What is fire ?
Fire can destroy your house and all of your possession¬s in less than an hour, and it can reduce an entire forest to a pile of ash and charred wood. It’s also a terrifying weapon, with nearly unlimited destructive power. Fire kills more people every year than any other force of nature.
But at the same time, fire is extraordinarily helpful. It gave humans the first form of portable light and heat. It also gave us the ability to cook food, forge metal tools, form pottery, harden bricks and drive power plants. There are few things that have done as much harm to humanity as fire, and few things that have done as much good. It is certainly one of the most important ¬forces in human history.
Typically, fire comes from a chemical reaction between oxygen in the atmosphere and some sort of fuel (wood or gasoline, for example). Of course, wood and gasoline don’t spontaneously catch on fire just because they’re surrounded by oxygen. For the combustion reaction to happen, you have to heat the fuel to its ignition temperature.
The 3 elements (in red) is known as the Fire Triangle and they are essential in order for fires to exist.
By removing any of these 3 elements, the fire will stop. So fire extinguishers are designed to remove one of these elements by applying an agent that either cools the burning fuel, or removes or displaces the surrounding oxygen.
The European Standard BS EN3 specifies that All Fire Extinguisher Bodies are to be coloured “RED” regardless of the contents of the extinguisher.
All Extinguishers now have a 5% area of the label that is Colour Coded which denotes its contents.
> Water Extinguishers
Water extinguishers are filled with regular tap water. The best way to remove heat is to dump water on the fire but, depending on the type of fire, this is not always the best option.
> Foam Extinguishers
The foam has a blanketing effect that knocks down the flames, smothering & cooling them, thus preventing re-ignition of the flammable vapours by sealing the surface of the solution.
> Dry Powder Extinguishers
Dry powder fire extinguishers interrupt the chemical reaction of the fire by coating the fuel with a thin layer of powder, separating the fuel from the surrounding oxygen.
> Carbon Dioxide (CO2) extinguishers
CO2 extinguishers contain carbon dioxide, a non-flammable gas. CO2 is heavier than oxygen so these extinguishers work by displacing or taking away oxygen from the surrounding area. CO2 is also very cold so it also works by cooling the fuel. CO2 is non corrosive and non conductive.
How fire extinguishers work (PASS)
Pull the Pin at the top of the extinguisher. The pin releases a locking mechanism and will allow you to discharge the extinguisher.
Aim at the base of the fire, not the flames. This is important – in order to put out the fire, you must extinguish the fuel.
Squeeze the lever slowly. This will release the extinguishing agent in the extinguisher. If the handle is released, the discharge will stop.
Sweep from side to side. Using a sweeping motion, move the fire extinguisher back and forth until the fire is completely out. Operate the extinguisher from a safe distance, several feet away, and then move towards the fire once it starts to diminish.
Remember: Aim at the base of the fire, not at the flames.
A typical fire extinguisher contains 10 seconds of extinguishing power. This could be less if it has already been partially discharged.
Once the fire is out, don’t walk away! Watch the area for a few minutes in case it re-ignites. Recharge the extinguisher immediately after use.
All fires can be very dangerous and life-threatening. Your safety should always be your primary concern when attempting to fight a fire.
Before deciding to fight a fire, be certain that:
The fire is small and not spreading. A fire can double in size within seconds.
You have the proper fire extinguisher for what is burning.
The fire won’t block your exit if you can’t control it. A good way to ensure this is to keep the exit at your back.
You know your fire extinguisher works. Assure the pressure is at the recommended level. On extinguishers equipped with a gauge, the needle should be in the green zone – not too high and not too low.
You know how to use your fire extinguisher. There’s not enough time to read instructions when a fire occurs.
Never fight a fire if:
The fire is spreading rapidly. Only use a fire extinguisher when the fire is in its early stages. If the fire is already spreading quickly, evacuate and call the fire department.
You don’t know what is burning. Unless you know what is burning, you won’t know what type of fire extinguisher to use. Even if you have an ABC extinguisher, there could be something that will explode or produce highly toxic smoke.
You don’t have the proper fire extinguisher. The wrong type of extinguisher can be dangerous or life-threatening.
There is too much smoke or you are at risk of inhaling smoke. Seven out of ten fire-related deaths occur from breathing poisonous gases produced by the fire.
Any sort of fire will produce some amount of carbon monoxide, the most deadly gas produced by a fire. Materials such as wool, silk, nylon and some plastics can produce other highly toxic gases such as carbon dioxide, hydrogen cyanide, or hydrogen chloride. Beware – all of these can be fatal.
Smoke inhalation or exposure to fire itself can be life threatening.