Imagine you’re driving down a gravel road in the middle of Nowherefontein when you smell burning; and then you see smoke.
You hop out of the car, wrench the bonnet open – and before you can blink, the engine bursts into flame. What do you do? Do you grab the extinguisher? Do you even have a fire extinguisher?
Fire is a powerful element, symbolising both destruction and rebirth. It is not to be taunted or played with; it can be your best friend in the middle of an icy winter, or your worst enemy come the hot, dry summer. Fire comes in different categories, as do fire extinguishers. But, what is a fire extinguisher, anyway?
Typically, a fire extinguisher is a hand-held cylindrical pressure vessel containing an agent which is discharged to extinguish a fire; but we need to know that there are different kinds of fire extinguishers. Tackling a fire with the wrong type of fire extinguisher can be ineffective and even dangerous. In SA, our classification of different fire types is based closely on the American model: each class designates the fuel involved in the fire, and thus defines the most appropriate extinguishing agent.
Class A - Combustible solids
Class B - Flammable liquids & gases
Class C - Electrical equipment
Class D - Combustible metals
Class K - Cooking oils or fats
An ‘ordinary combustible’ is the most common type of fire. These fires occur when solid, organic materials – such as wood, cloth, rubber, paper and textiles – become heated to their ignition point. At this point, the material undergoes combustion, and will continue burning as long as the three main components of fire (heat, fuel and oxygen) are present.
Statistics show that 75 percent of all vehicle fires are caused by an electrical fault. This is due to there being a great deal of heat generated, either as a direct result of combustion or motion, or from your vehicle’s heater. You may not think that your vehicle would burn very easily, what with the metal body and all, but a vehicle fire can be extremely dangerous.
First, the metals conduct heat very well, making the fire harder to put out; then the melting of the plastics and wiring create toxic gasses which can kill; and then the fuels and oils keep the fire burning for long periods and can spread the fire to the road or to other vehicles, and make it dangerous to put out the fire with water. It’s estimated that it may take only four minutes to burn out an entire caravan, and that in that short space of time temperatures can reach at least 600°C. This doesn’t give you much time to act.
What to Buy
Different fire extinguishers use different extinguishing agents. These include water, foam, dry powder, CO2, and Halon – although the last-mentioned has been discontinued because of environmental concerns. Water is best for class A fires, as water reduces the heat by cooling. Foam is best for class A and B fires as it also works as a coolant, and especially on class B fires as it blankets the fuel and cuts off the available oxygen. Dry Powder is effective on most fire types, but it doesn’t have the cooling effect that foam and water do – cooling is required after the flames are extinguished. CO2 can be extremely useful under certain conditions, but, as it is an inert gas that is heavier than air, if there is an opening in the area where the fire is, the gas will flow out to the lower level, leaving the fire to rage on.
As there is no extinguisher suited to all fire classes, it would be best to get an ABC extinguisher. These are drypowder extinguishers that cover most of the day-to-day fires which you’re likely to encounter. The smallest size they’re manufactured in is one kilogram, so be prepared to make space. They can also handle rough treatment, but Chubb Fire and Security suggests that off-roaders check their powder sooner than the recommended five year intervals, because it compacts when carried in a vehicle. The negatives of the dry-powder extinguishers are that they are extremely messy, and some powders are corrosive, so one has to be careful.
Charles van Niekerk, owner of Pyrotech in Knysna, who has been involved in the fire extinguisher industry for near 40 years, suggests that you should always have the biggest possible fire extinguisher for the space you have allocated, plus a spare. This might be difficult in your rig, as many of us pack our vehicles to the limit. Charles always travels with a 4.5 kilogram extinguisher. Bulky – yes, but well worth it if you can spare the space.
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