Ventilation Training

Firefighters recognize that the most dangerous part of a fire is not the flames, instead it is the smoke and super heated toxic gasses that the fire produces. More often then not, those who die in a house fire tragically do so because of the suffocating smoke. Beyond the risk for those still trapped inside a burning building, the heated gasses that a fire produces will also cause damage to the building and the items inside as they spread across the structure. That's why we work to remove these dangerous byproducts of combustion as soon as we can. We do this through a practice that we call ventilation.

Our goal in ventilating a building is to remove the toxic superheated gasses and smoke and replace them with cooler fresh air, we can do this in a variety of ways depending on where the fire is burning. If a fire is limited to inside a bedroom we can open a window and place a powerful fan to blow fresh air in through a door way on the opposite side of the house; this allows us to not only remove the toxic atmosphere but it also enables us to control the spread of the fire by pushing it out through the window to the exterior of the home. Once the fire gets into an attic space however our work gets a little more difficult. That scenario is what C Shift at Station 4 practiced last week when they worked on roof cuts at a donated building on 26th Avenue.

To perform this task we start by setting up ground ladders so that we can get on the roof of a building. We then use a special ladder called a "roof ladder" that has hooks on the tip of it so that they secure the ladder to the roof peak and allow us a safe platform to work from. Once there we work with power tools, axes, and long poles to cut a 4' x 4' hole (10' x 10' in commercial structures like apartments, manufacturing facilities, etc.) in the roof above the room where the fire is burning. We carefully cut through the roofing material and plywood sheeting and we work hard to make sure that we do not cut through the rafters or trusses of the roof structure. Cutting through a load bearing part of the roof can weaken the entire roof structure which could be deadly for us. It also makes it more difficult and costly for the homeowner to repair the damage after the fire is out if one of these structural members is damaged.

If you are standing on the street watching us ventilate a roof on a real house fire you may think that we are creating more damage then we are saving. The smoke that was coming from the eaves will begin to burn as it comes out of the ventilation hole. Believe it or not this is all part of the process to extinguish the fire, and actually causes less damage then if we didn't cut the roof. By working this way we create a chimney effect that will make the fire go where we want it to go, and prevent it from spreading across the rest of the home. This chimney effect also allows fresh air to rush in and replace the dirty toxic gasses so that we can quickly get inside the home and find the fire or any trapped victims.