The Why & When of Ventilation

Issue 5 and Volume 7.

When it comes to job functions, ladder companies have historically been tasked with ventilation as their bread and butter function. In ventilation training, a significant amount of time is spent on how to cut a ventilation hole, where to place the hole and what type of ventilation can be accomplished on any given fire. Although these are all extremely important things to know and train on, this article is going to focus on the two questions the younger generation is notorious for asking: when and why.

Ventilation Defined
We’ve all heard the basic definition of ventilation: “the systematic removal or heat, smoke and fire gases from a structure” with the associated benefits of victim survivability, increased visibility, reducing fire spread, etc. This is an extremely important description, as it gives us a solid understanding of this absolutely vital, and often overlooked, aspect of firefighting. With this in mind, let’s move to the “why” aspect of ventilation.

Why Do We Ventilate?
Simply put, we ventilate fire to improve interior conditions and to reduce the chances of getting people (citizens and firefighters) hurt or killed. The most severe event we face from fire is flashover, and ventilation needs to be a priority to reduce the likelihood of this occurring. Another benefit to ventilating: increased visibility, which allows interior crews to perform a rapid search and reduces the chances of crews becoming lost or disoriented.

The materials burning inside structures these days are producing more energy and reaching temperature extremes faster than ever before (Note: Fires are not burning hotter; they’re producing more energy and reaching peak temperatures at a faster rate.), and for us, that means that we can easily expect flashover conditions to build in the time it takes the fire to get reported and dispatched to the time we arrive on scene and start working. Further, whether performing engine or ladder work, each function takes time to set up (pulling handlines, throwing ground ladders, etc.). During this set-up time, fire conditions continue to grow rapidly and may ultimately create a different operational scenario for crews. With that in mind, it’s important to constantly reassess fire conditions and adjust tactics accordingly.

I’ve found that one of the best ways to understand the need for ventilation is to spend some time reading NIOSH firefighter fatality reports (www.cdc.gov/niosh/fire). In many of the reports, inadequate (or non-existent) ventilation was a contributing factor that resulted in the loss of a firefighter. Other reports that point to near misses cite poor or no ventilation as a factor.

When Should We Begin Ventilation?
Ventilation should be considered prior to fire crews operating inside a structure. Because not all fires (or buildings for that matter) are created equally, we should not necessarily hold back fire attack operations until a hole is cut; however, fire growth should be on everyone’s mind. Ventilation is too often an afterthought, only brought up when an interior company is driven to the ground from high heat and low visibility—and then frantically requested.

When dealing with smoke, heat and fire gases, science plays a vital role. In the most basic form, all elements of the fire triangle create pressure and are doing everything they can to equalize pressure by escaping out of the path of least resistance. So when we run into a fire building without addressing ventilation, we’ve essentially made our point of entry the path that fire will take (assuming it hasn’t already self-vented in an area closer to the fire). Because the point of entry is also “feeding” the fire with much-wanted oxygen and without an adequate exhaust, the fire will intensify once crews make entry.

With this in mind, the following are some key points that fire crews should consider:

Situational Awareness: This is where all our lessons on reading smoke play a vital role. If you pull up and see heavy smoke pumping out of every crevice in the structure, make a realistic decision as to the likelihood that anyone is alive inside. Addressing ventilation may seem like an extra step sometimes, but it forces the company officer to get a good scene size-up. Although it’s easy to focus on physically seeing fire, get a good look at the smoke and predict what the conditions will be by the time crews are able to make entry. Get to know building construction as it pertains to ventilation. Certain building types will pose ventilation challenges that will impact tactical decisions.

Keep Different Tools in the Toolbox: One good lesson I’ve learned over time is that there’s not a single “cure all” for everything. Whether you prefer vertical or horizontal ventilation, keep an open mind as to having multiple plans for different ways to vent the structure. Often, the building type and our resources will drive the way we do business, so keep your tactical toolbox full of options.

Entry and Exhaust: This goes back to some of your first days of fire school. When addressing ventilation, make an exhaust on the fire side of the structure, and attack from the unburned side. By creating an exhaust toward the fire, the path of least resistance will be opposite of the entry point of crews making their way interior. If heat and fire are driving you back from the point of entry, take a step back (both physically and mentally) and re-evaluate the game plan—this may mean picking a different point of entry or switching operational strategies.

Make Proactive (Not Reactive) Decisions: Fire conditions change—and they can change fast. If ventilation is needed, ensure that it’s taken care of prior to conditions becoming dire. Getting too deep into a structure and then identifying the need for immediate ventilation is a recipe for disaster.

Train: When trying to accomplish multiple tasks on the fireground, it’s important that everyone knows what to do prior to showing up on scene. Because fire dynamics are constantly changing, company officers should be able to initiate task-level tactics that require everyone to operate on the same page. This often requires training on multiple plans with different objectives.

Final Thoughts
The best way to ensure that everyone goes home at the end of the shift is to do everything possible to dictate the conditions in which firefighters are operating. We’re in the business of shaving seconds off of everything we do, and oftentimes, taking a few extra seconds in the beginning of the fire will drastically save time in the long run. This is why ventilation matters.