In order to get a fire under control, a firefighting team will conduct a short risk assessment. When dealing with a flame, it is essential to know the different stages of fire. Recognising the developmental stage of the fire will help the firefighters choose an appropriate tactic for extinguishing the flame.
Awareness of the fire development stages helps firefighting teams to
- find most effective extinguishing method
- minimise risk to firefighting personnel
- predict the progression of the fire
To help minimise the risk to your building during a fire, check out our fire protection services.
An incipient fire is a flame that is still in its beginning stage. Fires in this initial stage can be extinguished or controlled by portable firefighting equipment. Any fire that has progressed to a point where visibility has been compromised by smoke, or structuring firefighting is required, can no longer be called an incipient fire.
An incipient fire can be defined by the following factors:
- flames are small and aren’t widespread
- smoke allows visibility in the room
- the heat emitted from the flame is low (in comparison with later stages)
As we move through the phases of a fire, we come to the second stage – growth. The growth of a fire will be affected by the structure of the building and the fuel available.
The growth phases are characterised by the following indicators:
- there are sufficient oxygen and fuel to support the ongoing growth of the flame
- a defined layer of smoke above the flame
- the temperature in the room increases
- condensation disappears from windows
- brown stains on window glaze may appear
- cracks in windows
It is between the growth and the fully developed stages of fire when a flashover occurs. A flashover is defined as “the near-simultaneous ignition of most of the directly exposed combustible material in an enclosed area.”
After the flashover, the fire reaches the fully developed stage. Out of all the stages of fire growth, this phase is where energy release is at its greatest. The temperature will be at its highest point (generally somewhere between 700°-1200°C).
Fully developed fires can be identified by the following factors:
- darkened or black smoke
- dense smoke
- substantial heat
- blackened window glazing
- visible exterior flames
- flames obscured by smoke
During the final stages of fire, a flame will enter the decay phase. This stage occurs after the fully developed flame starts to run out of fuel or oxygen. Fires can be forced into the decay stage by reducing oxygen supply with firefighting equipment. Limiting the flame to one compartment (or area) will help to contain the available fuel and growth of the fire. It is critical during this phase to limit the fire’s access to combustible material and oxygen. Even if a fire appears to be out, there is a chance of reignition when the right materials are available.
Prevention in Your Building
To make sure your employees have the ability to combat the early stages of fire, make sure you maintain your fire protection equipment. At Jim’s Fire Safety, we test and inspect fire protection equipment for businesses across the nation.
Contact us today for more information about fire protection and prevention in your building. Call now on 131 546 or fill in the online form for a FREE QUOTE.