In which stage of the burning process does rollover occur?

Rollover, also known as "flame roll over," occurs during the explosive growth stage of a fire. This stage is characterized by a rapid increase in fire intensity and temperature, typically following the ignition of combustible gases and fuels in the room. During this phase, the products of combustion, such as smoke and gases, accumulate in the upper layers of the space. When these gases reach a certain temperature and concentration, they can ignite, creating a wave of flames that rolls across the ceiling and down into the lower areas of the space.

The explosive growth stage can be particularly dangerous as it indicates that conditions are becoming increasingly volatile. It highlights the need for firefighters to be aware of the signs of rollover, as it can signal a shift in the fire dynamic that may lead to flashover or rapid engulfment of the environment. Thus, recognizing the explosive growth stage is crucial for fire operations and safety measures.