A flashover is the simultaneous ignition of all combustible material in an enclosed area.
Flashover occurs when the majority of surfaces in a space are heated to the point (known as fire point) at which they give off flammable gases that are hot enough to sustain combustion. Flashover normally occurs at 500 °C (932 °F).
The classic example of flashover is where a piece of furniture is set alight in a domestic room. The fire on the furniture produces a layer of hot smoke across the ceiling in the room. The radiated heat from this layer heats the other surfaces in the room, causing them to give off flammable gases. When the surface temperatures become high enough, these gases ignite and, in the space of a few seconds, every surface in the room may be on fire.