Most of us have seen the movie Backdraft – starring Kurt Russell. In real life, backdraft does occur – maybe not just like in the movie – but it does occur. Signs of backdraft can be detected, and this phenomenon can be prevented if the proper techniques are utilized.
What is Backdraft?
Backdraft is basically an oxygen induced explosion. When oxygen has been burned from a fire inside a structure, the unburned and combustible gasses will remain and slowly begin to cool. If those gasses are not completely cooled before a supply of oxygen is present, they can reignite and violently explode.
A simple mistake such as improperly opening a window or door can easily feed oxygen to the unburned gasses – which will refuel those gasses – resulting in an instantaneous combustion of all unburned materials and fire gasses, producing the backdraft.
Signs of Potential Backdraft in a Structure
There are a number of signs that point to backdraft:
- brown-yellowish smoke that seems to be pressurized
- smoke exiting the structure as if it is "puffing"
- black stained windows with heat and smoke present inside
- vibrating or rattling noises coming from the structure due to internal pressure
If any of the above signs are noticed at a burning structure, take extreme caution before entering or attempting rescue. Other techniques to prevent backdraft might be needed if these events occur.
Preventing Backdraft
Normally, backdraft can be prevented with the proper techniques and methods. If the above signs of backdraft are noticed in a structure, it would be a wise idea to inform the Incident Commander of the situation so he/she can determine what steps will be needed to prevent the backdraft as well as any personal injury.
Backdraft is most commonly prevented by properly ventilating the room or rooms of concern. This type of ventilation is normally performed from the roof on single story structures and can be performed from the above floor on multi-story structures. Windows and doors can also be used to ventilate the structure – only if it is safe and the ventilation is properly performed.
Structure Fire Ventilation
Proper ventilation of a structure will normally eliminate the hazards from backdraft. Before attempting to ventilate a structure, always have a charged line (fire hose) available and ready. When a structure is ventilated, oxygen will enter the structure and the fire will normally grow very quickly (but without the backdraft hazard); and will need to be controlled.
Roof venting is commonly performed with a chainsaw or a hand axe. A section of roof is carefully removed from the structure and the internal ceiling is punctured – allowing the pressurized hot gasses to exhaust through the roof of the structure. Once this has completed, oxygen will normally flow through the ventilation hole and other areas of the structure and re-ignite the fire – which can be quickly controlled and extinguished by other personnel.
Resources:
Fire Safety Practices – Preparing for and Surviving a Home Fire
Home Protection and Safety – The Fire Extinguisher in the Home
Steve Farmer - Steve Farmer Jr. is an individual of many interests and hobbies. When not spending time with his wife and four children, he is an employee ...
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