Truck Tactics: Vertical Ventilation: Gable & Louver Vents

One of the most important tasks on the fireground is coordinated ventilation. In some areas, the procedure might be executed by a dedicated truck company; in others, it might be completed by whomever the incident commander or operations officer designates for the operation.

 

It doesn’t matter who does it, as long as the task is completed in a timely manner in a coordinated effort with the companies that are knocking down the fire or are opening up to create enough lift in an area to make a rescue.

 

All of us who are in the fire service understand that the fireground is an ever-evolving environment that has a plethora of variables that might occur as a result of every single action that we take. One of the most debated topics at the firehouse kitchen table or in the lounge in the back of the bay is vertical ventilation.

 

For the purposes of the discussion that’s presented in this column, the concept of vertical ventilation is centered on opening up a roof to relieve toxic gases, byproducts of combustion, smoke, heat and fire.

 

Working on a peaked roof has become somewhat taboo and, as a result, a lost art of truck company operations. We all understand that firefighting is inherently dangerous, and all of the tasks that are executed are vitally important. Removing smoke and heat through ventilation tactics allows for more than just good photos and videos to post online. When we remove those elements from a structure or building, it allows for light to enter the space and fresh air to take the place of air that’s charged with particulates and ultra-heated soot. As a fire is extinguished and being knocked down, energy is being transferred and most likely follows the path of least resistance, including openings, such as windows, vents and stacks in a structure or building.

 

In many U.S. departments, making the roof of a house that has a peaked roof and opening it up is an initial go-to option for a truck company when a fire has taken off in the attic or when there’s a buildup of an exponential amount of heat and smoke in the attic. In the process of “popping the top,” “making open,” “opening up” or whatever the department calls it, firefighters are committed to obtaining a position to use a variety of tools to remove the roof sheathing and potentially push down the ceiling to create that ventilation channel.

 

In many places, the tool selection might include axes, mauls, chainsaws or rotary saws. In some places, members might access a roof from a ground/portable ladder, a roof ladder or an aerial device. Every department is different.

 

The roof is one of most dangerous areas to operate. Firefighters can slip and fall off. They can fall into a ventilation opening while in the process of the act. The roof decking or the whole system itself can fail, which can cause a firefighter to fall in.

 

Firefighters should spend only enough time on the roof to complete their task. Get up, open up and get down.

 

On the opposite side of things, a well-executed, coordinated ventilation opening has the potential to create a deus ex machina, or God from the machine, effect on the fireground. Smoke lifts, and the engine company has a perfect view of the fire for a knockdown. Other fighters have enough visibility to confirm searches. Potential victims’ survivability profiles increase greatly. This only can happen when the firefighters who are tasked with opening up the roof are able to timely make the roof and execute the task. What about when things aren’t so perfect?

 

As we all know, the world works in funny ways, and nothing is perfect. We always can learn and get better from every incident at which we operate.

 

What happens if the aerial is unable to make the roof because of the positioning of other apparatus, buildings, trees or overhead obstructions? Are the truck chauffeur and aerial operator at least able to reach one end of the peaked roof or a dormer of some sort?

 

Depending on your jurisdiction, the structures and buildings that have peaked roofs might vary. Some of these structures and buildings might have engineered gable/roof vent points. Often, these might be as simple as a 12 x 12-inch vinyl cover that has a screen to prevent bugs from entering the attic. In some places, you might encounter the older, passive moving louvers from a power vent system. Elsewhere, you might find ornate openings that are made of hardwoods.

 

The gable/louver vent allows a home to breathe naturally, to let air flow in and out to avoid the buildup of condensation. Even in the newest, most-efficient homes, these vent concepts still exist.

 

Why is this important? If you must open up the roof and can’t make a workable position with an aerial or a ground ladder, work to remove these gable/louver vent points. Keep it simple. It often takes a couple swings and a pull of a hook.

 

The screen on a vent point or window has the potential to restrict as much as 50 percent of smoke/air flow.

 

The initial step in the opening up process if you have access to it: Clear out the opening. Heat and smoke will travel in an upward trajectory following the path of least resistance in the atmosphere.

 

Merely removing a natural engineered opening in the structure or building is nothing new, but why not extend these vent points even more? Sometimes if the operation calls for it, we extend windows and evolve them into doorways; in some operations, standard doorways are made into garage doorways.

 

In the event that you don’t have great positioning but still are able to make a window and “gable/louver” target, make your own opening.

 

One thing to remember is to not get caught in the overall tunnel vision of the task. If firefighters remove a window completely, that is great but only half the battle.

 

In the event that there’s extension above and/or smoke buildup in the attic space, there still is a need to open up above.

 

In suburban regions and areas that have newer construction, there should be a ceiling between the top floor and the attic space, which must be dropped to allow for the air movement to take place efficiently. On the other hand, in urban environments, there might be a completely finished attic apartment or bedroom that creates other variables for the operation. In some areas that are unkept or run down, there might be nothing in those rooms. Such a circumstance can create pockets/voids/divisions of the area. As with everything, building construction plays a vital role in decision-making processes.

 

Opening up a gable/louver vent is easy work. If you are able, make it bigger and overextend the opening—whether it’s a triangular or square base—similar to how you would extend your ventilation cut on the roof itself, to create a larger ventilation point.

 

If there is no designed gable/louver vent, make your own. Create a triangular or square opening that allows air movement in the respective area. Using a chainsaw allows you to rip the respective area with the respective depth of the bar.

 

Be mindful of the building construction and materials that were used. In theory, building materials should reflect the era and type of building that was constructed. The best way to find out is to get out and walk your streets and to pay attention on all incidents.

 

Many newer houses are built with engineered materials, such as Hardie Boards and modern farmed lumber. You needn’t overcomplicate a simple task, but you must understand the components that can change your process.

 

One negative of this concept is if the vent point isn’t as close as possible above the fire and, thus, doesn’t create an ideal chimney effect.

 

At the end of the day, you’ll conduct your ventilation operations however that you deem necessary. The process might involve removing all of the windows above the fire floor; it might involve opening up the roof and pushing down a ceiling; perhaps you only will use designed and natural ventilation points. Whichever way that you do it, understand the why, the how and the when.

 

One constant is the capability for heat to rise and seek the path of least resistance. If you’re behind the eight ball and end up with less-than-ideal aerial positioning but can make one end of the roof or a dormer, make your own gable/louver vent point.

 

There are pros and cons for every action and decision that’s executed at a job. Have the conversation, be prepared when the tones go off and get to work.