Heating Fires In Residential Buildings

Fire Safety Education

Findings:

  • The decline in the incidence of heating fires has been dramatic. Over the past 20 years, the estimated number of residential building heating fires has fallen from 200,000 to 49,000 in 2004.
  • Heating fires are the second leading causes of all residential building fires (behind cooking fires).
  • Confined heating fires, those fires confined to chimneys, flues, fuel boxes, or boilers, account for 86% of residential building heating fires.
  • Heating fires due to electrical failures are more prevalent in multifamily homes than in one and two family residences.
  • Over one quarter of residential building heating fires result from improper maintenance of heating equipment, specifically the failure to clean the equipment.

Between 2002 and 2004, an annual average of 49,100 heating fires occurred in residential buildings and were responsible for an estimated 125 civilian fire deaths, 575 injuries, and $232 million in property loss. The term heating fire applies to those fires that are caused by functioning or malfunctioning central heating units, fixed or portable local heating units, fireplaces, heating stoves, chimneys, and water heaters. This topical report examines the causes and characteristics of heating fires that occur in residential buildings.

Data from the National Fire Incident Reporting System (NFIRS) (2002-2004) show losses from residential building heating fires are lower than those averaged across all building fires. When the small-loss, confined-heating fires are segregated out, the loss per fire non-confined heating and non-confined, non-heating fires is nearly equal; deaths and injuries per thousand fires, however, are slightly higher for non-confined heating fires. For confined heating fires in residential buildings those fires confined to a chimney, chimney flue, fuel burner, or boiler malfunction-the loss per fire is nearly twice that of residential building, nonheating confined fires, while the injury rate is quite small. As deaths are a rare occurrence in confined fires, the death rates across these groupings are minimal and virtually indistinguishable.

LEADING CAUSES OF RESIDENTIAL BUILDING FIRES

Heating (19%) is second only to cooking (47%) as the leading cause of residential building fires. In the last 1970's and early 1980's, heating was actually the leading cause, due to a surge in the use of alternative space heaters and wood heating. This surge was stimulated in large part by an energy shortage and environmental concerns. While the overall number of fires in the Nation has decreased nearly 50% over the past 25 years, the decline in the incidence of heating fires has been dramatic. In 1983, there were nearly 200,000 heating fires; by 2004 that number had fallen to approximately 49,000.

  • Cooking 46.7%
  • Heating 19.1%
  • Incendiary, Suspicious 8.0%
  • Open Flame, Ember, Torch 7.4%
  • Other Heat, Flame, Spark 5.2%

WHEN HEATING FIRES OCCUR

As would be expected, heating fires begin to increase during the fall and continue the increase through the winter. They are most prevalent during the winter months of December through February when the use of central heating systems. portable heaters, and fireplaces is most common. The peak month for residential building heating fires is January, with a decline through the remainder of the winter season and into the early spring. Despite the increased use of heating equipment, heating fires still remain the second leading cause (behind cooking) of residential building fires in the fall and winter months.

Residential building heating fires are lowest in the early hours of the morning. As people awaken to begin daily activities, heating fires increase and hold constant during the morning and midday. As twilight approaches and outside temperatures decrease, heating equipment and systems are used more heavily. Correspondingly, residential building heating fires increase in the late afternoon and peak between 6 p.m. and 8 p.m.

RESIDENTIAL BUILDING HEATING FIRES BY MONTH OF OCCURRENCE

  • JANUARY 20.3%
  • FEBRUARY 15.4%
  • MARCH 11.5%
  • APRIL 6.7%
  • MAY 3.6%
  • JUNE 2.4%
  • JULY 2.1%
  • AUGUST 1.8%
  • SEPTEMBER 2.4%
  • OCTOBER 7.2%
  • NOVEMBER 10.5%
  • DECEMBER 16.2%

WHERE HEATING FIRES OCCUR - TYPE OF RESIDENCE AND TYPE OF INCIDENT

One and two family residences are disproportionately represented in residential building heating fires. Heating fires in one and two family residences account  for 81% of residential building heating fires while only 68% of current U.S. housing stock is single family housing. Mulitfamily dwellings, 32% of the housing stock, account for an additional 15% of these heating fires. That most multifamily dwellings (apartments, condominiums, and the like) have professionally maintained heating systems may account for these differences in fire incidence. The remainder of residential building heating fires (4%) occur in hotels, dormitories, and other miscellaneous residential properties.

Eighty-six percent of residential building heating fires are confined heating. These are fires that are confined to a chimney or flue or are the result of a fuel burner or boiler malfunction and are contained to the fuel burner or boiler. Confined residential building heating fires occur in roughly the same proportion across the major residential property types (86% for one and two family and 87% for mulit-family) but because heating fires in one and two family residences dominate the numbers of fires, these confined fires occur primarily there.

EQUIPMENT INVOLVED IN HEATING FIRES

When small, confined fires are included, chimneys are by far the largest source of residential heating fires, accounting for more than half of these fires (53%). Furnaces, both central heating units and local room units, account for 35% of residential heating fires. When these small fires are excluded, furnace fires are the largest proportion of heating fires.

