Friday, February 22, 2008

KEEPING THE HOME FIRES FROM BURNING


KEEPING THE HOME FIRES FROM BURNING


Home Fires
A few years ago while in Topeka, Kansas, I drove past the address where my childhood home once stood. I say, “once stood” because it is only a vacant lot now, with the lonely garage that my father built remaining as the only indication that a house had been there. I understand that the house burned down over a score of years ago--Abe Lincoln would be proud of my word usage--because of a faulty heater. Luckily, the family that lived there then was not at home at the time and was unharmed. On the other hand, perhaps, if they had been at home and been warned of the beginning fire by a fire detection device, they might have been able react fast enough to contact the fire department and save some of their valuable belongings. As it was, they lost everything that was in the house at the time. This brought to mind the safety in my own home, the lives of my family and our many irreplaceable possessions. Am I prepared? Have I done enough to safeguard my home from possible fire? Have I kept Al Gore away from my home?



This type of drama, like the destruction of my childhood home, is enacted many times each year in America, and I am possitive that manmade global warming is not responsible. A home fire is the disaster that a child will be most likely to experience during childhood and some of these may have deadly results. Fire fatality ranks fifth in accidental death in America, and is the primary cause of death for children at home. Twenty-five percent of fire fatalities will result from burns, while seventy percent will die from breathing poisonous gases—carbon monoxide is produced in any fire—or asphyxiation. In 2000, NFPA reports that 368,000 homes burned in America, resulting in 3,420 deaths, 16,975 injuries and $5.5 million in direct property damages. Fortunately, things have been getting better. Home deaths have fallen by 34% since 1980. Statistics gathered between 1994 and 1998 show that half of all fire fatalities happen between 10:00 p.m. and 6:00 a.m. while only a quarter of all fires occur during the same hours.

This suggests that undetected fires are much more likely to cause death. According to the NFPA, smoking was the leading cause of home fire deaths overall—alcohol consumption may also be a contributing factor here. However, during January, February, and December, the peak months for home fires, heating equipment caused as many fires as smoking did. It is noteworthy that fires in homes where smoke alarms had been installed caused only 20% of the home deaths between 1989 and 1998. Of course, in some cases the smoke alarms may not have operated, as they should have, due to faulty maintenance or installation. Also, victims may have been unable to respond to working smoke alarms due to heavy sleeping or unconsciousness due to the abuse of drugs or alcohol. If so, more lives might have been saved through proper smoke alarm installation and maintenance.

Fire Sources
Cooking related fires are the leading cause of home fires. The kitchen is the place where 3 of every 10 fires start. In 1998, cooking accidents resulted in 94,000 fires, 396 deaths, 4,650 injuries, and $419 million in property damages. The leading cause of these cooking fires was unattended cooking.




In the event of a kitchen fire, care must be taken to not panic. Burners on stoves and ovens and hood fans should be turned off immediately. A large lid can be used to smother a small fire and, if a dry-chemical fire extinguisher is not available, a large amount of table salt can be thrown on the fire. Water, which could cause a fire to flare, should never be used to extinguish a grease fire. If clothes catch fire, water may be used to extinguish the fire or the “Stop, Drop, and Roll” method may be used. Clearly, if the fire is not quickly extinguished, the fire department should be called immediately.

While cooking equipment is the leading cause of home fires overall, heating equipment is a close second and is the leading cause of home fires through the winter months and is usually much more deadly. There were 49,200 heating equipment related home fires in 1998, causing 388 deaths, 1,445 injuries, and $515 million in property damages. These fires, like the one that destroyed my childhood home, may have been avoidable if the proper precautions had been taken.

Outdated furnace equipment is a serious fire hazard. A typical gas fueled wall furnace that was often used in small two-bedroom tract homes built in the 1940s and 1950s homes had heated my childhood home. The Fire Protection Handbook describes them as:
…self-contained indirect-fired gas or oil heaters installed in or on the wall. They supply heated air directly to the space to be heated, either by gravity [as in our case] or a fan through grills on openings or boots in the casing by the
manufacturer. The furnaces may be of the direct-vent type or are vent-or-
chimney-connected, depending on the fuel. Limit controls limit outlet air
temperature. The fire problems with recessed wall furnaces [as in our case] are
similar to those encountered with most warm air furnaces.
Wall furnaces like other warm-air heating furnaces can become hot enough to ignite surrounding woodwork or other combustible materials due to inadequate clearances and the lack of efficient limit controls. Such furnaces require proper installation, servicing, and maintenance. Any source of heat has the potential to cause a fire under the right circumstances. Wood and other combustible materials can possibly ignite at temperatures well below their normal ignition temperatures if they are continually exposed to even moderate temperatures.

