Is that . . . smoke?

Editor's note: Jim West, a captain in the Sun City Fire Department (and a U.S. team member in the 1992 Camel Trophy), kindly contributed to OT&T this excellent article on fire safety for overland vehicles (or any other vehicle for that matter). Consider the information here critical for your journeys. - J. Hanson


So, departure day is almost here. Your vehicle is kitted out with all manner of overlanding equipment. As it sits in the driveway, you go through your mental checklist: clothes . . . check; recovery gear . . . check; food . . . check; petrol . . . check; spare petrol . . . check; propane . . . check. Then it hits you—Okay, that’s a bunch of fuel; no, I mean a BUNCH. If this thing catches fire, the crew on the International Space Station will wonder what’s burning down there. In a mild panic, you rummage through the truck and, in the back of a cabinet, you find the fire extinguisher. You dust it off and take a quick look at the gauge. Green—good to go, right? Well, throttle back and take a moment to ponder the following:

When driving a vehicle into the outback, whether for a day trip or a year-long adventure overlanding through South America, serious considerations should be taken for general fire safety. The farther afield you’re traveling, the more comprehensive your plan and equipment should be.

If you have a good close look at your particular rig, you’ll find it has all the potential fire hazards of any typical motor vehicle, plus some special ones. Larger fuel tanks and more of them; fuels for cooking, heating, and auxiliary generators. Start with the obvious place—under the hood. Fuel lines should be given a close inspection for cracks, abrasions, and leaking fittings. Repair or replace any suspected problems. Onto the electrics—take a good hard look at the wiring, in general, with special attention to any aftermarket wiring, i.e. additional lighting, batteries, winches, etc. Any cracked, abraded, or melted insulation should be repaired. Also, take a quick look at all tubes and wires to make sure they are not routed too close to any heat source, such as the exhaust.

Are there any fuel or electrical lines running too close to that Borla, or the catalytic converter ahead of it?

Time to get dirty. Get yourself under that vehicle and have a good look around. Better now, in your driveway, than out in the mud. This will be the same as the under-hood inspection: fuel lines, wiring, and brake lines as well (brake fluid can be flammable.) One more thing to think about under there is the catalytic converter. They produc tremendous heat and can quite easily catch tall brush on fire. That would add some excitement to a picnic or campsite. Finally, have a good general look around the outside. If you have additional fuel mounted, make sure it is mounted properly and won’t puncture or leak while traveling down rough trails.

Time for a quick chemistry lesson. (No, we don’t get to blow stuff up, sorry.) Let’s look at the “Petrol versus Diesel” debate. As a general rule, liquids don’t burn, vapors do. If a liquid fuel is not giving off vapors, it won’t burn. Cool, but what does that mean? Petrol starts giving off vapor at any temperature higher than about minus 45ºF (-43ºC). This figure is called its flashpoint. Diesel, on the other hand, has a flashpoint of about 120ºF (52ºC) or higher. This obviously makes Diesel a much safer fuel in general. For instance, you and your best buddy (not for long) are out on a sunny 80-degree day and you need to refuel. No problemo, as it just so happens you brought an approved jerry can full of petrol and the appropriate filler neck. During said filling operation your buddy walks up with a lit sparkler (hey, it’s my story). The petrol is producing enough vapor for things to get very exciting very quickly—i.e. time for new friend, new vehicle, and a trip to the local burn unit. In the same scenario with diesel fuel and a new friend also strangely attracted to sparklers, nothing happens—zip, zilch, nada.

All right—back to that dusty extinguisher. Once a fire starts, you’re going to have to put it out, whether it’s a campfire, your rig, or that guy with the sparkler. What’s burning determines how you put it out. The most common opitons are: remove the fuel; cool the fuel below its ignition temperature; smother the fire (remove its oxygen supply); and, finally stop the chemical reaction. To properly put out a campfire, for example, you simply shovel on some dirt to smother it and then add water to cool it. A grease fire in a pan on the stove can be quickly smothered with a lid over the pan. A fire from spilled fuel might be solved by simply moving vehicles and other combustibles away and letting it burn off. FYI, a one-inch deep puddle of petrol takes about 15 minutes to burn out. 

The idea here is you don't always need to use a fire extinguisher. But since you dug it out of that cabinet, let’s talk about it. Fire extinguishers are classified by what they put out: ‘A’ for combustibles, e.g, paper and wood; ‘B’ for flammable liquids, e.g., petroland diesel; ‘C’ for electrical fires; and ‘D’ for metal fires, e.g., magnesium. The most common extinguisher is an ABC type, which will be suitable for most fires you’ll encounter. A five-pound extinguisher is good for most normal-size cars and trucks. As the size of the vehicle goes up, so should the size of the the extinguisher.

