Understanding, Anticipating & Avoiding Flashover

Staying safe in extreme fire conditions starts with understanding fire behavior

By Ed Hartin
Published Friday, August 1, 2008 | From the August 2008 Issue of FireRescue

It goes without saying: Firefighting is dangerous work. Responding, for example, to a compartment fire, firefighters are faced with dynamic, rapidly changing conditions that present a significant threat to building occupants and firefighters alike.

We often make rapid strategic and tactical decisions based on our experiences and expectations of how the fire will behave. In 1948, fire scientist Harry Gisborne made several observations about wildland firefighters’ experienced judgment that can apply to structural firefighters today: “For what is experienced judgment except opinion based on knowledge acquired by experience? If you have fought fires in every type of building with every different configuration and fuel load, under all types of conditions, and if you have remembered exactly what happened in each of these combinations, your experienced judgment is probably very good.”1
None of us, of course, has this level of experience. The ability to read the fire, anticipate fire development and take appropriate action depends on integration of experience with a sound understanding of practical fire dynamics, coupled with an appreciation of our own limitations.

Wildland firefighters use the term extreme to describe “a level of fire behavior characteristics that ordinarily precludes methods of direct control action …”2 This term “is framed within the context of our perception with ‘extreme’ defining our limited ability to control it and its potential impact on firefighter safety.”3 Extreme can also be used to describe flashover, backdraft and smoke explosion in the structural firefighting environment. This article addresses the most common of these phenomena: the flashover.

Fire Development & Flashover
There are a number of definitions or ways to describe flashover. Basically, it’s a rapid transition to a fully developed fire. But it’s not unpredictable. Understanding this phenomenon and how it occurs is critical to firefighter safety.

A fuel package such as a couch burning in open air progresses through four phases:

  1. In the incipient stage, the fire is small and involves only a small amount of fuel.
  2. As the fire moves into the growth stage, more fuel becomes involved and the speed of the combustion reaction increases.
  3. Eventually, the entire object becomes involved and the fire is fully developed.
  4. As fuel is consumed, the fire begins to decay.

Throughout this process, fire development is fuel-controlled. The speed of fire development and energy release is dependent on the characteristics and configuration of the fuel,  in this example a couch.    
The heat of combustion is the energy released when a specific mass of fuel is completely burned. The total energy released when an object burns is dependent on the heat of combustion and the amount (mass) of fuel burned. However, this only provides part of the picture. 

When fuel burns inside a compartment, fire development becomes influenced by the characteristics of the compartment. Thermal energy released by the fire that’s retained in the compartment increases fuel temperature, which, in turn, increases the speed of combustion. The most significant difference with fire in a compartment: the compartment’s ventilation profile. The size, location and configuration of openings in the compartment influence both the oxygen available and the retention or escape of thermal energy in the hot gases and smoke produced by the fire. The speed of this energy’s release is the heat-release rate.
All of this is very interesting, you may say, but what does this have to do with flashover? As it turns out, heat-release rate has everything to do with flashover.

If the fire releases energy faster than it can escape from the compartment, temperature will increase; and if sufficient energy is released, flashover will occur and the fire will transition rapidly from the growth stage to the fully developed stage. As this occurs, the fire will spread across all combustible surfaces in the compartment and flames will exit through compartment openings.

Ventilation & Flashover
In the incipient and early growth stages of a compartment fire, the speed of fire growth is fuel-controlled, with fire development substantially influenced by the chemical and physical characteristics of the fuel. However, oxygen is required for fuel to burn and release thermal energy. As a compartment fire develops, the available air supply for combustion becomes more important. Increased combustion requires more oxygen, and as smoke fills the compartment, it restricts the flow of air into the compartment (see Figure 1). As the fire becomes ventilation controlled, heat-release rate and fire growth are limited by the available oxygen supply.

For many years firefighters have been taught that ventilation reduces the potential for flashover. Although this is often true, it’s only part of the story. Increasing ventilation to a fuel-controlled fire will allow hot gases to exit, transferring thermal energy out of the compartment and replacing the hot gases with cooler air. The combined influence of these two factors slows progression toward flashover and increases the heat-release rate required to reach flashover.

On the other hand, when a fire is ventilation controlled, heat-release rate is limited by the available oxygen. Under ventilation-controlled conditions, increased air supply (ventilation) results in increased heat-release rate and establishes a path for fire travel, which may result in flashover.

