The frequency and intensity of wildfires is on the rise around the world, and companies in the fire-safety industry are working tirelessly to introduce new, technologically advanced products that will help firefighters to better contain and put out these fires. However, there is a relatively old solution that is already available and is highly effective in stopping the spread of wildfires and protecting property from damage.
Class A foams were first used by firefighters in the mid-1980s. They are specially formulated to make water more effective when used to put out Class A fires. While Class A foam was frequently used to battle fires for years, it has fallen out of favour recently with some agencies, and its use is declining when battling wildfires, despite its documented advantages. That is something that needs to change.
Advantages of Class A foam
The key advantage of Class A foam is that it significantly enhances water’s effectiveness in putting out flames. Water’s strong surface tension causes it to bead up and roll off most fuels and away from heat too quickly for the fuel to be able to absorb the water’s full heat capacity. The infusion of hydrocarbon surfactants in water reduces its surface tension. When you add a small amount of foam to water, at low concentration levels between 0.1% to 1.0%:
- Water droplets are stretched out into a bubble and it is held that way, increasing its heat-absorbing surface.
- The water penetrates deep into Class A fuels (paper, wood, cloth and some plastics) to stop flames.
- Water also bonds with the infused carbons like a magnet, and that holds the water against the fuel while grabbing onto smoke, which increases visibility and reduces knockdown time.
By increasing water’s effectiveness, firefighters can accomplish a lot more using much less of it, which means that there will be much less property damage in structural firefighting. It also makes it easier to preserve the scene for arson investigation, increases firefighter safety with the shortened knockdown time, and reduces the amount of toxins released in the air through combustion.
Additionally, Class A foams can be used to create a temporary protective blanket on homes, vegetation and other fuels that are in the path of a fire, so that firefighters can focus their attention on attacking the active parts of a fire, again improving safety for firefighters.
The reduced use of water is especially important when working to stop the spread of wildfires. The availability of water in wildland spaces is sometimes scarce, and much of the time is incredibly difficult to transport to the areas where it is needed most, especially higher mountainous regions. Class A foam improves the effectiveness of water as a firefighting agent and reduces the number of times helicopters and other aircraft have to stop fighting the fire to refill at the closest source of water. In addition, during both ground and aerial application, Class A foam improves visibility of the application area.
Class A foam has an additional advantage when you consider costs. It is basically an industrial strength form of dish soap, and the concentration with water to create the optimum mixture is so minimal that fire departments and other agencies need to spend literally pennies per gallon to use it. That is a very low investment when you consider that it is being used to save people’s lives, homes and property.
The benefits of using Class A foam detailed above are well established, but equipment innovations were needed to make it an effective and easy-to-use tool for firefighters.
When the industry moved from using plain water to Class A foam in the 1980s, there was no efficient way to add foam in a water tank. Once foam is mixed with water, it creates a lot of bubbles – which makes it effective to combat fires, but the solution it creates is also hard on metal tanks. Foam always finds a way to escape, and when it was added directly to the metal tanks it caused a lot of leakage. That problem was exacerbated when firefighters would refill the tanks. No matter how well a tank was cleaned, there would be remnants of the used solution that would create more bubbles, and foam would leak everywhere.
Eductors are another option, but set-up is time consuming. You must also match your nozzle to your eductor flow rate, and there are limitations on hose lengths and the quantity of hoses that can draw from the same engine.
The batch-mixing issues and limitations of eductor use were remedied a few years later with the introduction of direct-injection foam proportioners. Rather than foam being added directly into the tanks, this piece of equipment added foam concentrate to the water on the discharge side of the pump. Operators simply turn the dial or press a button to activate foam injection and determine mix rate, depending on objectives. Some can also be pre-programmed to automatically turn on at a set injection rate. Direct-injection systems allow multiple hose lays; the only limitation is the size of the foam pump.
Advancements in nozzles also played a role in improving the effectiveness of Class A foams.
When a regular nozzle is used with a half percent solution, what is sprayed will look like a milkshake on the ground. By adding a foam attachment to the nozzle, air is injected into the solution, which helps you to create a much better bubble structure. Instead of running off like water tends to do, the foam blanket will smother a fire and stick to burning surfaces and pretty much everywhere that it is applied.
Declining interest in Class A foam
Despite the benefits mentioned above, and the improved ease of use by advancements in equipment, the use of Class A foam to battle wildland fires has declined in recent years. There are a few reasons for that.
The first is misperceptions about environmental impact. As mentioned earlier, Class A foam is similar to dish soap. In addition, the USDA Forest Service (USFS) tests and approves Class A foam products against their specification for fire suppressant foam for wildland firefighting, which includes tests for biodegradability and toxicity.
Another reason for the decline in the use of Class A foam is a lack of knowledge among today’s firefighters. When Class A foam was first introduced, fire departments trained their teams regularly on how to use it. These were intensive training sessions that were held throughout the year to ensure every firefighter knew when and how to use foam. That isn’t happening now, and if today’s firefighters aren’t being trained, they simply will not use it.
Making the case for Class A foam
There are multiple advantages of using Class A foam that are outlined in this article, but the two most important benefits it provides are improved firefighter safety and boosting water’s effectiveness to reduce the amount of time it takes to extinguish a fire. Those two factors alone should be reason enough for more fire agencies to use Class A foam to battle fires.
For that to happen, fire agencies and others in our industry have to be more proactive in training today’s firefighters on the benefits and use of Class A foam, so that they are more comfortable using it. We also need to address the misunderstandings about the composition of Class A foam, so that those inside and outside the industry know that it is not toxic and that it presents minimal risk to the environment.
People’s lives and property can be saved by simply incorporating Class A foam into efforts to fight wildfires. The time to do that is now.
For more information, go to www.perimeter-solutions.com