Tuesday, November 22, 2022

How to avoid chimney fires


Chimney fires occur during cold weather months when people use their chimneys. A chimney fire occurs when accumulated creosote in a flue or smoke chamber ignites from a spark.

All wood creates creosote - even dry hardwoods- so it is imperative that flues serving fireplaces or wood-burning stoves, or fireplace inserts are swept regularly to remove this flammable substance. The NFPA recommends sweeping once per year for fireplaces, and at least twice during the season for heating appliances (wood stoves or inserts). A house fire can occur if the fire in the chimney escapes the flue liner or if burning embers fly out of the top of the chimney onto the roof. (Asphalt roofs can catch fire as well as wood shingle roofs). 

Most chimney fires are of short duration and go unnoticed by the homeowner - with damages usually found later during an inspection by a chimney sweep. 
 
Signs of a chimney fire:
  •  Loud whooshing or roaring or freight train like sound
  •  Flames shooting out the top of the chimney
  •  Red glowing stove pipe
  •  Backup of smoke into the house
  • Sudden poor draft

It is a good idea to keep a chimney fire extinguisher near your fireplace or wood stove and use it if you notice a chimney fire, then get out of the house and call the fire department immediately. Fire can spread to nearby combustibles and cause a house fire. Be sure to keep an eye out for smoke smell or flames even after the fire department is gone because interior wood framing could smolder for hours afterwards and ignite if it gets enough oxygen. 
 
Blown out section of tile liner

After the fire:
Call your local professional chimney sweep to have a thorough inspection and any needed repairs completed before using the appliance again. Most chimneys are severely damaged on the interior during a chimney fire and should not be used until inspected by a qualified professional. Any breaks or blown out sections in flue tiles or warped or buckled seams in steel liners or chimneys can be a fire and Carbon Monoxide hazard.

For more information about Carbon Monoxide, visit COHeadquarters.com.

___________________________
The Chimney Lady, Marge Padgitt, is a veteran chimney professional, trainer, and author. She is the co-owner of HearthMasters chimney and fireplace service in Kansas City, Missouri. Contact her at office@chimkc.com.

Utility flue problems can cause carbon monoxide poisoning

Utility flues serving furnaces, water heaters, and boilers are often forgotten and ignored, yet can pose serious hazards for the occupants of the home. Most problems lie with older masonry chimneys with clay tile flue liners, or chimneys without liners. Homeowners are generally not aware that these flues need to be inspected annually as recommended by the National Fire Protection Association 211 Standard, and that professional chimney sweeps maintain these flues. HVAC contractors do not sweep or inspect flues or install replacement flue liners. 


Masonry chimneys deteriorate over time, starting from the interior, due to exposure to rain and acidic flue gasses, which damage mortar and clay tile liners. Over a period of years, this mortar falls and accumulates at the bottom of the flue, sometimes causing large restrictions that can cause carbon monoxide backup. Flue liners have been required by code since 1927, yet many homes built prior to 1950 do not have liners. Flue liners are installed to provide a complete sealed exit for toxic flue gases. They have mortar joints between each two-foot section of tile. But mortar joints that are deteriorated, have holes, or are missing can allow gases to escape the flue liner and enter the living space via a neighboring flue liner serving a fireplace, or through the masonry chimney. 

Masonry chimneys are designed to last for many years as long as they are maintained. However, lack of homeowner education usually results in improperly maintained chimneys and flues, which can be a health hazard to the occupants and cause appliances to work inefficiently. Flue liner size is very important – and must be correct in order for draft to occur. A flue liner that is too large for the appliance may cause backup of gases. This is common in homes where newer, mid-efficiency appliances have been installed which need a smaller liner, and in cases where a high-efficiency furnace is installed and vented through the side of the house, leaving an “abandoned” hot water heater to vent on its own in a flue that is very oversized. 


Carbon monoxide is an odorless, tasteless, colorless gas that is the by-product of incomplete combustion. The current standard for CO alarms is 9 ppm, however, recent testing proves that even very low levels of CO exposure over a long period of time can cause irreversible brain and organ damage. The Environmental Protection Agency states that CO detectors are to be used as a backup and are not a replacement for maintenance of appliances and flues. Even so, the EPA recommends the use of CO detectors placed strategically throughout the house.

Dr. David Penney, author of Carbon Monoxide Toxicity and Professor of Physiology at Wayne State University School of Medicine has devoted years of research to this topic and posts his findings on his website at www.coheadquarters.com. Penney suggests that SIDS may be due to low level CO exposure and that children, the elderly, and pets are more susceptible to its effects. 

According to the Center for Disease Control, 15,000 people visit emergency rooms and 500 people die every year due to CO poisoning. Symptoms of CO poisoning may include flu-like symptoms that go away or lessen after leaving the house, unexplained headaches, nausea, and dizziness; fainting, muscle weakness, inability to wake up, and death. If more than one family member has the same symptoms the EPA recommends visiting a doctor or hospital and mentioning that you suspect CO exposure.

Utility flue safety tips:

       Have the flue checked annually by a Certified Chimney Sweep who will look for clogs caused by bird nests, leaves, debris, dead animals, and mortar or bricks, cracked flue tiles, missing tiles, and missing mortar joints.
       Have a heavy-duty stainless-steel chimney cover installed to keep damaging rain and animals out of the flue.
       Make sure the flue is sized correctly to the appliances
       Never connect another appliance (water heater excepted) to the same flue as a furnace or boiler
       Have the flue examined when changing appliances


According to Gene Padgitt, owner of HearthMasters, Inc. in Kansas City, Missouri, he has encountered numerous utility flue problems over the years, citing that it is a common issue. “People don't think about the inside of their chimney, and it is usually ignored until a chimney sweep finds a problem or someone gets ill,” said Gene. In one example, another chimney sweep broke out flue tiles and left them in the flue, clogging it completely, which made the homeowners very ill for weeks. In another example, over five feet of debris was removed from a boiler flue that had not been maintained for years and had blocked the flue by 90 percent. The clog caused an entire church congregation to become very ill. 

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