Foam Use and Application
Foam can be an asset saver when used properly on Class A (ordinary combustibles) or Class B (flammable liquid) fires.
- Class A fires such as wood, paper, and plastics are the most common material found in most fires. These materials are usually suppressed with copious amounts of water. The WASP unit enhances water’s ability to suppress these fires with less water because of our Stinger Nozzle that creates smaller water droplets, which creates more surface. With more water surface area to a burning material, the material is quickly cooled and starved for oxygen thus suppressing the fire. We have eliminated two sides of the fire triangle in which burning material will no longer burn. Smaller water droplets are able to soak into most Class A materials without the use of foam.
- Smoldering material: Use straight stream to apply Class A foam.
- Class A foam use can and should be used if the fire continues to smolder when water does not have the ability to completely suppress the fire. Class A foam soaks into the burning material by breaking down the surface tension of water. This prevents the material from rekindle.
- Wildfire and foam: The use of foam can be used on wildfires when medium to heavy brush or thick matted grass needs to be completely penetrated, cooled and smothered. This is a good application of foam to prevent hot embers from escaping and spotting across your wet line or ahead of you.
- Class B foam should “always” be used on fires involving diesel or gas fuel to control the production and ignition of flammable vapors. Class B foam forms a blanket over the liquid to prevent flammable vapors from escaping and igniting. The technique to applying Class B foam should start from a safe distance of 15′ to 20′ with the wind at your back. Gently apply the foam with the straight stream to the front of the burning liquid working left to right or right to left. Keep providing the same sweep back and forth to the back burning edge of the liquid until a full blanket of foam covers the entire fuel area. Apply additional foam as needed.
- Caution: Vapors may reignite with any separation of foam during application.