Rollover occurs when superheated, unburned gases produced by a fire gather at the ceiling and suddenly ignite, sending flames rolling across the upper level of the space. It is a critical warning sign of impending flashover, indicating that the thermal layer is expanding downward and the environment is becoming rapidly untenable for interior crews.
Heard on the job
We had heavy rollover in the hallway, so we hit the ceiling with a straight stream to cool the gases.
Insider tip
When you see rollover, you must immediately cool the upper gas layer with water, or the entire room will flash over seconds later.
Also heard as
- flameover