What characteristic is indicative of rollover in a fire?

The characteristic indicative of rollover in a fire is flames propagating through the hot gas layer at the ceiling. Rollover occurs when the flammable gases that have accumulated in the upper part of a compartment reach their ignition temperature. As these gases ignite, flames can spread horizontally through the gas layer, often leading to an explosive fire behavior if not managed properly.

This phenomenon highlights the critical nature of smoke and heat management during firefighting operations, as it signals a significant increase in risk due to potential flashover conditions. Recognizing the signs of rollover is essential for firefighters to take appropriate action to mitigate dangers before they escalate.

Understanding this detail is also crucial for effectively preparing personnel for situational awareness and safety protocols during interior firefighting operations. It emphasizes the importance of monitoring conditions at the fire scene, including the temperature of the smoke layer and any visible smoke and flame behaviors.