Ventilation could be defined as the removal of smoke and hot fire gases from a burning structure. There are several situations where ventilation should be used and include fire attack, fire control, search and rescue and overhaul. As officers we have a choice of basic ventilation techniques to remedy each of these situations. This paper will be discussing vertical ventilation and its pros and cons, the resources needed to carry it out, and the best application to use.
Vertical ventilation allows heat and smoke to travel upwards and out of a structure. In a single family residence of one story the effects are noticed immediately. The vent crew (usually two men on the roof for a residence) begins by removing any existing vents or chimneys that may already exist. If this is not enough, then cutting a hole is needed. Fully protected, these firefighters also need cutting equipment, ladders, a charged hose line, and two means of escape. Firefighters should make cuts as close to the seat of the fire as possible. Once the cutting is done and venting has begun, it’s time to vacate the roof and get back to the ground and safety.
Vertical ventilation works because as we all know, heat rises. This is a natural movement and as the heat rises, it will take the smoke and hot gases with it out of the vent hole. It could be said that this is the most effective type of ventilation because it speeds the natural process along. When done properly, vertical ventilation reduces, prevents, or stops the mushrooming of gases and smoke and makes interior conditions clearer and safer.
There are, of course, drawbacks to using vertical ventilation. As the officer, you are placing at least two firefighters in a dangerous spot to accomplish a needed task. There is the risk of structure or roof collapse, disorientation from heavy smoke conditions, and or stepping off the roof by accident. Vertical ventilation is time consuming and many times impractical. If it is a multi-story structure and the fire is on the first floor, it may be better to use a different type of ventilation. Some roofs are extremely difficult to open up, which takes a long time and exposes your men to more risk. Not only having at least two men on the roof is required, others are needed for ladder placement, hose line work, and extra tool retrieval if needed. So it is easy to see that vertical ventilation takes extra resources. By comparison, breaking windows from the outside to effect horizontal ventilation takes one firefighter.
With adequate personnel, a department can perform vertical ventilation and other operations at the same time. Fire containment and extinguishment is most effectively accomplished with vertical ventilation. Search, rescue, and overhaul have other ventilation options that departments with limited personnel can perform. The goal in controlling the fire is to stop the horizontal and or vertical spread of the fire and vertical ventilation is best at doing this.
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