Live-fire training remains a vital part of the continuing education of any fire department.
It’s not always convenient to travel to a larger training facility, like the state fire academy, so many departments opt to build systems. Training systems come in all shapes and sizes, but among the first decision is which class of system would be appropriate for your fire department. Class A training systems use wood or wood products as fuel to generate realistic fire and smoke in a controlled burn. Class B training systems use propane, natural gas, or another fuel to generate the fire that’s managed by another firefighter at a control panel.
A decade ago, this question likely didn’t get asked or even considered. Class A systems were the standard for structure fires while Class B systems were relegated to props from cars to aircraft rescue and firefighting simulators. Today, the choice is not so simple. With occupational cancer at the forefront of considerations for firefighter safety and the growing sophistication of Class B systems, the lines between the two systems are blurred.
CLASS A
Structures that use one or more shipping containers are sometimes referred to as Swede Systems. After two firefighters in Sweden lost their lives to flashover in 1986, the Swedish government asked the country’s Rescue Service to develop an educational program. The program resulted in a progressive series to teach the basics of structural firefighting. North American fire departments have progressed to more customized structures built on the foundation of the Swede Systems.
Generally, these Class A systems use either 40- or 20-foot shipping containers. Sometimes a fire department may build permanent, specifically engineered concrete buildings using burn barrels and panels to generate the fire.
Wood products like oriented strand board (OSB) plywood, pallets, and wood boards and straw/hay are loaded in a specific manner, then set on fire. Properly loading a system ensures predictable, reproducible fires with accurate flames and smoke behavior. This is especially true when a training program wants to highlight a flashover experience, where the particulates in smoke ignite.
The key advantage of a Class A system is the accurate portrayal of smoke and fire. Smoke generates toxic gases and requires that all participants are in personal protective equipment (PPE) including full turnout gear and self-contained breathing apparatus (SCBA). Any experienced firefighter can confirm that working in a dark, smoke-filled structure limits visibility and makes firefighting even more difficult, but for accuracy, the combination of smoke and fire together is vital for training. Class A systems also tend to be less expensive.
The advantage of smoke is also a disadvantage. Wood and wood products naturally contain formaldehyde, a carcinogen. Proper use of SCBA and monitoring the toxic gas conditions near a Class A system help mitigate these concerns.
The use of OSB is becoming a serious concern. OSB is made by taking wood scraps, adding glue, and pressing it into the plywood. The glue acts as an accelerant for the fire and makes the toxic particulates in smoke stickier. The sticky particulates can adhere to PPE and become difficult to remove—even through normal cleaning procedures. Up until recently, most Class A systems were engineered for the use of OSB.
Medium-density fiberboard (MDF), particleboard, or other types of plywood still contain problematic adhesives. Some fire departments have switched to wood pallets, but some of those may include treated wood, which introduces even more chemicals into the smoky mix. Substituting anything other than the prescribed plywood could cause the resulting fire to be less predictable and damage the training system or cause a failure.
In recent years, a new wood board that doesn’t use any adhesives has been tested and approved for use in certain Swede Systems. The alternative board results in a cleaner burn yet still generates smoke. If your fire department or academy includes a Swede System or similar shipping container system, you may want to contact the manufacturer to determine if the alternative wood fuel is available. As an alternative, some training departments are moving to using a propane-based system.
1 Class B training systems burn much cleaner and lack the smoke, so firefighters can focus on the flame and its behaviors.
2 Class A training systems burn wood products that result in thick smoke—similar to the real-life circumstances firefighters confront in structural fires.
CLASS B
A Class B system generates a much cleaner burn. That’s the primary advantage of a Class B system. There’s less concern about cancer-causing particulates—although maintaining a safe distance and proper monitoring of toxic gases on the training ground are necessary.
With a more predictable emergency shut-off, a Class B training building allows the curriculum to focus on the fire itself. Class B systems rely on proper engineering and construction to generate the required flames and fire behavior that a firefighter confronts in real-life conditions. Systems can be very sophisticated and generate different types of flames or fire behavior. To simulate structure fires, Class B systems can be outfitted with theatrical smoke systems. From the control system, the training personnel can control the amount of smoke added to a training evolution.
The more sophisticated characteristic of Class B also requires more maintenance. Repairs in the engineering and control systems may put a system out of service for an extended time while determining what’s causing the issue and getting a certified tech to examine the system.
Additionally, the introduction of a propane tank or connecting a natural gas into the live-fire training system creates more challenges. The training ground may need to be larger to accommodate the tanks and plumbing.
While the addition of theatrical smoke helps create a more accurate simulation, it may lack the level of realism some trainers prefer. Additionally, some types of theatrical smoke are known to have adverse effects on respiratory health—suggesting that personnel remain on a supplied air system like SCBA if in an exposure area.
Further, simulations of flashovers—where the heat, smoke, and fire all combine—have failed to produce an accurate simulation of how these elements influence one another.
Class B systems can be more expensive for the initial investment. And while wood prices have varied in recent years, propane and other liquid fuels are more subject to volatile swings in costs.
Research and development on Class B systems continue, and significant advancements filter into the industry all the time. The primary challenge of Class B is accurate smoke and fire behavior. Eventually, Class B systems may meet the challenge of accurate portrayal. The challenge, of course, is filling the gap between what happens in real life vs. a simulation.
THE FUTURE of FIRE TRAINING
With the development of virtual reality technologies, some companies are investing in generating fire training. While far from useful for career firefighters, some virtual technology has been introduced to allow firefighters to see how different nozzle settings produce results on different fires. Additionally, some virtual systems are used within public safety to teach everyday people to use fire extinguishers.
The challenge of such virtual systems is meeting all the sensory inputs people experience in real life. While visual and audio cues might be present, the smells, heat, resistance, and other inputs aren’t sufficient to the point where someone could panic, resulting in a potential worse outcome.
Virtual reality training has its place, but it’s a long way from replacing the real-life educational experience from a Class A or Class B system.
PAUL TARTER has been an active-duty firefighter and an instructor at Texas A&M Engineering Extension (TEEX) for more than 20 years. He is a member of Texas Task Force 1 and the product manager for fire training systems at Dräger in Houston, TX.