Seemingly, the most dangerous home heating equipment is space heaters. Of all the heating related fires, devices other than central heating systems cause two of every three. Seventy-five percent of all heating equipment related deaths were caused by space heating equipment. Because of improper use or faulty installation, gas-fueled, kerosene-fueled, and electric space heaters and wood stoves and fireplaces can be very hazardous. Because they have the highest rate of deaths associated to their misuse, portable kerosene heaters are illegal in Massachusetts. Often, fires occur when they are not cleaned regularly, placed too close to combustible materials, or improperly fueled.

Space heaters obviously need space to operate safely. Normally, space heaters need at least three feet clearance from combustible materials and should be turned off when room occupants are sleeping. Portable kerosene heaters may be especially troublesome. They are not typically connected to a chimney and, because of their portability, they are often used in inappropriate places and fueled with inappropriate fuels. Gasoline use in a kerosene heater can produce flammable vapors.

Also responsible for some home heating fires are chimneys for fireplaces and wood burning stoves. According to David S. Johnson, the greatest hazards due to chimneys are: operator error or ignorance; control failure; improper installation; use of a defective appliance; ignition of combustible soot or creosote deposits in the chimney; serious cracks or internal collapse of the masonry; defective construction; and failure to secure joints of factory-built products.

To eliminate such hazards, construction of masonry fireplaces and chimneys must strictly follow building codes and factory-built systems must be installed according to factory specifications and directions, using only approved materials. For example, eighteen inches of air space is typically required between single-wall connector vent or chimney pipes and walls or other combustibles and two inches airspace with insulated chimneys and combustibles. Fireplace screens should always be used and periodic inspections and maintenance of chimneys are also necessary to keep chimneys free of hazards, such as creosote build-up.

Children are the subjects of some very sad fire statistics. Children represent 20% of all fire fatalities. Children are responsible for over 100,000 fires every year of which 20,000 are set in the home. It is estimated that the children themselves set 30% of fires that kill children. Eight hundred children under the age of ten die in-home fires every year. In the home, children will play with lighters, matches, and other ignitable tools while hiding in closets or under beds. Parents should search such hiding places for evidence of fire play and children must be taught that fire is a tool that must not be played with.

Fueling the Flame
If fires do occur due to aforementioned ignition sources, they require combustible materials (fuel) to build and spread the flames. The possible fuels for a home fire are many: wood framing and surfaces of the structure, furniture and furnishings, clothing, and books and paper articles. Wood products in a home, because of their cellulosic content and relatively low moisture content (10 to 12 %), are very combustible if subjected to enough heat for a long enough time. At temperatures between 392 and 536 degrees Fahrenheit, the majority of the water content of wood has been expelled. By the time most wood has been heated to 932 degrees Fahrenheit, a state of ignition has occurred. Some types of wood take longer to ignite than others. Tests show that firs and hemlocks take roughly twice as long to ignite (30.8 minutes) as long leaf pine (14.3 minutes) when subjected to a pilot flame at 356 degrees Fahrenheit. However, at 752 degrees Fahrenheit, all woods tested ignited within 3 to 5 seconds. Obviously, some woods are safer from fire than others, but only under less extreme heat exposure.

Fibers and textiles are the major components in clothing, furniture (apart from wood), and many furnishings. Cotton, a plant fiber, is perhaps the most common natural fiber in use in textile manufacturing and ordinarily ignites at 725 degrees Fahrenheit. Protein based fibers from animals, such as silk and wool, react differently to fire because of their chemical makeup. Wool is more difficult to ignite and burns much slower than cotton. Man-made fibers, either regenerated and reconstituted or synthetic, react still differently. Rayon, a regenerated fiber, chars and burns like cotton, while acetate, a combination of cellulose and acetic acid, melts before burning like thermoplastics such as nylon and polyester.

According to research consultant Salvatore A. Chimes, between 1989 and 1993, 99,600 structure fires were reported in the United States where textiles were the materials that were first ignited, with 1,699 deaths and $974.6 million in property damage. In those fires, 1/3 of the materials were in the form of mattresses, bedding, or pillows. Nearly 18% of the materials first ignited were in the form of clothing and nearly 15% were upholstered furniture. Bedding, clothing, and upholstery were involved in nearly 87% of the deaths and 71% of the property damage. Cotton, rayon, or cotton-polyester blends were types of material first ignited in 57.5% of those fires resulting in 53.7% of the deaths and 50.5% of the property damage. Manufactured fabrics were involved in 36.1% of the fires, 41.7% of the deaths and 43.6% of the property damage. Wool, silk, and other animal fibers were involved in just over 5% of the fires and less than 5% of the deaths and property damages. This would leave one to believe that natural animal fibers are much safer but, obviously, such fibers are possibly not as popular a material for use in mattresses, bedding, pillows, clothing, and upholstery as cotton and the man-made fabrics.

