Whilst a simple concept, the fire triangle (or combustion triangle) is a scientific principle that is important for all people to be aware of. Understanding how fires sustain themselves is essential background information in situations where you may have to use fire safety equipment. In this article, we will be summarising the fire triangle, and the lesser known fire tetrahedron, in order to give you vital insight into what maintains a fire.
What is the Fire Triangle?
The fire triangle, or combustion triangle, is the three components needed to ignite and sustain a fire. The three ingredients of a fire triangle are; heat, fuel and oxygen.
If just one of these components is removed, the fire triangle will collapse and the fire will be extinguished.
Let’s explore these components in more detail:
1. Heat
A source of heat is required in order for ignition to occur, and different materials have different ‘flash points’ e.g. the lowest temperature at which they ignite.
Unfortunately, combustion reactions also produce heat as they burn, further increasing the temperature of the fuel. For some types of fire, the heat can be cooled with the application of water.
2. Fuel
A fire cannot begin if there is no material to burn. Homes and businesses are full of flammable materials, such as paper, oil, wood and fabrics. Any of these can serve as a fuel for a fire.
Some materials burn more easily than others. Fuels are probably the most difficult ‘side’ of the fire triangle to remove, so it’s wise to store them appropriately to prevent them becoming a fire hazard.
3. Oxygen
To sustain the combustion reaction, oxygen (or an oxidising agent) is needed, as it reacts with the burning fuel to release heat and CO2. Earth’s atmosphere consists of 21% oxygen, so there is plenty available to trigger a fire if the other two components are present.
Fire blankets and certain fire extinguishers remove the oxygen ‘side’ of the triangle by removing it or displacing it, causing suffocation and thereby ceasing the combustion reaction.
Fire Triangle Facts
- Normal air contains 21% oxygen.
- Fuel may also contain oxygen
- Heat sources include: the Sun, hot surfaces, sparks, friction and electrical energy.
- Fuel sources can be a solid, liquid or gas.
What is the Fire Tetrahedron?
The fire tetrahedron is a slightly more complex model to describe the components needed to ignite and sustain a fire. It is afour-sided geometric representation of the four factors necessary for fire:
- Fuel –any substance that can combust
- Heat –heat energy sufficient to cause ignition
- Oxidizing agent –air containing oxygen
- Chemical chain reaction –sufficient reaction energy to produce ignition
Fire Tetrahedron Explained
The fire tetrahedron includes the three components covered in the fire triangle, with the addition of a chemical chain reaction.
This model is simply adding another dimension onto the traditional fire triangle model by treating the chemical reaction as its own separate component. Some fire extinguishers work by applying extinguishing agents to the fire to inhibit the chemical reaction on a molecular level.
Here at Fire Action, we’re committed to providing industry-standard fire safety equipment to homes and commercial clients across the South East region. With a huge range of fire extinguishers, alarm systems, and other products available, you can be sure to find the equipment that’s suitable for your premises. Contact us today to chat to one of our friendly advisers.
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FAQs
The Fire Triangle is a simple way of understanding the components of fire. Each side of the triangle represents one of three components needed to have a fire – oxygen, fuel and heat. Fire is a chemical reaction and without one of these components, fire cannot exist or be sustained.
What is the Triangle fire method? ›
Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished.
What are the 3 elements that make up the fire triangle identify and explain? ›
The three elements that make up the fire triangle are heat, fuel and oxygen. Each one of these elements make up the three sides of a triangle. If you take away one of these elements, or sides, you would not have a triangle. The same holds true for fires.
How does the fire triangle help firefighters? ›
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elements are present and combined in the right mixture. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle.
What are the three methods for breaking the fire triangle? ›
Fires of any kind are put out using one of three methods: cooling, starvation, or smothering. The fire triangle is a basic model for understanding the source and progression of any fire.
What is the explanation of Triangle of fire? ›
The Fire Triangle is a simple way of understanding the components of fire. Each side of the triangle represents one of three components needed to have a fire – oxygen, fuel and heat. Fire is a chemical reaction and without one of these components, fire cannot exist or be sustained.
How do you teach the fire triangle? ›
By considering the fire triangle, ask pupils to think about ways we can stop the candle burning. When we blow out the candle what are we stopping? - Heat. When we put water on the candle what are we stopping? - Heat. When we use a candlesnuffer what are we taking away? - Oxygen.
What is the most important in fire triangle? ›
Oxygen can effectively sustain a fire, and so it's important that it's removed from the triangle to prevent the spread of a fire.
What is the fire behavior triangle? ›
The Fire Behavior Triangle. Just like there is a fire triangle, made up of heat, oxygen, and fuel, there is another triangle called the fire behavior triangle. The three legs of this triangle are fuels, weather, and topography. The sections below go more in depth into each of thise and their influence on fire.
What is the explanation of fire? ›
Fire is a chemical reaction that converts a fuel and oxygen into carbon dioxide and water. It is an exothermic reaction, in other words, one that produces heat.
Extinguishing a fire requires the removal of one or more elements of the fire triangle. The most common methods are using fire extinguishers, water, or simply removing the fuel or oxygen sources.
How can a fire triangle be broken? ›
To stop a fire, one of the three elements of the fire triangle must be removed. So, if a fire runs out of fuel, it will smoulder out; if you can cool a fire down it will lose heat and go out; and if the oxygen is removed it will suffocate.
What is the red triangle for fire? ›
The signage provided on the external side of the fire access panels, either red or orange triangle helps firefighters on the ground to locate the designated fire access openings.
What element of the fire triangle does a fire blanket remove? ›
Fire blankets and certain fire extinguishers remove the oxygen 'side' of the triangle by removing it or displacing it, causing suffocation and thereby ceasing the combustion reaction.
What is the biggest cause of death in a fire? ›
Most fire deaths are not caused by burns, but by smoke inhalation. Often smoke incapacitates so quickly that people are overcome and can't make it to an otherwise accessible exit. The synthetic materials commonplace in today's homes produce especially dangerous substances.
What should you do if you are trapped in a room during a fire? ›
If you must escape through smoke, get low and go under the smoke to your exit. Close doors behind you. If smoke, heat or flames block your exit routes, stay in the room with doors closed. Place a wet towel under the door and call the fire department or 9-1-1.
