General
rollover
What does rollover mean?
When the hot gas layer at ceiling level hits its ignition temperature and flames go rolling across the ceiling, ahead of the main fire. It's a warning sign — flashover is coming if you don't cool the gases now.
"Saw rollover above the doorway and hit the ceiling with a quick pencil of water before it tipped into flashover."
Origin
Fire-service term distinguishing ceiling-level flame propagation from full compartment flashover.
Frequently asked questions
What does rollover mean in firefighting?
It refers to flame rolling across the ceiling as unburnt fire gases ignite overhead — a warning sign that conditions are heating toward flashover.
How do you use rollover in a sentence?
"We saw rollover across the ceiling and backed out before it flashed over."
Is a rollover the same as flashover?
No — rollover is the ignition of hot gases overhead and often precedes flashover, which is the sudden full ignition of everything in the room.
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