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The basics of horizontal ventilation

Horizontal ventilation can be accomplished with hydraulic, natural currents, positive pressure or negative pressure methods

As we pull onto the street, we can see smoke drifting across the road. We know we have a working fire and people are standing out in the street waving to us in a hurrying manner. All kinds of things are going through our heads and we know our job, especially if we are the first arriving company.

The arriving company really has it easy. We pull the line and go for extinguishment or, if confirmed victims are in the building, we search immediately for life.

In some cases, depending on where you are in the country and the amount of resources available, you may be doing both.

Where we are forgetting our responsibilities in some instances is
the second and third companies in.

During recruit school, we teach our candidates about coordinated attack. Simply put, we attack, search and ventilate with a coordinated effort.

However, we know resources are not always available or are late arriving. But, we cannot forget these other tasks of searching and ventilation.

For today’s discussion, we are going to target horizontal ventilation. This does not necessarily mean positive pressure ventilation. It can include that tool, but horizontal ventilation basically means that we force the smoke, heat and gases out of the building through windows and not a hole in the roof.

In my experience, it is also the method most used. Here are some things to consider when we ventilate horizontally.

First, make sure the attack and search crew are made aware that ventilation is being done.

Even if we are just opening windows, if active fire suppression and search activities are happening, it is imperative that we communicate these tactics with them.

Even without a fan, people placed between the fire and the vent hole can be dangerous.

When you decide to ventilate, know where other crews are operating.
Second, have a purpose to your destruction. Don’t just walk around a building breaking out windows.

We don’t want to create an avenue for fire travel into an unburned area if we can avoid it. We also don’t want to create more damage than is necessary.

More importantly, we don’t want to place victims between the fire and the vent hole.

In breaking out windows we also need consider wind direction. A strong wind blowing in the wrong vent hole can cause extreme conditions on the interior.

Third, if we are opening windows from the inside and it is possible to open the top portion of the window, as in double hung windows, it is preferred.

Many times I have seen the bottom part of the window opened instead of the top. It will still vent, but heat and gas want to go high, so create the vent hole as high as we can.

Remove curtains and blinds to keep from blocking the vent hole. Horizontal ventilation can be accomplished with hydraulic, natural currents, positive pressure or negative pressure methods. Which ever method you use, you must know where the fire is and coordinate your operations.

For this article, I’m not going to get into the specifics of each type, but know how and when to ventilate.

The important thing to know is where crews are and where possible victims could be. Understand that horizontal ventilation is not always the best answer. It could push fire, heat and gas into unburned or unaffected areas.

In some of these circumstances, vertical ventilation may be a better option.

Wear your personal protection including SCBA and bring the right tools. Always be prepared for fire when ventilating. That is what we are trying to do, right? Release heat, smoke and fire from the building.

Train hard and train like it’s real. Expect fire and be prepared. I’ll see you next month in “From the Fireground.”

Jason Hoevelmann is a deputy chief and fire marshal with the Sullivan (Mo.) Fire Protection District and a career captain and training officer with the Florissant Valley (Mo.) Fire Protection District. His experience spans more than 20 years, with more than 15 years as an instructor. Jason holds an associate’s degree in paramedic science from East Central College and a bachelor’s degree in fire service administration from Eastern Oregon University. He is a state advocate for the Everyone Goes Home initiative and a board member for the International Society of Fire Service Instructors. He is also co-owner of Engine House Training, LLC. He can be reached at