We spoke with the Secret Firefighter and had him break down this impressive backdraft video that was sent in to us. This is a great training tool if your station is trained in offensive firefighting. Here’s what he had to say!

Backdraft has not been a common occurrence during firefighting operations in the past but are we teetering on the edge of this extreme fire behavior becoming as common as Flashover or fire gas ignition? Modern fire behavior would suggest this is the case with our building construction methods and aim to be as energy efficient as possible all contributing to the necessary requirements for a backdraft to occur.

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We also educate the community to close doors if safe to do so when evacuating their house during a fire which also may be a contributing factor for backdraft becoming more common.

The fire is well developed
The fire is well developed

Looking at this video you can see a well developed fire in the container and then the container is closed up restricting the amount of oxygen required for combustion to take place and as a result the fire would decay back into a smoldering state, the history of the fire is an important aspect when conducting a size up.

Checking the fire tetrahedron, air is the critical element required for the extreme fire behavior of backdraft to occur.

Dirty smoke being released
Dirty smoke being released

In the video above when the container is opened smoke is released with some pressure and has a dirty yellow tinge to it, this is a result of dark smoke from when the fire was burning mixing with lighter colored pyrolysis smoke produced once the container was shut and the heat still causing the decomposition of the fuels.

Unlike the movie, the backdraft takes some time to occur this could be a result of the size or location of the opening restricting the air intake and in turn slowing the necessary premixing of fuel rich flammable fire gases and air entering their flammability range.

Judging by the impressive deflagration I would suggest that the flammable gases were very close to their ideal mixture.

WHOOSKA
WHOOSKA


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