Stages of fire in detail – what are the 4 stages of a fire?

4 Stages Of Fire

Who is not familiar with the Fire..!! Fire can be consider as boon and curse of any type of industries. Fire is useful if it is used under controlled manner. Fire is used in many place for the betterment of the humans but if any abnormalities happens and somewhat situation goes out of control, it can be curse and cause damaged to lives and property. To use fire we should be familiar with Fire triangle and fire tetrahedron which is described by Chemical tweak in details. Fire is integral part of industrial safety and learning industrial safety without fire in details in not possible. Today in this tutorial we will learn fire in detail i.e what are the stages of fire. Prior to know what are 4 stages of fire, let us refresh the basic definition of fire / what is fire.

What is Fire?

Chemical tweak had described in in Fire triangle post what is fire but as a refresher let us remind what is fire. Fire triangle is a model consists of three element which are the  basis requirement for fire to be established.

What are the stages of fire – what are the 4 stages of a fire?

As a fire broke out in any workplace, and if we breakdown fire then this can be known there are 4 stages of a fire. International Fire Service Training Association (IFSTA)  had stated that there are 4 stages of fire. All the stages of fire are enlisted below

  1. Incipient
  2. Growth
  3. Fully developed
  4. Decay

Now let us learn 4 stages of fire in details.

1. Incipient –Incipient is known as the first stage of fire. As the fire triangle elements like oxygen, fuel and spark/heat combine with each other and continuous chemical reaction resulting is breaking out of fire. This incipient stage of fire is also known as ignition. This is the initial stage in which fire is in smallest phase which provides the golden opportunity to take action and suppress the fire.

This is the stage in which the fire is at initial level and one can take measures and stop the fire to get into other stage and one can avoid the fire accident. The thing that requires in this stage to suppress the fire is detection of fire and quick action. Majority of time, fire can be suppress easily but the broke out of fire is not detected in incipient stage and hence the quick and immediate action has not been taken.

The other reason why fire get into other stage and result in fire accident stage is delay in action. Delay in fire fighting action can boost fire to get bigger stage and make the situation worst. There are number of reasons which are responsible for delay in action and those are listed below

  1. Not availability of fire fighting equipment
  2. Not availability of fire man
  3. Lack of trained personnel /worker/employee

This incipient/ ignition stage is the golden chance to stop fire and avoid the conversion of small fire to dangerous fire incident.

2. Growth – Fire if not controlled at the inition / incipient stage then it converts to second stage that is Growth stage. in this growth stage of fire. During this stage, fire keep on consuming combustible material as a fuel and presence of oxygen to multiply its growth and this result in conversion of fire stage from incipient to growth. This is the shortest and most dangerous stage as sometimes within fraction of seconds fire from just ignition turns into a huge fire. This stage is mostly responsible of trapping of persons and  firefighter.

3. Fully Developed – After Growth stage of fire, when all the combustible material caught fire and the growth stage has reached its maximum potential that stage of fire is is considered as fully developed.  The temperature at this stage is maximum among all stages of fire and it is the dangerous stage for firefighter or personel trapped in the affected site as leaving affected site during this stage of fire is very difficult.

4. Decay – Last stage and longest stage of a fire is decay stage. In this stage all the fuel present at site get burned or the presence of oxygen got decrease which result in fire to be put in final point. Special observation and care to be taken in this fire stage also as fire is stopped or getting slow down by reduction of fuel or insufficient oxygen. There is always a chance that the oxygen get rushed to the affected site and fire get reinitiated. Other possibility is presence of flammable presence of combustible material left as these left combustible material has a potential to initiate fire.

Graph of Stages of fire

Stages Of Fire
Graph Of Stages Of Fire

Wrapping Up

Hope you like the article on Stages of fire and you know what are the 4 stages of a fire? . If you had any confusion related to this article then feel free to use comment section we will try to help you. Don’t forgot to check out industrial safety article if you have interest in learning industrial safety in details. If you had any suggestion or what us to cover any specific topic then let us know through contact us section.

3 thoughts on “Stages of fire in detail – what are the 4 stages of a fire?”

  1. Fire’s could also be classified into different phases such as; the incipient (first phase) of fire, the rollover phase (warm gases rise), Steady-State Burning Phase, the falshover phase (combustible vapor that’s exposed to the heat rapidly and simultaneously ignites), and lastly the smoldering phase (flames almost begin to die but the burned area is filled with heat and thick black smoke).


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