By Kriss Garcia
Today’s structure fires are becoming more infrequent yet more aggressive all the time. This, along with the fact that we’re in a construction era where building materials are becoming less resistant to the damage fire can cause, makes it imperative that we get the most experience and education possible out of the fires we do have. How do we accomplish this in a manner that translates to real learning, where we can make decisions based on real-life experiences? How do we, in effect, get a “do-over”? The answer: We have the same fire again.
That said, we would never do anything that didn’t advocate fire prevention or making structures more fire-safe; in fact, we have to realize that the best fire we can have is the one that never starts. But regardless of all of our fire prevention efforts, fires will happen. And when they do, firefighters with increasingly less experience are faced with lightweight-constructed buildings and renovations that are much less resistive to fires, which in turn, burn hotter and spread faster, resulting in a deadlier fireground.
Another dramatic impact to firefighters’ safety relates to staffing. Due to budgetary constraints, we’re putting fewer firefighters on the fireground, so how could we not expect an increase in firefighter injuries and fatalities?
We constructed this model after a two-story structure fire that occurred on Christmas Eve. The fire started in a fireplace at the rear of the structure and quickly spread to the floor above and attic area. All photos courtesy American Fork Fire & Rescue
A close-up view of the two-story fire model.
Crews performed a positive pressure attack when entering the two-story house. This photo shows that the fire was held to the exhaust area as crews entered.
In this model of an arson basement fire, a fan was used to simulate the attack made on the main level, with fire exhausting appropriately from the fire area.
This photo shows the damage to the main floor after another basement fire. In this model, the attack was replicated based upon helmet cam documentation. The model demonstrated how, without adequate exhaust, fire was brought up to the main floor through the basement stairs. Floor collapse was also replicated exactly as it was in the in the actual fire.
Video demonstration of two-story house fire model
Despite these facts, it’s the fire service’s responsibility to train and educate firefighters in as real an environment as possible. It is our responsibility to provide realistic training on, as Gordon Graham calls it, our “high-risk/low-frequency” events. Unfortunately for many firefighters, structure fires are becoming one of these types of situations.
Predictable props that do little more than heat an area while adding theatrical obscuration are not real. Other props that use Class A burn material or place firefighters in a prop designed to demonstrate flashover are no more realistic and don’t demonstrate the behavior of fire in a real environment. Because today’s firefighters have little real-life experience, they oftentimes go to work with very limited, if any, real-life structure fire experience.
In short, we’re creating a situation where injury and death to our fellow firefighters are likely. And we’re doing our firefighters an injustice by putting them into the real world of structural firefighting without realistic and extensive live-fire training. Education & Experience
So how do we fix this problem? There are two possible solutions:Solution 1
The obvious answer is to utilize safe acquired structures with proven fire practitioners. If you’re a chief, you must carefully interview and select the instructor who will educate your firefighters to make sure they will teach your firefighters what they need to know and what you want them to learn. You would never turn your children over to an educator who was teaching outdated or incorrect material. Give your firefighters the same level of regard when selecting the person who will train and influence them.
Often the most willing instructor is not the one you want influencing your firefighters. The wrong instructor could do little more than instill their own, and possibly incorrect or outdated, personal beliefs on new, impressionable minds. Select an instructor after methodically evaluating their credentials. At the very least, get a curriculum vitae from all instructors before turning them loose to teach and influence your firefighters. Your firefighters deserve the best while they are yours. Remember: You are responsible for every bit of information that your firefighters learn.
When looking to obtain more acquired structures, one answer is to have an intimate relationship with the building departments in your jurisdictions. We have to have live burns or at least real buildings to train in, so become part of the demolition permit process so we can use buildings scheduled for demolition to our benefit.
There are extensive and various state and local regulations that come into play when using these buildings for either live fire or other training. For that reason, I won’t go into how to make a structure safe so that we can train in it. It’s enough to say that every building we allow to be torn down without taking advantage of whatever training opportunities is an opportunity lost. Additional restrictions placed on departments related to NFPA 1403, while important, also make it difficult. (A future article will look at the process of taking a structure and making preparations to burn it. For now, follow NFPA 1403 guidelines.)
The second possible answer to this question is to get more experience out of the fires we do have. Take every opportunity to educate firefighters on the challenges and successes of your recent fires. But wouldn’t it be great if we could recreate every aspect of a recent fire, including the fire itself, and fight it all over again? Well, with a little effort and time, we can.
A Model for Success
Each time we have a structure fire, my newly adopted department, American Fork (Utah) Fire/Rescue, builds a scale model of the building so we can re-create the fire. Floor plans are created, and the building is built on a –1-inch to 1-foot scale model.
What this means is that if we have a 2,000-square-foot house that measures 40 x 50 feet, we rebuild the structure in 2,000 square inches with measurements of 40 x 50 inches. Starting at the ground and working our way up, if the structure is a single story with a basement, we build it two stories high, one of which is the basement. Floor plans are roughly copied with appropriate dimensional windows and doors. The walls are made of 3/4" oriented strand board (OSB), and floors and ceilings are made of 7/16" OSB. We find these give off appropriate levels of smoke and flame while still being able to be fastened securely. Note: If you’re not trying to simulate floor collapse scenarios, build the floors out of 3/4" OSB as it will sustain itself through several fire scenarios.
Next, the exterior walls are built using ripped pieces of 3/4" OSB. Wall heights are dictated by the floor plan. For example, if interior partitions are a standard 8 feet, the wall sections are cut 8 inches. Pedestrian doors that are 3 feet wide are cut 3 inches wide. Most doors are 6 feet, 8 inches in height, therefore they are cut 6 3/4 inches high. Windows that are 5 feet x 3 feet are cut in their appropriate location to 5 inches x 3 inches. Window openings are covered with OSB and held in place by a single 1 1/2" wood screw placed so that the window can be pivoted open and then closed again during the demonstration. This usually works best when the screw is positioned at the top. Depending on the layout of porches or other structures, this may not be possible, in which case two screws can be used.
