Which is Worse: Fire or Smoke?
Contrary to what may be most commonly understood by non-firefighting professionals, one of the main risks of a fire is the smoke. This is because smoke carries heat and poisonous gases and makes is difficult to see. Which means reducing the smoke can save lives and make it easier to contain the fire.
In the case of a fire inside a building, here are two common strategies:
1) Isolation of the fire
Both of these involve controlling the flow of air around a fire to influence where a growing fire may or may not go.
Isolation of a fire can be as simple as closing an open door or window to diminish available oxygen and thereby reducing the chances of a fire expanding to that area.
Tactical ventilation involves opening paths where air can flow with the intent of controlling the behavior and direction of a fire. Again, this type of control is meant to help maintain the life safety of both firefighters and civilians, even if it means directing the fire into unburned areas of a building, for example, where there are ‘not’ occupants.
A common example of tactical ventilation in many cases of structural firefighting is opening a 4×4 foot hole into the roof directly over the fire room. This allows hot smoke and gases to escape through the opening.
It is important to coordinate such ventilation with interior firefighters since the opening of a ventilation hole supplies more air to the fire, which can accelerate the fire.
The main point here is that it is necessary to have an exit for the smoke and not let it thickly accumulate inside, which is deadly by itself and makes it more difficult to put out the fire. Determining ventilation tactics requires having an awareness of the building layout and fire location to predict where the smoke will go, and then opening and/or closing strategic doors and/or cutting holes in critical locations to direct the fire.
As stated earlier, this method may also accelerate the fire itself, so it’s important to have an awareness of other dynamic factors as well, such as where occupants may be, where firefighters are located, accessibility of equipment, how fast the fire is burning, etc.