Case Study
In 1999, two firefighters in Washington, D.C., died and two others were severely injured as a result of being trapped by flashover.4 The fire occurred in the basement of a two-story townhouse-style apartment (two stories in the front, three stories in the rear). The first-arriving crew entered the first floor from the front of the building to search for the seat of the fire. Another crew approached from the rear and made entry to the basement through a patio door. Due to confusion about the configuration of the building and command’s belief that the crews were operating on the same level, the crew at the rear was directed not to attack the fire. The additional air supplied by these changes in ventilation resulted in a rapid increase in heat-release rate and subsequent flashover.

The National Institute for Standards and Technology (NIST) performed a computer simulation of fire dynamics in this incident.5 Figure 2 illustrates the timing of changes to the ventilation profile and resulting influence on heat-release rate.

As this case illustrates, the location and configuration of exhaust and inlet openings determines air track (movement of smoke and air) and the path of fire spread. When a compartment fire reaches flashover, flames extend out of compartment openings, often into adjacent compartments, following the air track to the exhaust opening.

At this incident, the patio door to the basement acted as an inlet, providing additional air to the fire. The front door and windows on the first floor opened for ventilation served as exhaust openings and provided a path for fire travel when flashover occurred.

Reading the Fire
Fire behavior indicators include a wide range of factors that firefighters may see, hear or feel. Some factors are relatively static (i.e., building construction) and others are quite dynamic, changing as the fire develops (i.e., smoke conditions and flames).

Figure 3 lists indicators of potential for flashover.6 The left column focuses on flashover potential during the growth stage, while the right examines indicators of potential for ventilation-induced flashover. (Note: Many of these indicators are common to both vent-induced flashover and backdraft.)

Staying Safe
Training is often focused on what to do when things go wrong. But if firefighters must react to the occurrence of extreme fire behavior such as flashover, it’s already too late. Turnout gear and SCBA, as the last line of defense, provide limited protection. Most firefighters who have been severely injured and killed by flashover were wearing appropriate personal protective equipment (PPE) but were incapacitated by extreme thermal insult and unable to escape the fire building. Firefighters must place much more emphasis on staying out of trouble than on what to do when faced with the last few minutes of their lives!

Firefighters must read the fire on an ongoing basis throughout the incident and maintain an awareness of changing conditions. Recognizing the potential stage of fire development and if the fire is in a fuel or ventilation-controlled burning regime provides a starting point for managing the risk of flashover. However, firefighters should be proactive and control the fire environment to prevent flashover whenever possible.

Managing the risk of flashover should include the following:

  • Wear your PPE properly. Although this is the last line of defense against being injured or killed by flashover, it needs to be one of the first steps that you take.
  • Read the fire and watch for changing conditions and indicators of flashover potential. This is everyone’s job. If you see something, say something!
  • Identify and maintain an awareness of potential escape routes (alternate exits) and areas of refuge (uninvolved compartments). Although the best approach is to control the environment and prevent flashover, it’s important to be able to escape if conditions change.
  • Identify the current ventilation profile and how changes to ventilation may influence fire behavior. Control the air track to limit potential for flashover. Remember that your access point is a ventilation opening (inlet, outlet or both).
  • Do not perform tactical ventilation (increasing air supply to the fire) until a charged hoseline is in place.
  • Reduce the temperature overhead by applying brief pulses from a fog stream into the hot gas layer while moving to a point where direct attack on the fire is possible. This should not wait until flashover is imminent; rather, it must be an ongoing process when hot gases are present.

Conclusion
Remember, protecting yourself from flashover requires proactive—rather than reactive—firefighting based on a solid understanding of practical fire dynamics integrated with experience. If you or your crewmembers see indicators of flashover, speak up! A scene as dynamic as the fireground requires constant vigilance and anything less can quickly prove deadly.  

REFERENCES

  1. Gisborne, H. (1948) Fundamentals of fire behavior. Fire Control Notes 9(1), 13–24.
  2. National Wildfire Coordinating Group (NWCG). (2006). Glossary of Wildland Fire Terminology.
  3. Close, K. (2005) Fire behavior vs. human behavior: Why the lessons from Cramer matter. Paper presented at the Eighth International Wildland Fire Safety Summit, Missoula, Mont.
  4. National Institute for Occupational Safety and Health (NIOSH) (1999) Death in the Line of Duty, Report 99­-21.
  5. Madrzykowski, D. & Vettori, R. (2000). Simulation of the Dynamics of the Fire at 3146 Cherry Road NE Washington D.C., May 30, 1999, NISTR 6510.
  6. Grimwood, P., Hartin, E., McDonough, J., & Raffel, S. (2005). 3D Firefighting: Techniques, Tips, and Tactics. Stillwater, Okla.: Fire Protection Publications.
     

