Note: Allpar does not take responsibility for the veracity of any information or opinions here, does not claim expertise, may not have verified or performed the fixes, repairs, or modifications, and is not responsible for any consequences. Please proceed at your own risk.
by Bob Ricewasser and Ken McNeil • courtesy of Skinned Knuckles
When your car is on fire it's too late to think, "I wish that I had prepared sooner...." You need a working fire extinguisher, and you need it right now.
This article is about fires: the types, the causes, the options. It is also about fire extinguishers: the types, the differences, the uses. The information that follows comes from the people who know — the firefighters themselves. That should be your very first action at the time of a car fire. Call the professionals. Get on that cell phone and dial 9–1–1. Tell the operator, “FIRE,” give a location with cross streets, if possible, or distinctive landmarks if you can't identify your location. Then, and only then, should you address the fire itself.
Essentially, there are three types of fires that will generally occur in your classic or antique car. The first is known as a type B fire — flammable liquids. These include gasoline, oil, and greases. Next is an electrical fire, a type C. It could be burning wiring or a wiring short that ignited something else in the car. Finally is the type A fire — normal combustibles like paper, wood, or fabric.
Fire extinguishers are identified by the letters as to the type of fire that they are designed to control. Most portable extinguishers are at least type B and C; other also may include type A. These multi-purpose fire extinguishers are designed to put out a (car) fire regardless of which type it is. Frankly, if the car is burning, you don't care initially about what type of fire it is. You want it out! And so, a multi-purpose type A, B & C extinguisher.
What causes a fire and how does a fire extinguisher kill it? Combustion is an intense chemical reaction. Paper or wood, for example, when heated to a certain temperature produce volatile gases which combine with oxygen in the air; the reaction is known as fire.
The Fire Triangle — actually a tetrahedron — represents the four elements that must be present for a fire to exist. There must be oxygen to sustain combustion, heat to raise the material to its ignition temperature, fuel to support the combustion, and a chemical reaction among the other three elements.
We can consider several scenarios for a car fire. In the first case, a muffler or exhaust pipe fitted too close to the wooden flooring in an antique car can easily heat the wood to the point of combustion. In a car in original condition, especially when the wooden floor is 80 years old and is bone dry, the heat only has to reach 500° F to flame.
Over periods of exposure to heat, wood changes to charcoal, which can heat spontaneously, producing fire at much lower temperatures — as low as 212°). If the underside of the wooden floor shows evidence of “charcoaling,” it doesn’t take much to cause combustion with virtually no advance notice.
Next is an all too common scenario: a vacuum tank feeding an updraft carburetor. Perhaps the carburetor is flooded, either through excess cranking or a bad float bowl valve. The raw gas drips (or runs) down the body of the carb and drips onto a hot exhaust pipe. Whoosh!
What about electrical? How about a wire that goes through the firewall where the grommet has dried out and disintegrated. That wire can rub against the edge of the steel firewall, maybe even move back and forth accelerating the wear by movement of the gas linkage or the brake pedal. It finally shorts and the dry insulation and fabric wrapping ignites and there is number three.
This article originally appeared in the April 2006 issue of Skinned Knuckles. Skinned Knuckles is dedicated to the authentic restoration of cars and trucks and to the preservation of vehicles from the brass era through the early 1970s. It is available by subscription only. Articles are copyrighted and all rights reserved. Reprinting authorized by written permission of the publisher only.
Each month Skinned Knuckles is filled with articles and features on the restoration and maintenance of antique and classic automobiles. Many of the articles cover subjects found in no other publication. A one year, 12 issue subscription is only $26 (in the U.S.) Begin your own subscription right now by contacting Skinned Knuckles.
Skinned Knuckles may be reached by telephone at 714-963-1558, by email, and on-line at www.skinnedknuckles.net. Their mailing address is P.O. Box 6983, Huntington Beach, CA 92615
Fire extinguishers are designed to remove one or more of the three necessary elements and so alter the formula and put out the fire. For a Type A fire — paper or wood, for example — water is a more than adequate extinguisher, but only for the Type A fire. The water cools the temperature removing the heat source, and stopping the fire.
One of the most common types of fire extinguishers uses a dry chemical, very often sodium bicarbonate (normal baking soda), potassium bicarbonate (nearly identical to baking soda), or monoammonium phosphate, which blankets the fire, depriving it of oxygen. Further, as the baking soda decomposes at about 158 degrees F., it releases carbon dioxide (CO2) which is a heavier-than-air gas, smothering the flames and depriving them of oxygen. It is effective on small, limited fires, and it is portable (in a metal canister known as a fire extinguisher), but it leaves a mess to be cleaned up later; a small price to pay if it saves your valuable car.