LEADING EQUIPMENT INVOLVED IN IGNITION OF RESIDENTIAL BUILDING HEATING FIRES

  • FURNACES 19.3%
  • WATER HEATER 15.7%
  • HEATERS 14.0%
  • STOVES, HEATING 12.7%
  • UNSPECIFIED HEATING, VENTILATION, OR AIR CONDITIONING EQUIPMENT 11.1%
  • CHIMNEYS 8.5%
  • FIREPLACES 7.7%

WHAT IS IGNITED?

When specific information is provided, the leading items ignited in heating fires are structural framing, film, residue, including paint and resin; and electrical wire. There are variations, however, depending on the particular heating equipment involved. For example, fires involving heaters are more likely to involve bedding than other heating sources, and masonry chimneys are more likely to involve residues of resin, also known as creosote.

ITEM FIRST IGNITED IN RESIDENTIAL BUILDING HEATING FIRES

  • Structural member or framing 10.2%
  • Film, residue, including paint and resin 9.9%
  • Electrical wire, cable insulation 6.6%

WHY DOES THE FIRE START?

Three factors play a leading role in the ignition of residential building heating fires-Operational Issues, Misuse of the Heating Equipment, Mechanical Failures. Thirty seven percent of residential building heating fires are attributed to some form of operational deficiency. Failure to clean heating equipment (primarily chimneys, fireplaces, and fireplace and heating stoves) accounted for nearly three quarters (73%) of this category, or slightly over a quarter of all residential heating fires (27%). Misuse of heating equipment accounted for an additional 23% of residential heating fires. Placing combustible items too close to the heat source (primarily portable heaters and water heaters) accounted for the majority (71%) of this misuse. Twenty-one percent of residential building heating fires were the result of mechanical failures or malfunctions, over half of which (53%) were unspecified failures or malfunctions.

Approximately one-third of heating fires that specify factors contributing to the ignition of the fire involve some kind of mechanical or electrical failure (31%). The reason for that failure varies, depending on the type of residential property involved in the fire. In both one and two family residences and multifamily residences, 20 to 26 percent of heating fires are due to mechanical problems. (20% for one and two-family; 26% for multifamily). In contrast, electrical problems are more prevalent in multifamily residences (22% versus 8% for one and two family residences.)

CIVILIAN FATALITIES

Heating is the fourth leading cause of overall residential building civilian fire deaths, following arson, smoking, and open flame. When analyzed further, however, heating fires in residential buildings, along with children playing fires, are more likely to have multiple fatalities than other causes of fatal fires. In the case of residential building heating fires, half of these fatal fires occur between midnight and 6 a.m. when the victims were sleeping.

ALTERNATIVE HEAT SOURCES

Some fires are not necessarily coded as heating fires. A deadly phenomenon is that of fires caused when people use alternative sources of heat (such as a stove) to keep warm. This practice may be more common in impoverished areas where people may not be able to afford heating fuel and, instead, rely on space heaters or even open fires to heat their homes. In addition to posing a potential fire hazard, these practices can lead to the accumulation of dangerous carbon monoxide fumes, which are as deadly as fire.

Recent examples of heating fires:

  • October 2006: One man was hospitalized and a mobile home was destroyed in a fire that began in the mobile home's hallway near the furnace. The local fire chief noted that the fire appeared to be accidental and due to a sudden cold snap early in the season. The resident was in bed, asleep, at the time of the fire.
  • February 2005; Firefighters were called to a working chimney fire with embers coming from the chimney and smoke showing from the masonry. It was determined that the fire may have extended between the stove pipe and the inside of the chimney. Firefighters on the exterior worked on containing the chimney fire while the interior crews checked for any extensions and hidden fires.
  • October 2004; An electric space heater placed too close to a mattress, caused a fire that killed a  65 year old man. Arriving at 12:59 a.m. firefighters found a small fire involving a futon mattress. They brought it under control in less than 5 minutes, according to fire officials. The victim had been sleeping in the trailer when the fire broke out.
  • December 2002; Investigators from the State Fire Marshal's Office say an unlimited chimney was the cause of a predawn house fire that took the life of a 47 year old man. Firefighters noted that the unlined chimney had eroded over the years and the heat from a wood-burning stove appeared to have ignited the fire.

CONCLUSION

While declining in numbers, heating fires in residential buildings continue to occur. Many such fires can be prevented through proper maintenance and proper use of heating equipment. With the large percentage of chimney fires currently reported in NFIRS, most occurring due to lack of proper cleaning, the importance of proper maintenance cannot be overstated. Both furnaces and chimneys should be professionally inspected annually and cleaned as necessary. Chimney tar (creosote) build-up  is a common cause of chimney fires.

Other areas in which homeowners can help prevent heating fires:

  • Make sure wood stoves are properly installed, away from combustible surfaces, have the proper floor support, and adequate ventilation.
  • Make sure your space heaters and portable heaters have an emergency tip-over shutoff in case they tip over. Never refill a fueled powered space heater while it is operating or still hot. Refuel outside, away from the house.
  • Use a glass or metal screen in front of your fireplace to prevent sparks igniting nearby carpets or furniture.
  • Never use the range or oven to heat your home.

This information was obtained from the U.S. Fire Administration