Fires are dynamic events that move through different stages. Each stage presents unique challenges and calls for different responses. Recognizing these stages is key for effective fire safety and suppression.
This article outlines the four primary stages of fire. Learning them will give you insight into the characteristics of each stage and why it’s so important to intervene early.
Understanding the stages of fire can also help you decide when you need to call for professional help.
The Four Stages of Fire Development
Fires grow and change over time. Fire safety professionals recognize four distinct stages in fire development.
Incipient Stage (Ignition)
This initial stage begins when a fire starts, but the heat is still very limited. Because the fire is small, it’s easiest to put out at this stage. You might see a small flame or some materials that are smoldering.
The best way to handle an incipient fire is to eliminate the heat source or use a fire extinguisher. For some fires, like kitchen fires, a fire blanket or baking soda may also work.
Growth Stage
In the growth stage, the fire gets bigger and more intense. The temperature rises, and there’s more smoke. Flashover, a rapid and dangerous transition, can occur during this stage.
Early detection and suppression are important during the growth stage. A multidirectional temperature and smoke detector can be very useful.
Fully Developed Stage
In the fully developed stage, the fire is as large and intense as it’s going to get, consuming all the fuel that’s available. This is the most dangerous stage, because there’s extreme heat and the building may collapse.
At this point, you’ll need professional firefighters to put out the fire.
Decay Stage
In the decay stage, the fire begins to diminish as the fuel runs out or the oxygen level drops. However, there are still risks to be aware of, including reignition, backdraft, and smoldering.
Thermal imaging detection systems can help firefighters find hot spots during the decay phase.
Recognizing the signs and taking action
Each stage of fire has its own signs, starting with a whiff of smoke or a small flame and building to intense heat and raging flames. Being aware of these signs can help you detect a fire early, which is key to minimizing damage and saving lives.
Early detection systems can make a big difference. For example, thermographic cameras are sometimes used to detect fires during the warm-up stage.
Fire suppression systems are even better because they can automatically detect a fire and put it out, especially in remote locations. You might find these systems used to protect CNC machines running overnight or in wind turbines, for example.
When to call the professionals and prioritize safety
If a fire isn’t controlled in the incipient stage, call the fire department immediately. Trying to fight a fire that’s beyond your capabilities can be incredibly dangerous.
If you’re unsure about whether you can control the fire, get out! Evacuate everyone from the house or building.
It’s important to understand the limitations of manual firefighting. Some situations require specialized equipment and a level of expertise that the average person doesn’t have.
More than anything, prioritize safety. Possessions can be replaced, but lives cannot.
Frequently Asked Questions
What are the 4 stages of combustion?
The four stages of combustion, or fire development, are: Incipient, Growth, Fully Developed, and Decay. These stages describe how a fire starts, grows, reaches its peak intensity, and eventually diminishes.
What are the 5 steps in the event of a fire?
While not directly related to the stages of fire, the five key steps to take if a fire occurs are: 1) Activate the alarm, 2) Call emergency services (911), 3) Evacuate the building, 4) Assist others if safe to do so, and 5) Stay out until authorities say it’s safe to re-enter.
What are the 4 stages of fire?
This is essentially a repeat of the first question! The four stages of fire are: Incipient, Growth, Fully Developed, and Decay. Each stage has distinct characteristics in terms of heat release rate, oxygen consumption, and smoke production.
What are the fire stage names?
The names of the four fire stages are:
- Incipient Stage
- Growth Stage
- Fully Developed Stage
- Decay Stage
These names help to easily identify what phase a fire is currently in.
The Bottom Line
Knowing the stages of fire helps you develop good fire safety and prevention habits. Spotting a fire early and putting it out quickly can reduce property damage and save lives.
By knowing the signs of a fire and acting accordingly, you can protect yourself, your property, and the people around you. Prevention and preparedness are essential for fire safety, so don’t overlook them.