Fire Dynamics, Firefighter Training, Firefighting

Understanding and Avoiding a Flashover

By Michael Salzano

The International Fire Service Training Association’s (IFSTA’s) Firefighter Essentials textbook defines a flashover as “the temperature in a compartment that results in the simultaneous ignition of all the combustible contents in the space.” However, I don’t care what the book says! Don’t get me wrong, “the book” helped teach us the initial essentials of firefighting—the tip of the proverbial iceberg—that is “enough to get you injured or killed.” However, the book won’t help you at 3 a.m. in a dark hallway with zero visibility and no visible fire. The only thing that will help you is realistic training and remembering the critical signs during a fire’s lifespan. As a probationary firefighter, rookie, or veteran firefighter, it is imperative to have the necessary critical information to help you recognize, prevent, and survive a flashover.

Understanding a Flashover. If a flashover or “full-room involvement” is the leading cause of firefighter injuries and deaths, then you must treat it as the enemy. As cliché as this reads, if you don’t know and study or understand the enemy, how can we defeat it? These basic principles apply to all things successful. As firefighters, we pride ourselves on knowing our equipment. However, sometimes we forget to train on the basics of fire behavior, specifically, remembering when, where, why, and how a flashover will occur.

What is a flashover?  I’ve heard firefighters state that a flashover is “the rapid fire development followed by full-room involvement and finally thermal collapse,” and “the sudden full-room involvement in flame.” These definitions are good to know. However, will you remember them when it matters? The answer is no, but you will care if you or your crew is in the midst of a flashover and doesn’t recognize the signs? Will the book and these fancy definitions really help you when you need it the most? Again, the answer is NO! If you can grab one “nugget” from this article, remember that flashover is a heat-driven phenomenon.” It’s that simple. If the phenomenon is heat driven, it must be your primary and only concern that you constantly monitor and recognize conditions.

Up to this point, I have discussed the simple definition of a flashover and the topic of heat-driven phenomena. Now, to take this topic a step further, I will share my “firefighter” (or “working”) definition of a flashover, which is not a true definition; it is simply what you will hear, personally say, or remember from your personal experiences. You might hear “It’s hot,” “I can’t see,” “get down,” “where’s the fire at?” “Someone get the TIC,” “Hey Lou, are you hot?” “Open the nozzle.”  When these terms are voiced, expressed by fellow firefighters, or thought of at a fire, then a flashover might be imminent.

Factors that influence flashover. Although the obvious signs of a flashover are superheated, uninfluenced gases and heat, there are many other factors that will significantly increase your chance of being caught in one. One of the most prevalent factors that influences impending flashover is building construction with illegal modifications. These include, most notably, concealed spaces, energy efficient / hurricane windows, room size and/or ceiling height, and illegal partitions inside occupancies. You must be aware of these components of building construction. Some of these factors might be known prior to entering the building. However, you must discover others if heat levels continue to rise regardless if cooling or venting has taken place.

Other factors also influence a flashover way before the fire starts. For example, cell phones have aided in ensuring we are arriving faster to the fire scene than we did 15 years ago. Almost everyone has and carries a cell phone and knows how to dial 911 when there is an emergency, specifically a fire. We are being made aware of fires faster, especially those in their incipient phases. In return, we are getting on the trucks and to the scene faster than those who did this job 10 to 15 years ago. That being said, you must not allow your adrenalin to take over your ability to perform your job correctly on arrival. When the bells go off, your natural instincts are to race to the truck, rush getting dressed, and rush to the scene. These factors, once added up, create the potential to make a bad decision or miss a key sign the building may be telling you because you rushed. Unfortunately, the lack of live fire training coupled with fewer fires has altered the amount of experience the newer generation firefighter receives. The fire service becomes complacent because it is not getting the repetition of fires and experience. However, do not use this concern as an excuse for why you are losing firefighters each year to flashovers.

Today’s modern bunker gear allows you to push deeper and farther than ever before. This amazing technology is ultimately a double-edged sword; it acts as a protecting bubble, providing a false sense of security to the firefighter wearing the gear. The vapor, water, and thermal barriers of most bunker gear do protect you but only for a limited time when things go wrong. According to IFTSA Firefighter Principles & Tactics, the bunker gear of today will protect an individual for no more than 15 seconds if succumbed to flashover conditions. Yet, we tend to ignore this fact. More often than not, we find ourselves deeper inside buildings and increasing our chances of being involved in fatal flashover conditions.

Today, fires are much more dangerous than 30 to 40 years ago. The synthetics, plastics, and other “methy-ethel bad stuff” being used to build the furniture and products that typically combust are burning hotter and faster, thereby increasing the intensity and the speed for which the fire travels through the stages.

