Which temperature range is widely accepted as corresponding to flashover?

Which temperature range is widely accepted as corresponding to flashover?

• A. 400-900
• B. 900-1200
• C. 1200-1500
• D. 1500-1900

Answer: (D)

Flashover is the rapid shift in a room from isolated burning to almost instantaneous ignition of all fuels in the space, driven by the buildup of heat in the gas layer until it reaches a threshold where ignition of contents occurs across the room. The temperature range commonly cited for this transition is about 1500 to 1900 degrees Fahrenheit, which reflects the extreme heat level in the upper layer that drives everything to ignite almost simultaneously. At this level of heat, the radiant and convective heat fluxes are sufficient to ignite many fuels on contact, causing the entire space to engulf in flame. The lower ranges represent earlier heating stages where ignition is not yet simultaneous, while higher ranges would indicate conditions well past the moment of flashover, not the threshold at which flashover occurs.

Flashover is the rapid shift in a room from isolated burning to almost instantaneous ignition of all fuels in the space, driven by the buildup of heat in the gas layer until it reaches a threshold where ignition of contents occurs across the room. The temperature range commonly cited for this transition is about 1500 to 1900 degrees Fahrenheit, which reflects the extreme heat level in the upper layer that drives everything to ignite almost simultaneously. At this level of heat, the radiant and convective heat fluxes are sufficient to ignite many fuels on contact, causing the entire space to engulf in flame. The lower ranges represent earlier heating stages where ignition is not yet simultaneous, while higher ranges would indicate conditions well past the moment of flashover, not the threshold at which flashover occurs.