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A flashover demonstration being conducted at the Swedish Rescue Services Agency in Revinge, Sweden. Photo Ed Hartin
Figure 1: As combustion takes place in a compartment, a lack of oxygen and the retention of gases and smoke lower the neutral plane, creating conditions ripe for flashover. Photos adapted from National Institute of Standards and Technology, ISO-Room/Living Room Flashover
Figure 2: Heat-Release Rate Curve. From Simulation of the Dynamics of the Fire at 3146 Cherry Road NE Washington D.C., May 30, 1999, NISTR 6510 (p. 14) by Dan Madrzykowski and Robert Vettori, 2000, Gaithersburg, MD: National Institute for Standards and Technology
Figure 3: Indicators for potential flashover


Flashover Simulators Provide Life-Saving Training

Firefighters can learn the indicators of flashover in a safe, realistic training environment

By Charles L. French Jr
Published Wednesday, December 1, 2010 | From the December 2010 Issue of FireRescue

The first time I heard the words “the Swede,” I was watching a movie called “Heartbreak Ridge” starring Clint Eastwood as a rough and tough Marine Gunnery Sergeant trying to train a group of misfit recon Marines. One of them, a large, muscle-bound guy who’d just got out of the brig, was nicknamed “the Swede.” Eventually, Eastwood’s character faced off with the Swede and knocked him out with one great punch to the chin.

I remembered that scene recently when my department acquired a Swede Survival System flashover trainer. Although these two Swedes are very different, the lesson I learned while watching “Heartbreak Ridge” applies to flashover training as well: Understanding the hazards that you may face and being ready for them is a formula for survivability in almost any situation.

Although my department uses the Swede Survival System, other flashover trainers are available. This article will focus on the broader concepts in flashover training and what a flashover trainer can provide.

Flashover 411
A flashover is a transitional phase that happens between the growth stage and the fully developed stage of a fire (see figure). During a flashover, all the objects within a space are heated to their ignition point due to thermal radiation feedback. Auto ignition of all the contents, including the smoke, occurs in the room almost instantaneously, and the entire space is consumed by fire.

The temperature range in a room when flashover occurs lies somewhere between 900 and 1,200 degrees F. The heat produced by flashover is not survivable for more than a few seconds, even when wearing full PPE and SCBA. If you survive such an event, you’ll likely be severely burned.

We’re faced with the possibility of a flashover at every fire we respond to. With the development of smoke detection systems and traffic-control devices, we’re getting on scene faster than we did years ago, and this means we’re more likely to go into a structure before flashover occurs. Products of incomplete combustion (smoke) are basically fuel; when we enter these structures, we’re “swimming” in that fuel.

Carbon monoxide (CO) is also present at every fire, and it’s a contributing factor to flashover as well. The auto-ignition temperature of CO is 1,128 degrees F, similar to temperatures found during flashover. Therefore, there’s a real possibility that flashover conditions may exist or could rapidly develop during interior operations at any fire. Without an understanding of and ability to recognize flashover conditions, personnel are at great risk of serious injury or death.  

Learning from Oklahoma City
On March 8, 1989, at 0809 hrs, three Oklahoma City firefighters died during a routine house fire that involved a small, single-story, two-bedroom home. The cause of all three deaths was attributed to a flashover that occurred within minutes of an interior fire attack being initiated. The effect on the department was devastating, to say the least. At the time, the Oklahoma City Fire Department had not lost a firefighter in the line of duty in 39 years.

During the incident, flashover indicators were present, with high levels of heat and heavy smoke being reported by first-in companies. However, the fire gave a false indication that it had vented itself through the roof. Unknown at the time to the fire crew operating inside was that the house had two additions. The fire they saw outside the structure was between an existing roof and one of the two added-on roof coverings.

The fire crew gained access through the front door while carrying a preconnected hoseline. Once inside, they crawled through a 30' living room to a doorway toward the rear of the house, where they found what they thought was the seat of the fire in a bedroom. They knocked down the main body of the fire and thought it was extinguished, so they put down their hoseline and made their way toward the exit for reassignment. That’s when the flashover occurred. The additions made to the house held in a tremendous amount of heat, which built up, contributing to the flashover.

