A necessary fire-arm
Fire extinguishers are like refuse collection trucks: You don’t pay them much attention until they’re not around and you’re knee deep in it.
Where there’s smoke there’s fire. Keep your extinguisher close
It’s common knowledge that there is an inverse relationship between how long it takes to tease a damp piece of wood into flames and how quickly things can catch alight by accident around the campsite. This is not the time to wonder where you packed the fire extinguisher. And when you do get your hands on it, it had better work, because no one will be laughing if your caravan goes up in flames while you’re trying to figure out how to get foam out of the extinguisher.
The National Road Traffic Act is clear when it comes to fire extinguishers and caravans: A caravan or trailer with a tent on top must be equipped with one or more portable fire extinguishers (the dry chemicals type and at least 1 kg). And you must store it in a safe, easily accessible place – right next to the doorway.
There are six general types of fire extinguishers – each filled with different contents to fight a particular type of fire. These include carbon dioxide, foam and water. Depending on where in the world you find yourself, fires will be divided into six classes, but we will be taking a closer look at three of them:
A class. This includes things like wood, paper and textiles – more or less everything your caravan is made of.
B class. This is fire in a flammable liquid or gas. There are quite a few around your campsite, including cooking oil, grease and LP gas.
C class. These are electrical fires. Most caravans and offroad caravans are hooked up to the power supply via a 220V plug. The power is then distributed to a wall plug nearby, or converted to 12V in the Hella plug. You might therefore encounter a fire around one of these connections.
Fire extinguishers filled with dry chemicals can be used to fight all three of these types of fires, and that is why the law stipulates that you must carry this kind of extinguisher in your caravan at all times.
FOOD FOR THOUGHT
Raymond Nel of Transfire says the powder in dry chemical extinguishers is in fact a type of salt – monoammonium phosphate, or MAP for short. How effectively the powder will fight a fire is expressed as a percentage, for example 40% MAP, 70% MAP and 90% MAP. The 40% MAP extinguisher is therefore less effective than the 90% MAP one. According to Raymond, the 40% MAP is almost always the minimum standard in the industry.
The way dry chemicals work might surprise you: They don’t smother the flames, don’t cool the heat and don’t remove the oxygen. Rather, they counteract the chemical reaction that causes ignition. These extinguishers have a range of 2,53 m, which means you’ll reach every corner of your Exclusive when standing in the middle of it.
However, Raymond believes caravanners should consider getting themselves a larger fire extinguisher than the 1 kg stipulated by law, because the 1 kg is often simply not adequate (1 kg is what most caravan and trailer manufacturers install as standard equipment).
HOW DOES IT WORK?
Fire extinguishers are one of those things you don’t want to think about using, because it means there is trouble. But it is important to be prepared for a fire and to know how your extinguisher works. The contents of the canister are under pressure of 1 400 kpa. Along with the monoammonium phosphate, the canister contains nitrogen gas. Nitrogen is a clean, dry gas that helps keep the phosphate dry as well.
As soon as you remove the safety pin from the extinguisher and depress the lever, the seal on the contents of the cylinder is broken and the nitrogen can escape. The phosphate is heavier than the nitrogen and is therefore at the bottom of the cylinder. When the valve is opened, the nitrogen wants to escape, and the way out is via a pipe that extends to the bottom of the cylinder – which therefore results in the phosphate being propelled out along with the nitrogen.
ONE YEAR CONSCRIPTION
Around the camp fire you will sometimes hear tales of how someone lost the wheels on their caravan because the wheel bearings hadn’t been serviced in years. But, fortunately, horror stories of fire extinguishers going missing or not working because they hadn’t been serviced are not all that common.
Raymond says that by law all fire extinguishers must be serviced at least once a year. Such a service takes only 1520 minutes and should cost in the region of R50. But it will take a little more effort than simply popping into your local hardware store.
To find your nearest registered dealer, have a look on the website of the South African Qualification & Certification Committee for the Fire Industry (SAQCC). Go to saqcc re. co.za/search_town.asp,
type in the name of your town and you will see a list of experts in your area.
Extinguishers are under enormous pressure and this makes them dangerous to service. When the canister is serviced, it is first weighed to ensure there is still enough powder in it. Then they check that the powder is still in fact a powder. Because it is a type of salt, it can clump together, like salt in a salt cellar when the air is damp.
THE FIVE-YEAR PLAN
In addition to the annual service, a fire extinguisher needs a thorough service every five years. This includes a pressure test in which pressure of approximately 3 000 kpa is exerted on the cylinder of the extinguisher to make sure the cylinder doesn’t have any weak spots.
The head is also checked as is the condition of the powder. The pressure test and replacing the phosphate costs about R100 (this excludes any parts such as the O rings that might need replacing). A new fire extinguisher costs R220-R300, depending on the size.
HELP THE GUY
Hold tight. Those clasps and straps keeping the fire extinguisher in place are not there just for show. They ensure you can always find your extinguisher when you need it, and it will last longer if stored somewhere it isn’t subjected to severe vibratations. The mount has been designed to absorb most of the shocks of a journey, Raymond explains.
Have a look. Try to make a cursory examination of your fire extinguisher about once a month. Have a look at the pressure meter and make sure the needle is in the middle of the green section of the scale. If it’s in the red to the left or right, there is a problem with the pressure. In this case it has either lost or is losing pressure, or the pressure in the cylinder is too high.
Upside down. To determine if the powder is still good – and to help prevent clumping at the bottom of the cylinder – invert the bottle and listen carefully close to the cylinder. If you can hear the powder slowly and evenly sinking to the bottom, then you can rest assured all is well in your extinguisher.
Contact: 021 931 8704 or 011 822 2230; [email protected]fire.co.za; transfire.co.za
1 Pressure meter 2 Nitrogen 3 Monoammonium phosphate 4 Nozzle 5 Squirt lever 6 Handle 7 Safety pin 8 Escape tube