The third type of extinguisher is a gas-filled canister. Generally the most common of these gases is carbon dioxide (CO2) in liquid form. As it hits the air, it warms instantly, becoming the heavy-than-air gas mentioned above, and smothers the flames. CO2 is extremely cold when it changes to a vapor and causes a cloud that can impair the view of the fire or even cause frost-bite if sprayed directly onto exposed skin.
Another gas was the halon family, a liquefied gas, pressurized with nitrogen, which discharged as a vapor causing no cold or static shock and no impairment of the operator's vision. It left no residue and was recommended where a clean environment was desirable, such as under a dash or with a computer-operated ignition system. It cooled the surface and chemically interfered with the combustion process. This nontoxic gas is attracted to heat, moves around barriers, and tracks to a fire. The Halons, though, have been found to be destructive to the atmosphere and are not generally available now.
A new class of gas-extinguisher is the Halotron type. It has most of the same beneficial features of the Halon without the harmful atmospheric qualities. The Halons are a good choice in compressed gas extinguishers; used Halon 1211 and 1301 extinguishers might be available through a commercial fire extinguisher dealer or service center, but getting them recharged after use is going to be difficult. Halotrons (a HydroChloroFluoroCarbon nonconductive agent pressurized with argon) are available new, and recharging services are available. The cost of a Halotron can be considerably more than a comparably sized CO2; in a car fire the carbon dioxide is often more than adequate.
Finally, covering the fire to deprive it of oxygen with sand or a blanket or coat might be effective on a very small fire, but it exposes you to direct flames, and doesn't reach flames which might be hidden from view or getting oxygen from another source. It is not a recommended alternative except in very limited situations.
Fire extinguishers, in addition to having the letters to identify the type of fire for which it is meant, also carry several numbers that precede the letters for type A and B fires. The number indicates the relative extinguishing effectiveness. For a type A extinguisher, the number represents an equivalency to gallons of water. A number 1 represents roughly 1.25 gallons of water, a number 2, about 2.5 gallons of water. For type B fires, the number represents the number of square feet that the extinguisher will handle. A number 2 is 2 square feet, a number 5, 5 square feet, etc. So a 1A5BC rated extinguisher is designed to have about a 1.25 gallon-of-water equivalency and is designed to handle a fire not larger than five square feet.
Why are certain fire extinguishers recommended for certain types of fires? Well, for example, water will not only act as a conductor for electricity but will also spread oil and grease fires. The oil or grease, being lighter than water, float on the surface, and the burning substances can be carried to other areas, thereby spreading rather than controlling the fire. Both dry chemical and gas are non-conductive, and will not spread the fire. (A number of other types of extinguishers are available, but most are too large or too bulky to be portable enough for vehicle use.)
Even the best quality fire extinguishers have a limited life. An advantage of the gauge-type is that there is a visible indication that internal pressure still exists. This is not possible with the inexpensive 'one-shot' extinguishers.
In California, regulations are mandated by the State Fire Marshal’s office and all municipalities are required to follow these regulations. Outside of the state, regulations may vary somewhat, but generally require that fire extinguishers in places of business be checked annually by a professional. Some high-risk businesses, like service stations or auto repair shops, might have to have them checked more frequently. That's a good recommendation for you too. And then after a certain number of years (depending on the local regulations, but normally five years) a fire extinguisher must be emptied and refilled, regardless of its condition. That is to insure that seals and gaskets are new and fresh and that the chemical contents have not leaked out.
Most extinguishers are built to have a shelf-life of at least six years. They may last a few years longer, but the worst way to find out that they didn't is to need them in an emergency. If the fire extinguisher in your car (or home, for that matter) is five years old or older, have it serviced by a professional fire extinguisher company (a fairly inexpensive job) or discard it and replace it with a brand new one.
The first rule is to have the fire extinguisher readily accessible. Even the best unit will do you no good if you can't get at it. If it is locked in a trunk, or under heavy tools, it may be as good as useless. Although not a thing of beauty, a fire extinguisher located in the cabin of a car is really best. Be sure that it is securely mounted; lying on a seat during an emergency stop can turn that steel canister into a deadly projectile.
There is a simple acronym to remember to operate most fire extinguishers — PASS. PASS stands for Pull, Aim, Squeeze and Sweep.
Pull the pin at the top of the cylinder. Some units require the releasing of a lock latch or pressing a puncture lever.