What about that ‘D’ extinguisher? A lot of modern vehicles use magnesium parts, and if they do catch fire, an ABC extinguisher won’t put it out. The bad news is, ‘D’ extinguishers are bigger, heavier, and more expensive (about $300.) The (sort of) good news is, magnesium is hard to ignite. So by the time it gets burning and you need that ‘D’ extinguisher, the vehicle would be fully engulfed in flames and a total loss. So you have that going for you.

Some final thought on extinguishers: They should be inspected no less often than annually. This entails checking the pressure gauge to make sure it is in the green. Also, and as importantly, you should shake the extinguisher and feel the dry chemical powder moving up and down. If you can’t feel this movement, the powder has caked into a solid and the extinguisher will not function. 

Finally, where does one put the thing? There is a very narrow window of time after a fire starts when an extinguisher is effective. Fire doubles in size every minute. Let’s just ponder that one for a minute . . . okay, the fire just doubled in size. An extinguisher should always be mounted in a readily accessible area for quick access.

Since most vehicle fires ignite in the engine compartment, it makes sense to locate the extinguisher some distance away, but quickly accessible. The mount here ensures it can't be covered by luggage.

Now we have the basics taken care of. We’ve inspected the vehicle, we’re practicing good fire-prevention safety, we have all manner of ways to put out a fire. It’s time for the hero stuff. 

You’re driving happily down the trail (remembering to Tread Lightly); you hear a pop under the hood, and see what looks like smoke billowing out of the engine compartment. It could have been a heater or radiator hose. Maybe an AC line. Maybe an engine fire. How do you know? First of all, steam and freon dissipate quickly, smoke doesn’t. Second, fire is hot (rocket science, I know.) If you see the beautiful paint on your hood start turning brown and bubbling up, it’s hero time. The clock just started ticking and you have very little time to make some decisions and start to act on them. Here is a example of how it will play out if you do every thing perfectly:

  • Stop the vehicle off the trail/road, preferably in an open space. Dirt, not grass—wildland fires are a bigger problem than car fires. If there’s nothing but grass, leave the vehicle on the trail.
  • Turn off the ignition.
  • If your hood latch is inside the car, open it immediately (the cable will burn through quickly).
  • Get everyone out of the car and well away.
  • Grab your extinguisher and, if at all possible, gloves—that hood is going to be hot.
  • With the hood popped but not fully open give a quick burst from the extinguisher through the opening between the hood and fender. Never fully open the hood before this step. The fire could travel up the angled hood and burn you.
Displaying a regrettable lack of commitment to authenticity, Jim did not actually light a fire in the engine compartment of his Discovery. But you get the idea.

Displaying a regrettable lack of commitment to authenticity, Jim did not actually light a fire in the engine compartment of his Discovery. But you get the idea.

  • Open the hood completely and continue to use extinguisher until fire is out. Short bursts of dry chemical are preferred because you don’t want to waste a very limited resource. The goal is to ‘blanket’ the fuel in order to smother the fire.
  • Now comes a very important step: Make sure the fire is completely out and won’t reignite. This should take about ten or fifteen minutes. A good way to judge the time is to take your pulse rate. When it drops below 100 beats per minute, you should be about good.

So now what? You and your passengers should all be standing around the front of your rig, staring at the engine compartment, with that ‘deer in the headlights’ look. The extinguisher is still in your hand. You’ll find it very hard to put it down for the next 24 hours—that’s ok, you'll get over it. The engine compartment itself will be a mess of white dry chemical and melted wires and hoses. Time to break out the water can and tool kit and get to work. During the cleaning and repair process there will probably be some raw fuel leaking or just puddled in there so keep all ignition sources (i.e. sparklers) away.

Here are a few final thoughts to wrap this up:

Ninety two percent of all car fires are preventable with good maintenance (I just made that stat up but I know the percentage is really high.) The old saying ,“An ounce of prevention is worth a pound of cure” is spot on. With regards to extinguishers, if you don’t have one, get one. Actually, get two—a good one and a cheap one to practice with. The directions are right on the label and quite easy. They’re only about $20 and it’s money well spent. If you would like more training most local fire departments have classes and/or demonstrations for fire extinguisher use. And on that note, may your adventures be plentiful and safe.


Jim West