One positive outcome of this tragedy: The citizens of Oklahoma City passed a 0.0075 cent sales tax increase, earmarked to help better equip their fire department and to train its members. Needless to say, however, the price that this community paid and the lives that were affected by this event should not be the way to secure fire service funding.

Flashover Indicators
The most effective way for firefighters to minimize their risk of being caught in a flashover is by maintaining an awareness of developing fire conditions and controlling the fire environment with effective water application and ventilation tactics (IFSTA 5th Ed). Flashovers push out of openings, such as doors and windows, faster than a firefighter on their hands and knees can move. When a flashover happens, you may not have enough time to escape, which is why it’s so important to practice your firefighting skills and understand the indicators of a flashover.

A flashover can present itself in a variety of ways during a fire incident. The following are indicators that an impending flashover is about to occur:

  • Buildings: Flashover can happen in any type of structure, but certain building features and contents contribute to how fast a flashover can develop, including fuel load, ventilation profile and thermal properties. The size of the room is also a contributing factor; the smaller the room, the faster flashover conditions can develop. Contents also add to the hazards. The synthetic materials commonly used today have a higher heat release rate than natural products and therefore create flashover conditions much faster than in years past.
  • Smoke: Smoke build-up, density and pressurized movement are typically strong indicators of an impending flashover. Remember: Smoke is a fuel, and smoke conditions indicating a rapidly developing fire should not be ignored. After making entry, the presence of thick black smoke, hot gases and layered smoke are strong indicators that a flashover is about to occur. Heavy smoke banking down with increased heat, keeping firefighters on their hands and knees, is also a strong predictor.
  • Air flow: A strong air current in which air is moving inward and smoke is pushing out should also be a flashover indicator to fire personnel. This is when ventilation can be helpful, if performed correctly, in controlling the heat build-up within the structure. Vertical ventilation can help channel the smoke and the hot gases out of the fire area, reducing the possibility of flashover. However, if ventilation isn’t performed correctly, it can be a contributing factor in a flashover situation.
  • Heat: Rapidly increasing temperature or high heat build-up is also a strong indicator of flashover. However, this is usually a late indicator and means that everything in the room is about to ignite.
  • Flames: The combination of flames traveling out of the hot gas layer and smoke (sometimes referred to as “snaking” or “ghosting”) is another indicator to watch out for. This can be confused with rollover, but it precedes rollover behavior and exhibits a snake-like movement pattern that moves more slowly than rollover flames. The problem for firefighters with this indicator is that it may not be visible due to the smoke conditions in the structure. A thermal imaging camera (TIC) can help firefighters see through the smoke and identify this condition.
  • Rollover: This is an event in which the unburned gases accumulate at the top of a compartment and the smoke ignites, then flames begin to propagate through the hot smoke and gases and roll across the ceiling. Rollover will precede flashover and is a strong indicator that an impending flashover will occur.

Flashover Training
Now that we’re aware of the indicators associated with flashovers, how do we train and gain the necessary experience to be able to recognize them? Flashover simulators like the one my department acquired are an excellent way to train firefighters in safe, yet realistic conditions.

A flashover simulator works like a split-level room, with an upper level for the flashover to occur and a lower level in which firefighters can observe the conditions of the upper level. On the top level, plywood panels used for the fire load are inserted on the walls and ceiling. Then a 55-gallon drum stuffed with wood scraps is set up as a burn barrel to help get the fire started. Once everything is set up, the firefighters and instructor(s) crawl into positions on the floor of the lower level. They watch as the smoke builds and banks down to the level of the floor of the upper container. They can observe the conditions of a flashover begin to develop, as “snaking” of flames begins to stream out into the smoke. Then a small air vent on top of the flashover simulator is opened, and almost instantly, the smoke above the firefighters turns to flames.

To control the flames in our simulator, we use a pre-connect with a fog nozzle and apply three straight bursts from one side to the other, then reverse our pattern with three quick medium-sized fog bursts. At this point, we rotate and watch the whole thing again until each member has taken a turn on the hoseline. This gives everyone a chance to watch a flashover take place several times, become familiar with the indicators of flashover and learn how just a little bit of water, with effective nozzle tactics, can cool the atmosphere.

