(classical music)
- Hey, everybody.
If you're like me,
then you constantly worry
about building catching on fire
when someone plays your newest mixed tape,
and since you can't compromise your
artistic integrity because of
a few exploding sound systems,
you have to be prepared
for the blazes that
inevitably ensue once the beat drops.
A fire extinguisher is
one of your best options,
but what are these things, anyway?
How do they work?
(static noise)
Great question!
It's the subject of this episode.
First, let's talk about fire.
Fire is the result of a
chemical combustion reaction
typically between oxygen
and some sort of fuel
like wood or gasoline.
For the reaction to occur,
the fuel has to reach
its ignition temperature.
For wood, that's about
500 degrees Fahrenheit
or 260 degrees Celsius.
The heat decomposes some
of the wood's cellulose
and that decomposed stuff is released
as volatile gases like a compound
of hydrogen, carbon and oxygen.
When the gas is hot enough,
its molecules break apart,
the atoms recombine with the oxygen
to form water, carbon
dioxide and other products.
This heat keeps the fuel
at the ignition temperature
so it keeps burning as long
as there is fuel and oxygen.
There you have it.
Fire.
The result of extreme
heat, oxygen and fuel.
Fire extinguishers remove at
least one of those elements
from the equation.
Imagine a fire extinguisher cut in half.
So, that plastic syphon tube there
leads from the bottom of the
fire suppressant reservoir
to the top of the extinguisher.
A spring-mounted valve
locks the passageway
from the syphon to the nozzle.
At the top of the cylinder,
there's a smaller cylinder
filled with a compressed gas:
liquid carbon dioxide, for example.
A release valve keeps the
compressed gas from escaping.
When you pull out the safety pin
and depress the operating lever,
it pushes on an actuating rod.
The rod presses the
spring-mounted valve down
to open up the passage to the nozzle.
The bottom of this actuating
rod has a sharp point,
which pierces the gas
cylinder release valve.
The compressed gas escapes,
applying downward pressure on
the fire suppressant material.
And this drives that
fire suppressant stuff
up the syphon, out the nozzle.
The proper way to use the extinguisher
is to aim it directly at
the fuel, not at the flames,
and spray in a sweeping motion.
There are three main
types of extinguishers.
A water extinguisher can put
out things like burning wood
or paper or cardboard,
but it's not great shakes
at electrical fires
or fires involving inflammable liquids.
In an electrical fire,
water might actually conduct the current,
which could electrocute you.
Then there's the carbon
dioxide extinguisher.
The CO2 is kept in a
pressurized liquid form.
When the container is opened,
the CO2 forms a gas.
This gas is heavier than oxygen,
so it displaces the oxygen
surrounding the fuel.
This type of extinguisher
is the one you'll
find most often in restaurants
because it won't contaminate
cooking equipment or food.
However, ladies and
gentlemen, drum roll please.
The most popular fire
extinguishing material
that's the dry chemical extinguisher.
These cylinders contain foam or powder,
typically made of sodium bicarbonate.
You may know it by its street name:
baking soda.
Baking soda starts to decompose at only
about 158 degrees Fahrenheit,
which for everybody but the
U.S. is 70 degrees Celcius.
And when this stuff decomposes,
it releases CO2.
The CO2, along with the
insulation of the foam,
smothers fire.
However, be careful.
Most fire extinguishers
contain a small amount
of suppressant.
You can use it up in seconds,
and that's why they are only effective
on relatively small fires.
To put our a bigger blaze,
you need more equipment,
like a fire engine, as well as, hopefully,
some trained professionals.
But, for the conflagrations
that can pop up in your house,
a fire extinguisher is a life saver.
That's it.
I mean, remember again,
if you have to use one,
hit the fuel, not the flame,
and sweep across the fire.
Thank you so much for watching.
Toss me a Like if you dug this video.
Let me know which other gadgets
I should cover in the future,
and stay tuned next week
for more Brain Stuff.