Interior walls are cut from remaining pieces of 3/4" OSB to the appropriate wall height. Interior doors are cut and the walls are placed in the structure. Doors that you want to represent as being closed during the interior fire do not have to be cut. Doors that will remain open during the simulation can be left as unprotected openings. If you would like to open an interior door during the simulation, use a 1/2" wooden dowel fastened to a scrap piece of OSB, which can then be manipulated during the simulation. A small channel can be fabricated out of scrap materials to ensure the door opens and closes as desired.
If a roof with an attic is needed, a truss system is built from solid 3/4" OSB. Large holes are drilled with a hole saw throughout this piece of 3/4" OSB to simulate air flow. The roof is hinged at the peak to allow manipulation of the fire to match conditions that were present during the original fire. A single sheet of drywall glued to the underside of the ceiling deck will allow extensive fire conditions below so that various situations can be replicated.Fire Loading
Synthetic fire loading of today’s dwellings generates roughly two to three times the British thermal units (BTUs) of ordinary combustibles. Using this as a basis to design your fire load, a crib of 3/4" x 3/4" pine is built to twice the size of whatever synthetic material you are trying to replicate. As an example, if you are trying to replicate a couch that is roughly 3 feet x 7 feet, a pine crib 6 inches x 14 inches is made. Either of these measurements can be manipulated, depending on what you’re attempting to create. Using the crib concept, you’ll get much more surface area that will give you the desired burn and representative BTUs. Plastic dollhouse-type furniture may have flame-retardant material designed into it, and we’ve seen inconsistent fire behavior when these are used. Therefore, we’ve found that it’s better and more representative of the actual fire and fire spread to use the pine cribbing that duplicates twice the size and roughly three times the surface area of the material we wish to replicate.
We’ve also found it quite accurate to use synthetic low-nap floor coverings as carpet. This also adds to the synthetic fuel loading and appears to create a fairly consistent fire. If the drapery seems to be related to the fire behavior, we re-create these using scrap cloth made of either rayon, felt or cotton, whichever most closely represents the actual window covering.
The goal should be to build a quick and rough re-creation of any notable fire your department has—emphasis on quick. The building should take no longer than 2 to 3 hours to construct. The goal should not be to build an exact replica; don’t get caught up in the aesthetics. You’ll get better at building replicas as you build more of them. Making Fire
Fires for re-creations are started most often with a plumber-type propane torch and allowed to free burn by leaving exterior windows and doors off until you get the burn you want. At this point the windows and doors can be closed to re-create the fire situation. If accelerants are used and you want to replicate this, try to match the surface area of the accelerant. We have found these to be representative of actual fire conditions and fire behavior. Atmospheric conditions such as wind are best created with an electric positive pressure ventilation (PPV) fan placed several feet from the building. Wind gauges are cheap and readily obtained from most hiking or outdoor retail stores and are used to re-create the exact wind conditions present during the fire. Most of these electric fans are adjustable, so if you need gusts of a certain wind speed, these are easy to reproduce. Tip:
Get these figures before you start the burn as things will move fast once you get to a free burn.The Fire Attack
If so desired, tactics used can be evaluated and then changed to see what would have happened if different tactics were used. This gives you the chance to do what you always wanted to do—fight the fire again. Controlling the fires is best done by using a pressurized waster extinguisher. Have a couple of them on hand or a garden hose with a small nozzle so you can keep the fire in check. Keep the water application representative of the actual amount of water used during the attack. Increased restriction to the nozzle size may be necessary.
Fans are becoming a staple of many fire departments’ tool boxes and are being used more often. High-pressure fans are represented by either a 2" computer-type fan or a variable-speed hair dryer. I have used both and, personally, found the hair dryers more representative and much easier to use.
Setting the prop on a picnic table is best for demonstration purposes. Place a sheet of 7/16" OSB on blocks to keep the prop stable and off the table surface by a couple of inches so you can have a significant burn without damaging the table.
To observe interior fire conditions in various locations during the fires, small wired glass is used to create an observation area. These pieces are generally 12" x 12" and oftentimes can be found at door and glass shops that generally have extras or slightly damaged ones that they are willing to donate.
Personal protective gear should be worn by the instructors as they will be in smoky and light fire conditions. Appropriate safety precautions should be used.Application
A lot of firefighters have seen a series of recent news broadcasts called “Seconds from Death.” I contacted one of the firefighters involved in one of these situations, and even though the fire wasn’t in my city, they assisted me in re-creating their fire. We created fire conditions that were representative of the helmet cam video that had been posted on the Internet. We were also able to repeatedly re-create the aggressive fire behavior that almost took the lives of three young firefighters. As a result, we determined that if recommended procedures for the correct use of a fan were implemented, firefighters wouldn’t have been placed in harm’s way, and the fire would have been contained to the basement area.
There’s no doubt that firefighters like fire, but we need more fire experience and experienced-based learning opportunities. With scale models, firefighters can rebuild the fire and get the chance to do what they have always wanted to do—fight the same fire again. Everything from incident management to hose crew tactics can be re-created in a realistic scenario. With safe acquired structures and these scaled demonstrations, we have a model for success.Experience is the best teacher, but a fool will learn from no other.
Kriss Garcia has retired from Salt Lake City Fire Department after 26 years most recently as a battalion chief. Garcia has recently taken a position as fire chief for the City of American Fork, also in Utah. An instructor for the National Fire Academy, he is a voting member of the Air Movement Control Association standard-review committee and a member of the NFPA 1021 Technical Committee. Garcia is also an original member of the IFIW.
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