be a threat in your home.
Northeastern Chimney, Inc
37 Cody Street, West Hartford, CT 06110