Firefighters get to see how smoke builds and stratifies, and how it banks down and out when it has no place to go inside a compartment. They get to feel a bit of the heat associated with a flashover and see how untenable conditions are in a room that’s flashed over, making search-and-rescue operations pointless. Finally, they get to learn how, with just a small amount of water from a hoseline, they can change the conditions and cool down the atmosphere without creating a disruption of the thermal balance in the room.

I’m sure some of you reading this article are thinking, “This sounds great, but my department could never afford one of these props.” But grant funding can help, and you may be able to pool resources with regional training centers, community colleges or state training agencies. You can also look into conferences where such classes are offered. Even a few times through a flashover simulator can provide invaluable experience.

Conclusion
Although a flashover simulator does not actually produce a “true” flashover, it can provide an excellent opportunity to teach and recognize the signs of an impending flashover and how to effectively prevent it, thus improving your chances of survival. Training combined with experience allows us to develop the skill sets and knowledge we need when we go to combat, keeping us from becoming another fatality statistic.

If nothing else, I hope you’ll gain more knowledge about flashover and study the warning signs so that you know what to do if you ever find yourself in these dangerous conditions during a fire incident.

Resources

  1. Oklahoma City Flashover [DVD]. American Heat Video. 1989.
  2. Swede Survival System. Drager Safety Inc. 2008. Retrieved Dec. 31, 2009. from www.swedesurvival.com.
  3. Flashover. Firetactics.com/3D Firefighter. 1999–2008. Retrieved Dec. 31, 2009, from www.firetactics.com/FLASHOVER.htm.
  4. Goodson C, Murnane L, eds. IFSTA Essentials of Firefighting and Fire Department Operations, 5th ed. Fire Protection Publications/Oklahoma State University: Stillwater, OK, 2008.
  5. Dunn, V, McGee M (director). Flashover [DVD]. Penwell Corp./Fire Protection Publications/Oklahoma State University: Tulsa, OK, 2006.

    
The Swede Survival System
For the past 4 decades, the Swedish fire service has been developing techniques to help combat flashover. One such technique, the Swede Survival System, is made in Skovde, Sweden. Its main purpose is to teach firefighters how to deal with flashover in a controlled and safe training environment.

The Swedish were some of the first to introduce nozzle tactics utilizing fog patterns and short, controlled spurts to help firefighters cool the hot gases found during a fire. Through these techniques, they discovered they could reduce the heat in the environment without disrupting the thermal balance.

They were also some of the first to develop fire training simulators out of steel shipping containers. Their Swede Survival System is now used to train fire service personnel worldwide about the risks associated with flashover and how to identify the indicators of this powerful and deadly event. 

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A flashover simulator, like Tulsa Fire Department's simulator shown here, works like a split-level room, with an upper level where the flashover occurs and a lower level in which firefighters can observe the conditions of the upper level. Photo Charles L. French
Flashover Tool: The Stages of Fire Development



PHOTO GALLERIES

Recognizing the Warning Signs of Flashover

You must understand the confitions that lead to flashover & how to change the operation to minimize risk

By Homer Robertson
Published Saturday, August 1, 2009 | From the August 2009 Issue of FireRescue

When you ask fire service folks who are in the know about weak areas of training for firefighters, two always seem to rise to the top of the list: building construction and fire behavior. And these two subjects are tied to a lot of firefighter line-of-duty deaths.

No fire department training program can spend too much time on these two important areas. Both have been responsible for firefighter deaths since the beginning of the fire service. The problem: They’re always changing, because technology is always changing.

This month’s Quick Drill focuses on one critical aspect of fire behavior: flashover. To stay safe on the modern fireground, you must understand the conditions that lead to flashover and possess the situational awareness to make changes in the operation to minimize your risk.

What’s Changed
There are a lot of different definitions of flashover; for our purposes, let’s use a common sense definition most of us can agree on: the stage of fire when the contents are heated to their ignition temperatures and flames break out over the entire area almost simultaneously.

We see a lot more flashovers in today’s structure fires than we did 30 years ago, for several reasons. Today, we have a lot more carbon-based interior furnishings, which reach peak temperatures faster and produce up to 500 times the smoke. This can create flashover conditions in just a few minutes, as opposed to the 30 minutes it might have taken in the past.

In addition, buildings now feature thermal pane windows and improved insulation, which trap heat and gas inside. No longer do windows fail easily and rooms vent themselves. Instead, as we make the interior attack, we’re surrounded by a highly flammable and explosive environment.

