Which statement best describes Backdraft?

Which statement best describes Backdraft?

• A. It occurs only in open air
• B. It is a rapid ignition due to external flame contact
• C. It is a deflagration caused by chemical chain reactions
• D. It is a deflagration caused by the sudden introduction of air into oxygen-deficient products of incomplete combustion

Answer: (D)

Backdraft occurs when a fire burns in a confined space and consumes most of the available oxygen, leaving hot, fuel-rich combustion products behind. When air is suddenly introduced—by opening a door, window, or vent—fresh oxygen mixes with those hot gases and unburned fuel, producing a rapid deflagration that can unleash flames and pressure. The defining idea is that the explosion comes from the sudden influx of air into oxygen-deficient products of incomplete combustion, not from an outside flame or a generic chemical chain reaction. So the correct description is a deflagration caused by the sudden introduction of air into oxygen-deficient products of incomplete combustion.

Backdraft occurs when a fire burns in a confined space and consumes most of the available oxygen, leaving hot, fuel-rich combustion products behind. When air is suddenly introduced—by opening a door, window, or vent—fresh oxygen mixes with those hot gases and unburned fuel, producing a rapid deflagration that can unleash flames and pressure. The defining idea is that the explosion comes from the sudden influx of air into oxygen-deficient products of incomplete combustion, not from an outside flame or a generic chemical chain reaction. So the correct description is a deflagration caused by the sudden introduction of air into oxygen-deficient products of incomplete combustion.