What is the term for the ignition of gases in the upper layers of a compartment?

The term "flameover" refers to the phenomenon where flames and combustion gases in the upper layers of a compartment ignite, typically due to the accumulation of heat and combustibles in those areas. This event is a key indicator of fire progression, as it signals a transition from an incipient stage to a more dangerous phase in which the smoke and vaporized fuels can ignite, creating intense fire behavior.

Understanding flameover is crucial for fire investigators, as it helps them analyze fire dynamics and assess the spread of fire within a structure. Observations of flameover can provide valuable insights into the conditions leading to fire escalation, informing both the investigation process and fire suppression strategies.

While rollover, flashover, and combustion pertain to different aspects of fire behavior, they do not specifically describe the ignition of gases in the upper layers of a compartment. Rollover involves flames moving through hot gases, flashover is a rapid transition to full room involvement, and combustion is a broad term encompassing the chemical reaction of burning. Therefore, flameover is the most accurate term for this scenario.