Our personal protective equipment (PPE) has also been greatly improved, which allows us to make these deep-seated interior attacks. When our gear wasn’t as good and we didn’t have hoods, we simply couldn’t go in as far as we do now. But because we can get in deeper, we experience more flashovers, which has a direct affect on our personnel and our operations. We must make a shift in our tactics so that we’re not relying on staying in until we just can’t take the heat any longer.

Recognize the Conditions
High heat and smoke/gas are the keys to recognizing flashover. Smoke is the fire talking to you. Let’s take a closer look at conditions that warn of flashover:

  • High heat. Flashover is a heat-driven phenomenon. Without heat, the interior contents won’t off-gas and reach their ignition temperatures.
  • Growth-stage fire. A bedroom burning in the back of the house that you can’t get water on provides provides the heat for the flashover event. Remember: Flashover can occur some distance from the area of involvement. If we don’t get water on growth-stage fires, they will continue to feed the fire with two of the three things it needs for flashover: heat and fuel (fire gases).
  • Changing conditions. A rapid increase in the heat level may be a good indicator of impending flashover. Also pay close attention to the smoke conditions. The smoke is loaded with unburned fire gases that ignite under the right conditions. These changes can slow the attack, preventing you from getting that much-needed water on the seat of the fire and allowing the fire cycle to continue.
  • Rollover. The term “flashover” is often misused when interior fire crews see a rollover, which is the ignition of the fire gases in the upper ceiling area. This is the last warning sign before a flashover occurs. It’s very important to be aware that you may or may not see the rollover prior to flashover.

 
Keys to Survival
Following are some keys to surviving a flashover event:

  • Recognize warning signs. Because our PPE now allows us to get in deeper and closer to the fire, we’re more at risk for experiencing flashover, which is why it’s critical to understand and predict the signs leading up to a flashover before it happens. Such recognition may give you time to make changes in the fire attack, such as increasing ventilation or withdrawing from the danger area.
  • Always wear full PPE and wear it correctly. We see folks on the fireground all the time with skin exposed around their hood or with their chinstraps undone or improperly attached. Something as simple as having your helmet knocked off during a flashover—exposing your head to temperatures of 1,500 degrees or higher—could lead to injury or death.
  • Maintain situational awareness. Don’t get so focused on the fire that you miss the big picture. This includes, but is not limited to, your location, your secondary means of escape, fire conditions and where other crews are operating.
  • Stay low. This is old-school, but holds just as true today as it did 50 years ago. In the past, we were taught to stay low because the air near the floor is easier to breathe. Today we have SCBAs, but it still helps to stay low to the ground, where it’s cooler and the visibility is much better so you can read the conditions above you. Today’s PPE has gotten us into some bad habits because it allows us to stand up more than we should.
  • Bring a charged, operating handline. The cooling affect of water is the enemy of the flashover. Using a small amount during the early warning signs of the event will greatly slow the process, allowing time to get out of the area. Note: If you’re searching an area without a line, take extra caution.
  • If caught in a flashover, fight. Get as low as possible and open the nozzle into the overhead to reduce the temperature of the fire gases below their ignition temperature. If operating a fog nozzle, open it to a full-fog above your head and flow water. This will disrupt the thermal balance, creating large amounts of steam. Note: The steam will make interior conditions very uncomfortable and reduce any visibility that was available.

A Final Word
Recognizing the keys to flashover is an essential skill for today’s firefighters. Don’t let fire behavior be a weak area for your crew. Drill regularly on how to recognize, mitigate and survive flashover conditions.
 

 

Drill 1: Flashover in the Classroom

  1. Review the definition of flashover and the conditions that lead to it.
  2. Discuss flashover variables: room size, contents and their combustibility/heat release, insulation qualities of the building, ceiling height and availability of ventilation.
  3. Discuss proper use of PPE at structure fires.
  4. Review warning signs of flashover: high heat, changing conditions, free-burning fire, rollover and heavy smoke.

 

Drill 2: Flashover in the Field

Equipment: Pumping apparatus and the handline that your department most often uses in initial attack.

  1. Let each member of your crew operate the handline so they can practice penciling and aggressive cooling during pre-flashover conditions.
  2. Demonstrate the two nozzle patterns to meet the changing conditions of flashover: full fog (left for life) or straight stream for reach or cooling walls or ceilings.
  3. With two members on the handline, practice opening the nozzle into the overhead while operating at a full fog while members are as low to the ground as possible. The member in the backup position should move as close as possible to the nozzleperson to have protection from the full fog.

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