Aim the nozzle at the base of the fire.
Squeeze or press the handle.
Sweep the contents from side to side at the base of the fire until it goes out. Shut off the extinguisher and then watch carefully for a rekindling of the fire.
The first rule of fighting a fire is to call a professional. When on the road, use a cell phone and dial 9-1-1. Calmly (I know, it's your valuable antique car) tell the operator the problem first, FIRE, and then the location or, if not known, provide some identifiable landmarks. The operator will immediately contact the proper authorities although he/she may continue to speak with you and ask further questions [editor’s note: many 911 sites send alerts by computer, so the operator types codes into a computer which are picked up by fire, police, and ambulance dispatchers]. But be assured that professional help is on its way.
Next, be sure that the fire is small. If it is an inferno, or threatens to ignite the gas tank, forget it. Get away and save your life. It's more important than the car. Make sure that you have an escape route at your back and that you know how to properly use the fire extinguisher. When your car is burning, it's not the right time to start to read instructions.
When looking to purchase a fire extinguisher, pass on the bargain one-shot types sold in a local discount or home building centers. Often these same places sell a range of fire extinguishers, both dry-chem and CO2 or Halotrons. Also check your local marine supply store. Coast Guard regulations for fire extinguishers are stringent, and boat fires and car fires are often of the same type. Motor home and trailer supply shops are also good sources.
Make sure that the fire extinguisher is marked for at least BC fires, and A is also recommended. Be sure that the extinguishers carry either the FM (Factory Mutual) or UL (Underwriters Laboratory) label. This indicates that they have been tested and certified by an independent laboratory. A serial number on the unit often indicates tighter manufacturing control.
The best choice for an extinguisher, preferably a commercially-accepted brand name, should be one with a gauge and a mounting bracket and one that is simple to use. Metal hardware, exclusive of the handle or operating lever, should be aluminum. Those with a hose give the best control over a fire, but a small extinguisher often doesn’t offer that option.
Most Concours and many small car shows require that a fire extinguisher be displayed for the car to be judged or entered. As long as you have to have one anyway, why not make it a quality fire extinguisher which will do the job for which it was intended if that emergency arises.
Back in 1920, the Pyrene Fire Extinguisher Company ran an ad expressing the need for a fire extinguisher in an automobile. “This PYRENE Will Protect My New Car Against Fire” screamed the ad’s headline.
Fire has always been a frightening but very real threat, not only in the car, but also in the home. Wooden- framed residential and commercial buildings, and wooden bodied automobiles all presented very real opportunities for fires which could very quickly devour the entire car or structure.
General, Pyrene, FyrFyter, Buffalo, Babcock, Kiddie, American La France and C-O-Two were only some of the companies manufacturing and selling portable fire-fighting equipment for the car and the home. One of the most interesting examples, dating back to the 1880s, was the Hayward Hand Grenade Fire Extinguisher. Essentially a globe of glass or ceramic, filled with water or a water/chemical mix, it could be tossed at the base of the fire, helping to put it out.
Getting help for a fire was not nearly as fast as it is today. Telephones were not yet a fixture in every home, so professional fire response was often much slower. Immediate response was necessary and the state-of- the-art portable equipment at the time is looked upon as primitive today.
Firefighting advertising and accessories are often collectible. The Ford extinguisher, patented in 1938, was a dealer add-on item. Today they can command as much as $1000.
The fire-fighting contents of the extinguishers varied but included foam, water, carbon tetrachloride and carbon dioxide. Some of the extinguishers were small and really portable, while others were large, bulky and cumbersome. Some could easily and readily be recharged, while others required professional servicing. Pyrene (and more than likely other companies) sold containers of fire fighting liquid to refill their extinguishers.
Many of these antique fire extinguishers are beautiful examples of a time gone by, but are not usable today as functional fire extinguishers. Some of them do make fascinating and beautiful accessories for your antique or classic car, and there are companies that can polish and/or replate the brass, nickel or chrome canisters to bring them back to their original beauty.
To view some of these relics, log on to the website for Vintage Fire Extinguishers. Along with examples of original condition and restored extinguishers, there are many accessories and vintage advertisements and instructions on how and when to restore these units.
This article originally appeared in the April 2006 issue of Skinned Knuckles. It is copyrighted by SK Publishing and may not be reproduced, in whole or in part, without written permission from SK Publishing. See Skinned Knuckles for more vintage and classic car tips. Also see vintage car repairs and these other articles from Skinned Knuckles:
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