Speaker 1: Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Speaker 1: I'm Lauren Vogelbaum, and this is a classic episode from
Speaker 1: our previous host, Christian Sager. The fire extinguisher is an
Speaker 1: amazing piece of simple equipment that can help you smother
Speaker 1: of fire should it happen to get a little out
Speaker 1: of control. In this episode, we explain how they work
Speaker 1: and what kinds work for what kinds of fires. Hey,
Speaker 1: brain Stuff, it's Christian Sager. Let's talk about fire. Fire
Speaker 1: is the result of a chemical combustion reaction, typically between
Speaker 1: oxygen and some sort of fuel like wood or gasoline.
Speaker 1: For the reaction to occur, the fuel has to reach
Speaker 1: its ignition temperature. For wood, that's about five hundred degrees
Speaker 1: fahrenheit or two hundred and sixty degrees celsius. The heat
Speaker 1: decomposes some of the woods cellulose, and the decomposed stuff
Speaker 1: is released as volatile gases, like a compound of hydrogen, carbon,
Speaker 1: and oxygen. When the gas is hot enough, its molecules
Speaker 1: break apart. The atoms recombine with the oxygen to form water,
Speaker 1: carbon dioxide, and other products. The heat keeps the fuel
Speaker 1: at the ignition temperature, so it keeps burning as long
Speaker 1: as there is fuel and oxygen. So there you have it.
Speaker 1: Fire the result of extreme heat, oxygen and fuel. But
Speaker 1: what about fire extinguishers They remove at least one of
Speaker 1: these elements from the equation. Fire extinguishers are metal cylinders
Speaker 1: filled with water or smothering material, and when you depress
Speaker 1: a lever at the top, the material is expelled by
Speaker 1: high pressure, kind of like an aerosol. Can imagine a
Speaker 1: fire extinguisher cut in half. Okay, that plastic siphon tube
Speaker 1: leads from the bottom of the fire suppressant reservoir to
Speaker 1: the top of the extinguisher. A spring mounted valve blocks
Speaker 1: the passageway from the siphon to the nozzle, and at
Speaker 1: the top of the cylinder there is a smaller cylinder
Speaker 1: filled with compressed gas liquid carbon dioxide for example. A
Speaker 1: release valve keeps the compressed gas from escaping. When you
Speaker 1: pull out the safety pin and depress the operating lever,
Speaker 1: it pushes on an actuating rod. The rod presses the
Speaker 1: spring mounted valve down to open up the passage to
Speaker 1: the nozzle. The bottom of the actuating rod has a
Speaker 1: sharp point which pierces the gas cylinder. Release valve. The
Speaker 1: compressed gas escapes applying downward pressure on the fire suppressant material.
Speaker 1: This drives the material up the siphon and out the nozzle.
Speaker 1: The proper way to use the extinguisher is to aim
Speaker 1: it directly at the fuel, not the flames, and spray
Speaker 1: in a sweeping motion. There are three main types of extinguisher.
Speaker 1: A water extinguisher can put out things like burning wood, paper,
Speaker 1: or cardboard, but it doesn't work well on electrical fires
Speaker 1: or fires involving inflammable liquids. In an electrical fire, water
Speaker 1: may conduct the current, which could electrocute you. Water will
Speaker 1: only spread an inflammable liquid, making the fire worse. Then
Speaker 1: there's the carbon dioxide extinguisher. The CEO two is kept
Speaker 1: in a pressurized liquid form. When the container is opened,
Speaker 1: the CO two forms a gas. This gas is heavier
Speaker 1: than oxygen, so it deplaces the oxygen surrounding the fuel.
Speaker 1: This extinguisher is common in restaurants because it won't contaminate
Speaker 1: cooking equipment or food. The most popular extinguisher material is
Speaker 1: the dry chemical extinguisher. These cylinders contain foam or powder,
Speaker 1: typically made of sodium bi carbonate, also known as baking
Speaker 1: soda potassium bicarbonate or mono ammonium phosphate. Baking soda starts
Speaker 1: to decompose at only a hundred and fifty eight degrees
Speaker 1: fahrenheit or seventy degrees celsius, and when it decomposes, it
Speaker 1: releases c O two. The CEO two, along with the
Speaker 1: insulation of the foam, smothers fire. The best way to
Speaker 1: tell which fire extinguisher you have and which fires it's
Speaker 1: best suited to fight is to look at the rating.
Speaker 1: All fire extinguishers have an A, B or C rating.
Speaker 1: A Class A fire extinguisher works best against fires involving paper, wood, plastic,
Speaker 1: and textiles. A Class B fire extinguisher can put out
Speaker 1: flammable liquid fires, you know, things like cooking oil, gasoline, paint,
Speaker 1: or oil, and a Class C extinguisher is your go
Speaker 1: to for live electrical fires. Each extinguisher will have a
Speaker 1: number by the letter indicating the size of the fire
Speaker 1: that it can tackle. But please be careful. Most fire
Speaker 1: extinguishers contain a small amount of suppressant. You can use
Speaker 1: it up in seconds. That's why they're only effective on
Speaker 1: relatively small fires. To put out a bigger fire, you
Speaker 1: need more equipment. Like a fire engine as well as
Speaker 1: trained professionals, but for the blazes that can pop up
Speaker 1: in your house, a fire extinguisher can be a life sapor.
Speaker 1: Today's episode was written by Ben Boland and produced by
Speaker 1: Tyler Clang. For more on this and lots of other topics,
Speaker 1: visit how stuffworks dot com. Brain Stuff is a production
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Speaker 1: you listen to your favorite shows.