Certified Fire Investigator Practice Exam

What is a Backdraft?

1. A sudden explosion of a fuel tank

2. A deflagration resulting from air entering a confined space

3. An explosion triggered by a spark

4. A rapid release of smoke and heat

The correct answer is: A deflagration resulting from air entering a confined space

A backdraft is defined as a deflagration resulting from air entering a confined space. This typically occurs in a situation where a fire has depleted the available oxygen, leading to incomplete combustion. When a fresh supply of oxygen suddenly enters the space—such as through an opening created by a window breaking or a door being opened—combustible gases that have built up can ignite explosively. Understanding backdraft is crucial for fire investigators and firefighters because it presents significant dangers during firefighting operations. Recognizing the signs of a potential backdraft—such as smoke puffing in and out of openings, a darkened room, and the absence of flames—can help in making informed decisions to either ventilate the space safely or avoid unnecessary risks. The other options do not accurately define the phenomenon of a backdraft. Thus, recognizing it specifically as a deflagration that results from the sudden influx of air into a previously oxygen-depleted environment is essential for understanding fire dynamics and ensuring safety during firefighting efforts.