Controlling the Fires
Measures can be taken to reduce the likelihood of a fire spreading quickly, allowing occupants more time to respond positively to home fires. As explained, home furnishings and decorations are often constructed of cellulosic materials and thus very combustible, but can be treated to be fire-retardant or flame-resistant. James R Shaw says that fire-retardation is accomplished by treating materials in a way that reduces thermal buildup by increasing thermal conductivity and dissipating the heat of combustion, by increasing thermal absorption to reduce the amount of heat available for pyrolysis, and/or providing thermal insulation to reduce heat’s access to the material. Fire-retardant treatments are performed in several ways: by chemical change (especially effective with plastics and synthetic fibers); impregnation, soaking materials in a water-based flame retardant solution (effective with wood products); pressure impregnation, replacing air in materials by the flame-retardant solution under pressure (more effective with wood products); and by coating non-absorbent materials with chemicals, altering the surface’s combustibility.

The proper storage of flammable and combustible liquids and good housekeeping are practical ways of reducing fire hazards. Gasoline, kerosene, and other flammable liquids should be kept in metal safety cans out of living quarters where fumes will not accumulate, and away from ignition sources. Clutter in and out of doors can be fire hazards for the home. John T. Higgins’ thoughts about the hazards of poor housekeeping in the workplace also apply to the home:
Poor housekeeping contributes to loss potential by increasing fire and
explosion hazards in several ways:
It provides more places for a fire to start.
1. It creates a greater continuity of combustion, which makes it easier for fire to spread.
2. It provides greater combustible loading for the initial fire to feed on.
3. It creates the potential for flash fire or dust explosions when layers of lint or dust are allowed to accumulate.
4. It allows spills or drips of flammable or combustible liquids to accumulate, which could catch fire (including spontaneous ignition in some cases).
5. When not properly addressed, friction, static, or electrical connections can be sources of ignition.
6. Poorly controlled smoking policies can lead to a source of ignition.
7. It increases the potential for spontaneous combustion.
Care must be taken to eliminate collections of dust and lint, to cleanup spills and accumulation of oil and grease, dispose of rubbish (wasted paper, cardboard, rags, leaves, and empty plastic and metal containers) in proper receptacles. Waste products may need to be segregated. Different chemicals combined in trash receptacles may explode. Tall grass and weeds must be cut short or eliminated along the sides of the home. And smoking and smoking materials should be eliminated or closely monitored in the home.

Fire Detection
However, even with serious efforts to eliminate them through design, maintenance, rigorous housekeeping, and inspections, fire hazards may still go undetected and fires may occur. The next line of defense against fire loss in the home is necessarily fire detection and alarm. With early enough detection, the risk of injury, death, and property damage may be greatly reduced. Thus, we must turn our attention back to smoke alarms.

Smoke detection and alarm systems have been an important tool to save lives during the past half-century. We have had smoke alarm technology since the 1960s and the battery-powered alarms have been available to us since the 1970s. By the mid 1980s, thirty-eight states and municipalities had passed laws requiring smoke alarms to be installed in new and existing homes and residences. By 1995, ninety-three percent of all American homes of all descriptions were equipped with smoke detectors.

A concerted effort in recent years by the National Fire Protection Association and other fire safety-minded organizations to educate people to the effectiveness of smoke alarms in saving lives seems to have paid off. NFPA statistics show that 94% of homes in America have at least one smoke detector and that one half of all deaths occur in the 6% of homes without smoke detectors. But again, in three of every ten fires that happen in homes with smoke detectors, the detectors do not work properly. In most cases they fail to work because of missing or dead batteries.

Heat detectors, according to Wayne D. Moore, are the oldest type of fire detection devices in use, being developed along with sprinkler systems as early as the 1860s. Such systems are designed to both detect and extinguish fires. Heat sensing devices are also employed in fire detection alone, some that are triggered to react at fixed temperatures and others that are triggered by an unusually rapid increase of room temperature. Still other detection systems use both types of temperature-sensing devices to trigger a fire alarm.

However, smoke detectors are the most popular for use in the home and the most effective for saving lives in home fires because of the dangerous effects of smoke on the human body. Many people killed in fires are likely dead or incapacitated because of the effects of smoke long before flames or heat would likely trigger heat or flame sensing devices. Of the deadly effects of smoke, Gordon E. Hartzell writes:
The thermal effects of decomposition or combustion of every combustible
material or product produces a smoke atmosphere that is toxic. In sufficiently high concentrations, these smoke atmospheres present hazardous conditions to exposed humans. Predominant among the hazards are impaired vision due to eye irritation, narcosis from inhalation of asphyxiants, and irritation of the upper and/ or lower respiratory tracts. These effects, often occurring simultaneously in a fire, contribute to the physical incapacitation, loss of motor coordination, faulty judgment, disorientation, restricted vision, and panic. The resulting delay or prevention of escape my lead to the subsequent injury or death from further inhalation of toxic gases and/or the suffering of thermal burns. Survivors from a fire also may experience postexposure pulmonary (lung) complications that can lead to delayed death. When one considers the immediate hazard that smoke presents, smoke detectors seem to be the logical choice for home fire detection.