Now that you know the definition of a flashover, what causes it, and what are the factors that influence it? Start by developing a plan to avoid it. To be successful, you must not be blind to the signs of an impending flashover. To me, being blind (or stubborn) typically involves your will to “keep pushing” until you find the fire and ultimately extinguish it. This is not your fault; it’s simply the fabric from which you are cut when you swore the oath to becoming a firefighter. We all want to be the first one on scene and the first one to stretch the line into the fire and extinguish it. It’s these “bragging rights” that define us as firefighters. We want to succeed, and succeeding means getting to the fire and putting it out.

Early on in my career, I always believed fire was the danger, and that fire would be the single most dangerous element I faced. I have since changed this thought process. I have learned over time and through experience that the true danger is not being able to find the fire when inside a structure because of zero visibility. I’ve learned how important reading smoke and identifying conditions are prior to entering a building. These conditions will forecast what my crews and I will face once inside.

An example of why zero visibility and high heat without visible fire is dangerous would be when you and your crew advance toward where you believe is the location of the fire. If heat levels are doubling and tripling for every 10 to 15 feet, advance the hoseline, and you cannot find the fire while you are being pushed to the floor because of the incredible amount of heat. Alarm bells should be ringing that a flashover is imminent. If not corrected quickly, this is a recipe for disaster and could result in serious injury or a line-of-duty death.

Years ago, many of us were taught to never apply water to smoke. Today, we have completely changed our tune on that outdated tactic. The above scenario clearly dictates that the situation has to be cooled, specifically, overhead. If water does not “rain” down on you after hitting the ceiling (or what is above), then you know the temperature above is well above 1,000 F°.

So, how do you limit and survive a flashover? First, you must remember that not every fire progresses to a flashover, but every fire can. Second, you must not get tunnel vision and miss the signs of flashover. Communication between interior crews is paramount, and you must always have an exit strategy. Regardless, if you are inside the building 10 feet or 100 feet, have a plan and consistently communicate that plan to each other. Search and attack areas must be limited, and interior crews have to be cognizant of how far they have advanced. Use a search rope and be part of everyday search tactics, especially in large occupancies or commercial structures. Finally, always be prepared to “dive or die.” Surviving a flashover means you have approximately 15 seconds of bunker gear protection. Realistically, used gear that has been exposed to heat and elements offers closer to six to eight seconds once you have realized the room is about to flash and your self-contained breathing apparatus (SCBA) mask is still intact.

Limiting your chances for encountering flashover relies on three important factors. First, know and sense the flashover signs and notice the increased heat levels with a thermal imaging camera or your senses. Second, understand the heat-driven phenomenon and the fact that this heat has to be cooled, and quickly. Third, if cooled, the fire needs to be ventilated. Finally, once you have attempted ventilation or cooling and conditions are not changing, put your pride aside and vacate the building. Vacating does not mean you are “going defensive”; it just means you are figuring out what is going on, potentially outside of your view and control. “Regrouping” is a better term that could reveal where the fire is and where another tactic is needed to successfully and safely put out the fire. Your job is to confine and extinguish. If you cannot make this happen and conditions deteriorate, take a step back, reevaluate your tactics, and possibly go another route.    

Remember, anyone inside a fire building not wearing a SCBA is most likely dead, so exercise an aggressive risk vs. reward assessment. A successful tour at the firehouse is when everyone goes home to his family. To accomplish that, be aggressive, chose the right nozzle and line for the job, aggressively sweep the floor and ceiling during advancement, perform vigorous nozzle work, and communicate so the attack and ventilation is coordinated. When you have constantly monitored smoke and heat conditions, aggressively applied the right amount of water, and reduced the chances of flashover, your training and experiences have kept you out of harm’s way for yet another tour. This will keep you alive and give you one more chance to leave the firehouse and go home safe!

Photo found on Wikimedia Commons courtesy of Slick-o-Bot

 

References

International Fire Service Training Association, Firefighter Principles & Practices.

International Fire Service Training Association, Firefighter Essentials.

 

Michael Salzano is a second-generation firefighter and a 15-year veteran of the fire service, serving the last 14 years in the Fort Lauderdale (FL) Fire Department. He is a lieutenant on Engine Co. 2 and a member of the Technical Rescue Team. Mike is the founder and fire training coordinator for the Fort Lauderdale Fire Expo. He has taught Flashover Awareness, Vent-Enter-Search, Engine Company Operations as well as Vehicle Machinery Rescue, Rope Rescue and Trench Rescue to firefighters around the nation. Over the past seven years, Mike has been one of the lead Engine Company Operations instructors at the Orlando Fire Conference. He is a Minimum Standards Fire Instructor at the Coral Springs Fire Academy and has Bachelors Degree in Fire Science Management from St. Thomas University.