How Does Fire Work?

It may come as an elementary question to many. When the idea, “fire”, pops into someone’s mind, the first thing they think of is an oxygen-fueled element that consumes & illuminates everything in its path. As common that knowledge is, there is more that meets the eye.

There is More to This Element

Even though fire appears to be an intuitive phenomenon to understand, it really is a more complex chemical reaction that requires all the right scenarios to occur at once. Unlike other elements it is compared with (earth, air, and water), fire isn’t matter formed by millions of atoms compacted. Instead, it is a result of matter changing form.

Unfortunately, it is an element that one needs to be cautious when understanding. It is responsible for destroying all sorts of material that range from steel and wood to chemical alterations of textile dyes. These are the following mechanisms that are involved in a fire damage scenario:

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Heat

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Corrosion

What is a Fire Triangle?

Otherwise known as a combustion triangle, it is almost like a metonymy for understanding how fires. Three main factors come into play for a fire to exist. Technically speaking, it never starts nor ends. Fires only exist when heat, oxygen, and fuel are at play. It only disappears when one of those factors is removed. For example, fire blankets are meant to remove oxidative elements such as the air we breathe as a means of as a means of extinguishing the fire. On the other hand, when flames spread to cover large areas, firefighters use fire hoses to spray water that removes the heat at play.

We at The Fire Restoration Team understand all of the facets of damage involved in a fire. Therefore, you need us to come evaluate the effects on your property and personal belongings. Only then can we gauge the severity of the damage in order to properly attend to it.

Let’s Go Over An Example

Let’s say that we use wood as a source of fuel. Then, a match is taken as an example of heat. From there, you place these two objects together and get a chemical reaction/combustion when the fuel agent reaches a temperature threshold of 150 centigrade before succumbing to the heating agent by decomposing composite material that makes up the piece of wood. 

Subsequently, the material that decomposed from this combustion converted into volatile gases, many of which are compounds of carbon, oxygen, and hydrogen. This is otherwise known as smoke.

You may be asking the following question, “what happens with the rest of the compound?” Some of it turns into char. Have you had a barbecue before? This is one of the minerals that charcoal is made from as it is also made out of wood; thus, this combination of material and absence of volatile gases allows you to burn charcoal without smoke developing.

Two Reactions Occur As Follows:

When the volatile gases are hot enough (about 500 degrees F (260 degrees C) for wood), the compound molecules break apart, and the atoms recombine with the oxygen to form water, carbon dioxide and other products. In other words, they burn.
The carbon in the char combines with oxygen as well, and this is a much slower reaction. That is why charcoal in a BBQ can stay hot for a long time.
A side effect of these chemical reactions is a lot of heat. The fact that the chemical reactions in a fire generate a lot of new heat is what sustains the fire. Many fuels burn in one step. Gasoline is a good example. Heat vaporizes gasoline and it all burns as a volatile gas. There is no char. Humans have also learned how to meter out the fuel and control a fire. A candle is a tool for slowly vaporizing and burning wax.

More About This Chemical Reaction

Like all chemicals, carbon is made out of atoms. When heated up, these atoms get “excited.” During this process, known as incandescence, they emit light.

Speaking of flames, they come in a few layers of colors. Have you noticed the center of a flame in a stovetop? That is because the middle (blue) layer of the flame is hotter than the outer edges (red/orange). This goes to show that fire is a dynamic element because there is no even temperature.

 

Fire forms a sphere in microgravity.
The dangerous thing about the chemical reactions in fire is the fact that they are self-perpetuating. The heat of the flame itself keeps the fuel at the ignition temperature, so it continues to burn as long as there is fuel and oxygen around it. The flame heats any surrounding fuel so it releases gases as well. When the flame ignites the gases, the fire spreads.

On Earth, gravity determines how the flame burns. All the hot gases in the flame are much hotter (and less dense) than the surrounding air, so they move upward toward lower pressure. This is why fire typically spreads upward, and it’s also why flames are always “pointed” at the top. If you were to light a fire in a microgravity environment, say onboard the space shuttle, it would form a sphere!

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