Fire Suppression
If a fires is detected in time, one may be able to extinguish it, but one must know what to safely do and have the right tools to do it with. Since automatic sprinkler systems may not be practicable in the home, hand-held portable fire extinguishers are a good choice for fighting a fire in its first stages. Portable fire extinguishers are designed for specific types of fire, so it is important know the nature of likely fuels in the home. Fire extinguishers are divided into 4 classes: A, B, C, and D.



Class-A-rated fire extinguishers are designed for ordinary fires fed by wood and other cellulous materials. Water and other aqueous foams or liquids are the agents used in class-A-extinguishers. Class-B-rated extinguishers are designed for flammable liquid fueled fires. Carbon dioxide, dry chemicals, or halogen are the agents used to suppress class-B fires. Class-C-fires are electrical and are suppressed by similar agents as class-B, but water is not used because of the hazard of electrocution. Class-D-fires are combustible metal fires and special dry chemicals are the agents used to suppress them. A safe choice for a portable fire extinguisher in the home is one that is rated for A, B, and C class fires together. Portable fire extinguishers are easy to operate. One must aim at the fire and its fuel, and spray, holding the trigger mechanism open until the fire is extinguished or the suppressing agent is completely spent. If the fire is beyond suppression with a portable fire extinguisher at that point, get out of the home immediately and notify the local fire department. Rely on professionals to do the job.

If such measures had been followed in years past, my childhood home might have still been there when I drove by today. And, if such fire prevention and detection measures are followed more strictly today, we will continue to see reductions in home fires in America with fewer fatalities, injuries, and property damage. And more importantly for me, if I am diligent in my own efforts to make my own home safer, by eliminating fire hazards: keeping an orderly home; storing flammable liquids and combustible materials properly; replacing old furniture, old furnishings, and worn siding and shingles with furniture and materials treated with fire retardants; inspecting and maintaining our fire places and chimneys properly; testing and maintaining our smoke detectors properly; and having an effective fire escape plan for my family, I will be much less likely to drive—if, I am alive and able to drive—by my current address on some future date and find an empty space where my home had been. I will, in essence, be helping to keep the home fires from burning.


References

Chobin, Salvatore A., “Fibers and Textiles,” Fire Protection Handbook,18th ed.
Quincy, Massachusetts, National Fire Association, 1997.

Chobin, John M., “Wood and Wood-based Products,” Fire Protection Handbook,18th ed.
Quincy, Massachusetts, National Fire Association, 1997.

Conroy, Mark T., “Fire Extinguisher Use and Maintenance,” Fire Protection
Handbook,18th ed. Quincy, Massachusetts, National Fire Association, 1997.

Hartzell, Gordon E., “Combustion Products and Their Effects on Life Safety,”
Fire Protection Handbook,18th ed. Quincy, Massachusetts, National Fire Association, 1997.
Higgins, John T., “Housekeeping Practices,” Fire Protection Handbook,18th ed. Quincy,
Massachusetts, National Fire Association, 1997.

Johnson, David S., “Heating Systems and Appliances,” Fire Protection Handbook, 18th ed.
Quincy, Massachusetts, National Fire Association, 1997.

Morse, Wayne D., “Automatic Fire Detectors,” Fire Protection Handbook, 18th ed. Quincy, Massachusetts, National Fire Association, 1997.

Shaw, James R., “Fire-retardant and Flame-resistant Treatments of Cellulosic Materials,”
Fire Protection Handbook, 18th ed. Quincy, Massachusetts, National Fire Association, 1997.

http:ci.lexington.ma.us/Fire/heat.safely.htm

http://www.enid.org/fire/Cooking_Fires.html

http://www.hanford.gov/fire/safety/hm_firefacts.htm

http://www.nfpa.org/Research/NFPASheets/Cooking/cooking.asp

http://www.nfpa.org/Research/NFPAFactsheets/NFPAHomeFireStats/NFPAHome
FireStats.asp
http://www.nfpa.org/Research/NFPAFactsheets/Home_heating_Holiday_safety.asp

http://www.nfpa.org?Research/NFPAFactsSheets/Smoke_Alarms/smoke_alarms.asp

http://www.redcross.org/services/disaster/keepsafe/fire.html

http://www.usfa.fema.gov/public/alarms.cfm

http://www.usfa.fema.gov/public/bedroom.cfm

http://www.usfa.fema.gov/public/curious.cfm

http://www.usfa.fema.gov/public/spaceheaters-mh.cfm

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