The existence fire can be explained through The Fire Triangle theory. This theory states that there are three components that needed to create and sustain a fire. Following The Fire Triangle, we have The Fire Tetrahedron. Then, are they the same? Through this article, we will discuss what The Fire Triangle and The Fire Tetrahedron are. In addition, we will also discuss how The Fire Tetrahedron plays a role in fire suppression.

The Fire Triangle

The Fire Triangle is a triangular-shaped model in which each side represents one element that contribute to forming and sustaining a fire. The three elements are fuel, oxygen, and heat. From this model, we know that a fire will not form if one of the three elements is absent. In addition, these three elements also play a role in sustaining the fire. If one of the elements is removed, then the fire will cease to exist. 

The Fire Tetrahedron

The Fire Tetrahedron theory is the updated version of The Fire Triangle theory. It is the result of research and development on extinguishing materials such as Dry Chemical and Halogenated Carbon. Based on research, it was concluded that there is one more element that plays a role in sustaining a fire. This additional element is a chemical reaction chain, or simply called as a chain reaction.

In the combustion process, a chemical reaction occurs that produces several burning products, such as carbon dioxide (CO2), carbon monoxide (CO), and Sulfur Dioxide (SO2). Moreover, chemical reactions in combustion also produce free radicals from hydrogen and oxygen atoms in the form of hydroxyl (OH). Two OH groups can rupture, then produce H2 O and free radicals O. These radicals O will serve as bait in the next combustion process which then produces a chain combustion reaction. The chain combustion reaction will continue to occur until one of the four components of The Fire Tetrahedron is run out/lost or removed.

The Fire Tetrahedron and Fire Suppression

From the explanation above, we can conclude that The Fire Tetrahedron is the latest model of The Fire Triangle. The concept of fire described through this model does seem simple, but this analogy played a big role in the development of fire extinguishing methods. In this article, we will discuss simply how removing any of the components in The Fire Tetrahedron can extinguish a fire.

• Fuel: All flammable objects, such as wood, paper, clothing, gas, etc., are fuels that can initiate and sustain a fire. Naturally, the fire will die when the fuel supporting the flame has run out. However, waiting until the fuel runs out is usually not a viable or safe option. For example, if there is a fire on the ground floor of a high-rise building that uses ACP material that is not fire-resistant and we wait until everything is burned out, then all the occupants inside that building will be in danger. Material losses are also ensured to be even greater, compared to if the fire is extinguished before spreading to the floor above. As a preventive measure, be sure to identify flammable objects and store them in a safe place. In the event of a fire, moving flammable objects away from the fire can prevent a larger fire from occurring.

• Oxygen: Oxygen is a compound that is the key to chemical reactions in combustion. To ignite and maintain the flame, an adequate supply of oxygen is required. The air contains approximately 21% of oxygen. This percentage is sufficient to accommodate the occurrence of combustion. Have you ever heard of tips for throwing wet towels or fire blankets to put out fires? That's right. This technique aims to prevent the fire from getting oxygen supply. In addition to wet towels or fire blankets, removing oxygen around the fire can be done by spraying a carbon dioxide fire extinguisher. Keep in mind that this fire extinguisher should only be used for Class B fires and electrical fires. Unfortunately, removing oxygen can usually only be done on fires on a small scale.

• Heat: Heat plays a role in triggering or aggravating a fire. With heat, the humidity from the fuel will continue to decrease until it is finally lost. Heat also raises the temperature around the fuel until it is sufficient for ignition to occur. There are several ways that we can use to reduce or even eliminate heat sources. We can use a cooling agent.  This cooling agent can be in the form of water, chemical powder, gas, or chemical inhibitors, which can be found in fire extinguishers. Make sure the type of fire extinguisher used is in accordance with the type of fire that is burning. Choosing the wrong type of fire extinguisher can aggravate the fire. In addition to the use of cooling agents, shutting down the electricity in burning buildings can also reduce heat. 

• Chemical Reaction Chain: Interfering or breaking the chain reaction can be another option for extinguishing a fire. As previously explained, radical oxygen resulting from a chemical reaction due to combustion is the cause of the fire to remain burning. In these cases, we can use Halon to get rid of free radicals arising from the flame. This can slow down the chemical reactions that occur so that the fire can be extinguished.

Written by : Fitri Endrasari

Sources:

https://www.firesafe.org.uk/information-about-the-fire-triangletetrahedron-and-combustion/

https://protectanddetect.co.uk/blog/what-are-the-fire-triangle-and-the-fire-tetrahedron/